OPERATIONS

Drilling at the Medford site began on Monday, 24 April 2007. Drilling operations were superintended by Gene Cobbs III, Head Driller, USGS Eastern Earth Surface Processes Team (EESPT); Dave Queen and Jeff Grey were the assistants. The Medford Township South Street Maintenance Yard provided space, water, and electricity. The drillers arrived late in the day on 23 April. On 24 April they began rigging up and ran electricity and water from the maintenance yard buildings. On 24 April, a field trailer was set up as a portable laboratory and electric hookups were made to the yard. A Canon PowerShot G5 digital zoom camera (7.2–28.8 mm lens; 5 megapixel resolution), Macintosh G4, and the Delaware Geological Survey (DGS) photography stand were set up to photograph 2 ft (0.61 m) core segments; the camera's default settings with fill-in flash were used.

All cores were measured in feet (all depths are given in feet below land surface with metric conversions provided). We continued to adopt the ODP convention of top justifying depths for intervals with incomplete recovery for all field notes and photos.

The first core was obtained on 24 April using a Christensen 94 mm (HQ) system, 4.5 inch (11 cm) Longyear bit, and 2.5 inch (6.5 cm) core diameter. For unconsolidated sand, an extended ("snout") shoe was used to contact the sample 1.5–2.5 inches (4–6 cm) ahead of the bit; core diameter is 2.4 inches (6 cm) with a rock shoe and 2.1 inches (5 cm) with the snout shoe. The uppermost 1.5 ft (0.5 m) was blown away while setting surface casing. The first core was obtained at 1400 h on 24 April with 2.9 ft (0.9 m) recovered from 4.5 ft (1.4 m) run (1.5–6.0 ft; 0.5–1.8 m) in glauconitic clay. Good coring continued through the rest of the day in glauconite clay. The day ended at 20 ft (6.1 m) with 12.5 ft (3.8 m) recovered from 18.5 ft (5.6 m) drilled (recovery = 67.6%).

On 25 April the first run of the day from 20 to 30 ft (6.1 to 9.1 m) recovered 76%. Because of cemented intervals within the Vincentown Formation, the next run stopped 2.5 ft into the run (30–32.5 ft, 0.8 m; 9.1–10.4 m) with 1.6 ft (0.5 m) of recovery. The following run was limited to 1.5 ft (32.5–34 ft; 10.4–10.9 m) and ended in an indurated zone consisting of medium to coarse calcarenite. Recovery was 120%. The next two runs were 6 ft (1.83 m) from 34 to 40 ft (10.4 to 12.2 m) and 7 ft (2.13 m) long (40–47 ft; 12.2–14.3 m) with excellent recovery of 110% and 80%, respectively. An 8 ft (2.43 m) run (47–55 ft; 14.3–16.8 m) recovered only 1.6 ft (0.5 m). Clayey glauconite sand with a high percentage of broken shell fragments was recovered in the core. The drillers returned to the bottom of the hole (BOH) for a 1 ft (0.3 m) run (55–56 ft; 16.8–17.1 m) with 60% recovery of glauconite sand. Drilling stopped at this point because of a clogged core barrel. Coring restarted with a 4 ft (1.22 m) run (56–60 ft; 17.1–18.3 m) and 2.4 ft (0.7 m) recovery of glauconite sand. The next run also had poor recovery; from 60 to 70 ft (18.3 to 21.3 m), 23% was recovered. It fortuitously contained the Cretaceous/Tertiary (K/T) boundary at 60.7 ft (18.5 m). From 70 to 75 ft (21.3 to 22.9 m), 50% was recovered. The same recovery was duplicated from 75 to 80 ft (22.9 to 24.4 m). Recovery was perfect from 80 to 85 ft (24.4 to 25.9 m). From 85 to 90 ft (25.9 to 27.4 m), 5.2 ft (1.6 m) was recovered. On the final run of the day (90–100 ft; 27.4–30.5 m), 9.2 ft (2.8 m) was recovered, including a beautiful Navesink/Mount Laurel Formation contact. For the day, 80 ft (24.4 m) was drilled with 54.5 ft (16.6 m) recovered (68%).

