The on-site 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). Subsequent studies integrated preliminary descriptions with additional descriptions, biostratigraphy, biofacies studies, isotopic stratigraphy, and the downhole gamma log. Unconformities were identified on the basis of physical stratigraphy, including irregular contacts, reworking, bioturbation, major facies changes, and gamma ray peaks. Paraconformities were inferred from biostratigraphic breaks. Core photographs (see the "Appendix") illustrate sequence bounding unconformities and facies variations within sequences.
For the nonmarine and nearshore sections, lithofacies interpretations provide the primary means of recognizing unconformities and interpreting paleoenvironments and systems tracts. For the neritic sections, biostratigraphic studies and Sr isotopes provide an additional means of recognizing unconformities and interpreting paleoenvironments and systems tracts.
Cumulative percent plots of the sediments in the cores were computed from washed samples. 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.
Facies changes within onshore sequences generally follow repetitive transgressive–regressive patterns (Sugarman et al., 1993, 1995) that consist of
LSTs are usually absent in the coastal plain and the TSTs are generally thin. Because the TSTs are thin, MFSs are difficult to differentiate from unconformities. Shell beds and gamma ray peaks can mark both TSTs and MFSs. Flooding surfaces, particularly MFSs, may be differentiated from sequence boundaries by the association of erosion and rip-up clasts at the latter, lithofacies successions, and benthic foraminiferal changes. The transgressive surface, marking the top of the LST, represents a change from regressive to transgressive facies. Because LSTs are generally absent, these surfaces are generally merged with the sequence boundaries. Where present, LSTs are recognized as thin, regressive, fluvial-estuarine sediments underlying TSTs and overlying sequence-bounding unconformities.
The gravel and sand of the Cape May Formation at Cape May Zoo (Fig. F2) form a modern terrace that has been correlated with MIC 5 (Ashley et al., 1991). Our preliminary interpretation is consistent with an upper sequence correlated with the Cape May Formation Unit II of Newell et al. (2000) and a lower sequence correlated with the Cape May Formation Unit III of Newell et al. (2000). Alternatively, it is possible that there are three Cape May sequences at Cape May Zoo and that the uppermost sequence is the Cape May Formation Unit I sequence of Newell et al. (2000) and not the Cape May Formation Unit II.
The upper 20.5 ft (6.3 m) at Cape May Zoo consists of sand and thinner beds (<0.7 ft; 0.2 m) of well-rounded pebbly gravel (Fig. F2). The sand is mostly yellowish and grayish brown well-sorted quartz with occasional very dark opaque heavy mineral (OHM) laminae (1–3 mm), though there are also faintly bioturbated intervals within the laminated beds. OHM concentrations are 3%–5%. The sand is medium to coarse to 11 ft and predominantly fine–very fine from 11 to 20.5 ft (3.4 to 6.2 m). Gravel layers occur at 0–1.2, 4.0–4.3, 4.6–4.7, 7.0–7.7, 8.1–8.3, and 15.6–16.1 ft (0–0.4, 1.2–1.3, 1.4–1.43, 2.1–2.3, 2.47–2.53, and 4.75–4.91 m). The gravel beds consist primarily of rounded to subrounded quartz pebbles (typically 3 mm, but up to 13 mm) in a coarse sand matrix. At Ocean View, Miller et al. (this volume) interpreted similar facies as reworked fluvial sediments deposited in a nearshore environment (foreshore at top, upper shoreface below 11 ft [93.35 m]), an interpretation followed here.
A facies change occurs in an unrecovered interval between 20.5 and 21 ft (6.25 and 6.40 m), associated with a gamma log increase, and an iron-stained interval of brown clay and sandy pebbles below. The clay is weathered, possibly because of subaerial exposure. A gamma log kick occurs at this level in the nearby Cape May Court House New Jersey Water Company Well 8, though the kick is less pronounced on the Cape May Zoo gamma log (Fig. F2).
Yellow-brown sand and gravel are found from 21 to 24.3 ft (6.40 to 7.41 m) with clay rip-up clasts and clay laminae. The succession from 21 to 24.3 ft (6.40 to 7.41 m) shows abrupt changes from clay to gravel, suggesting rapid changes in flow regime, and we interpret them as deposition in a tidal channel (Carter, 1978). There is a coring gap from 24.3 to 27 ft (7.41 to 8.23 m). From 27 to 29 ft (8.23 to 8.84 m), the gravel is finer grained, with opaque heavy mineral laminations and hints of bioturbation; these are nearshore (probably shoreface) sediments. A coring gap from 29 to 35 ft (8.84 to 10.67 m) is underlain by coarse to very coarse sand with some granules and pebbles (35–36.8 ft; 10.67–11.22 m) and very fine silty sand with opaque heavy minerals (36.8–37 ft; 11.22–11.28 m), which are interpreted as foreshore deposits (Fig. F2). We term this sequence the Cm2. No datable material was found in Sequence Cm2 at this site, though it is constrained as younger than the underlying sequence (300–400 k.y.).
