The onsite scientific team provided preliminary descriptions of sedimentary textures, structures, colors, fossil content, identification of lithostratigraphic units (NJGS Information Circular 1, 1990), and lithologic contacts (Table T1; Figs. F2, F3, F4, F5, F6, F7, F8). Subsequent studies integrated preliminary descriptions with additional descriptions, biostratigraphy, biofacies studies, isotopic stratigraphy, and the gamma ray log (Table T1; Figs. F2, F3, F4, F5, F6, F7, F8). Unconformities were identified on the basis of physical stratigraphy, including irregular contacts, reworking, bioturbation, major facies changes, gamma ray peaks, and paraconformities inferred from biostratigraphic breaks. For the marine sections, benthic foraminiferal biofacies (e.g., Fig. F9) and lithofacies were used to infer paleoenvironments. For the nonmarine and nearshore sections (primarily the upper Miocene and younger section and Magothy and Potomac Formations), lithofacies interpretations provide the primary means of recognizing unconformities and interpreting paleoenvironments. Examples of the various lithofacies are given in Figures F10, F11, F12, F13, F14, F15, and F16; full photographs of all cores are given in the visual core descriptions (see the "Appendix").
Cumulative percent plots of the sediments in the cores were computed from samples washed for paleontological analysis (Table T2; Figs. F2, F3, F4, F5, F6, F7, F8). Each sample was dried and weighed before washing and the dry weight was used to compute the percentage of sand. This differs from the method used in previous New Jersey coastal plain cores (Bass River, Island Beach, Atlantic City, and Cape May) in which the samples were not dried before washing.
Pebbly gray sand with asphalt (1.3 ft; 0.40 m) occurs from 1.3 to 3.4 ft (0.40 to 1.04 m) and represents modern fill.
The upper strata at Sea Girt are poorly dated (?Holocene–?Pleistocene) and have uncertain formational assignments, though the facies interpretations are clear (Fig. F2). A dark, organic-rich fine–medium sand from 3.4 to 3.9 ft (1.04 to 1.19 m) is interpreted as a paleosol. A sharp color change from dark brown to light brown silty fine–medium sands at 3.9 ft (1.19 m) probably represents a change within the soil horizon from O to A. Light brown paleosols continue to 6.6 ft (2.01 m). The soils probably formed in the current back dune environment. Below 6.6 ft (2.01 m), there is a change to better sorted, yellow-brown medium sands. Uniform, massive, medium sands continue to a thin (<0.1 ft; <3 cm) gravel layer at 14.6 ft (4.45 m). Bedding appears below this gravel layer with heavy mineral laminations and a "beachy" aspect. Another thin gravel layer (20.0–20.2 ft; 6.10–6.16 m) appears below a coring gap (15.5–20.0 ft; 4.72–6.10 m); this gravel may be caved. From 20.2 to 20.6 ft (6.16 to 6.28 m), slightly silty, medium- to coarse-grained quartz sands with ~1% opaque heavy minerals (ohms) coarsens downsection below 20.6–22.0 ft (6.28–6.71 m) to a medium–coarse sand with scattered pebbles and granules. From 22.0 to 22.1 ft (6.71 to 6.74 m) is a thin gravel. From 22.1 to 23.1 ft (6.74 to 7.04 m) is a gravely medium–coarse sand with heavy mineral laminations at 22.35 ft (6.81 m) and a heavily iron-stained section from 22.7 to 22.9 ft (6.92 to 6.98 m). From 22.9 to 23.15 ft (6.98 to 7.06 m) is a very coarse sand with abundant granules and pebbles (to 14 mm). The section fines upward from 22.1 to 23.15 ft (6.74 to 7.06 m). There is a sharp, irregular contact at 23.15 ft (7.06 m). The sediments from 6.6 to 23.15 ft (2.01 to 7.06 m) were deposited in a nearshore setting in upper shoreface to foreshore environments. The formational assignment of the ?Holocene–?Pleistocene sands and paleosols is unclear, though the paleosols are probably Holocene. In New Jersey, these surficial sediments are generally assigned to the Cape May 1 Formation (Newell et al., 2000).
A sharp surface at 23.15 ft (7.06 m) (Fig. F2) separates gravelly yellow-brown sands of the ?Cape May Formation from well sorted, micaceous, whitish gray fine sand (23.15–23.7 ft; 7.06–7.22 m). The white sands have sparse heavy mineral laminations and appear to be shoreface deposits. Fine sands with organic-rich and mica-rich laminae appear below this (23.7–24.2 ft; 7.22–7.38 m). It is unclear if these sands are in situ Kirkwood Formation, cryptically reworked Kirkwood lithology, or part of the Cape May Formation.
Below a coring gap (24.2–30 ft; 7.38–9.14 m), micaceous organic-rich clays with thin sandy silt laminations (30–31 ft; 9.14–9.45 m) appear in the cores. This section below 30 ft (9.14 m) is clearly assignable to the Kirkwood Formation and was deposited in lagoonal or lower estuarine environments (Fig. F2).
Uniform, tight, dark olive-green clays (35–42.3 ft; 10.67–12.89 m) appear below 31–35 ft (9.45–10.67 m). The clays have rare sand wisps at the top and traces of mica. The environment of deposition is not clear based on lithofacies interpretations. The presence of Elphidium sp. and the absence of other foraminiferal taxa at 36 ft (10.97 m) suggests a lagoonal/bay environment. The paucity of laminations, mica, shells, and lignite all argue against a prodelta environment. These clays compose a confining unit that may correlate with one of the Kw2 sequences of Sugarman et al. (1993) (Fig. F2).
A thin coarsening-upward section occurs from 42.0 to 45.5 ft (12.80 to 13.87 m). A very silty, very fine sand bed (42.0–42.5 ft; 12.80–12.95 m) overlies a very fine sandy, clayey silt (42.5–43.1 ft; 12.95–13.14 m), a coring gap (43.1–45.0 ft; 13.14–13.72 m), and a silty clay (45.0–45.5 ft; 13.72–13.87 m). This thin succession is probably also lagoonal–estuarine and thus genetically associated with the clays above (Fig. F2).
We tentatively interpret a sharp lithofacies shift from clays above to sands below at 45.5 ft (13.87 m) as a sequence boundary (Fig. F2). Sands are burrowed up to 0.3 ft (9 cm) above the sequence boundary. There is a gamma ray log minimum at 47–45 ft (14.33–13.72 m) and a gamma ray log increase at 45–38 ft (13.72–11.58 m), consistent with this interpretation.
Sands from 45.5 to 51.5 ft (13.87 to 15.70 m) are silty and very fine, laminated, have common ohm (5%–10%), and rare shells (44.5 ft; 13.56 m). A medium sand (51.5–51.7 ft; 15.70–15.76 m) overlies a dark, slightly silty micaceous clay bed (51.7–52.4 ft; 15.76–15.97 m). Structureless, slightly micaceous fine sands with common ohms return from 52.4 to 57.9 ft (15.97 to 17.65 m). A thin gravel at 57.9–58.1 ft (17.65–17.71 m) has large (as much as 2 cm) quartz pebbles, returning to fine sand from 58.1 to 63.6 ft (17.71 to 19.39 m), though the sands below are more organic rich and micaceous than above. The environment of the sands from 45.1 to 57.9 ft (13.75 to 17.65 m) could be either proximal upper shoreface or lagoonal–estuarine, though the association with rapid facies changes at ~51 and 58 ft (15.54 and 17.68 m) and the organic-rich sands below suggest the latter. The sands compose the HST of a sequence that probably correlates with the Kw1b sequence of Sugarman et al. (1993). A sample at 86.0 ft (26.21 m) contains planktonic foraminifers indicative of shelfal deposition, including Globorotalia ?praescitula, which suggests an age probably younger than 18.8 Ma (i.e., this sequence is equivalent to Kw1c or younger), although this cannot be said for certain. Considering regional correlations, including the presence of two distinct sand units at 100 and 110 ft (30.48 and 33.53 m) that are probably equivalent of the Atlantic City 800-foot sand (Kw1a and Kw1b), we favor correlation of this unit to the Kw1b sequence (~19–20 Ma) (Fig. F2).
Beginning at 63.6 ft (19.39 m), the lithology becomes interbedded and interlaminated sand and sandy silt interpreted to represent bay fill/estuarine deposition (Fig. F2). The sands are micaceous and peaty. Lenticular beds at 76.3–76.7 ft (23.26–23.38 m) suggest tidal effects, consistent with the shallowest part of the bay fill. Below an unrecovered interval (76.7–80 ft; 23.38–24.38 m), micaceous silty fine sands (80–91.6 ft; 24.38–27.92 m) are heavily burrowed and appear to represent shelf deposits influenced by a delta. The environmental shift from shelf below to bay above does not appear to be associated with a sequence boundary, though there is a minor gamma ray log kick in the unrecovered interval between the bay fill above and shelf sands below. Instead, the shift appears to reflect a transition from maximum water depths at 80–90.2 ft (24.38–27.49 m) to HST bay fill above.
Another major facies change occurs at ~91 ft (27.74 m) (Fig. F2). From 91 to 96.5 ft (27.74 to 29.41 m), the lithology is interbedded fine sand and peaty clayey silt, with some minor coarse sand beds (e.g., 95.7–96 ft [29.17–29.26 m]). These sands are interpreted as delta front and are part of the TST. A coarse delta front sand (100–102.5 ft; 30.48–31.24 m) occurs below an unrecovered zone (96.5–100 ft; 29.41–30.48 m). Below this, from 102.5 to 106.4 ft (31.24 to 32.43 m), is an interbedded/interlaminated clayey silt and very fine–medium sand deposited in a delta front environment. A coarse–very coarse sand bed occurs from 106.4 to 106.9 ft (32.43 to 32.58 m). There is a possible sequence boundary at 106.4 ft (32.43 m); this could be facies shift, though a major log shift at 105 ft (32.00 m) indicates that it is a sequence boundary separating Kw1b from Kw1a (Fig. F2).
There is a return to interbedded silts and sands at the bottom of the run at 107.4 ft (32.74 m). From 110 to 111.2 ft (33.53 to 33.89 m), the interval is dominantly a massive coarse to very coarse sand deposited in a delta front; the sand might be thicker, but was not recovered to 120 ft. Gamma ray logs suggest a thick sand from ~105 to 112 ft (32.00 to 34.14 m) and a confining bed from 116 to 122.9 ft (37.46 m). From 120 to 122.9 ft (36.58 to 37.46 m), a micaceous, woody interbedded clay with silt and sand is present. This fine-grained unit comprises the base of a sequence; the sands from ~106.4 to 116 ft (32.43 to 35.36 m) may constitute a parasequence or the HST of a thin sequence.
A probable sequence boundary occurs at 122.9 ft (37.46 m) (Fig. F2), separating a prodelta silty clay above from a delta front medium–coarse sand (122.9–123.2 ft; 37.46–37.55 m) below. A silty, organic-rich, slightly micaceous delta front sand continues below (123.2–124.9 ft; 37.55–38.07 m). A thin layer of interbedded clay and sand returns in 124.9–125.4 ft (38.07–38.22 m), with a thin coarse-sand bed from 125.4 to 125.9 ft (38.22 to 38.37 m). The interval below this was lost, suggesting the sand may be thicker. A thin coarse-sand bed from 130 to 130.6 ft (39.62 to 39.81 m) was present at the top of the next run. From 130.6 to 134.3 ft (39.81 to 40.93 m), brownish gray organic-rich interbedded silts and clays with thin sand laminae are present; these appear to be prodelta deposits. The coarser beds from 122.9 to 130.6 ft (37.46 to 39.81 m) comprise the upper HST sands, whereas the finer beds from 130.6 to 134.3 ft (39.81 to 40.93 m) comprise the lower HST of a sequence. From 134.4 to 136.3 ft (40.97 to 41.54 m), there are muddy sands, sandy muds, and a thin clayey silt at the base that appear to be shelfal. The unit from 134.4 to 136.6 ft (40.97 to 41.64 m) may comprise a TST; alternatively, there may be a sequence boundary at 134.4 ft (40.97 m) and the sands below could be the HST of an underlying sequence. The contact at 134.4 ft (40.97 m) is irregular, consistent with it being a sequence boundary. This sequence (122.9–134.3/136.3 ft; 37.46–40.93/41.54 m) may correlate to the Kw0 sequence of Miller et al. (1997).
