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IODP Expedition 339
Mediterranean Outflow
Daily Science Report for 31 December 2011
LOCATION: Hole U1389E (36°25.52′N, 7°16.69′W, water depth 655 mbrf) [proposed site GC-11A]
SCIENCE UPDATE: We retrieved RCB Cores U1389E-53R to -65R (818.7 to 943.5 mbsf) with a recovery of 38%. Cores U1389E-44R to 58R have been split and measured for physical and paleomagnetic properties. The sediment composition remains the same, dark greenish gray calcareous mud with interbedded silty mud with biogenic carbonate and sandy mud with biogenic carbonate. The age at the bottom of Core U1389E-65R is 3.57 Ma. Geochemical analyses of sediment and interstitial water samples from Hole U1389E are ongoing.
Daily Science Report for 30 December 2011
LOCATION: Hole U1389E (36°25.52′N, 7°16.69′W, water depth 655 mbrf) [proposed site GC-11A]
SCIENCE UPDATE: We retrieved RCB Cores U1389E-40R to 52R (694 to 819 mbsf) with a recovery of 64%. Cores U1389E-32R to 44R have been split and measured for physical and paleomagnetic properties. The sediment is predominantly dark greenish gray calcareous mud with interbedded silty mud, silty sand, and sandy mud with biogenic carbonate. The Matuyama/Gauss boundary (2.581 Ma) was identified in Core U1389E-40R at ~695 mbsf. Geochemical analyses of sediment and interstitial water samples from Hole U1389E are ongoing.
Daily Science Report for 29 December 2011
LOCATION: Hole U1389E (36°25.52′N, 7°16.69′W, water depth 655 mbrf) [proposed site GC-11A]
SCIENCE UPDATE: We retrieved RCB Cores U1389E-25R to 39R (550 to 694 mbsf) with a recovery of 79%. Cores U1389E-19R to 32R have been split and measured for physical and paleomagnetic properties. The sediment is predominantly dark greenish gray calcareous mud interbedded with silty mud, silty sand, and sandy mud with biogenic carbonate. Sediment is slightly bioturbated. Shell fragments and pyritized burrows occur throughout the cores. The top (1.778 Ma) and bottom (1.945 Ma) of the Olduvai subchron were found in Core U1389E-24R and Core U1389E-30R, respectively. The age at the bottom of Core U1389E-35R is estimated at 2.01 Ma based on biostratigraphic events. Geochemical analyses of sediment and interstitial water samples from Hole U1389E are ongoing.
Daily Science Report for 28 December 2011
LOCATION: Hole U1389E (36°25.52′N, 7°16.69′W, water depth 655 mbrf) [proposed site GC-11A]
SCIENCE UPDATE: Cores U1389E-7R to 24R were taken from 377.5 to 550 mbsf and recovered 89.85 m (52%). Cores U1389E-2R to 18R have been split and measured for physical and paleomagnetic properties. The sediment is predominantly dark greenish gray calcareous mud interbedded with silty mud and sandy mud with biogenic carbonate. The age at the bottom of Core U1389E-20R is estimated at 1.6–1.9 Ma according to calcareous nannofossils and planktonic foraminifers. Geochemical analyses of sediment and interstitial water samples from Hole U1389E are ongoing.
Daily Science Report for 27 December 2011
LOCATION: Hole U1389E (36°25.52′N, 7°16.69′W, water depth 655 mbrf) [proposed site GC-11A]
SCIENCE UPDATE: Hole U1389E was drilled down without recovery to 335 mbsf. We started RCB coring from this depth down and Cores U1389E-1W (0–335 mbsf), and 2R to 6R (335–377.5 mbsf) were taken before midnight. Cores U1389D-1H to 11H have been split and measured for physical and paleomagnetic properties. The interval (0–94 mbsf) sampled in Hole U1389D consists of Pleistocene to Holocene age interbedded dark gray to greenish gray calcareous mud, calcareous silty mud and sandy mud with biogenic carbonate. Geochemical analyses of sediment and interstitial water samples from Site U1389 are ongoing.
Daily Science Report for 26 December 2011
LOCATION: Hole U1389C (36°25.52′N, 7°16.68′W [final], water depth 656.2 mbrf) and Hole U1389D (36°25.51′N, 7°16.68′W [final], water depth 655.5 mbrf) [proposed site GC-11A]
SCIENCE UPDATE: XCB Cores U1389C-31X to 38X advanced from 278.5 to 350 mbsf. Total recovery for Hole U1389C is 328.5 m (93.9%). The vessel was offset 20 m south and APC coring operations began in Hole U1389D with the objective of resampling the upper ~100 m of the stratigraphic record. Cores U1389D-1H to 11H advanced from the seafloor to 94 mbsf with a recovery of 104%. Temperature measurements using the APCT3 tool were taken at 24.5, 53 and 75 mbsf. The drill string was pulled out of the hole and the rotary core barrel (RCB) bottom hole assembly was made up to prepare for drilling operations at Hole U1389E. The strategy for the next hole is to drill down without recovery to 335 mbsf and then start RCB coring from this depth down to 990 mbsf. Cores U1389C-17X to 30X have been measured for physical properties and split into working and archive halves. The sediment consists of dark greenish gray calcareous mud, silty mud and sandy mud with biogenic carbonate. Distinct bigradational sequences, as well as normal grading fining upward sequences are present.