We tentatively place a sequence boundary between Sequences Cm2 and Cm1 at 37 ft (11.28 m), although the interval between 37 and 41 ft (11.28 and 12.50 m) was not recovered (Fig. F2). The contact is placed primarily to reflect the transition from barrier beach–type facies above (Sequence Cm2) to nearshore facies below (Sequence Cm1). Slightly micaceous fine sand (41–41.6 ft; 12.50–12.68 m), medium sand (41.6–42.6 ft; 12.68–12.98 m), fining-upward shelly sand (42.6–45 ft; 12.98–13.72 m), and slightly bioturbated micaceous fine–medium shelly quartz sand (48–52.6 ft; 14.63–16.03 m) occur in this unit. The sediments become bioturbated below 36 ft (10.97 m), and shell fragments appear below 44 ft (13.41 m). We interpret that these sediments were deposited in nearshore environments. A gamma log kick at 42.5 ft (12.95 m) is associated with a minor change to siltier sand below 42.7 ft (13.01 m). There is no major facies change in the core at this level.
There is a contact at 52.6 ft (16.03 m) with yellow micaceous laminated shelly sand above and gray clayey silty fine to very fine micaceous sand with common shell fragments below (Fig. F2). This contact could be interpreted as a sequence boundary and the sequence from 37 to 52.6 ft (11.28 to 16.03 m) could be correlated to the Cape May Formation Unit II of Newell et al. (2000). It is more likely, however, that the section from 37 to 93.8 ft (11.28 to 28.59 m) represents one sequence, as indicated by the general coarsening upward from ~63 to 37 ft (19.2 to 11.3 m), the lack of a major log kick associated with the surface, and the relative uniformity of facies.
Medium cross-laminated sand with wood and shell fragments (55–62.6 ft; 16.76–19.08 m) overlies micaceous woody silty clay to silt with clay and sand laminae (62.6–66.5 ft; 19.08–20.27 m). Very fine shelly sand, micaceous silty clay, and sandy silty clay are interbedded to ~78 ft (23.77 m), where the section becomes predominantly clay (Fig. F2). The presence of shells throughout this interval indicates that it is shallow marine. The presence of an Elphidium biofacies (61–81.9 ft; 18.59–24.96 m) indicates bay/lagoon to inner shelf environments. The interval from 77 to 79 ft (23.47 to 24.08 m) is very shelly (Fig. F3). The section from 78 to 92.6 ft (23.77 to 28.22 m) is clay, the upper part of which is laminated and contains lignite. The clay becomes massive and blue from 85 to 92.6 ft (25.91 to 28.22 m) and contains common disseminated lignite. This is probably an estuarine or bay deposit.
A dramatic pebble contact (Fig. F3) with an abrupt change back to sand below at 93.6 ft (28.53 m) is associated with a gamma log increase at 94 ft (28.65 m). We place the base of the Cape May Formation at 93.6 ft (28.53 m). Six Sr isotopic ages averaging 0.4 Ma favor an age correlation of this sequence with MIC 9 or 11. This is also supported by amino acid racemization analyses of shells at 44.8 and 77.0 ft (13.66 and 23.47 m) that yield ages of 300–400 ka (middle Pleistocene; see "Amino Acid Racemization Stratigraphy").
Beneath the 93.6-ft (28.53 m) pebble contact, greenish gray, coarse to very coarse, poorly sorted pebbly sand generally coarsens downsection to 113.2 ft (34.50 m) (Fig. F4). There are several fining-upward channels with bases at 105.8, 106.6, and 107.5 ft (32.25, 32.49, and 32.77 m). Pebbles are as large as 1.5 cm in diameter and OHM and rock fragments are common (to 5%). The section was deposited in fluvial environments, probably in upper estuarine subenvironments (e.g., paleo-Delaware Bay) (Fig. F4).
A large coring gap (113.2–125 ft; 34.50–38.10 m) apparently missed coarser grained sediment (e.g., sand and gravel), as interpreted from gamma and resistivity logs. There is a facies shift below the gap (125–129.4 ft; 38.10–39.44 m) to yellow to gray medium–coarse silty quartz sand with clay drapes (noted at 126.2–126.3; 127.5–127.7; 128.6–128.7, and 129.0–129.4 ft [38.47–38.50, 38.86–38.92, 39.20–39.23, and 39.32–39.44 m]). Compared to the sand above, this sand is better sorted, has fewer OHM (1%–2%), no lithic fragments, and is bioturbated. These facies probably represent beach environments and are similar in aspect to the Cohansey Formation, although fluvial-dominated upper estuarine facies are also possible.