The top of the Shark River Formation is placed in a coring gap (136.3–140.0 ft; 41.54–42.67 m) at the first downhole appearance of glauconite sand and a sharp gamma ray peak (~139 ft; 42.37 m) (Fig. F2). The top part of the Shark River Formation (140–155 ft; 42.67–47.24 m) is glauconitic (~5%), slightly micaceous, bioturbated clayey sand with fine, white sand–filled burrows. Clay increases downcore from muddy sand to a sandy clayey silt (155–167.5 ft; 47.24–51.05 m). A very slightly sandy clay (167.5–173 ft; 51.05–52.73 m) overlies a slightly sandy, slightly glauconitic clayey silt (173–200 ft; 52.73–60.96 m); there is no evidence that this facies shift from clay to silt represents a sequence boundary. There are no calcareous fossils from 140 to 169 ft (42.67 to 51.51 m); shells appear at 169 ft (51.51 m), where mica begins to decrease downsection. The slightly shelly clayey silt (173–200 ft; 52.73–60.96 m) overlies a laminated shelly/foraminiferal-rich, occasionally pyritic clay (200–220 ft; 60.96–67.06 m). The sands were deposited in lower shoreface environments. The presence of common gypsum crystals and sulfides on the core surface indicates shell dissolution. The finer clays and silts were deposited in an inner–middle neritic environment.
Glauconite increases from ~5% above 215 ft (65.53 m) to >20% below 220 ft (67.06 m). Very glauconitic sandy clay (220–228.1 ft; 67.06–69.52 m) overlies a heavily burrowed, glauconitic shelly clay (228.1–231.6 ft; 69.52–70.59 m); the contact between these two units (228.1 ft; 69.52 m) may be the MFS (i.e., there is little evidence that it is a sequence boundary and has no biostratigraphic break). Glauconite increases again downsection from 231.6 to 234.2 ft (70.59 to 71.38 m), becoming a clayey glauconite sand from 234.2 to 236.1 ft (71.38 to 71.96 m). A sharp lithologic change occurs at 236.1 ft (71.96 m) to a hard, slightly glauconitic ash-colored clay below (236.1–255.5 ft; 71.96–77.88 m); this contact is heavily burrowed and is a sequence boundary that marks the top of the lower Shark River Formation (Figs. F2, F3). It is associated with a biostratigraphic break from Zone NP16 above to NP15 below (Fig. F3; see "Calcareous Nannofossils"). Scattered shells are found throughout the interval from 169 to 236.1 ft (51.51 to 71.96 m). The glauconitic clays from 220 to 236.1 ft (67.06 to 71.96 m) were deposited in inner–middle neritic environments. The sequence from 140 to 236.1 ft (42.67 to 71.96 m) correlates with Sequence E8 of Browning et al. (1997) and is assigned to the upper Shark River Formation. The sandy bed at the top (140–167.5 ft; 42.67–51.05 m) may correlate with the Toms River Member.
The hard, foraminiferal-rich, slightly glauconitic, very slightly sandy, laminated clay continues below a coring gap (2236.50–240 ft; 72.09–73.15) to 255.5 ft (77.88 m). Glauconite increases from <5% to ~10% below 255.5 ft (77.88 m) and is mostly concentrated in burrows. The cores are indurated from 250 to 260 ft (76.20 to 79.25 m), with intervals of porcellanitic clay. Glauconite increases below 261 ft (79.55 m); by 263 ft (80.16 m), the section is a glauconitic sand with numerous large clay burrows. A surface at 265.8 ft (81.02 m) with small (as much as 10 mm) indurated clay clasts separates the clayey, heavily burrowed glauconite sand above from a more massive glauconite sand with sparse burrows below. A major biostratigraphic break occurs between 261 ft (79.55 m; Subzone NP15b) and 266 ft (81.08 m; Subzone NP14a). Therefore, we interpret the surface at 265.8 ft (81.02 m) as a sequence boundary separating Sequence E7 above from Sequence E5 of Browning et al. (1997) below (Fig. F3); Sequence E6 does not appear to be represented at Sea Girt.
Glauconite sand below the contact at 265.8 ft (81.02 m) grades downward to a clayey glauconite sand at 268 ft (81.69 m). A large (355 mm) brown clay clast occurs at 269.2–269.3 ft (82.05–82.08 m). Clayey glauconite sand continues downward to a major irregular erosional contact at 271.75 ft (82.83 m). This contact is a sequence boundary separating Subzone NP14a and Sequence E5 of Browning et al. (1997) from a slightly glauconitic clay, Zone NP12, and Sequence E3, below (Fig. F3). Sequence E4 does not appear to be represented at Sea Girt.
Uniform slightly glauconitic clay (ash-colored "marls") assigned to the Manasquan Formation appear below the sequence boundary at 271.75 ft (82.83 m) (Fig. F3). The Manasquan Formation at Sea Girt is predominantly a slightly calcareous to calcareous silty clay to clay (marl) with varying abundances of quartz (1%–40%) and glauconite (0%–12%, except for two distinct beds) sands with porcellanitic intervals (279.4, 285.2–285.6, 288.3–283.5, 290.7, 291.55–292, 305–305.8, 307.3, 307.5–307.7, 323, and 325.5–326 ft; 85.16, 86.93–87.05, 87.87–86.41, 88.61, 88.86–89.00, 92.96–93.21, 93.67, 93.73–93.79, 98.45, and 99.21–99.36 m).
There is burrowing of common glauconite below the sequence boundary at 271.75 ft (82.83 m) to ~275 ft (83.82 m), with glauconite from the base of the Shark River Formation burrowed into the ash marl of the Manasquan Formation. Large shells occur at the sequence boundary to 1 ft (0.30 m) below.
The upper part of the Manasquan Formation to 285 ft (86.87 m) is slightly sandy (20% quartz), with low amounts of carbonate, particularly in the sand-sized fraction (Fig. F3). There are some silty and scattered very fine sand laminae and interbeds. We interpret this as the upper part of the HST.
There is a heavily burrowed zone at 288 ft (87.78 m) associated with a peak in clay content (288–290.5 ft; 87.78–88.54 m). Quartz sand content increases below a coring gap (300–311 ft [91.44–94.79 m]; ~20%–35%), suggesting deepening up to this level. The surface at 288 ft (87.78 m) is thus interpreted as a flooding surface, possibly a MFS (Fig. F3).
Quartz sand decreases below 311 ft (94.79 m) to 318 ft (96.93 m), where there is a coring gap overlying a tight clay (320–324 ft; 97.54–98.76 m). We tentatively place a sequence boundary in the coring gap, which is also a break from nannofossil Zone NP12 above 316 ft (96.32 m) and Zone NP11 below 321 ft (97.84 m), separating Sequence E3 above from E2 below (Fig. F3).
Quartz sand increases downsection from 324 ft (98.76 m) to a tight clay (330–333 ft; 100.58–101.50 m). Quartz sand and glauconite increase again downsection below 333 ft (101.50 m). From 340 to 346.8 ft (103.63 to 105.70 m), the beds are greenish gray (1%–4% glauconite sand) and laminated, with clay and silt toward the top and silt and very fine sand (as much as 41%) toward the bottom of this interval, with sand concentrated in small bacilliform burrows. A heavily burrowed irregular contact (3–5 cm relief) at 348.6 ft (106.25 m) separates sandy clayey silt above from tight clay below (348.6–357.6 ft; 106.25–109.00 m). We initially placed a sequence boundary at 348.6 ft (106.25 m). This contact occurs within Sequence E2 based on the assignment of the section to 356 ft (108.51 m) to Zone NP11. Alternatively, this burrowed surface may be a MFS of Sequence E2.
Glauconite appears in burrows at 357.6 ft (109.00 m) and increases to 80% at 358.8 ft (109.36 m). A contact at 358.8 ft (109.36 m) separates glauconitic clay above from clayey glauconite sand below, with burrows ~0.3 ft (9 cm) from the contact. Nannofossil biostratigraphy suggests that the section above 356 ft (108.51 m) correlates to Sequence E2. This further suggests that the contact at 358.8 ft (109.36 m) is a sequence boundary separating Sequence E2 above from E1 below (Fig. F3). Further study is needed to evaluate the significance of surfaces at 348.6 ft (106.25 m) and 358.8 ft (109.36 m) and the correlation of the section from 348.6 to 365.2 5 ft (106.25 to 111.31 m).
The glauconite sand continues to an irregular contact at 365.2 ft (111.31 m) that is a clear sequence boundary (Fig. F3). At the boundary is a layer of phosphate and a small amount of fine quartz sand. The glauconite sand was burrowed ~0.7 ft (21 cm) in distinct burrows; there was also a rip-up clast of the clay from below. This sequence boundary separates Sequence E1 above from an unnamed clay and sequence below.
A clay appears below a spectacular sequence boundary at 365.2 ft (111.31 m) (Fig. F11). Below the burrowed contact zone (365.2–365.9 ft; 111.31–111.53 m), the section consists of a dark greenish gray clay to 366.65 ft (111.75 m), turning into a brown to progressively reddish brown clay 370–377.15 ft (112.78–114.96 m). Greenish clay returns from 380–384.7 ft (115.82–117.26 m), where there is a burrowed surface. At the contact are pyrite nodules and possible phosphate pellets; 0.1 ft (3 cm) above is a rip-up clast. Burrows extend ~1 ft (0.30 m) below the contact. The lithology changes from clay above the surface to a glauconitic (10%–20%) sandy silty clay to 384.7 ft (117.26 m). Glauconite concentration is higher in burrows toward the base of this interval. The silty clay is more similar to the downdip Vincentown Formation of Owens et al. (1997) than the clay above, which is a unique lithologic unit associated with the PETM (Cramer et al., 1999). We assign this PETM clay above 384.7 ft (117.26 m) as an "unnamed clay," though we have previously termed them "Vincentown equivalent" (see Miller et al., this volume) (Fig. F3). It comprises a distinct sequence here at Sea Girt that we term Pa4 (i.e., immediately above Sequence Pa3 of Liu et al. [1997]). The clays to clayey silts below the 384.7 ft (117.26 m) sequence boundary are assigned to the Vincentown Formation sensu Owens et al. (1997) and Miller et al. (this volume).
Uniform, slightly micaceous, slightly sandy, clayey silts occur from 384.7 to 420 ft (117.26 to 128.02 m). The silts appear to be finely laminated (1–2 cm scale, though the laminations are broken by bioturbation). Glauconite is common to abundant from 384.7 to 401 ft (117.26 to 122.22 m); total sand-sized fraction is ~40% in this interval. This sandier section from 384.7 to 401 ft (117.26 to 122.22 m) is the upper part of the HST. The section fines downward from a slightly sandy, slightly glauconitic micaceous clayey silt (401–420 ft; 122.22–128.02 m) to a massive to finely (1–2 mm scale) laminated, slightly micaceous, slightly glauconitic silty clay with only a trace of quartz sand from 420 to 430 ft (128.02 to 131.06 m). Two large brown nodules (421.8 and 426.9 ft; 128.56 and 130.12 m) may represent replaced shell material (equivalent of the G. dissimilis bed?) that may mark the MFS (Fig. F3).
Silty clays to clayey silts continue from 430 to 452 ft (131.06 to 137.77 m). Glauconite increases from generally <5% from 411 to 443 ft (125.27 to 135.03 m) to >10% at 445 ft (135.64 m). Small, thin shells appear at 452 ft (137.77 m) and persist to 461.5 ft (140.67 m). A carbonate concretion occurs at 454.7 ft (138.59 m). Slightly micaceous glauconitic clay continues from 452 ft (137.77 m), with glauconite increasing downsection, to a clayey glauconite sand at 456 ft (138.99 m). Large Thalassinoides burrows appear downsection at 460 ft (140.21 m). From 456 to 461.5 ft (138.99 to 140.67 m), the lithology is a silty, slightly clayey glauconite sand. There is an irregular contact between 461.3 and 461.5 ft (140.60 and 140.67 m). We interpret this as a sequence boundary at 461.5 ft (140.67 m), separating a glauconite sand above from a glauconitic sandy clay below (Fig. F3). This is probably the base of Sequence Pa3 of Liu et al. (1997). Glauconitic sandy clay (461.5–465 ft; 140.67–141.73 m) at the top of the underlying sequence becomes more glauconitic from 463.5 to 465 ft (141.27 to 141.73 m; Zone P3) and changes to >50% glauconite at 465 ft (141.73 m), where we place the top of the Hornerstown Formation.
The base of the Vincentown Formation has been defined in various ways. Based on Owens et al. (1988), the base of the Vincentown Formation would be placed at the contact of the glauconite sand with the glauconitic clay at the base of the sequence (461.5 ft; 140.67 m). It could be placed at the first place downsection where glauconite exceeds 50% (455 ft; 138.68 m) or where glauconite consistently remains >50% (465 ft; 141.73 m). We use the latter as the definition of the base (Figs. F3, F4).