On 26 April, the first run (19) from 100 to 107 ft (30.48 to 32.61 m) had nearly full (93%) recovery (6.5 ft; 2 m). The next two runs in semi- to indurated glauconitic quartz sand were drilled with a rock shoe with moderate recovery. Run 20 (107–113 ft; 32.6–34.4 m) recovered 3.9 ft (1.2 m), and the next run from 113 to 120 ft (34.4 to 36.6 m) recovered 6.2 ft (1.9 m). During Run 22 from 120 to 130 ft (36.6 to 39.6 m), the rock shoe became loose and recovery was poor (2.7 ft; 0.82 m; 27%). On the next run (130–140 ft; 39.6–42.7 m), shell beds limited recovery to 4.1 ft (1.3 m). Recovery progressively improved on the next two runs (140–150 ft, 42.7–45.7 m; 150–160 ft, 45.7–48.8 m) with 57% and 85% recovery. In coring 160–170 ft (48.8–51.8 m), only 2.9 ft (0.9 m) was recovered. We had excellent recovery during the next several runs. Run 27 (170–180 ft; 51.8–54.9 m) recovered 83%; 180–190 ft (54.9–57.9 m) recovered 97%; 86% from 190 to 200 ft (57.9 to 61 m); and 96% from 200 to 210 ft (61 to 64 m). For the day, 110 ft (33.5 m) was drilled with 76.7 ft (23.4 m) recovered (70%).

Pouring rain in the morning on 27 April slowed the pace of coring. In the afternoon the rain became more sporadic, allowing drilling operations to speed up. The first run of the day (Run 31; 210–220 ft; 64.0–67.1 m) recovered a full 10 ft (3.0 m). The second run (32; 220–223.5 ft; 67.1–68.1 m) recovered 2.7 ft (0.8 m). Run 33 (223.5–225 ft; 68.1–68.6 m) was cut short after encountering an indurated bed; 1.1 ft (0.34 m) was recovered. Sandstone led to poor recovery of 32% between 225 and 230 ft (68.6 and 70.1 m). Runs 35–37 (230–260 ft; 70.1–79.2 m) were much smoother as the rains abated. Better recovery of 75% was recorded between 230 and 240 ft (70.1 and 73.2 m), 89% between 240 and 250 ft (73.2 and 76.2 m), and 104% from 250 to 260 ft (76.2 to 79.3 m). The final run (38) of the day (260–270 ft; 79.2–82.3 m) slipped out of the barrel while being brought to the surface. Most of the core was subsequently recovered (7.95 ft; 2.4 m). The day ended at 270 ft (82.3 m) with 50 ft (15.2 m) recovered from 60 ft (18.3 m) drilled (recovery = 83.3%).

On 28 April, the first run (Run 39) in clayey silt recovered 7.4 ft (2.3 m) from 270 to 280 ft (82.3 to 85.3 m). Run 40 (280–290 ft; 85.3–88.4 m) had excellent recovery of 97%, whereas Run 41 (290–300 ft; 88.4–91.4 m) had even better recovery of 103%. Recovery was 6.7 ft (0.2 m) from 300 to 310 ft (91.4 to 94.5 m), a perfect 10 ft (3 m) from 310 to 320 ft (94.5 to 97.5 m), and 9.5 ft (2.9 m) from 320 to 330 ft (97.5 to 100.6 m). A change in lithology from silty clay above to medium sand below led to a short run of 330–333 ft (100.6–101.5 m) with 3.9 ft (1.2 m) recovered; the top 0.9 ft (0.3 m) is probably from the bottom of the last run. Recovery in the sand was 100% during Run 46 (333–340 ft; 101.5–103.6 m) but fell off sharply during the next two runs: 36% from 340 to 350 ft (103.6 to 106.7 m) and 20% from 350 to 360 ft (106.7 to 109.7 m). The day ended at 360 ft (109.7 m) with 70.1 ft (21.4 m) recovered from 90 ft (27.4 m) drilled (recovery = 77.9%).