From 130.0 to 133.0 ft (39.62 to 40.54 m) is a generally fining-downward succession from bioturbated, silty, slightly micaceous fine–medium sand to clayey silty sand. Interbedded sandy silt and organic-rich brown clay are common from 133.0 to 136.0 ft (40.54 to 41.45 m). The section is bioturbated with sand-filled burrows as large as 8 mm in diameter. These facies were deposited in back-barrier lagoonal environments. A micaceous, organic-rich clay occurs at 136.0–136.8 ft (41.45–41.70 m), with a lignite bed from 136.8 to 139.2 ft (41.70 to 42.43 m). This may be a fringing marsh deposit.
From 139.2 to 143 ft (42.43 to 43.59 m), the sequence is homogenized, fine–medium quartz sand with scattered common chunks of lignite as large as 2 cm in diameter. Below a coring gap, (143.0–150.0 ft; 43.59–45.72 m) there is an interbedded fine–medium slightly silty sand (with beds ~13 mm thick) and a bioturbated clayey medium sand (beds of 34 mm). Clayey sand (150.95–151.4 ft; 46.01–46.15 m) overlies clay (151.4–151.5 ft; 46.15–46.18 m) with lignite laminae. Lignitic sand returns from 151.5 to 157.4 ft (46.18 to 47.98 m) and 158.0 to 160 ft (48.16 to 48.77 m), and interbedded, highly bioturbated sand and clayey sand return from 157.4 to 158.0 ft (47.98 to 48.16 m). A sticky, greenish gray sandy clay occurs from 160.0 to 160.6 ft (48.77 to 48.95 m). These facies represent a continuation of lagoonal back-barrier environments.
There is a facies change to a foreshore environment from 160.6 to 168.0 ft (48.95 to 51.21 m). There is cross-laminated, medium–coarse quartz sand with OHM and scattered granules and pebbles from 160.6 to 166.6 ft (48.95 to 50.78 m). Sand from 168.0 to 170.0 ft (51.21 to 51.82 m) is coarser, consisting of coarse sand with abundant granules and small pebbles. From 170 to 171.3 ft (51.82 to 52.21 m) is granuliferous coarse sand with abundant lignite in layers (e.g., 171.1–171.3 ft; 52.15–52.21 m) and scattered chunks. These deposits might represent tidal channel and fringing marsh environments.
There is a change in compaction and core competence at 175 ft (53.34 m) and 185 ft (56.39 m) between two coring gaps (171.4–175 and 180.4–185 ft; 52.24–53.34 and 54.99–56.39 m), both associated with large gamma log increases. The core from 175.0 to 176.5 ft (53.34 to 53.80 m) is interbedded medium sand and clayey sand deposited in upper to lower shoreface environments, whereas 176.5–180.4 ft (53.80–54.99 m) consists of medium–coarse quartz sand with rare OHM laminations deposited in foreshore environments. A sequence boundary is tentatively placed at 180.4 ft (54.99 m) at the top of the coring gap (180.4–185 ft; 54.99–56.39 m) and the top of the large gamma ray increase. It is possible that the sequence boundary could also be placed in the interval of no core recovery at the base of the gamma log increase at ~183 ft (55.78 m). The sequence boundary is also inferred from the transition from shoreface-dominated deposits above to lower estuarine deposits below.
The formational assignment of lignitic, occasionally pebbly, primarily gray sand found from 93.6 to 180.4 ft (28.53 to 54.99 m) at the Cape May Zoo corehole is uncertain (Fig. F4). It might be the equivalent to the ?Cohansey (107.5–166.7 ft; 32.77–50.81 m) and Cohansey Formation (166.7–220.55 ft; 50.81–67.22 m) at Ocean View, the unnamed estuarine clay unit at Cape May (140–357 ft; 42.67–108.81 m), or the "unnamed unit beneath Cape May Peninsula" of Newell et al. (2000). The sand lacks the distinct yellow color, except for an interval at 125 ft (38.10 m) of the Cohansey Formation, though it may be an equivalent, as shown by Newell et al. (2000). The unnamed estuarine clay unit at the Cape May borehole contained dinocysts assigned to lower upper Miocene Zone DN8? (de Verteuil, 1997). We name this unit the Stone Harbor Formation (see the "Appendix") and assign it to Sequence Ch4 of de Verteuil (1997).
Below an interval of no recovery (180.4–185 ft; 54.99–56.39 m), uniform, heavily bioturbated, lignitic sandy clay occurs from 185 to 201.3 ft (56.39 to 61.36 m) (Fig. F4). The clay is blue to greenish gray on fresh exposure and weathers to grayish white. The clay from 187 to 188 ft (57.00 to 57.30 m) is oxidized red. Sands are generally fine grained and restricted to the burrows except for beds at 198.6–198.7, 198.9–199.0, and 200.6–200.7 ft (60.53–60.56, 60.62–60.66, and 61.14–61.17 m), the latter with a sharp base. Lignite is particularly common from 200.0 to 200.6 ft (60.96 to 61.14 m). There is a change to coarse, poorly sorted, granuliferous sand with clay rip-up clasts (200.6–205.75 ft; 61.14–62.71 m). A lignitic, burrowed, fine–medium quartz sand occurs from 205.75 to 210.4 ft (62.72 to 64.13 m), with an interbed of lignitic, slightly sandy clay (208–208.5 ft; 63.40–63.55 m). The juxtaposition of high- and low- energy environments suggests that this section was deposited in lower estuarine environments (Fig. F5).