The sequence (461.5–469.8 ft; 140.67–143.20 m) that spans the Vincentown/Hornerstown Formational boundary is heavily bioturbated with numerous clay-lined burrows concentrated from 463 to 466.2 ft (141.12 to 142.10 m). Glauconite sand continues to comprise >50% to 469.8 ft (143.20 m). Scattered brachiopod shells (Oleneothyris and other taxa) appear at 467 ft (142.34 m), becoming more common downcore to a brachiopod-rich shell hash from 469 to 469.8 ft (142.95 to 143.20 m). We tentatively place a MFS at ~467 ft (142.34 m) at a gamma ray log peak (Fig. F4). We place a sequence boundary at 469.8 ft (134.20 m) separating the glauconitic shell hash above from silty, clayey, very quartzose glauconitic sand below. The sequence boundary is associated with a gamma ray log increase (Fig. F4). This sequence boundary separates Sequence Pa2 of Liu et al. (1997) from Sequence Pa1 below, as supported by nannofossil assignment of 466 ft (142.04 m) to Zone NP6 and 471 ft (143.56 m) to Zone NP4. Sandy upper HST facies are absent, with a clayey HST and glauconitic TST, both deposited in a middle neritic environment.
The interval from 469.8 to 474.3 ft (143.20 to 144.57 m) is composed of silty, very glauconitic, very fine to fine quartz sand (Fig. F4) with some glauconitic clay interbeds. There are thin shell hashes (?oysters) from 472.8 to 473.0 and 473.6 to 473.7 ft (144.11 to 144.57 and 144.35 to 144.38 m). Large oyster shells occur at 476.3 and 476.6–476.7 ft (145.18 and 145.27–145.30 m). These sands may have been deposited within a storm wave base and represent lower shoreface environments. Glauconite increases from 475.0 to 476.6 ft (144.78 to 145.27 m) to >50%; this glauconite-quartz sand (476.6–478.1 ft; 145.27–145.27 m) was deposited in offshore (middle neritic, based on benthic foraminifers) environments. A possible MFS occurs at a gamma ray log peak at ~475 ft (144.78 m). There is a lithologic change at 478.1 ft (145.27 m), with silty glauconite-quartz sand overlying a slightly micaceous glauconitic sandy silt (478.1–480.0 ft; 145.78–146.30 m) also deposited in middle neritic environments (on the basis of benthic foraminifers; see "Benthic Foraminifers"). Glauconite increases downsection from 480 to 481 ft (146.30 to 146.61 m), where glauconite sand returns and continues to 482.4 ft (147.04 m) and a possible sequence boundary (hard zone, pyrite nodule, and lithofacies shift). Foraminiferal biostratigraphic data indicate a break from Subzone P3a to P1c below, though nannofossil data indicate that this boundary occurs within Subzone NP4a. The sequence from 469.8 to 482.4 ft (143.20 to 147.04 m) correlates with Sequence Pa1 partim of Liu et al. (1997) and is designated Sequence Pa1b here.
Micaceous interbedded glauconitic silty clay and clayey silts with sand burrows continue from 482.4 to 495.2 ft (147.04 to 150.94 m), becoming slightly clayier below 493 ft (150.27 m). This level may be a MFS (Fig. F4). These silts and clays may represent prodelta environments, probably deposited in outer inner to middle neritic paleodepths (sparse benthic assemblage with Gavelinella, Cibicidoides, Bulimina, and no plankton). There is a coring gap from 495.2 to 500.0 ft (150.94 to 152.40 m) associated with a large gamma ray log kick and a biostratigraphic gap from Zone NP2 below to Subzone NP4a above. This is clearly a major hiatus and unconformity (497.5 ft [151.64 m] on Fig. F4). A sample from 494.7 ft (150.78 m) has high glauconite (>50%) because of burrowing from below. The sequence from 482.4 to 497.5 ft (147.04 to 151.64 m) correlates with Sequence Pa1 partim of Liu et al. (1997) and is designated Sequence Pa1a here.
The base of the Hornerstown Formation at Sea Girt from 500.0 to 509.65 ft (152.40 to 155.34 m) is a heavily bioturbated, dark black, clayey silty glauconite sand with sporadic thin clay laminae and traces of mica. The section becomes clayier toward the base. The environment of deposition of this thin sequence was probably middle neritic. The base of this sequence (Subzone P1a) appears to be older than Sequence Pa1 (Subzone P1c, partim) of Liu et al. (1997) and we named it Sequence Pa1a (Subzone NP1a through Zone NP2 and Subzone P1a).
The interval from 500 to 519 ft (152.40 to 158.19 m) is a black, silty glauconite sand, with glauconite varying from ~50% to 75% (Fig. F4). It is difficult to differentiate the Hornerstown Formation (glauconite sand) from the Navesink Formation (clayey glauconite sand) at Sea Girt because the Red Bank Formation that is present at outcrop is not represented because of a facies change. We place the base of the Hornerstown Formation at the base of a friable sand (509.65 ft; 155.34 m) overlying a thin (509.65–510.0 ft; 155.34–155.45 m) glauconitic clay. The sand has lithic fragments of apparently Cretaceous chalk with glauconite grains; this may be the equivalent to the clay clast unit overlying the K/T boundary at Bass River (Olsson et al., 1997). The clay is overlain by Tertiary strata of Subzone P1a (509 ft [155.14 m]; Eoglobigerina eobulloides and reworked Cretaceous species); samples at 509.5 and 510 ft (155.3 and 155.45 m) appear to be Upper Cretaceous based on the absence of Tertiary planktonic foraminiferal species and the presence of Cretaceous taxa. Thick shell fragments appear at 510.1 ft (155.48 m), suggesting assignment to the Navesink Formation.
The upper part of the Navesink Formation (509.65–514.75 ft; 155.34–156.90 m) consists of a black, clayey, silty, slightly micaceous, massively burrowed glauconite sand. It weathers to very dark greenish gray and contains sandier intervals that are generally lighter green and richer in sulfur and gypsum (509.5–509.65, 511.1–511.15, 511.5–511.6, 512.2–512.3, 512.6–512.7, 512.8–512.9, and 513–513.55 ft; 155.30–155.34, 155.78–155.80, 155.91–155.94, 156.12–156.15, 156.24–156.27, 156.30–156.30, and 156.36–156.53 m), clayier intervals (509.65–510; 155.34–155.45 m), and intervals where these two lithologies appear to be burrowed together. The depositional environment of this section is interpreted as offshore interfingering with lower shoreface.
The section below 514.75 ft (156.90 m) is a clayey, silty, glauconite sand. Shells occur from 517.1 to 519.9 ft (157.61 to 158.47 m) and at 519.3 ft (158.28 m) and increase downsection below 529 ft (161.24 m) to a peak at 555 ft (169.16 m). Pyritized, slightly, sandier burrows with lighter green glauconite occur at 517.5–517.7, 518.6, 519.5, 531.1, and 531.4 ft (157.73–157.79, 158.07, 158.34, 161.88, and161.97 m). Clay increases downsection from 522 to 524 ft (159.11 to 159.72 m) with more visible burrows. The section contains light gray clay (more carbonate) bioturbated with glauconite sand from 522 to 524, 529.2 to 530, and 531.6 to 533.0 ft (159.11 to 159.72, 161.3 to 161.54, and 162.03 to 162.46 m). The section from 532.8.0 to 535.8 ft (162.40 to 163.31 m) is similar to above but has slightly higher glauconite and is darker (black vs. dark gray) and more friable when dried. A contact at 532.8 ft (162.40 m) is distinct but does not appear to be a sequence boundary. There is another lithologic contact at the base of this sandier interval at 535.8 ft (163.31 m), separating the sandier zone from intensely burrowed silty glauconite sand with more common interbedded light gray clay; this may represent a sequence boundary (Fig. F4). The sandier bed is associated with a gamma ray increase at its base and a minimum at its top. If there is a sequence boundary between 532.8 ft (162.40 m) and 535.8 ft (163.31 m), it would be equivalent to the Navesink I/II contact postulated by Miller et al. (2004).
This interbedded glauconite silty sand and carbonate clay facies is typical of the deepest water Navesink marls and were deposited in deeper shelf environments (middle–outer neritic). There is little mica in this interval. An interval with higher glauconite sand (550–551.1 ft; 167.64–167.98 m) is associated with a gamma ray increase. This is not noted in the cumulative percentage on Figure F4 because it is between samples. Quartz sand disappears below 550 ft (167.64 m). Carbonate increases downsection from 535.8 ft (163.31 m) to a maximum at 555 ft (169.16 m), which may represent the MFS (middle–outer neritic; ~60–100 m paleowater depth) and a regressive section above. The carbonate-rich glauconite silty sand becomes slightly clayier from 564 to 565.1 ft (171.91 to 172.24 m), where there is a contact zone from 565.1 to 566.2 ft (172.24 to 172.58 m) in which the glauconite clays of the Navesink Formation are mixed together with the quartz sands of the Mount Laurel Formation.
The contact with the Navesink and Mount Laurel Formations (Fig. F4) is a zone between 565.1 and 566.12 ft (172.24 and 172.55 m) that includes large oyster shells and phosphate layers at 565.15 and 566.15 ft (172.26 and 172.56 m). The zone compares well with that reported from the Route 34 Matawan, New Jersey, outcrops (Miller et al., 2004) and consists of
Below the contact, the Mount Laurel Formation consists of medium- to coarse-grained muddy quartz sand (565.2–585.2 ft; 172.27–178.37 m) that fines downsection. The sand is slightly glauconitic, has traces of large mica flakes, contains carbonate (probably largely as foraminifers), and is heavily bioturbated, yielding a mottled texture. From 575 to 577.9 ft (175.26 to 176.14 m), the formation is finer grained, primarily medium sand. Clay-lined burrows appear in the medium sands at 581.2 ft (177.15 m). The sands are indurated from 583.1 to 583.9 ft (177.73 to 176.97 m). This section was deposited in distal upper shoreface environments. From 583.2 to 590 ft (177.76 to 179.83 m), the sand becomes finer and large mica flakes appear, as well as silt interbeds. Scattered shells occur at 585–587 ft (178.31–178.92 m) with numerous clay-filled burrows. This interval was deposited in lower shoreface environments and is transitional to the Wenonah Formation.
Silty, fine, micaceous bioturbated sands and interbedded clayey silts (590–600 ft; 179.83–182.88 m) could be placed in either the Wenonah or Mount Laurel Formation; we follow the convention of Miller, Sugarman, Browning, et al. (1998) in placing the top of the Wenonah Formation at a level where sand is <50% (Fig. F4). From 600 to 602.35 ft (182.88 to 183.60 m), the lithology is an interbedded clayey, silty, very fine sand with slightly glauconitic, micaceous, woody medium quartz sand. These finer grained units were deposited in lower shoreface environments. There is a slightly irregular contact at 605.1 ft (184.43 m), associated with a gamma ray log increase; it lacks obvious rip-up clasts, heavy bioturbation, and other characteristics of a sequence boundary. Therefore, we interpret this as a flooding surface.
The lithology is sandier from 605.1 to 610 ft (184.43 to 185.93 m). It is mostly slightly glauconitic fine sand with interbeds of darker clay. The sand is coarser from 610 to 614.8 ft (185.93 to 187.39 m), consisting of medium quartz sand interbedded with sand containing clayey silt laminae. The entire section from 605 to 614.8 ft (184.40 to 187.39 m) is interpreted as a lower shoreface.
These shoreface sediments may continue below a coring gap (614.8–620 ft; 187.39–188.98 m) to 621 ft (189.21 m). Below a contact at 621 ft (189.21 m), the lithology changes to interbedded micaceous, lignitic, clayey silt with very fine sand. We place the Wenonah contact at this level. The contact is gradational, with clay beds at 613.65–613.7 ft (187.04–187.06 m) and 620.7–620.8 ft (189.19–189.22 m).
Micaceous, lignitic, sandy clayey silt with very fine sand laminations from 621 to 675.7 ft (189.28 to 205.95 m) is placed in the Wenonah Formation (Fig. F4). The Wenonah Formation at Sea Girt is coarser grained and has more sedimentary structures than at Ancora or Bass River, suggesting a shallower paleoenvironment (lower shoreface with a prodelta influence). Recovery in the Wenonah Formation was moderate (60%).
