The Double Trouble corehole penetrated several currently used or potential aquifer sand bodies (e.g., Sugarman et al., 2005a). Though no hydrologic studies were conducted at this site, sedimentological and log analyses suggest that the unconfined Kirkwood-Cohansey aquifer system is divided into an upper and lower aquifer at Double Trouble. The upper aquifer is 94 ft (0–94 ft; 28.7 m) thick at Double Trouble and consists of medium to coarse quartz sand deposited in nearshore and inner neritic environments. Thin (<5 ft, 1.5 m) finer-grained units, shown on the gamma log at 40 and 73 ft (12.2 and 22.3 m), consist of fine to very fine quartz sand. A 21 ft thick (6.4 m) unit from 94 to 115 ft (28.7 to 35.1 m) contains >50% silt and clay deposited originally in lagoonal or tidal flat environments and likely acts as a leaky confining unit dividing the Kirkwood-Cohansey aquifer system. The lower aquifer is 70 ft (21.3 m) thick (115–185 ft; 35.1–56.4), comprising the lower Cohansey and upper Kirkwood Formations. The section consists of fine to medium sand. The section from 115 to 165.6 ft (35.1 to 50.5 m) was deposited in foreshore and offshore bar environments, and the section from 165.6 to 185 ft (50.5 to 56.4 m) was deposited in a delta-influenced inner neritic environment. The lower Kirkwood Formation (185–293.8 ft; 56.4–89.6 m) is a confining unit with the finest parts deposited mostly as bay fill and prodelta environments.
The Eocene Piney Point aquifer (Nemickas and Carswell, 1976) was a target at this corehole, where it is represented by the Toms River Member of the Shark River Formation at Double Trouble; it is 161.2 ft (49.1 m) thick (293.8–455 ft; 89.6–138.7 m) and was deposited in lower to upper shoreface environments. The aquifer is coarser at the top, consisting of poorly sorted coarse to very coarse sand and fining downsection to medium to coarse sand. Granules are found throughout the aquifer. The Piney Point is an excellent aquifer in the Toms River area. The installed pump capacity for various wells screened in this aquifer has ranged between 160 and 1900 gpm (~600 and 7200 L/min). At Double Trouble, the Piney Point aquifer is equivalent to middle Eocene Sequence E8 of Browning et al. (1996). Below 455 ft (138.7 m), the core consists of the middle Eocene lower Shark River Formation through the Upper Cretaceous Navesink Formation and is part of the composite confining unit.
Double Trouble proved to be one of the more challenging coreholes drilled as part of Leg 174AX because of coring issues in the sandy Cohansey Formation and dating issues in the targeted Toms River Member and the Vincentown Formation. The K/Pg boundary appears to be biostratigraphically relatively complete, though it lacks a distinct spherule layer found at the most complete New Jersey coastal plain sections (Bass River and Ancora; Olsson et al., 1997, 2002; Miller et al., 2011). The Paleocene Hornerstown Formation is thin (<25 ft; 7.6 m). The overlying Vincentown Formation lacks the Marlboro Clay Member that includes the CIE and carbon isotopic recovery. However, the upper Vincentown Formation consists of a ~35 ft (10.7 m) thick sequence that has proven to be a Rosetta Stone for deciphering sea level history associated with the Paleocene/Eocene boundary. This sequence (706.5–741.9 ft; 215.3–226.1 m) is here named E0 (E-zero) and is assigned to upper Zone NP9b and NP10 and is overlain by Eocene Sequence E2 at this corehole. A major sea level lowering occurred before the deposition of Sequence E0 and eroded the Marlboro Clay, which is represented in other Leg 174AX New Jersey coastal plain coreholes but not in Double Trouble and the nearby Leg 150X Island Beach corehole. Eocene sequences at Double Trouble follow a familiar (Browning et al., 1997a, 1997b) pattern of "marly" slightly glauconitic clays of the lower Eocene Manasquan Formation (Sequences E2–E4) and more glauconitic clays of the middle Eocene lower Shark River Formation (Sequences E5–E8). The Toms River Member at Double Trouble is a 223.6 ft (66.2 m) thick unit that comprises the HST of Sequence E8 and was deposited at high sedimentation rates (~34 m/m.y.). The Double Trouble corehole provides a means of evaluating the age and geological relationships of the Toms River Member. The Kirkwood and Cohansey Formations proved difficult to date at Double Trouble, though the Kirkwood appears to represent two sequences that are likely correlated to the Kw1a and Kw1b (Miller et al., 1997). The ?Kw1a is a classic prograding shelf–prodelta–delta front succession, whereas the ?Kw1b is a less complete bay–delta front succession. The Cohansey Formation appears to be a lower prograding shoreface succession (?HST) and an upper retrogradational tidal-shoreface succession (?TST). Surficial deposits apparently represent reworked Cohansey lithology in a fluvial terrace setting.