Sand from 210.4 to 220.9 ft (64.13 to 67.33 m) is coarse to very coarse, with beds of granules and fine pebbles. The sand is arranged in distinct fining-upward channel deposits with bases at 215.2 and 220.9 ft (65.59 and 67.33 m). These facies appear to be more fluvially influenced and are interpreted as upper estuarine. From 220.9 to 230.2 ft (67.33 to 70.16 m) is lignitic medium–coarse sand that is highly bioturbated and interpreted as lower estuarine. A woody, interbedded fine–medium quartz sand and clay (230.2–230.8 ft; 70.16–70.35 m) with a thin gravel laminae (230.2 ft; 70.16 m) overlies a sandy, slightly micaceous laminated clay (230.8–231.4 ft; 70.35–70.53). This section was deposited in a lower estuarine environment. The base of the clay is irregular and associated with a sharp gamma log increase (Figs. F4, F5), interpreted as a sequence boundary between Sequence ?Ch3 above and the Kirkwood-Cohansey sequence (Ch2) below. We also place this sequence in the Stone Harbor Formation. There were no definitive dates derived from material contained within this sequence. At 205 ft (62.48 m), abundant nonmarine palynomorphs are dominated by oak and are clearly pre-Quaternary based on the presence of Pterocarya. The sample from 205 ft (62.48 m) is similar to upper Miocene samples from the Scotian Shelf (see "Palynomorphs and Dinocysts").
Below the sequence boundary (Fig. F6), clean medium–coarse sand (231.4–248.7 ft; 70.53–75.80 m) is heavily bioturbated, has few opaque minerals, and is interpreted as a distal upper shoreface deposit influenced by a delta. A gravel layer (with pebbles as large as 1.5 cm) is present at 231.8 ft (70.65 m). Dark laminations appear at 241.5 ft (73.61 m), with the section fining and becoming progressively more organic rich to 248.6 ft (75.77 m). Interbedded silty fine to medium sand with thin clay beds (250–261.2 ft; 76.20–79.61 m) was deposited as a lower shoreface deposit influenced by a delta. A sample from 261 ft (79.55 m) is assigned at a minimum to Zone DN9 (>7.4 Ma) of de Verteuil (1997) and could be older.
The base of the Cohansey Formation is defined here at the base of the sand that dominates the corehole above 261.2 ft (89.40 m). The laminated prodelta clay below 261.2 ft (89.40 m) is more typical of the Kirkwood Formation. The formational boundary is uncertain here and at the nearby Ocean View corehole because it is often difficult to place (see the "Appendix"). The sand from 231.4 to 261.2 ft (70.53 to 79.61 m) at Cape May Zoo could be placed in the Kirkwood Formation based on color (gray-green vs. yellow typical of the Cohansey); however, the sand is relatively coarse grained and more typical of the Cohansey Formation. Correlations with Ocean View (Miller et al., this volume) suggest that the equivalent unit at ~220–245 ft (67.06–74.68 m) correlates lithologically and in sequences with this unit at Cape May Zoo. This sequence spans the Cohansey/Kirkwood Formation contact.
Sequence Kw-Ch2 spans the Cohansey/Kirkwood Formational boundary at the Cape May Zoo corehole. Laminated, slightly micaceous, slightly silty clay with common sulfur is present from 261.2 to 283.5 ft (79.61 to 86.41 m). Cross laminations are present from 271.1 to 272 ft (82.63 to 82.91 m). These sediments were deposited in prodelta environments (Fig. F7). Laminated to interbedded shelly sand and clayey silt is found from 283.5 to 293.3 ft (86.41 to 89.09 m). The sand is cross-bedded to highly bioturbated. Shells first appear at 285.5 ft (87.02 m). The section from 283.5 to 293.3 ft (86.41 to 89.09 m) appears to be an offshore shelf deposit with intermittent prodelta influences. Sr isotope age estimates of 12.0 and 12.1 Ma were obtained from shell fragments at 285.5 and 292.9 ft (87.02 and 89.28 m). A contact at 293.3 ft (89.40 m) is a sequence boundary separating Sequence Kw-Ch2 (~12 Ma) above from Sequence Kw-Ch1 (13.1–13.7 Ma) below. The Kw-Ch2 sequence is a classic transgressive-regressive coarsening-upward sequence at this site. It is unclear how the Kirkwood-Cohansey sequences relate to the Ch sequences of de Verteuil (1997), though age relationships suggests that Sequence Kw-Ch2 is equivalent to Sequence Ch2 and Sequence Kw-Ch1 is equivalent to Sequence Ch1.