Micaceous, lignitic, clayey fine sand to silt with traces of glauconite from 621 to 650 ft (189.21 to 198.12 m) (Fig. F4) is dominated by physical structures including thin sand cross laminae (e.g., 625.3–625.4 ft [190.59–190.62 m]). The section is burrowed to heavily burrowed in places, with sand carried into burrows. Clay increases downsection in this interval. The section was deposited in lower shoreface environments, though shells are rare. Common mica and lignite indicate the proximity of a deltaic influence that dominates below 650 ft (198.12 m).
Micaceous clayey silts with scattered sand laminae and scattered pyrite nodules (650–671 ft; 198.12–204.52 m) are more laminated than above. The dominance of laminae over bioturbation with common lignite and mica suggest that these sediments were deposited in prodelta environments (Fig. F4). Scattered small shell fragments (660–671 ft; 201.17–204.52 m) and glauconite-rich sandy zones occur (665.5–671 ft; 202.84–204.52 m), suggesting offshore deposition influenced by a delta. Glauconite increases in micaceous silts (671–675.7 ft; 204.52–205.97 m), where there is a change to a very glauconitic (>30%) silt. We place the top of the Marshalltown Formation at this level.
The Marshalltown Formation (Fig. F4) consists of very glauconitic (~38%–53%), slightly quartzose, structureless to heavily burrowed silt and subordinate glauconite sand (675.7–687.2 ft; 205.95–209.46 m). Large, clay-lined brown burrows, rare thin scattered shell fragments, and pyrite nodules occur throughout the Marshalltown Formation. Several very large (as much as 0.5 ft [15 cm]) tan burrows occur at 677.5–679.5 ft (206.50–207.11 m). We tentatively place the MFS at 676 ft (206.04 m) near the top of a glauconite-rich interval where clay is at a maximum, quartz sand is absent, and there are rare carbonate shells. The Marshalltown Formation was deposited in environments deeper than inner neritic (i.e., middle–outer neritic) and represents the TST of the Marshalltown-Wenonah-Mount Laurel sequence. The Marshalltown Formation is less glauconitic and clayier at Sea Girt than in outcrop or at Ancora (~60% glauconite) and Bass River (~50% glauconite). The Marshalltown Formation is readily differentiable from the Wenonah Formation at Sea Girt by its high abundances of glauconite, smaller mica flakes, less sand, and green vs. brown color and its deeper water paleoenvironment.
A contact at 687.2 ft (209.46 m) is very irregular with 0.1 ft (3 cm) of relief and separates micaceous, bioturbated, clayey, silty, fine-grained glauconite sand above from a thin (0.5 ft; 15 cm) brown clay below. This contact separates the Marshalltown Formation from the upper Englishtown Formation (Fig. F5). Glauconite is burrowed down to 687.25 ft (209.47 m). The section from 687.25 to 691.8 ft (209.47 to 210.86 m) consists of very micaceous, silty medium–fine quartz sand with numerous brown clay burrows that give the core a mottled aspect. Phosphate pellets occur at 690.4 and 691.2 ft (210.43 and 210.68 m), immediately above an irregular contact. The interval from 691.1 to 691.2 ft (210.65 to 210.68 m) contains clay (mud chip) rip-up clasts. A surface at 691.2–691.25 ft (210.68–210.68 m) is irregular and separates clayey, clast-rich sands above from classic delta front lignitic medium sands below. We interpret the succession as follows:
The Englishtown Formation, and particularly the upper Englishtown sequence, is greatly expanded at Sea Girt, where it is 149.9 ft (45.69 m) vs. 35 ft (10.67 m) at Ancora and 31.5 ft (9.60 m) at Bass River. Below the LST lag unit, the top of the Englishtown Formation (691.2–701.5 ft; 210.68–213.82 m) consists of fine- to medium-grained, micaceous sands with thin beds and laminae of sandy clayey silt and lignite. The sections are burrowed with obvious circular (10 mm diameter) clay-lined burrows. Occasional pyrite nodules are present. Some of the thin interbeds are dark silts; others are lighter brown clays. The lignite layers are ~0.1–0.2 ft (3–6 cm) thick. Below a nodule-rich layer (701.5 ft; 213.82 m), the section becomes finer grained to 710 ft (216.41 m); the lithology is similar to above, although the dark organic clay-silt beds predominate and sands are <20 cm thick. This appears to be a delta front deposit (Fig. F5).
Interbedded fine–medium sands and subsidiary sandy, silty clays (710–731 ft; 216.41–222.81 m) contain laminae to thin beds of lignite. There is a pebbly sand bed at 710.9–711 ft (216.68–216.71 m). Lignite occurs in laminae, cross laminae (e.g., 725–726 ft [220.98–221.28 m]), and in disseminated form; it increases in abundance in thicker beds downsection in this interval. The sands are occasionally iron-stained and there are nodule zones (e.g., 714.6–714.7 ft [217.81–217.84 m]). There are no clear channel structures (e.g., cut and fill or fining-upward successions) and no thick organic-rich beds; therefore, we interpret the depositional environment as delta front (Coleman, 1975; Owens and Gohn, 1985). The presence of nannofossils (see "Calcareous Nannofossils") indicates that these delta front facies were submarine.
There is a layer of angular clasts at 730.9–731 ft (222.78–222.81 m), with other clasts disseminated to ~746 ft (227.38 m). The clasts include a large (5 cm) piece of petrified wood; some appear to be purple clasts that are probably fragments of large concretions.
A minor facies change occurs below the angular clast layer, with the section from 731 to 750 ft (222.71 to 228.60 m) consisting of organic-rich (finely disseminated organic material) sands with abundant clay and lignite laminae. There also appear to be diagenetic concretions, burrows, and large mica flakes. Lignite increases below 736 ft (224.33 m). The interval from 740.5 to 745.1 ft (225.70 to 227.11 m) is predominantly sand with disseminated organic matter and may represent an interdistributary bar. Organic-rich sands return from 745.1 to 745.9 ft (227.11 to 227.35 m). These sands were deposited in a delta front environment (Fig. F5).
There is a coring gap from 745.9 to 760 ft (227.35 to 231.65 m), except for 0.6 ft (18 cm; placed arbitrarily at 750–750.6 ft [228.60–228.78 m]) of fragmented ironstone concretions and lignite. Thus, the contact between the upper sand facies and lower clay facies of the upper Englishtown sequence was lost in the interval, though logs suggest it should be placed at ~757 ft (230.73 m) (Fig. F5).
A silty clay upper Englishtown facies is found in the core beginning at ~760 ft (231.65 m; there is 0.1–0.2 ft [3–6 cm] of caved material at 760 ft [231.65 m]), where it consists of slightly micaceous interbedded and interlaminated silts and silty clays with occasional very fine sand laminae and sand-filled burrows. Thin shells appear at 764.9 ft (233.14 m), along with an increase in bioturbation. The laminated clays and silts are interpreted as prodelta deposits (Fig. F5).
There is a contact at 780.05 ft (237.76 m) separating laminated silty clay with wispy sand laminae from a slightly glauconitic clay. The glauconite is fine to very fine and concentrated in burrows. From 781.05 to 782.3 ft (238.06 to 238.45 m) there are numerous brown carbonate concretions (as long as 2.5 cm in longest dimension) that are replaced shell material. From 782.3 to 782.8 ft (238.45 to 238.60 m) is a bioturbated clay with few concretions, fine mica, and some silt. There is an irregular surface at 782.8 ft (238.60 m) with glauconite clay below that continues to 783.4 ft (238.78 m). A shell hash (including aragonitic shells) occurs at 783.3–783.5 ft (238.75–238.81 m). Another surface at 783.4 ft (238.78 m) is a very heavily bioturbated micaceous clay with scattered shells. A large concretion occurs at 783.6 ft (238.84 m) with additional concretions from 784.5 to 784.8 ft (239.12 to 239.21 m). Below this, there are few concretions. This interesting and complex interval (780.05–784.8 ft; 237.76–239.21 m) is probably a condensed section/flooding surface. The depth of the flooding surface probably should be placed at 782.8 ft (238.60 m), where there is a peak in glauconite and gamma ray log values (Fig. F5).
Below the glauconitic zone, the sediments return to micaceous interbedded and interlaminated silt and clay grading to clay below ~803.5 ft (244.91 m). The sediments are bioturbated with silts burrowed into clays; laminations are generally disrupted. Scattered shells occur throughout. There is an indurated shelly clay with carbonate cement at 787.0–787.1 ft (239.88–239.91 m). The clay from 803 to 828 ft (244.75 to 2552.37 m) is relatively uniform with scattered silt laminae, silt burrows, sulfur-rich burrows (812.2 ft; 247.56 m), and pyrite concretions (e.g., 813.0–813.1 ft [247.80–247.83 m]). If exposed in outcrop, this section would be identified as the Woodbury Formation. The clayey silts and clays comprise an excellent confining unit on top of the lower Englishtown Formation sands and were deposited in a distal prodelta environment, though the siltier sediments above ~803–810 ft (244.75–246.89 m) may have been deposited in more proximal prodelta environments (Fig. F5).
Abundant glauconite occurs in burrows from 824 to 825.7 ft (251.16 to 251.67 m), but there is less glauconite from 825.7 to 828.3 ft (251.67 to 252.47 m). The section becomes slightly siltier at 827–828.6 ft (252.07–252.56 m), with interlaminations of silty clay and clay deposited in distal prodelta environments.
The section from 828.6 to 829.7 ft (252.56 to 252.89 m) consists of micaceous silty clay with glauconite that was deposited in neritic environments with little deltaic influence. We place the MFS at 829 ft (252.68 m) (Fig. F5) at a maximum in glauconite and the top of a zone with concretions and brown clay.
The section from 829.7 to 832.2 ft (252.89 to 253.65 m) consists of glauconitic (~10%–15%) silty clay with burrows and laminae of slightly glauconitic (~5%) brown clay and indurated concretions. Silty, burrowed, glauconite quartz sand occurs from 832.2 to 834.8 ft (253.65 to 254.45 m). Common shells appear at 829.5 ft (252.83 m), and the section becomes very shelly with brown, indurated burrows and brown carbonate (?siderite) concretions from 834.8 to 836.5 ft (254.45 to 254.97 m). This zone has the appearance of a heterolithic interval, but the clasts are concretions, mostly after shell material. This interval also was deposited in lower shoreface environments. A glauconitic, silty quartz sand with shells (836.5–837.5 ft; 254.97–255.27 m) was deposited in lower shoreface environments. We interpret the facies from 829.7 to 837.5 ft (252.89 to 255.27 m) as part of the TST deposited in lower shoreface environments with reworked glauconite.
A thick indurated zone (837.6–839.1 ft; 255.30–255.76 m) marks a sequence boundary (Fig. F5). The top of the indurated zone has a few shells and glauconite; below ~838.1 ft (255.45 m), the section is a clean sandstone that overlies unlithified micaceous, slightly glauconitic quartz sands (839.1–841.5 ft; 255.76–256.46 m). We interpret the shells and glauconite at the top of the indurated zone as burrows and place the sequence boundary at the top of the sandstone (837.6 ft; 255.30 m); the interval from 837.5 to 837.7 ft (255.27 to 255.33 m) has quartz sand mixed from below and either is a mixing zone above the sequence boundary or the sequence boundary may be slightly higher (837.5 ft; 255.27 m). This sequence boundary separates the TST glauconite quartz sands of the upper Englishtown sequence from the upper HST aquifer sands of the lower Englishtown Formation that is part of the Merchantville–Woodbury–lower Englishtown sequence of Miller et al. (2004).
The expanded upper Englishtown sequence (150.4 ft; 45.84 m) was a major target of drilling at Sea Girt. Owens et al. (1998) first observed that the subsurface upper Englishtown sequence had a classic boxcar log pattern in northern Ocean and southern Monmouth counties, where the sequence is best developed. The logs show low values in the upper HST sands and a sharp change to high values in the lower HST silty clays and TST glauconite sands/glauconitic clays. Owens had planned to name this the Manchester sequence (J.P. Owens, pers. comm., 1992), though the name was never approved. Our studies at Sea Girt should provide better age control on this middle Campanian sequence and possibly allow recognition of additional sequences or parasequences within it. Our studies should also provide valuable information on aquifer potential for the upper Englishtown sands in this region.