Daily Science Report for 25 December 2011
LOCATION: Hole U1389C (36°25.52′N, 7°16.69′W, water depth 656.2 mbrf) (proposed site GC-11A)
SCIENCE UPDATE: APC Cores U1389C-6H to 10H advanced from 47.5 to 95 mbsf with a recovery of 104%. Once APC refusal was reached, the coring system was switched to the extended core barrel (XCB) and coring operations continued. XCB Cores U1389C-11X to 30X advanced from 95 to 278.5 mbsf with a recovery of 97.5%. Cores U1389C-1H to 16X have been measured for physical properties and split into working and archive halves. The sediment consists of calcareous mud, calcareous silty mud and calcareous silty sand with distinct bigradational sequences (contourite bedding), and normal grading fining upward sequences (turbidites). The age at the bottom of Core U1389C-26X is estimated to be between 0.46 and 0.6 Ma. Geochemical analyses of samples from Hole U1389A are ongoing.
Daily Science Report for 24 December 2011
LOCATION: Hole U1389B/C (36°25.52′N, 7°16.69′W, water depth 656.2 mbrf) (proposed site GC-11A)
SCIENCE UPDATE: Hole U1389A was successfully logged using the Triple Combo, FMS-Sonic and VSI tool strings from the bottom of the hole (354 mbsf) to the seafloor. The Triple Combo logging tool suite recorded spectral gamma ray, caliper, and resistivity logs, while the FMS-Sonic tool recorded resistivity images of the borehole, sonic velocities, and natural gamma data over the entire interval. The vertical seismic profile experiment was conducted without incident following the marine mammal protection protocol. Coring operations continued in the evening in Hole U1389B (offset 20 m east of Hole U1389A) and Hole U1389C. The first core at Hole U1389B recovered 9.7 m of sediment (102%). Because of the full core barrel, which prevented us from establishing a mudline depth, we decided to start a new hole. Hole U1389C was spudded at 2025 hr and Cores U1389C-1H to 5H advanced from the seafloor to 47.5 mbsf with a recovery of 104%. The age at the bottom of Core U1389C-4H is estimated at <0.27 Ma.
Daily Science Report for 23 December 2011
LOCATION: Hole U1389A (36°25.5183′N, 7°16.6907′W, water depth 656.2 mbrf) (proposed site GC-11A)
SCIENCE UPDATE: Cores U1389A-30X to 39X advanced from 167.4 to XCB refusal at 357 mbsf. Total recovery for Hole U1389A is 335.6 m (94%). Following the end of coring operations in Hole U1389A, the hole was conditioned for downhole logging and by midnight the first logging tool string (Triple Combo) was being deployed. Cores U1389A-8H to 26X have been split, measured for physical and magnetic properties and described. The sediment consists of alternating beds of calcareous mud, silty mud and sandy silt with biogenic carbonate. The age at the bottom of Core U1389A-35X is estimated at >0.9 Ma. Geochemical analyses of samples from Hole U1389A are ongoing. The tug boat ‘Obama’ visited the ship at 1340 hrs to deliver charts, fresh goods and other supplies; and took on one departing scientist back to Cádiz, Spain.
Daily Science Report for 22 December 2011
LOCATION: Hole U1389A (36°25.52′N, 7°16.69′W, water depth 656.2 mbrf) (proposed site GC-11A)
SCIENCE UPDATE: Cores U1389A-1H to 11H advanced from 0 to 97.2 mbsf with a recovery of 103%. Once APC refusal was reached, the coring system was switched to the extended core barrel (XCB) and coring operations continued. Cores U1389A-12X to 29X advanced from 97.2 to 167.4 mbsf with a recovery of 98%. Cores U1389A-1H to 7H consist of alternating beds of calcareous mud, calcareous silty and calcareous sandy mud. The age at the bottom of Core U1389A-29X is estimated at 0.7 Ma. Expedition scientists continue to review their precruise sample requests and research plans.