A sharp facies contact at 293.3 ft (89.40 m) is associated with a gamma log kick that is a sequence boundary (Fig. F6). From 293.3 to 304.0 ft (89.40 to 92.66 m), the section is cross-bedded to laminated, fine–very fine, silty, slightly micaceous quartz sand with silt and clay laminae and beds. Bedding in this section is highly variable:
• 293.3–296 ft (89.40–90.22 m): heavily bioturbated,The section appears to be distinctly shallower and with higher energy than the shelf-prodelta sections above, and we interpret it as delta front.
Below a coring gap (304–310 ft; 92.66–94.49 m), slightly micaceous sandy silty clay with rare shells continues across a coring gap (314.5–320.0 ft; 95.86–97.54 m) to 323.7 ft (98.66 m). The section from 310 to 314 ft (94.49 to 95.71 m) represents a downhole transition from delta front (interbedded and highly variable, as shown on logs) to prodelta (more laminated and more consistent lithology) environments that continue to 323.7 ft (98.66 m). From 323.7 to 324.6 ft (98.66 to 98.94 m) is a very shelly, slightly micaceous, silty clayey sand with medium to fine sand laminae deposited in offshore environments. A contact associated with a gamma log kick was lost between shelly sandy clayey silt at 324.6 ft (98.94 m) and medium sand at 325.5 ft (99.21 m) deposited in proximal lower shoreface environments.
Sequence Kw-Ch1 at Cape May Zoo (293.3–325 ft; 89.40–99.06 m) has Sr isotope age estimates of 13.1 (311.7 ft; 95.01 m), 12.7 (323.7 ft, 98.66 m), and 13.7 Ma (324.4 ft [98.88 m]; just above the sequence boundary) and diatoms assigned to ECDZ 7 of Andrews (1988). These indicate a middle Miocene age for Sequence Kw-Ch1 with a best estimate of 13.2–13.6 Ma. This is comparable in age to the Ch1 sequence of de Verteuil (1997).
Sequence Kw3 has a moderately thick TST (9.7 ft; 2.96 m) and a very thick HST (72 ft; 24.69 m) punctuated by at least two FSs at 352.8 and 368.5 ft (107.53 and 112.32 m). Sr isotope ages and diatom zonations both suggest that the thick succession from 325 to 415.7 ft (99.06 to 126.71 m) is one sequence. Gamma log kicks and surfaces at 352.8 and 368.5 ft (107.53 and 112.32 m) are quite dramatic, and we initially interpreted them as sequence boundaries; however, further examination of facies successions, Sr isotopes, and diatoms suggest that these surfaces are FSs.
Below the contact at 324.6/325.5 ft (98.94/99.21 m), burrowed, silty fine sand with traces of mica, wood, and shell was recovered from 325.5 to 332.7 ft (99.21 to 101.41 m) (Fig. F8). Faint bedding laminae are preserved despite the extensive bioturbation. This sand is a distal upper to lower shoreface deposit and represents the upper part of an HST.
An abrupt facies change occurs at 332.7 ft (101.41 m), with the section fining downward to sandy silt to 334 ft (101.80 m) and clayey silt to 352.8 ft (107.53 m). Common shells appear at 340 ft (103.63 m) with a very abundant shell layer at 351–351.7 ft (106.98–107.20 m). From 351.7 to 352.8 ft (107.20 to 107.53 m) is shelly clayey silt deposited in a lower shoreface environment (Fig. F9). A FS is placed at 352.8 ft (107.53 m), marked by a sharp contact between shelly clayey silt above to sand below (Fig. F8). Silt is burrowed to ~0.5 ft (0.15 m) below the contact.
Below a coring gap (353.4–355 ft; 107.72–108.20 m), the section is bioturbated silty, very slightly micaceous, slightly shelly fine sand (355–360 ft; 108.20–109.73 m) with 2%–3% glauconite that weathers with a yellow sulfur-rich rind. This is a distal upper shoreface deposit. The section fines downward to bioturbated, very slightly micaceous, slightly shelly sandy silt (360–368.6 ft; 109.73–112.35 m) deposited in lower shoreface environments (Fig. F9). Large, whole shells occur at 363.1 and 364.0 ft (110.67 and 110.95 m). A contact at 368.5 ft (112.35 m) has blebs of darker brown sandy silt from above with gray clayey silt below (Fig. F9). The two lithologies are burrowed and ripped into each other over 0.5 ft (0.15 m). This contact (368.5 ft; 112.35 m) is also interpreted as an FS.