Below the base of the sandstone (839.15 ft; 255.77 m) and a minor coring gap (839.15–840 ft; 255.77–256.03 m), the top of the lower Englishtown Formation consists of a heavily burrowed, silty, fine–medium slightly micaceous sand (Fig. F6). The sand contains finely disseminated lignite (840–841.8 ft; 256.03–256.58 m) that is lighter colored and more mottled than the section below, reflecting heavy bioturbation from the sequence boundary. Below this to 862 ft (262.74 m), is a very micaceous, heavily burrowed, silty, fine sand that is slightly fossiliferous. It represents deposition in a lower shoreface setting. There is a sharp facies change across an irregular surface at 861.9 ft (262.71 m) to interbedded and interlaminated, bioturbated, very micaceous (including chlorite), very fine silty sand and sandy silt with rare clay laminae and beds, common lignite laminations (e.g., 862–862.3 ft [262.74–262.83 m]), and scattered shells that continue 869.5 ft (265.02 m). These are interpreted as delta front deposits. The section fines below 869.5 ft (265.02 m) to homogenized, heavily bioturbated, sandy, slightly clayey, micaceous, slightly shelly silt. These silts were deposited in offshore environments slightly influenced by a delta (i.e., some laminated intervals might be prodelta to distal prodelta). The cores become increasingly finer grained downsection from 869.5 to 900 ft (265.02 to 274.32 m), becoming a shelly silty clay at ~891 ft (271.58 m), which is where the top of the Woodbury Formation is placed. The boundary between the lower Englishtown and the Woodbury Formations is gradational and was placed at a change from clayey silts to shelly silty clays; sand disappears between washed samples at 891 and 896 ft (271.58 and 273.10 m) and gamma ray log values increase at 890 ft (271.27 m), consistent with the placement of the formational boundary at ~891 ft (271.58 m). The lower Englishtown Formation comprises the upper HST of the sequence.
The Woodbury Formation is a micaceous silty clay to clay (Fig. F6). It contains scattered shells, pyrite, and gypsum on the core surface. The top of the formation is moderately to heavily burrowed and represents offshore environments. At ~904.5 ft (275.69 m), the clay changes from predominantly bioturbated to laminated and the section is predominantly laminated to 940 ft (286.51 m). Laminations are faint and many are broken by bioturbation. This laminated interval is probably a prodelta deposit. The section becomes more clay rich at 931 ft (283.77 m). Traces of glauconite appear at 916 ft (179.20 m) in the washed samples and reaches 1%–2% at 931 ft (283.77 m). Between 930 and 940 ft (283.46 and 286.51 m), the lithology becomes a clay with some silt that is less micaceous and has fine glauconite in burrows. Glauconite continues to increase to 943.7 ft (287.64 m), where the amount of glauconite exceeds 50%. The section from ~931 to 943.5 ft (283.77 to 287.58 m) was deposited in neritic environments (probably middle neritic). The Woodbury Formation at Sea Girt is thinner (52.5 ft; 16.00 m), less laminated, and lighter colored than at Bass River (160 ft; 48.77 m) and Ancora (100 ft; 30.48 m).
The contact between the Merchantville and the Woodbury Formations is gradational and is placed at 943.5 ft (287.58 m), the depth where glauconite sand concentration is >50% (Fig. F6). We place a MFS at 943–944 ft (287.43–287.73 m) in a very clayey, gray (carbonate rich?), glauconite sand at a peak in glauconite, a minimum in quartz sand, and a peak in gamma ray values. The section from the MFS to 947.1 ft (288.68 m) is very heavily bioturbated ("churned") clayey, slightly quartzose glauconite sand. Below a coring gap (947.1–950 ft; 288.68–289.56 m), very fine quartz sand is more common to 955 ft (291.08 m) in clayey micaceous quartzose glauconite sands, with occasional sulfide-filled burrows. Mica is common throughout the upper Merchantville Formation at Sea Girt, but appears to peak at 950–952 ft (289.56–290.17 m). The section from 943.5 to 945 ft (287.58 to 288.04 m) was deposited in neritic (probably middle neritic) environments, and the section from 950 to 955.1 ft (289.56 to 291.11 m) was probably inner neritic based on common quartz sand. There is a coring gap from 955.1 to 960 ft (291.11 to 292.61 m).
From 960.0 to 964.4 ft (292.61 to 293.95 m) is a slightly micaceous glauconite sand with bicolored (green and brown) grains. From 960.4 to 960.9 ft (292.73 to 292.88 m) is an indurated glauconite sand with bicolored grains. From 960.9 to 962.1 ft (292.88 to 293.25 m) is a clayey, finely micaceous, slightly shelly, quartzose glauconite sand with bicolored glauconite. We interpret the section with bicolored glauconite (960–962.15 ft; 292.61–293.26 m) as lower shoreface with reworked glauconite (Fig. F6).
There is a burrowed contact at 962.15 ft (293.26 m) with an abrupt change in lithology from limonitic glauconite sand above to burrowed, micaceous, slightly shelly, sandy silt with sulfide burrows and virtually no glauconite below. This silt continues downward to a coring gap (964.5–974 ft; 293.98–2996.88 m) and was deposited in lower shoreface environments. The burrowed contact is irregular and has large (as much as 1 cm in diameter) vertical and horizontal burrows. We tentatively place a sequence boundary at the 962.15 ft (293.26 m) contact with glauconite burrowed to as much as 5 cm into the brown clay below, though the boundary lacks obvious rip-up clasts and gamma ray expression. Alternatively, it is possible that the sequence boundary occurs in a coring gap (964.5–974.0 ft; 293.98–296.88 m) associated with a large gamma ray kick. However, the sandy silt from 962.15 to 964.5 ft (293.26 to 293.98 m) is unusual in that it lacks glauconite and is best interpreted as the HST of the underlying sequence. There is a biostratigraphic break between Zones CC18 (961 ft [292.91 m] and above) and CC17 (964.4 ft [293.95 m]) (see "Calcareous Nannofossils"), consistent with a major sequence boundary at 962.15 ft (293.26 m).
The sequence from 837.7 to 962.15 ft (255.33 to 293.26 m) includes the lower Englishtown, Woodbury, and upper Merchantville Formations and is equivalent to the Merchantville III sequence of Miller et al. (2004). This sequence is restricted to Zones CC18 and CC19 at Sea Girt (see "Calcareous Nannofossils"), as it is at Ancora and Bass River (Miller et al., 2004). A gamma ray log increase at ~970 ft (295.66 m) occurs in an interval of no recovery (964.4–974 ft; 293.95–296.88 m). It is possible that an unconformity could be associated with this kick (with implications to the age of the overlying sequence), though the micaceous clayey silts above and below the coring gap are similar and we favor placing a sequence boundary at 962.15 ft (293.26 m), as discussed above.
Below the coring gap, the interval from 974 to 979.9 ft (296.88 to 198.47 m) is similar to 962.15–964.5 ft (293.26–293.98 m), consisting of a micaceous, burrowed clayey silt with some dispersed shell fragments and a few intervals of pyrite nodules. At the top of this section (974–976 ft; 296.88–297.48 m), glauconite sand is found only in the silt fraction. Glauconite increases in size and abundance, mica decreases, and the section becomes less clayey downsection from 976 to 979.9 ft (297.48 to 298.67 m). The section from 962.15 to 979.9 ft (293.26 to 298.67 m) was deposited in an offshore, "dirty" inner neritic environment, perhaps influenced by a prodelta (Fig. F6).
A facies change occurs at 979.9 ft (298.67 m) from silty clay above to muddy glauconite sand that is intensely burrowed with cemented burrows. The cemented burrows are brown and have the false appearance of rip-up clasts. The glauconite is mostly dark green, with subordinate rusty brown glauconite grains. Burrows consist of rusty brown silty clay to clayey silt that has more carbonate than the surrounding section. From 982.5 to 983.2 ft (299.47 to 299.68 m) is a more homogenized rusty and green glauconite sand. Two burrowed surfaces at 982.5 and 983.2 ft (299.47 and 299.68 m) could be flooding surfaces (Fig. F6). The section becomes less burrowed and muddier from 983.2 to 988.4 ft (299.68 to 301.26 m), with burrows becoming smaller downsection. Another surface is present at a distinct horizon at 988.4 ft (301.26 m), separating very fine glauconite sand above from medium weathered glauconite sand below. We interpret the section from 979.9 to 988.4 ft (298.67 to 301.26 m) as a zone of maximum flooding associated with gamma ray log values, and tentatively place the MFS at 988.4 ft (301.26 m) at a gamma ray log peak (Fig. F6). The section from 979.9 to 988.4 ft (298.67 to 301.26 m) appears to shallow upward based on larger burrows upsection.
From 988.4 to 991 ft (301.26 to 302.06 m) is a coarser, medium-grained, bicolored, muddy glauconite sand. There is an indurated zone from 991 to 991.6 ft (302.06 to 302.24 m); this indurated zone is browner, coarser grained, and contains more bicolored glauconite and is interpreted as the shallowest paleodepths in this section. Spotty induration of a muddy, bicolored glauconite sand continues to 993.2 ft (302.73 m), with brown glauconite decreasing downsection. This interval is associated with low gamma ray and high resistivity values on the downhole logs (Fig. F6). Clayey, quartzose, heavily burrowed (with burrows to 10–15 mm), micaceous, fine, predominantly green glauconite sand occurs from 993.2 to 996.4 ft (302.73 to 303.70 m). The interval from 996.4 to 1000.9 ft (303.70 to 305.07 m) contains interbedded glauconitic sand and brown muddy glauconitic sand. We interpret the section from 988.4 to 1000.9 ft (301.26 to 305.07 m) as the TST (Fig. F6), though the section does not appear to uniformly deepen upsection. Rather, it appears to deepen upsection from 996 to 1000.9 ft (303.58 to 305.07 m), stay deep from 996 to 993.2 ft (303.58 to 302.73 m), shallows from 993.2 to 991.6 ft (302.73 to 302.24 m), and deepens upsection above this. Benthic foraminiferal biofacies data are needed to evaluate these paleodepths trends. One possibility to consider is that the section from 991.6 to 1000.9 ft (302.24 to 305.07 m) is actually a regressive LST. There is a major sequence and facies shift at 1000.9 ft (305.07 m), where clayey glauconite sand overlies micaceous burrowed clay (to 1001.7 ft [305.32 m]) and laminated clay across a burrowed contact. This sequence boundary is associated with a major gamma ray kick. The sequence from 962.15 to 1000.9 ft (293.26 to 305.07 m) is probably equivalent the Merchantville II sequence of Miller et al. (2004). At Sea Girt, this sequence is restricted to Zone CC17 (see "Calcareous Nannofossils"); at Ancora and Bass River, the top of the Merchantville II sequence includes Zone CC18 (Miller et al., 2004).
From 1000.9 to 1004.0 ft (305.07 to 306.02 m) is slightly clayey, micaceous, dark, faintly laminated (with laminations slightly broken to broken by bioturbated), gray silt with scattered shells and distinct pyritized burrows. It probably represents a prodelta environment (Fig. F6). The micaceous silt becomes glauconitic and more intensely burrowed from 1004 to 1008 ft (306.02 to 307.24 m); the silt is slightly clayey and has glauconite concentrated in burrows, lignite, plant fragments, and laminae and thin beds of quartz sand (1005.7–1005.8, 1006.9, 1006.35–1006.45, 1007.9–1008.0 ft; 306.54–306.57, 306.90, 306.74–306.77, 307.21–307.24 m). Some burrows have been indurated. The environment of deposition was distal delta front to prodelta (Fig. F6).
From 1008 to 1015.7 ft (307.24 to 309.59 m), the section becomes finer grained downsection from a micaceous, glauconitic, sandy, clayey silt to a micaceous, glauconitic, quartzose sandy silty clay. Small pyritic, mottled burrows occur. The environment of deposition was probably inner–middle neritic with a prodelta influence (Fig. F6). There is a coring gap from 1015.7 to 1020 ft (309.59 to 310.90 m).
From 1020 to 1030 ft (310.90 to 313.94 m), the section transitions downward from burrowed, slightly clayey, very silty, slightly glauconitic quartz sand to a more heavily burrowed, siltier quartzose glauconite sand (Fig. F6). There are scattered sandy pyritic burrows and an increase in larger clay lined burrows downsection from 1025 to 1030 ft (312.42 to 313.94 m). Scattered shells occur throughout, with nested shell beds at 1020.35 and 1022.8 ft (311.00 and 311.75 m). The environment of deposition was inner to middle neritic.