The first run of 29 April (360–370 ft; 109.7–112.8 m) slipped out of the barrel on retrieval, but 2.65 ft (0.8 m) was recovered. The drillers went back into the hole and drilled 3 ft more and recovered an additional 9.4 ft (2.9 m). We logged this as two separate runs, the first from 360 to 362.5 ft (109.7 to 110.5 m) and the second from 362.5 to 373 ft (110.5 to 113.7 m). The next run (51) was completed from 373 to 380 ft (113.7 to 115.8 m) with 8.2 ft (2.5 m) of recovery. Superb recovery continued during the next several runs. Recovery from Run 52 (380–390 ft; 115.8–118.9 m) and Run 53 (390–400 ft; 118.9–121.9 m) was 101%. Two 5 ft (1.5 m) runs from 400 to 410 ft (121.9 to 125 m) recovered 51% and 53%, respectively. On the next run from 410 to 420 ft (125 to 128 m), only 6.1 ft (1.9 m) was recovered, as swelling clays blocked the bottom of the core barrel. The bottom 3 ft (0.9 m) of Run 57 (420–430 ft; 128.0–131.1 m) slipped out of the bottom of the barrel. We drilled another 5 ft (1.5 m) hoping to recover the missing 3 ft (0.9 m). The next run (58; 430–435 ft; 131.1–132.6 m) recovered 8.2 ft (2.5 m) of core from a 5 ft (1.5 m) run. We assume the extra core came from the previous run, and we assigned the overrun to the last core and labeled the cores starting at 427 ft (130.1 m). The last run of the day (Run 59) recovered 5.3 ft (1.6 m) from 5 ft (1.5 m) of drilling (435–440 ft; 132.6–134.1 m). The day ended at 440 ft (134.1 m) with 77.25 ft (23.5 m) recovered from 80 ft (24.4 m) drilled (recovery = 96.6%).

The first core (Run 60) on 30 April (440–448.5 ft; 134.1–136.7 m) recovered 5.5 ft (1.7 m). Run 61 (448.5–452.5 ft; 136.7–137.9 m) recovered 3.8 ft (1.2 m). Run 62 was dominated by sand and recovered 6.5 ft (2.0 m) from 452.5 to 460 ft (137.9 to 140.2 m). Drilling resumed without incident with the next run (460–467 ft; 140.2–142.3 m), retrieving 5.6 ft (1.7 m). Run 64 saw the first break from sand when two thin clay zones appeared in the bottom of the 3.9 ft (1.2 m) recovered (467–476.5 ft; 142.3–145.2 m). Drillers returned to the BOH and drilled another 3.5 ft (1.1 m) from 476.5 to 480 ft (145.2 to 146.3 m) with 3.9 ft (1.2 m) recovered of white kaolinite that varied from silty clay to clayey silt with some thin very fine sand lenses. The top 0.4 ft (0.1 m) appeared to have dropped out of the bottom of the previous run as indicated by markings on the core. Run 66 (480–490 ft; 146.3–149.4 m; 8.4 ft [2.6 m] recovered) contained 4.5 ft (1.4 m) of clay on top and an abrupt change to fine sand with lignitic laminae. Sand continued through the next core as recovery dropped to 5.9 ft (1.8 m) from 490 to 500 ft (149.4 to 152.4 m). The final core of the day (500–510 ft; 152.4–155.4 m; 6.2 ft [1.9 m] recovered) remained in sand but the overall size coarsened. The day ended with 49.7 ft (15.1 m) recovered from 70 ft (21.3 m) drilled (recovery = 71%).