Below the contact, gray clayey silt (369–370.2 ft; 112.47–112.84 m) with common sulfur was deposited in an offshore environment. Tight clay from 370.2 to 371.1 ft (112.84 to 113.11 m) yields a distinct gamma log kick. This clay overlies a bioturbated, shelly, slightly silty clay (371.1–400 ft; 113.11–121.92 m) also deposited in offshore environments. Shells become more common toward the bottom of this section. The section from 369 to 404 ft (112.84 to 123.14 m) is an excellent confining bed. From 404 to 406 ft (123.14 to 123.75 m) is fine–medium sand deposited in lower shoreface environments. From 406 to 412 ft (123.75 to 125.58 m) is a heavily bioturbated, slightly silty fine–medium sand with scattered shell fragments and numerous granules deposited in lower shoreface environments, which fines upward, suggesting transgression. Phosphate pellets from 408.6 to 412 ft (124.54 to 125.58 m) yield a hot zone on the gamma ray log for the sand and may be reworked from the sequence boundary (Fig. F8). Muddy fine–medium sand (412–414.5 ft; 125.58–126.34 m) is also a lower shoreface deposit, though mud in this section may be intruded drilling mud. An indurated calcite-cemented sandstone (414.5–415.7 ft; 126.34–126.71 m) marks a sequence boundary that separates Sequences Kw3 and Kw2b (Fig. F8). The sand at the base of the sequence (406–414.5 ft; 123.75–126.34) represents the TST, though it may be possible to place the sequence boundary at 412 ft (125.58 m) at the base of the phosphate pebbles, with the section from 412 to 414.5 ft (125.58 to 126.34 m) obscured by drilling slurry.
Drilling the thick (100 ft; 30.48 m) Kw2b sequence recovered a thin LST, a thin TST, and a thick HST punctuated by at least one FS (438.5 ft; 133.65 m). Facies within this sequence are more complex than typical New Jersey sequences, though both Sr isotopes and diatoms indicate that the succession is one sequence.
Below a coring gap (415.7–420 ft; 126.71–128.02 m), silty fine–medium sand (420.0–438.5 ft; 128.02–133.65 m) was deposited in wave-dominated shoreface environments (Fig. F10). From 420.0 to 422.2 ft (128.02 to 128.68 m) is a massive, slightly micaceous, silty fine–medium sand that weathers brown as a result of iron staining, particularly within burrows. A surface at 422.2 ft (128.69 m) separates laminated to thin bedded slightly micaceous fine sand (422.2–424.0 ft; 128.69–129.24 m) with silty interbeds that yields a distinct gamma log high. We interpret both sections as distal upper shoreface deposits. Below a coring gap (424.0–430.0 ft; 129.24–131.06 m) is heavily bioturbated, shelly, slightly micaceous, slightly silty fine–medium sand (430.0–438.5 ft; 131.06–133.65 m) that coarsens downward to medium sand. These sands were deposited in lower shoreface environments and are probably equivalent to the Rio Grande water-bearing zone at the Cape May corehole based on Sr isotope age correlations.
A calcareous, clayey, slightly glauconitic, fine–medium sandstone with less indurated zones is present from 438.5 to 442.9 ft (133.65 to 135.00 m). This indurated interval is a similar facies to the lower shoreface sand above and is interpreted as an FS (Fig. F10). It lies atop a bioturbated, muddy, very shelly fine–medium sand (442.9–474.9 ft; 135.00–144.75 m) that shows a slight fining at the top. Phosphorites, glauconite sand, and lithic fragments, including a glauconitic clay ~1 cm thick, are present. There is a shell hash from 474.9 to 476.0 ft (144.75 to 145.08 m). This sand from 442.9 to 476.0 ft (135.00 to 145.08 m) is interpreted as upper shoreface with slight deepening at the top. The interval from 476.0 to 479.2 ft (145.08 to 146.06 m) is an interval of reworking, with organic-rich clays at 476.0–476.4, 476.8–477.0, 477.9–478.0, 478.5–478.7, and 478.9–479.05 ft (145.08–145.21, 145.33–145.39, 145.66–145.69, 145.85–145.91, and 145.97–146.01 m). Only the top and bottom clays cut across the core, whereas the other clays are clearly ripped up from below.
A distinct contact at 479.2 ft (146.06 m) (Fig. F11) separating the shelly muddy sand above from organic-rich laminated mud below is interpreted as an FS or autocyclic change in depositional environments from delta front to upper shoreface sand. Below this FS is muddy cross-bedded sand with interbedded clean sand, lignite clay, and silty brown organic-rich clay (479.2–483.7 ft; 146.06–147.43 m). These sediments become progressively finer from 483.7 to 493.7 ft (147.43 to 150.48 m), with predominantly laminated organic-rich clay with thin sand laminae and scattered thin (0.1–0.4 ft; 3–12 cm) sand beds. The section from 479.2 to 483.7 ft (146.06 to 147.43 m) represents delta-front deposition in one of several subenvironments (distributary channels, bays/lagoons, and marshes). The sediments from 483.7 to 493.7 ft (147.43 to 150.48 m) were deposited in prodelta environments (Fig. F11). There is a facies shift at 493.7 ft (150.48 m) to burrowed sand without shells deposited in indeterminate shoreface environments. A coring gap from 494.0 to 500.0 ft (150.57 to 152.40 m) is associated with another facies shift.