The clayey, silty, quartzose glauconite sand becomes darker green with larger burrows from 1030 to 1037.5 ft (313.94 to 316.23 m). There is an indurated zone consisting of a carbonate-cemented glauconite sandstone from 1035.8 to 1036 ft (315.71 to 315.77 m). The environment of deposition of the section from 1030 to 1036 ft (313.94 to 315.77 m) was middle neritic. Recovery was poor between 1037.5 and 1060 ft (316.23 and 323.09 m), but segments recovered are similar muddy glauconite sand as above, with some of the material well lithified. The lithology showed a notable change in the short length of core (1060–1060.5 ft; 323.09–323.24 m) recovered between 1060 and 1070 ft (323.09 and 326.15 m). The recovered section is a soft, homogenous, dark, micaceous, slightly glauconitic, slightly clayey silt, with more mica and less glauconite sand than the interval above. In addition, the glauconite sand is very fine. We place a major sequence boundary at 1056 ft (321.87 m) based on a large, sharp kick in the gamma ray log across this facies shift in the cores (Fig. F6). The sequence from 1000.9 to 1056 ft (305.07 to 321.87 m) correlates with the Merchantville I sequence of Miller et al. (2004); it is assigned to Zones CC16–CC17 at Sea Girt (see "Calcareous Nannofossils"), CC17 and ?CC16–CC17 at Ancora, and CC16 at Bass River.
We may not have recovered the MFS of this sequence, with candidate levels at gamma ray peaks at 1027, 1037, 1043, 1047, and 1053 ft (313.03, 316.08, 317.91, 319.13, and 320.95 m) (Fig. F6). Possible flooding surfaces occur at facies changes at 1004, 1014, 1029.9 and 1037 ft (306.02, 309.07, 313.91, and 316.08 m). The possible flooding surface at 1029.9 ft (313.91 m) and gamma ray kick at 1027 ft (313.03 m) separate more micaceous below from less micaceous sediments below and is the best placement of the MFS considering recovery.
Very little of the Cheesequake Formation was recovered. Between 1060 and 1060.5 ft (323.09 and 323.24 m), very micaceous silt with scattered small shells and minor glauconite is assigned to the Cheesequake Formation (Fig. F6). Neither the upper nor lower bounding surfaces were recovered. We place the base of the Cheesequake Formation and sequence at 1063 ft (324.00 m) at the base of an interval of high gamma ray log values; alternatively, it may be possible to place the contact at 1064.5 ft (324.46 m) at the base of transitional log values.
Poorly sorted gravels were recovered somewhere in the interval from 1060 to 1070 ft (323.09 to 326.14 m) and may be cavings; clays from 1070 to 1072 ft (326.14 to 326.75 m) are probably a drilling artifact. The first definitive Magothy Formation was encountered at 1072 ft (326.75 m), where it consists of cross-bedded to burrowed, slightly micaceous to micaceous fine sand and interbedded organic-rich micaceous sands. The formational contact is placed at a gamma ray log increase at 1063 ft (324.00 m) (Figs. F6, F7). This facies continues to 1093 ft (333.15 m). Sand beds are typically 0.3–0.6 ft (9–18 cm) thick with scattered thin clay and lignite laminae; mud beds are as thick as 0.6 ft (18 cm). Sands vary from very clean fine sands with some medium sands to slightly muddier fine sands. Iron staining occurs and siltier beds have a red hue (e.g., 1075.7–1078 ft [327.87–328.57 m]). More lignitic beds are also more micaceous. Cross-bed sets are generally <0.3 ft (9 cm) thick. The environment of deposition is deltaic (lower delta plain to upper delta front). Heavy burrowing indicates marginal marine to marine conditions (e.g., the thin beds argue against barrier/tidal delta/lagoonal environment). Iron staining appears to indicate some subaerial exposure, although it could be post depositional. Common mica and abundant lignite indicate a fluvial influence. Differentiation of lower delta plain with marine influence vs. delta front submarine is a classic problem in facies interpretation.
Below a coring gap (1093–1100 ft; 333.15–335.28 m), the section consists of thicker bedded, cleaner, heavily burrowed, granuliferous medium well-sorted sands with lignitic interbeds (1100–1105.9 ft; 335.28–337.08). The sands are "beachy" and are interpreted as a proximal upper shoreface deposit (Fig. F7). These sands are underlain by a faintly laminated, organic-rich, slightly micaceous, slightly silty clay with thin sand laminae (1105.9–1110.65 ft; 337.08–338.53). There is an iron-cemented sand concretion at 1108.5 ft (337.87 m). The clays are interpreted as a bay/lagoon deposit (Fig. F7).
There is a coring gap from 1110.65 to 1120.0 ft (338.53 to 341.38 m) and the interval from 1120.0 to 1120.15 ft (341.38 to 341.42 m) appears to be drilling slurry. There is an indurated pyritic zone from 1120.15 to 1120.2 ft (341.42 to 341.44 m) with an irregular surface at 1120.2 ft (341.44 m). We tentatively place a sequence boundary in the coring gap (1115 ft [339.85 m] on Fig. F7) in association with a large gamma ray decrease (Fig. F7) and a shift in facies from lagoon/bay above to delta front below. We may have captured the sequence boundary at 1120.2 ft (341.44 m), though this may actually be a diagenetic surface. The sequence from ~1063 to ~1115 ft (324.00 to 339.85 m) has been named the Magothy IVB sequence (Kulpecz, 2005) and may correlate to the Cliffwood Beds in outcrop (Sugarman et al., 2005).
The section from 1120.2 to 1148 ft (341.44 to 349.91 m) is a generally cross-bedded sand with intermittent mud beds that was deposited in a delta front to lower delta plain environment (Fig. F7). From 1120.2 to 1125.1 ft (341.44 to 342.93 m) is a micaceous, trough cross-bedded, fine sand with some medium sand, common lignite laminae, and thin clay drapes that appear to be flaser beds. The subenvironment of this delta front deposit is not clear but may be tidal channel. A slightly sandy mud with thin lignite laminae and fragments occurs from 1125.1 to 1125.65 ft (342.93 to 343.10 m); it has a mottled texture from either rooting or burrowing. A yellow sulfur film occurs on the surface of the core. We interpret these clays as possibly a marsh subenvironment. From 1125.65 to 1130.1 ft (343.10 to 344.45 m) is a trough cross-bedded, micaceous, silty, fine–very fine sand with abundant mud laminae/drapes, minor organic material, and lignite. We interpret the subenvironment as possibly tidal channel. From 1130.1 to 1130.45 ft (344.45 to 344.56 m) is another sandy mud with an irregular texture reflecting burrowing or rooting. There is a fining-upward sand interval from 1130.45 to 1135.7 ft (344.56 to 346.16 m), fining from medium to fine micaceous, lignitic, trough cross-bedded sand with discontinuous mud drapes. Mica decreases upsection. Lignitic zones occur at 1130.5, 1133.1, 1134.5, and 1135.4 ft (344.58, 345.37, 345.80, and 346.07 m). The subenvironment is probably tidal channel. Another organic-rich silty clay interval from 1135.7 to 1139.3 ft (346.16 to 347.26 m) has interlaminated micaceous fine sands with sands mixed into the clay by burrowing or rooting. The burrows/roots appear almost chaotic, with various scales from large (1 cm) to very small (1 mm; ?worms). The organic-rich clay appears to be a marsh deposit. Sand increases downward and occurs in thin cross beds in the clay from 1139.3 to 1140.5 ft (347.26 to 347.62 m). Very lignitic, micaceous, medium–fine sands that occur from 1140.5 to 1148.05 ft (347.62 to 349.93 m) generally fine and becomes less micaceous upsection. Lignitic beds (e.g., 1146.6–1146.8 and 1147.6–1148.05 ft [349.48–349.54 and 349.79–349.93 m]), lignite laminae, and clay beds and laminae occur. A lighter tan clay at 1146.4–1146.5 ft (349.42–349.45 m) is transitional to clay below. The interval from 1147.95 to 1148.05 ft (349.90 to 349.93 m) is a lignite bed of possibly in situ bedded lignite (?marsh). The subenvironment of the sands is tidal channel/bay.
A possible sequence boundary occurs at 1148.05 ft (349.93 m) (Fig. F7), where a bedded muddy sandy lignite overlies a fine-grained sand with irregular pyrite cement and iron staining (1148.05–1148.25 ft; 349.93–349.99 m). The sequence from 1110.65 to 1148.05 ft (338.53 to 349.93 m) has been named the Magothy IVA sequence (Kulpecz, 2005) and may correlate to the Morgan Beds of the Magothy Formation in outcrop.
The section from 1148.05 to 1153.7 ft (349.93 to 351.65 m) consists of tan clays with thin sand beds and laminae. These clays show minor evidence of rooting and sporadic sphaerosiderite microconcretions. The sands are micaceous and fine–very fine grained. These clays are soils that were deposited in a delta plain setting (interfluve overbank?) (Fig. F7).
From 1153.7 to 1162.1 ft (351.65 to 354.21 m) the section consists of interbedded sand (0.1–1.0 ft; 3–30 cm) and clay (<0.1–0.3 ft; 3–9 cm) beds. The sands are cross-bedded, micaceous, and generally fine-grained, with some medium and very fine zones. Lignite fragments and layers are common in the sands. The clays are laminated, silty, and sandy in places. There are a few reddish zones, including hard hematite concretions at 1157.45 and 1159.3 ft (352.79 and 353.35 m). The section from 1162.1 to 1166.7 ft (354.21 to 355.61 m) is similar to above but has approximately coequal amounts of sand and clay and very fine laminations. It consists of fine–very fine micaceous sands with organic debris and dark gray, light gray, and reddish laminated clays. The dark gray clays are rich in organic material. The environment of deposition from 1153.7 to 1166.7 ft (351.65 to 355.61 m) was lower delta plain and may be a levee or crevasse splay deposit. Based on changes upsection from finer material below, it is probably a proximal levee (Fig. F7).
The interval from 1166.7 to 1175.0 ft (355.61 to 358.14 m) consists of interlaminated, dark gray, organic-rich, slightly silty clay; subordinate reddish tinged clay; and thin (1–3 mm) fine sands. The section becomes increasingly lignitic and sandier downsection. There are small spherical pyrite concretions and pyrite is scattered throughout. This is interpreted as a distal levee deposit (Fig. F7).
From 1175.0 to 1175.7 ft (358.14 to 358.35 m) is a bedded sandy lignite with pyrite concretions interpreted as a near-levee swamp (Fig. F7). In general, the section from 1153.7 to 1175.7 ft (351.65 to 358.35 m) coarsens upward and probably represents a migrating levee complex.
The section from 1175.7 to 1186 ft (358.35 to 361.49 m) is a fine-grained, organic-rich unit similar to above, but with less sand. The section from 1175.7 to 1180 ft (358.35 to 359.66 m) consists of gray and common reddish brown clay laminae, common interlaminated organic-rich laminae and beds, and micaceous sand laminae. There are numerous 1- to 2-mm spherical pyrite-cemented sand concretions. The section from 1180 to 1186 ft (359.66 to 361.49 m) is similar to above, but is less sandy and less organic rich. It consists of interbedded gray-brown clays, very dark brown clays, and a few lighter brown clays with common organic-rich laminae, rare sand laminae, and a few red rip-up clasts (common pyrite-cemented sand concretions 1–2 cm in diameter). The reddish brown laminae appear to be incipient soils that have undergone minor pedogenesis, though they could be reworking of red clays found below 1242 ft (378.56 m). We interpret this interval as lower delta plain overbank swamps (Fig. F7).
There is a coring gap from 1186 to 1190 ft (361.49 to 362.71 m) (Fig. F7). The section generally fines upward from 1190 to 1212.7 ft (362.71 to 369.63 m), passing downsection from organic-rich clays with interlaminated sands to sands with organic-rich interlaminated clays. From 1190 to 1193.5 ft (362.71 to 363.78 m) the section consists of interlaminated lighter gray, darker gray, and light brownish red clays, with common thin, micaceous, very fine sand and organic-rich laminae and beds that range in thickness from <0.5 mm to 5 cm. Pyrite cement is present in intervals. The section from 1193.5 to 1212.7 ft (363.78 to 369.63 m) consists of fine micaceous sands with zones that contain abundant clay and lignite laminae and red clay rip-up clasts. Clay laminae are black, very organic-rich/peat intervals include wood fragments.
The environment of deposition of the section from 1190 to 1212.7 ft (362.71 to 369.63 m) could be delta plain or delta front (i.e., Owens and Sohl [1969] used siderite concretions to differentiate these environments). The lack of clear bioturbation, thin laminations, common rip-up clasts, common organic matter indicative of swamps, and the lack of coarsening-upward sections argues against a subaqueous delta front interpretation. We interpret these deposits as lower delta plain overbank deposits including cut-off channels and oxbow lakes (Fig. F7).