On 1 May, Run 69 recovered only 32.5% (510–520 ft; 155.4–158.5 m) because of gravel. Hard layers in the next two runs (520–526 and 526–528.5 ft; 158.5–160.3 and 160.3–161.1 m) stopped drilling short, though recovery was very good (97% and 80%, respectively). Runs 72–74 (528.5–539 ft; 161.1–164.3 m) each went 10.5 ft (3.2 m) to jam core into the shoe and recovered 9.9, 10.35, and 9.45 ft (3.0, 3.2, and 2.9 m), respectively, of beautiful core, including indurated zones. We ran one last 10 ft (3.0 m) core to 570.0 ft (173.7 m) and anticipated running two 5 ft (1.5 m) runs the next day to capture the Magothy/Raritan Formation contact predicted at ~570–580 ft (173.7–176.8 m). The final run (75; 560–570 ft; 170.7–173.7 m) recovered only 3.4 ft (1.0 m) of core because concretions in the core tore up the shoe. The day ended at 570 ft (173.7 m) with 44.15 ft (13.5 m) recovered from 60 ft (18.3 m) drilled (recovery = 73.6%).

The first run of 2 May recovered 4.2 ft (1.3 m) from 570 to 575 ft (173 to 175.3 m) and captured the Magothy/Raritan Formation contact. On the following 5 ft run (575–580 ft; 175.3–176.8 m), 4.7 ft (1.4 m) was recovered. On Run 78, 3 ft (0.9 m) was recovered from 580 to 585 ft (176.8 to 178.3 m). The next run recovered 3.3 ft (1.0 m) from 585 to 590 ft (178.3 to 179.8 m). While drilling Run 80 from 590 to 600 ft (179.8 to 182.9 m), the fuel filter clogged. Recovery was 2.8 ft (0.9 m) or 28%. From 600 to 610 ft (182.98 to 185.9 m) 4.6 ft (1.4 m) was recovered. The bottom of the core (604.2–604.6 ft; 184.8–184.3 m) was sand, and the driller believed the rest of the core was also sand and dropped out. The final run of the day from 610 to 620 ft (185.9 to 189.0 m) had 75% recovery. For the day, 29.8 ft (9.1 m) out of 50 ft (15.2 m) was recovered (59.6%).

On 3 May, smooth coring through the lower Raritan Formation from 620 to 675 ft (189.0 to 205.7 m) recovered 42.7 ft (13.0 m) from 55 ft (16.8 m) drilled (recovery = 77.6%).

On 4 May, Run 90 (675–680 ft; 205.7–207.3 m) recovered 3.85 ft (1.2 m), but on Run 91 (680–688.5 ft; 207.3–209.9 m) we recovered only 2 ft (0.6 m), with the remaining core slipping out. The next run (688.5–690 ft; 209.9–210.3 m) recovered 3.7 ft (1.1 m), recovering some from the previous run; this was bottom justified assuming that the lost core was from the middle of the two runs. Runs 93 and 94 (690–695 and 695–700 ft; 210.3–211.8 and 211.8–213.4 m) went 5 ft (1.5 m), recovering 3.15 and 5.0 ft (1.0 and 1.5 m), respectively. Run 95 recovered 10.2 ft (700–710 ft; 3.1 m; 213.4–216.4 m), but Run 96 (710–720 ft; 216.4–219.5 m) recovered only 4.7 ft (1.4 m). The day ended with 34.45 ft (10.5 m) recovered from 45 ft (13.7 m) drilled (recovery = 76.5%).

On 5 May, 4 ft (1.2 m) was recovered from 720 to 730 ft (219.5 to 222.5 m). Run 98 recovered 3.6 ft (1.1 m) from 730 to 733.6 ft (222.5 to 223.6 m). Recovery was 10.5 ft (3.2 m) from 740 to 750 ft (225.6 to 228.6 m); 5.5 ft (1.7 m) from 750 to 760 ft (228.6 to 231.6 m), and 5.2 ft (1.6 m) from 760 to 770 ft (231.6 to 234.7 m). Run 102 (770–780 ft; 234.7–237.7 m) recovered a full 10 ft (3.0 m) in the "birch log" (soft and lignitic) sand that continued to be difficult to wash free of drilling mud without having the core fall apart. Run 103 collected 6.8 ft (2.1 m) out of 10 ft (3.0 m) drilled. The day ended at 790 ft (240.8 m) with 45.6 ft (13.9 m) recovered from 70 ft (21.3 m) drilled (recovery = 65.1%).