Thin transgressive and ?lowstand systems tracts are present below the coring gap. Slightly clayey silt (500–510.4 ft; 152.40–155.57 m) with shell fragments are present below the gap and continues to a sequence boundary at 515.7 ft (157.19 m). The silt from 500 to 510.4 ft (152.40 to 155.57 m) represents offshore environments (Fig. F10). Within this fairly uniform facies is slightly clayey silt (506.0–506.6 ft; 154.23–154.41 m) and an irregular contact (506.6 ft; 154.41 m). It might be possible to place a sequence boundary at the irregular contact in association with a major gamma ray log increase. Facies successions are not consistent with this placement as a sequence boundary but are consistent as a transgressive surface. Below the contact is a fine to very fine, laminated to bioturbated fine–very fine sand (506.6–507.0 ft; 154.41–154.53 m), a clay bed (506.9–506.95 ft; 154.50–154.52 m), and a clayey, sandy silt (507.0–507.35 ft; 154.53–154.64 m) that weathers to brownish gray. Medium–coarse, bioturbated, granuliferous shelly muddy sand is present from 510.4 to 515.7 ft (155.57 to 157.19 m), deposited in proximal upper shoreface environments. The section may, therefore, be a regressive lowstand deposit from 510.4 to 515.7 ft (155.57 to 1557.19 m). The interval from 515.1 to 515.7 ft (157.00 to 157.19 m) has sand and laminated clay that have been ripped up from below. This contact is interpreted as a sequence boundary separating Sequences Kw2b and Kw2a. The Kw2b sequence is correlative with ECDZ 3–4 at this site and has Sr isotope age estimates between 16.2 and 15.6 Ma.
The thick (115 ft; 35.05 m) Sequence Kw2a may be divided into three higher order sequences (Kw2a1, Kw2a2, and Kw2a3) as noted at Ocean View (Miller et al., this volume). Both Sr isotopes and diatoms indicate a break between Sequence Kw2b (ECDZ 3–4) above and Sequence Kw2a below (ECDZ 2; 17.8–16.9 Ma).
A change from silt and sand above to micaceous, organic-rich laminated clay to thin bedded silty clay with occasional fine sand beds and shell fragments (515.7–527.2 ft; 157.19–160.69 m) (Fig. F10) is interpreted as a prodelta deposit that is the lower HST of Sequence Kw2a3.
Below a coring gap (527.2–530 ft; 160.69–161.54 m), there is a change to a slightly clayey, shelly medium sand with a trace of mica and glauconite (530–549.5 ft; 161.54–167.49 m) deposited in lower shoreface (Fig. F11) to offshore environments. We interpret this facies shift from sand below to silt above in the coring gap as a sequence boundary (529 ft; 161 m) associated with a minor gamma ray increase. This sequence boundary separates Sequence Kw2a3 above and Sequence Kw2a2 below. The section fines slightly downward and shells become less common. This sandy unit represents the upper HST that may be the equivalent of the Rio Grande water-bearing unit as defined by Sugarman (2001).
A dramatic contact at 549.5 ft (167.49 m) (Fig. F11) separates intensively burrowed sand from an underlying laminated clay to laminated clayey silt deposited in prodelta environments. This is a sequence boundary separating Sequence Kw2a2 from Sequence Kw2a1 below. The clay and silt are equivalent to the great diatom bed (Woolman, 1895; Palmer, 1986). The unit from 549.5 to 620 ft (167.49 to 188.98 m) is generally fine grained and monotonous, with the following lithologies:
It might be possible to place a sequence boundary at the top of the sand at 558.5 ft (170.23 m) associated with a gamma log kick, even as the overlying sequence boundary was placed at 510.4 ft (155.57 m), though a good physical break is associated with the facies shift at 515.7 ft (157.19 m) (Fig. F11); however, the major physical break appears not at 556 ft (169.47 m) but at 549.5 ft (167.49 m), and we place the sequence boundary here. The section from 620.1 to 625 ft (189.01 to 190.50 m) is interbedded very fine sand and slightly sandy silty clay that comprises a TST deposited in prodelta environments. A contact in a coring gap (624.0–625.0 ft; 190.20–190.50 m) with weathered brown clay and sulfur blooms (625.0–625.4 ft; 190.50–190.62 m), a very fine sand bed (625.4–625.6 ft; 190.62–190.68 m), and a hard brown clay (625.6–626.0 ft; 190.68–190.80 m) is below. The environment of deposition of these clays and sands is uncertain. A contact is present at 626.0 ft (190.80 m) with a granuliferous medium–coarse sand with phosphate pebbles below; therefore a major facies shift is present between 624 and 625.6 ft (190.20 and 190.68 m). The section from 625.0 to 625.6 ft (190.50 to 190.68 m) shows evidence of exposure (weathering, including kaolinization), with a gray clay from 625.6 to 626.0 ft (190.68 to 190.80 m). It is possible to interpret this contact (626 ft; 190.80 m) as a sequence boundary; however, we prefer to interpret it as a transgressive surface and the interval from 625 to 630.7 ft (190.50 to 192.24 m) as an LST (Fig. F12) based on the following points:
The uniform sequence from 549.5 to 630.7 ft (167.49 to 192.24 m) is correlated with Sequence Kw2a1. With the exception of the sand from 558.5 to 561.7 ft (170.23 to 171.21 m), HST sand is mostly lacking from this sequence. The Kw2a sequences have been correlated with ECDZ 2 and have Sr isotope age estimates ranging from 16.9 to 17.8 Ma.