There is a contact at 1213.2 ft (369.78 m) with micaceous, organic-rich fine sand above and poorly sorted, slightly silty, granuliferous medium–coarse sands below. There may a contact zone from 1212.7 to 1213.2 ft (369.63 to 369.78 m), with an iron-stained interval with granules at 1212.7 ft (369.63 m) and a micaceous fine sand from 1212.8 to 1213.2 ft (369.88 to 369.78 m) that may be burrowed down from above. We interpret the contact at 1213.2/1212.7 ft (369.78/369.63 m) as a probable sequence boundary associated with a gamma ray log increase (Fig. F7). The organic-rich section from 1148.05 to 1212.7 ft (349.05 to 369.63 m) is a sequence that is assigned to pollen Zone V (see "Pollen"). It thus correlates to the Magothy III sequence of Miller et al. (2004) and may be equivalent to the Amboy Stoneware Clay in outcrop.
From 1213.3 to 1233.5 ft (369.81 to 375.97 m) is a structureless, granuliferous medium–very coarse sand with a few 1- to 15-mm-thick organic-rich laminae. There are several fining-upward packages ~1–3 ft (30–90 cm) thick, as seen on the gamma ray log. This is clearly a channel deposit, though it could be fluvial delta, subaqueous bay mouth delta front, or tidal channel. Based on the facies succession (with paleosols below), we favor a fluvial channel interpretation. There is a coring gap at the base of this sand unit (1233.5–1240 ft; 375.97–377.95 m). This unit may be equivalent to the Old Bridge Sand of the Magothy Formation (Fig. F7).
Below a pyrite-cemented sand concretion (1240.0–1240.1 ft; 377.95–377.98 m) is a light–medium gray, slightly silty clay with thin, silty, very fine sand and a few organic-rich laminae (1240.1–1242.05 ft; 377.98–378.58). This gray clay contrasts with paleosols found below 1242.05 ft (378.58 m), and its environmental and sequence stratigraphic significance is not clear. We believe that this clay probably represents an interfluvial upper delta plain deposit and is best placed with the paleosols below and contrasts with the channel sands above.
Across this abrupt contact at 1242.05 ft (378.58 m), there is a shift from clay with sand laminae above to yellow, white, and red mottled clay containing sphaerosiderite below. Reddish mottles within the orange-yellow-white clay appear to follow root traces. The sphaerosiderites are weathered with hematite rinds. These clays represent paleosols (Fig. F7) deposited in an upper delta plain environment; pollen suggests that it is equivalent to the South Amboy Fire Clay of the Magothy Formation in outcrop (see "Pollen"). The mottled clay becomes banded with red and white clay at 1252 ft (381.61 m) and continues to 1253.7 ft (382.13 m), where there is an abrupt contact with very fine silty sand below.
From 1253.7 to 1262.8 ft (382.13 to 384.90 m) is light–medium gray, very fine silty sand that changes to a sandy silty clay with a trace of mica. These appear to be incipient or deeper horizon paleosols deposited in an upper delta plain environment. At 1262.8 ft (384.90 m) is an irregular contact associated with a facies shift from paleosols above to estuarine sands below and a major gamma ray kick (Fig. F7). This contact is interpreted as a sequence boundary (Fig. F7). The sequence from 1212.7 to 1262.8 ft (369.63 to 384.90 m) is assigned to pollen Zone V and thus correlates to the Magothy II sequence of Miller et al. (2004), possibly equivalent to the Old Bridge Sand and South Amboy Fire Clay in outcrop (Fig. F7).
The interval from 1262.8 to 1268.2 ft (384.90 to 386.55 m) consists of interbeds (as thick as 0.4 ft [12 cm]) of very fine–medium sand with thin clay and organic-rich cross-laminae and clay with sand and organic-rich laminae. From 1268.2 to 1272.0 ft (386.55 to 387.71 m) is a fining-upward package going from gravelly coarse sand with wood fragments and weathered pyrite concretions to silty medium sand. The interval from 1272 to 1272.5 ft (187.71 to 387.86 m) is a heterolithic mixture of sand, clay, and granules. From 1272.5 to 1273 ft (387.86 to 388.01 m) is silty fine–very fine sand with muddy sand and organic-rich laminae. There is a coring gap from 1273 to 1280.0 ft (388.01 to 390.14 m). From 1280.0 to 1282.8 ft (390.14 to 391.00 m) is a fining-upward, poorly sorted, muddy sand that fines from granules to coarse–medium sand. From 1282.2 to 1285.3 ft (390.81 to 391.76 m) is an interval of laminated sandy to silty clay and muddy very fine sand with cross laminations. From 1285.3 to 1286 ft (391.76 to 391.97 m) is a very muddy, granuliferous coarse to very fine sand. From 1286 to 1286.5 ft (391.97 to 392.13 m) is poorly sorted muddy medium sand with granules that may be caved from above. These sands and clays from 1262.8 to 1286.5 ft (384.90 to 392.13 m) are bioturbated and cross-bedded with coarse material and have contrasts in grain size from granules to clay, all of which suggest an estuarine environment (Fig. F7).
Below a coring gap (1286.5–1289 ft; 392.13–392.89 m), a kaolinized, white, slightly sandy micaceous silt (1289–1290.7 ft; 392.89–393.41 m) marks the top of the Bass River Formation. The kaolinized silts are weathered Bass River lithology because they appear to be distinct from the Magothy sands and clays. The contact is a significant disconformity associated with a gamma ray log kick (Figs. F7, F8). The sequence from 1262.8 to 1289 ft (384.90 to 392.89 m) may correlate to the Magothy I sequence of Miller et al. (2004) and the Sayreville Sand in outcrop.
Kaolinized, very sandy micaceous silt and clayey silt characterize the top of the Bass River Formation (1289–1290.4 ft; 392.89–393.31 m) (Fig. F8). Laminae and beds range from >1 to >4 cm thick. These silts contain ~3% mica (including large grains of chlorite characteristic of this formation) and ~3% dark grains that appear to be lignite. A zone of concretions occurs at 1290.4 ft (393.31 m) at the contact of whitish kaolinitic silts and unweathered medium to dark gray sandy silts.
From 1290.4 to 1300 ft (393.31 to 396.24 m) the Bass River Formation consists of thinly bedded to laminated to bioturbated, micaceous, very sandy silt to silty sand, clayey silt, and silty clays. The upper part of this section (1290.4–1294 ft; 393.31–394.41 m) is finer grained and the lower part (1294–1295 ft; 394.41–394.72 m) is sandier, more heavily bioturbated, and contains abundant mica and plant fragments. A cemented concretion (weathered to hematite) is associated with a gamma ray log kick at 1294.7 ft (394.62 m); it is possible that this is a sequence boundary with a thin sequence above. The environment of deposition is distal lower shoreface to offshore (~10–20 m paleodepths) (Fig. F8), but with a strong deltaic influence.
Below a coring gap (1295–1300 ft; 394.72–396.24 m), the section deepens downsection from delta front sands and silts (1300–1302.9 ft; 396.24–397.12 m) to proximal prodelta silty clay (1302.9–1303.5 ft; 397.12–397.31 m), to a shelf sand influenced by a delta (1303.5–1319.7 ft; 397.31–402.24 m) (Fig. F8). The delta front sands are silty, micaceous, and contain scattered plant debris. The prodelta silty clays are laminated and micaceous. The shelf sands are very fine, micaceous, very bioturbated, silty, and very fine grained and grade downsection to silty sand below 1315 ft (400.81 m). The shelf sands have finely disseminated organic matter and scattered pyrite and were deposited below wave base ("offshore") on a delta-influenced shelf.
There is probably a flooding surface at 1319.7 ft (402.24 m). Below this, micaceous, lignitic, laminated clayey silt to silty clay (1319.7–1323.0 ft; 402.24–403.25 m) represents a shallower, more deltaic influenced unit (prodelta). There are thin fining-upward successions (1319.7–1321 and 1321.0–1323.0 ft; 402.24–402.64 and 402.64–403.25 m).
Bioturbated to laminated slightly micaceous silty clay to clay with thin wispy sand laminae dominates from 1323 to 1346 ft (403.25 to 410.26 m) (Fig. F8). The section contains laminations with either lignite or pale brown sideritic clay that may be altered shells. Pyrite is also present. This unit probably was deposited in a prodelta environment or a shelf influenced by a delta.
An indurated very shelly sandstone occurs from 1346.3 to 1347.2 ft (410.35 to 410.63 m) consisting of a shell hash (1346.3–1436.4 ft; 410.35–437.81 m) associated with a gamma ray log low (Fig. F8). Shells and shell fragments persist in a shelly clayey silt to 1349.1 ft (411.21 m), including a hash at 1348.1–1348.2 ft (410.90–410.93 m). The environment of deposition may be lower shoreface, with a flooding surface at 1346.3 ft (410.35 m) equivalent to flooding Surface 4 of Sugarman et al. (1999) (Fig. F8).
Organic-rich and less organic-rich intervals characterize the Bass River Formation from 1349.1 to 1416 ft (411.21 to 431.60 m). A very dark gray laminated clay bed (1349.1–1349.5 ft; 411.21–411.33 m) is the uppermost of organic-rich beds that are primarily found below 1370 ft (417.58 m). A light brown-gray, laminated to thick bedded, slightly finely micaceous silty clay with scattered lignite (1349.5–1367.75 ft; 411.33–416.89 m) appears less organic rich. A siderite concretion with pyrite occurs at 1360 ft (414.53 m). A very light gray micaceous silt bed (1360.6–1361.0 ft; 414.71–414.83 m) punctuates the tight clays. The unit from 1349.1 to 1367.75 ft (411.21 to 416.89 m) was deposited in an offshore inner neritic environment (Fig. F8) with a deltaic influence.
There is a coring gap from 1367.75 to 1370.0 ft (416.89 to 417.58 m), with a large siderite concretion from 1370.0 to 1370.15 ft (417.58 to 417.62 m). From 1370.15 to 1379.5 ft (417.62 to 420.79 m), the cores are very dark gray to black and laminated, faintly micaceous silty clays. They are assigned to lower Turonian Subzone CC10b through Zone CC11 (see "Calcareous Nannofossils"), suggesting correlation to OAE2 (Fig. F8), though another organic-rich bed at 1395.5–1416.0 ft (425.35–431.06 m) could also be correlated to OAE2. There are several more siderite concretions in this interval. From 1372.4 to 1372.5 ft (418.31 to 418.34 m) is another bioturbated silt bed. Shells appear at ~1372 ft (~418.19 m), with scattered thin bivalve shells and shell fragments to 1379.5 ft (420.47 m). A very shelly silty clay with thick mollusk shells (vs. thinner shells above) occurs from 1379.5 to 1381.2 ft (420.47 to 420.99 m). The shell bed may represent lower shoreface environments, and the top of the shell bed (1379.5 ft; 420.47 m) may be a flooding surface equivalent to flooding Surface 3 of Sugarman et al. (1999). The base of the shell bed at 1381.2 ft (420.99 m) is an irregular surface that may be the base of a submarine channel.
From 1381.2 to 1386.9 ft (420.99 to 422.73 m) is a dark gray laminated to bioturbated clayey silt (Fig. F8) with interspersed wispy sands, shells, and shell fragments. The coarser material is more bioturbated (proximal prodelta) and the finer beds are more laminated (distal prodelta).
There is an indurated zone from 1386.9 to 1388.5 ft (422.73 to 423.21 m) consisting of a very shelly, slightly micaceous, very fine sandy siltstone with carbonate cement. Again, the shell bed may represent lower shoreface environments and the top of the shell bed (1386.5 ft; 422.61 m) may be a flooding surface (Fig. F8) equivalent to flooding Surface 2 of Sugarman et al. (1999).
From 1388.5 to 1394.6 ft (423.21 to 425.07 m) is a very dark gray, shelly, slightly clayey silt with scattered fine sand. There is a very fine sand from 1391.2 to 1391.3 ft (424.04 to 424.07 m). There are occasional cross laminations. There are 0.1-ft (3 cm) regular color cycles from 1394 to 1394.6 ft (424.89 to 425.07 m), with shell laminae and light gray clays that darken upward to very dark clays. The cycles appear to continue to 1388 ft (423.06 m), though the cycles are thicker and less distinct. Another indurated shelly (with thick shells) very fine sandstone with carbonate cement (1394.6–1395.5 ft; 425.07–425.35 m) may have a flooding surface at its top (Fig. F8) equivalent to flooding Surface 1 of Sugarman et al. (1999). We tentatively identify this as the MFS (Fig. F8) of the sequence from 1289 to 1418.95 ft (392.89 to 432.50 m).