On 6 May, the drillers only drilled one core (Run 104; 790–800 ft; 7.7 ft recovered [240.8–243.8 m; 2.3 m]) and returned to Reston, Virginia, for a half-day vacation. Because only one core was planned, none of the scientific team came to the drill site. The drillers washed the core and left it to dry overnight for description the following day.

On 7 May, the first two runs of the day (Run 105; 800–810 ft, 10 ft recovered [243.8–246.9 m; 3.0 m] and Run 106 (810–820 ft; 6.8 ft recovered [246.9–249.9 m; 2.1 m]) came up without incident. Loose sand at the bottom of Run 106 was only partially recovered. While preparing to drill Run 107, the quad latch on one of the inner core barrels would not release, and it had to be pulled. The other inner core barrel was put in, and drilling was delayed for a short time. The faulty quad latch was rebuilt and used later that day. Run 107 (820–830 ft; 249.9–253.0 m) recovered 5.05 ft (1.5 m) in soft, medium to coarse sand. Runs 108 and 109 (830–850 ft [253.0–259.1 m]; 5.1 and 4.7 ft recovered [1.6 and 1.4 m], respectively) continued with about 50% recovery. Run 110 (850–859 ft; 259.1–261.8 m) recovered 10.45 ft (3.2 m) from a 9 ft (2.7 m) run. Core 110 is uniform at top, and we assume the excess core came from the bottom of the previous run (Run 109); therefore, we bottom justified Core 110 at 859 ft (261.8 m). The day ended at 859 ft (261.8 m) with 42.1 ft (12.8 m) recovered from 59 ft (18.0 m) drilled (recovery = 71.4%).

On 8 May, no core was recovered on the first run (859–869.3 ft; 261.8–265.0 m). Drillers went down again to recover core and failed a second time. On the third try, 2 ft (0.6 m) of core was recovered. The core had slid out of the core barrel. On the second run, we had poor recovery (2.4 ft; 0.7 m) from 869.3 to 879.3 ft (265 to 268.0 m). On the final run of the day (879.3–890 ft; 268.0–271.3 m), 3.8 ft (1.2 m) was recovered. The drillers stopped for the day for rig maintenance. For the day, recovery was 8.2 ft (2.5 m) from 31 ft (9.4 m) drilled (27%).

On 9 May, coring resumed with 4.2 ft (1.3 m) recovered from 890 to 900 ft (271.3 to 274.3 m). For the next run (115) from 900 to 910 ft (274.3 to 277.4 m), 7.55 ft (2.3 m) was recovered, and 8.4 ft (2.6 m) was recovered on the following run (116; 910–920 ft; 277.4–280.4 m). Poor recovery of 2.5 ft (0.76 m) occurred during the next run (920–930 ft; 280.4–283.5 m). During the final run of the day from 930 to 940 ft (283.5 to 286.5 m), 7.75 ft (2.4 m) was recovered. For the day, 61% (30.35 ft; 8 m) was recovered from the 50 ft (15.2 m) drilled.

The first run on 10 May recovered 3.2 ft (0.98 m) from 940 to 944.5 ft (286.5 to 287.9 m). The next run to 950 ft (289.6 m) recovered 5.2 ft (1.6 m). Run 121 recovered 8.7 ft (2.7 m) from 950 to 960 ft (289.6 to 292.6 m), and 8.6 ft (2.6 m) was recovered between 960 and 970 ft (292.6 and 295.7 m). Recovery slipped to 22% on the next run between 970 and 980 ft (295.7 and 298.7 m) and finished at 50% on the final run of the day from 980 to 990 ft (298.7 to 301.8 m). Recovery for the day was 66% from 50 ft (15.3 m) drilled.

Recovery gradually improved on 11 May. Run 125 (990–1000 ft; 301.8–304.8 m) only recovered 1.9 ft (0.6 m), but Runs 126 and 127 (1000–1020 ft; 304.8–310.9 m) enjoyed full recovery. The drillers replaced the wireline between Runs 126 and 127. Run 128 (1020–1030 ft; 310.9–313.9 m) was pulled at the end of the day and described on 12 May. In total 32.4 ft (9.9 m) was recovered from 40 ft (12.2 m) drilled (recovery = 81%).