A major drilling objective was attained by the recovery of sequence Kw1c. The sequence is dated as 19.0–18.8 Ma. A major indurated zone (628.0–631.7 ft; 191.41–192.54 m) marks a sequence boundary (Fig. F13). The sandstone from 628.0 to 630.7 ft (191.41 to 192.24 m) is poorly sorted, granuliferous, phosphatic, dominantly medium grained, and shelly deposited in proximal upper shoreface to foreshore environments. We place a sequence boundary at 630.7 ft (192.24 m) at the base of the shelly section above a well-sorted, clean, cross-bedded sandstone below deposited in a proximal upper shoreface environment. There is a minor gamma ray log increase ~2 ft (0.61 m) above the sequence boundary.
Below the indurated zone around the sequence boundary (631.7–633.05 ft; 192.54–192.05 m) is moderately sorted, slightly muddy, fine–medium sand. This sand was deposited in distal upper shoreface environments. The interval from 639.5 to 643.45 ft (194.92 to 196.12 m) is silty medium sand with shell fragments and sand-sized lignite deposited in lower shoreface environments. A thin, indurated, medium-grained sandstone (643.0–643.5 ft; 195.99–196.14 m) with pebbles and large shells (including oysters) that marks either an FS or an autocyclical change is a depositional facies from delta front to lower shoreface deposits.
Below the FS at 643.5 ft (196.14 m) is black, organic-rich, shelly silty fine–medium sand interbedded with organic-rich sandy clayey silt (643.45–652.5 ft; 196.12–198.88 m). These beds are associated with moderate and variable gamma ray log values. We interpret this depositional environment as a delta front. A shift to laminated silty clay from 652.5 to 656.5 ft (198.88 to 200.10 m) (Fig. F14) with thinly interbedded, fine, organic-rich, slightly shelly sand (~0.1 ft; 3 cm) represents prodelta environments, whereas the sand may represent storm events.
We place a sequence boundary at 656.6 ft (200.13 m) associated with a dramatic gamma ray log kick and a facies shift from the organic-rich silty clay to massive, well-sorted, medium sand below. Sr isotope age estimates for Sequence Kw1c at this site are ~19 Ma. The Kw1c sequence is much thicker (140 ft; 42.67 m) at the Cape May site (Miller et al., 1996a) to the south vs. this site (25.8 ft [7.86 m] thick). This is consistent with the pinching out of Sequence Kw1c 5 km to the north before the Ocean View site (Miller et al., this volume).
Slightly silty, slightly coarse, medium sand (656.5–665.0 ft; 211.10–202.69 m) with scattered shells that becomes more common downsection and a thin clay (660.8–660.9 ft; 201.41–201.44 m) represent distal upper shoreface environments. Heavy bioturbation obscures bedding. A very shelly, very fine sand bed (665.0–666.5 ft; 202.69–203.15 m) was deposited in lower shoreface environments. Silty fine–medium sand (666.5–667.2 ft; 203.15–203.67 m) was also deposited in lower shoreface environments, with a coring gap from 667.2 to 670.0 ft (203.67 to 204.22 m). Very shelly fine–medium sand from 670.0 to 674.0 ft (204.22 to 205.44 m) with large shell fragments and whole clam shells has decreasing amounts of shell downsection and appears to be an upper shoreface deposit (probably proximal). The section from 670.0 to 713 ft (204.22 to 217.32 m) consists of bioturbated fine–medium sand deposited in lower shoreface environments (Fig. F14), with alternating amounts of shells, silt, coarser beds, and organic-rich beds, as follows:
The section from 656.5 to 713 ft (200.10 to 217.32 m) is potentially an excellent aquifer that correlates to the upper sand of the Atlantic City 800-foot sand aquifer of Zapecza (1989).