Black to very dark gray to light gray color-banded, laminated, interbedded, clayey silt and silt (1395.5–1416.0 ft; 425.35–431.06 m) probably represents the highest organic matter associated with OAE2 (Fig. F8), though OAE2 could be at 1370.15–1379.5 ft (417.62–420.79 m), as noted above. Shells are rare except in distinct laminae. There are 0.1- to 1.3-ft-scale (3–40 cm) interbeds of light gray silts, medium gray silty clays, and dark gray-black clays. Very fine sands occur as silty, wispy laminae in the coarser beds. Bioturbation ranges from bioturbated in the coarser beds to laminated in clays.
There is a large indurated zone from 1416.0 to 1418.95 ft (431.60 to 432.50 m) consisting of a shelly, very slightly micaceous, glauconitic (as much as 10%?), burrowed, silty, very fine quartz sandstone. There is an irregular surface at 1418.95 ft (432.50 m) separating the sandstone from slightly micaceous sandy silt below. We place a major sequence boundary at the base of this indurated zone associated with a very large gamma ray log shift (Fig. F8). The sequence from 1289 to 1418.95 ft (392.89 to 432.50 m) spans the Cenomanian/Turonian boundary, is assigned to Subzone CC10b through Zone CC11 (see "Calcareous Nannofossils"), and correlates with the Bass River III sequence of Miller et al. (2004). In general, the section fines upward from the sequence boundary at 1418.95 ft (432.50 m) to ~1381 ft (420.93 m), with more wispy sands at the base and more clays above 1381 ft (420.93 m).
A coarsening-upward succession occurs between 1418.95 and 1430.5 ft (432.50 and 436.02 m). The section consists of (1) a micaceous, heavily burrowed, slightly lignitic, shelly, sandy, slightly clayey silt (1418.95–1421 ft; 432.50–433.12 m); (2) a very similar unit that is a slightly finer grained clayey silt (1421–1430 ft; 433.12–435.86 m); and (3) an organic-rich clay (1430–1430.5 ft; 433.86–436.02 m). These facies represent deposition on a storm-dominated shelf below mean wave base (inner neritic to middle neritic). A laminated shelly silt (1430.5–1431.4 ft; 436.02–436.29 m) overlies a calcarenite that consists of a calcareous, cemented, very shelly siltstone. There is distinct contact at 1432.1 ft (436.50 m), with interbedded to laminated clayey silts, sandy silts, and clays below (1432.1–1442 ft; 436.50–439.52 m). We favor interpreting the 1432.1 ft (436.50 m) contact as the MFS (Fig. F8) of a sequence that continues to 1457.7 ft (444.31 m). Alternatively, the contact could represent a sequence boundary with a MFS associated with the organic-rich clays (1430–1430.5 ft; 435.86–436.02 m). The interbedded clays and silts appear to represent prodelta environments, though mica is rare.
Prodelta laminated clays and silts interfinger with shelfal bioturbated shelly sandy silts from 1442 to 1445.5 ft (439.52 to 440.59 m). At 1445.5 ft (440.59 m) is a burrowed surface with glauconite in the burrows that separates shelf facies above from a prodelta sandy silt with wispy sand burrows below; therefore, the surface at 1445.5 ft (440.59 m) potentially could represent a MFS (Fig. F8). Micaceous silt with wispy sand laminae and disseminated lignite occurs from 1445.5 to 1456 ft (440.59 to 443.79 m). The silts vary from laminated to burrowed and generally lack shell material. We interpret these sediments as primarily prodelta environments with varying shelfal influence. Slight variations from gray to black may reflect varying amounts of organic material. The micaceous silts become very shelly with nested shells and shell fragments from 1456 to 1457.7 ft (443.79 to 444.31 m); the base of the section becomes clayier and sandier. The shelly zones represent reworking on a storm-dominated shelf. A contact at 1457.7 ft (444.31 m) occurs just above an interval of no recovery (1457.9–1460 ft; 444.37–445.01 m). Carbonate nodules, hematite staining, and a mixture of sand and gray clay clasts ripped up from below mark the contact that has been disturbed by drilling. This contact is interpreted as a sequence boundary (Fig. F8). The sequence from 1418.95 to 1457.7 ft (432.50 to 444.31 m) is assigned to middle Cenomanian Subzone CC10a and unzoned (see "Calcareous Nannofossils"). It could correlate with either the Bass River II (Subzones CC10a–CC10b) or Bass River I (Zone CC9 through Subzone CC10a) sequence at Ancora (Miller et al., 2004). Based on superposition, we favor correlation to the Bass River II sequence.
The section below the sequence boundary changes to clay, starting with slightly silty clay from 1460 to 1465.1 ft (445.11 to 446.56 m), with finely dispersed lignite and thin silt laminae. Rare scattered shell fragments occur from 1462 to 1465 ft (445.62 to 446.53 m). Two indurated beds or concretions occur at 1463.4–1463.55 ft (446.04–446.09 m) and 1464.9–1465.1 ft (446.50–446.56 m). The environment of deposition of the section from 1460 to 1470 ft was probably prodelta (Fig. F8).
Slightly micaceous, slightly silty clay occurs from 1470 to 1471 ft (448.06 to 448.35 m) below a coring gap (1465.1–1470 ft; 446.56–448.06 m). The section becomes sandier clay from 1471 to 1476.9 ft (448.36 to 450.16 m), with some variation in amount of bioturbation and preservation of laminae. Rare glauconite occurs at 1476 ft (449.88 m). A thin zone of very fine sand was recovered from 1476.9 to 1477.15 ft (450.16 to 450.24 m) above a 2.85 ft (87 cm) coring gap. The gamma ray log (Fig. F8) suggests the sand is ~3 ft (91 cm) thick. A similar sand occurs from 1480 to 1480.15 ft (451.10 to 451.15 m). This section, from 1470 to 1480.15 ft (448.06 to 451.15 m), was deposited in delta front (sandier, more bioturbated) to prodelta (finer grained, more laminated) environments.
At 1480.15 ft (451.15 m), a silt-dominated section begins that is characterized by a banded appearance and dark colors suggestive of high organic content. An interval of very organic rich sediments (1482.4–1484.4 ft; 451.84–452.45 m) reaches a peak in organic content at 1482.6–1483.2 ft (451.90–452.08 m). Organic-rich sediments (1484.4–1491.6 ft; 452.45–454.64 m) have a transition to organic-poor sediments (1491.6–1494.95 ft; 454.64–455.66 m) overlying a probable sequence boundary at 1494.95 ft (455.66 m). The environment of these organic-rich beds is prodelta. Distinct banding of darker and lighter layers in organic-rich sediment may contain a Milankovitch cyclicity. This succession of organic-rich sediments at Sea Girt lies in an undated sequence (1457.7–1494.95 ft; 444.31–455.66); the overlying sequence is dated at middle Cenomanian Subzone CC10a (Fig. F8). Thus, the sequence from 1457.7 to 1494.95 ft (444.31–455.66 m) clearly predates global OAE2 (the Bonarelli bed, spanning Subzone CC10b through Zone CC11). Based on superposition and assignment of the overlying sequence to Subzone CC10b, we correlate the sequence from 1457.7 to 1494.95 ft (444.31 to 455.66 m) to the Bass River I sequence of Miller et al. (2004).
The Bass River Formation at Sea Girt generally lacks the common chlorite typical of the formation to the south at Bass River and Ancora (Miller et al., 2004, and references therein). The micas are dominated by muscovite, with rare chlorite. Nevertheless, the marine clayey silts, silty clays, and occasional sands from 1290.7 to 1494.95 ft (393.41 to 455.66 m) are clearly assigned to the Bass River Formation (Fig. F8). Assignment of the section below to either the Bass River Formation or the Potomac Formation is uncertain.
A sequence boundary at 1494.95 ft (455.66 m) consists of a shift from fine-grained sediments to "sugar" sands below (Fig. F8). Very slightly silty fine–very fine sands with abundant mica and occasional lignite cross-laminae continue downward from the sequence boundary to 1505.45 ft (458.86 m), where there is a cemented zone/concretion. The sands represent delta front environments. Below this, a clayey, slightly micaceous bioturbated silt (1505.65–1507.5 ft; 458.92–459.49 m) and very slightly micaceous clay continue to 1520.2 ft (463.36 m), though recovery is poor. The silts represent prodelta environments. A probable sequence boundary was recovered at 1520.2 ft (463.36 m), separating clay with sand burrows above from sands below. The sequence from 1494.95 to 1520.2 ft (455.66 to 463.36 m) has a distinct blocky gamma ray log signature (Fig. F8) more typical of the Potomac Formation. However, the upsection change from lower HST prodelta silts to upper HST delta front sands is typical of Upper Cretaceous marginal marine to marine sequences and is not typical of the Potomac Formation. We tentatively term the sequence from 1494.95 to 1520.2 ft (455.66 to 463.36 m) the Bass River 0.5/Potomac IIIc sequence and correlate it with the upper Potomac sequence at Ancora that was assigned to the pollen Zone III/IV transition (Miller, Sugarman, Browning, et al., 1998). This section at Sea Girt is assigned to pollen Zone III (see "Pollen"), which suggests correlation to the Potomac Formation.
Fine, micaceous, lignitic, cross-bedded to bioturbated sands (1520.2–1534.2 ft; 463.36–467.62 m) occur below the 1520.2 ft (463.36 m) sequence boundary (Fig. F8). The sands contain lignite laminae, scattered clay drapes, and large micas and are thickly (1.5 ft; 46 cm) to thinly (0.1 ft; 3 cm) bedded. The section from 1522 to 1525 ft (463.91 to 464.82 m) is heavily bioturbated. The sands could be interpreted as representing nearshore/delta front or lower delta plain environments. We favor the latter based on the upsection change from lower delta plain clays and sands below. The sands are bracketed by pollen Zone III (see "Pollen") and comprise the upper HST of the 1520.2–1563.0 ft (463.36–476.40 m) sequence (Fig. F8).
Micaceous to very micaceous clays with subordinate interbedded very fine sands occur from 1534.5 to 1556.4 ft (467.72 to 474.39 m). This unit contains common leaf fossils (1543.5–1543.8 ft; 470.46–470.55 m), is bioturbated (e.g., 1550–1551 ft; 472.44–472.74 m) to very finely laminated (1551–1552 ft; 472.74–473.05 m), and contains common plant debris (1554–1556 ft; 473.66–474.27 m). There is an uncored interval between 1556.4 and 1560 ft (474.39 and 475.49 m). Below this, a lignitic to very lignitic silty clay (1560–1563.0 ft; 475.49–476.40 m) appears to be an oxbow lake deposit. The sandy clays were probably deposited in lower delta plain environments, with oxbow and interfluvial marsh subenvironments. They comprise the lower HST of the 1520.2–1563.0 ft (463.36–476.40 m) sequence.
There is a contact at 1563.0 ft (476.40 m), with very lignitic clay above and lignitic fine sand below; the sands contain sphaerosiderite from 1564.0 to 1564.3 ft (476.71 to 476.80 m). We place the top of the definite Potomac Formation at the top of the sphaerosiderite-bearing sands (Fig. F8). The correlation of the sequence from 1520.2 to 1563.0 ft (463.36 to 476.40 m) is unclear, though it may correlate with the section below 1145/1158.2 ft (349.00/353.02 m) at Ancora (pollen Zone III/IV transition; Miller et al., 2004). We tentatively name this sequence the Bass River 0/Potomac IIIb sequence.
Fine sugar sand (1563.0–1564.9 ft; 476.40–476.98 m) with sphaerosiderite beginning at 1564 ft (476.71 m) overlies a white, kaolinitic hard clay (1564.9–1565.4 ft; 476.98–477.13 m). The white clay shows red mottles below 1568.5 ft (478.08 m) typical of the nonmarine Potomac Formation (Fig. F8). Silty clay with sphaerosiderite (1571.9–1578.7 ft; 479.12–481.19 m) overlies mottled red and white clayey silt to silty clay (1578.7–1596.0 ft; 481.19–486.46 m) with sphaerosiderite and obvious root casts. A silty fine sand (1596.0–1596.5 ft; 486.46–486.51 m) overlies a dark gray, silty clay with thin lignite stringers at the base of the hole (1596.5–1598.1 ft; 486.51–487.10 m); these sediments appear to be lacustrine/oxbow lake (Fig. F8). The transition from more organic rich to less organic rich clays to sand represents a drying out of the lake.
The mottled clays are typical of the overbank/interfluvial deposits of the Potomac Formation and correlate with Potomac Unit 3 (as indicated by pollen Zone III). Thus, drilling the Sea Girt corehole reached one prime objective in penetrating the marine Bass River Formation and the marginal marine uppermost Potomac Formation to the terrestrial Potomac Formation.