On 12 May, the first core slipped out of Run 129 (1030–1040 ft; 313.9–317 m), so on the second run (Run 130) the drillers only advanced 2 ft (0.6 m), hoping to catch the lost sediment. Run 130 (1040–1042 ft; 317–317.6 m) appeared to have captured 1 ft (0.3 m) from the bottom of Run 129 and the core is bottom justified. Based on drilling behavior, Run 130 (0.9 ft; 0.3 m recovered) is also bottom justified. Run 131 (1042–1047 ft; 317.6–319.1 m) recovered 3.3 ft (1 m) of mostly coarse sand. It is believed the coarse sand slipped out of the bottom of the barrel. The drillers had difficulty getting the inner core barrel to latch into place, preventing full recovery. Run 132 (1047–1055 ft; 319.1–321.6 m) recovered 6.35 ft (1.9 m). On the last run of the day (Run 133; 1055–1065 ft; 321.6–324.6 m), the shoe jammed with pebbles and cobbles, limiting recovery to 1 ft (0.3 m). The day ended at 1065 ft (324.6 m) with 12.55 ft (3.8 m) recovered from 35 ft (10.7 m) drilled (recovery = 35.9%). At the end of the day P. McLaughlin obtained a gamma log through the rods to 1065 ft (324.6 m).

Two cores were drilled on 13 May; they were washed by the drillers and described on 14 May. The sandy gravels made it difficult to latch the inner core barrel in, and Run 134 (1065–1070 ft; 324.6–326.1 m) recovered 1 ft (0.3 m) of pebble-rich coarse sand and Run 135 (1070–1073 ft; 326.1–327.1 m) had no recovery. The day ended at 1073 ft (327.1 m) with 1 ft (0.3 m) recovered from 8 ft (2.4 m) drilled (recovery = 12.5%).

There were two core runs on the last day of drilling (14 May). Run 136 (1073–1080 ft; 327.1–329.2 m) recovered 6.2 ft (1.9 m), and Run 137 (1080–1090 ft; 329.2–332.2 m) recovered 2.9 ft (0.9 m). Pebbles in the cores caused chattering of the drill string while drilling and made penetration difficult. The day ended at 1090 ft (332.2 m) with 9.1 ft (2.8 m) recovered from 17 ft (5.2 m) drilled (recovery = 53.5%).

Following Run 137, the drillers circulated drilling mud to condition the hole for logging and pulled the drill rods. McLaughlin began open-hole logging operations at approximately 1600 h with the DGS Century Gamma-Electric Multitool (Model 8144A). This logging tool simultaneously records a gamma ray log and a suite of electric logs, including spontaneous potential (SP), short normal resistivity (16N), long normal resistivity (64N), point resistance, and lateral resistivity. The first open-hole run was stopped by an obstruction at 463 ft. The drillers put rods back in the hole past the level of the obstruction, circulated the drilling mud, and removed the rods for another attempt at logging. The next attempt to log again encountered an obstruction and several subsequent attempts encountered obstructions at various depths. In the evening, a partial open-hole log was obtained by running the logging tool through the drilling rods to 435 ft and in the open hole to another obstruction at 669 ft; at that point, ~2200 h, logging was abandoned for the day.

On 15 May, the drillers mixed a new batch of drilling mud, put the entire drill string back into the hole, and circulated the mud for >1 h. Two partial log runs were made as the rods were being pulled in case of further obstruction problems. The drillers pulled the drill rods up to 815 ft and a partial open-hole log was obtained by running the multitool (Model 8144A) through the drilling rods to near the bottom of the hole at 1088 ft. The drillers pulled additional rods, and another run was made with the multitool from 615 to 1088 ft. A continuous gamma-multipoint electric log was constructed in the office by splicing together the logs from the various runs with splice depths of 450 and 655 ft. Logging was completed by ~1430 h.

The Medford site concluded with 137 cores (762.65 ft; 232.46 m) obtained, 70% recovery, and 110 boxes moved to the IODP Rutgers core repository.