Daily Science Report for 21 December 2011
LOCATION: Hole U1388C (36°16.15′N, 6°47.64′W [final], water depth 674 mbrf); transit to Site U1389 (proposed site GC-11A), and Hole U1389A (36°25.52′N, 7°16.69′W, water depth 656.2 mbrf)
SCIENCE UPDATE: We recovered RCB Cores U1388C-2R to 4R from 205 to 229 mbsf before the drill string became stuck in the hole at 229 mbsf. After several attempts to free the pipe, rotation was restored and the drill string was freed. Hole U1388C and Site U1388 operations were ended because of an unstable sandy formation. We were underway to Site U1389 (proposed site GC-11A) at 1730 hrs and arrived on station at 2000 hr. After making up the APC/XCB bottom hole assembly and running the drill string down to sea bed, we deployed the underwater camera system and began an inspection of the seafloor to ensure that it was free of obstructions before coring operations begin at Hole U1389A. Cores U1388C-2R to 4R were split, measured for physical and magnetic properties and described. The sediment consists of very dark to dark greenish gray silty-muddy nannofossil ooze, calcareous silty sand and sandy-silty nannofossil ooze.
Daily Science Report for 20 December 2011
LOCATION: Hole U1388B (36°13.83′N, 6°47.66′W, water depth 669 mbrf) and Hole U1388C (36°16.14′N, 6°47.66′W, water depth 674 mbrf) (proposed site GC-04D)
SCIENCE UPDATE: We recovered Cores U1388B-12X to 24X from 101 to 225.7 mbsf and ended operations at Hole U1388B because of persistent XCB cutting shoe damage. Our plan is to switch to rotary coring and begin Hole U1388C. Core recovery for Hole U1388B was 47%. All cores from Hole U1388B have been split and measured for physical and paleomagnetic properties. Sediment composition varies from nannofossil mud to silty muddy with biogenic carbonate to silty sand with biogenic carbonate. The age at the bottom of Hole U1388B is estimated between 0.6 and 0.9 Ma. Expedition 339 scientists continue to discuss their precruise sample requests and research plans. RCB drilling began in Hole U1388C at 1915 hr. We will drill ahead without recovery to 205 mbsf and then start RCB coring.
Daily Science Report for 19 December 2011
LOCATION: Hole U1388B (preliminary 36°16.14' N, 6°47.66' W, water depth 674 mbrf; proposed Site GC-04D)
SCIENCE UPDATE: Hole U1388B was spudded with the XCB at 0835 hr. Cores U1388B-1X to 11X (0-101 mbsf) yielded silty sand, sandy mud and sand with biogenic carbonate (recovery 14.3%). Once the upper sandy interval was penetrated, Cores U1388B-12X to 19X (101-178 mbsf) recovered predominantly nannofossil mud and mud with biogenic carbonate (85% recovery). The age at the bottom of Core U1388B-19X is estimated at ~0.5 Ma. Expedition 339 scientists met to discuss their precruise sample requests.
Daily Science Report for 18 December 2011
LOCATION: Underway to Site U1388
Hole U1388A (preliminary 36°16.14' N, 6°47.66' W, water depth 675 mbrf; proposed Site GC-04D)
SCIENCE UPDATE: We completed the ~5 hr transit to Site U1388 at 0745 hr. After making up the APC/XCB bottom hole assembly, we deployed the BHA and the underwater camera system to 670 mbrf to conduct an inspection of the seafloor. No obstructions were observed. Hole U1388A was spudded at 1500 hr establishing a seafloor depth of 675.1 mbrf. APC Core U1388A-1H recovered 3.4 m of fine sand with biogenic carbonate, but Core U1388A-2H registered an incomplete stroke and we were unable to retrieve the core barrel. After failed attempts to recover the core barrel, it was required to deploy the Kinley cutting tool to sever the coring line. The coring line and the drill string were retrieved, and the BHA was found to be full of sand, which prevented retrieval of the core barrel. We will attempt to advance Hole U1388B with the XCB to assess the thickness of the sand layer and the character of the sediment below the sand. The Chief Scientists presented the background, scientific objectives, and operations plan for Site U1388 - proposed site GC-04D.
Daily Science Report for 17 December 2011
LOCATION: Hole U1387C (36°48.3139' N, 7°43.1277' W, water depth 570 mbrf; proposed Site GC-09A)
SCIENCE UPDATE: We completed downhole logging operations at Hole U1387C with the deployment of the Triple Combo, VSI and FMS-Sonic tool strings. Deployment of the Triple Combo logging tool started at 0230 hr, but we were unable to advance the tool suite past a bridge or ledge at ~650 mbsf. We successfully recorded spectral gamma ray, caliper, and resistivity logs over this interval. Following the marine mammal protection protocol and taking advantage of daylight, the vertical seismic profile (VSP) experiment was conducted next. Data were recorded upward from 254 mbsf because we were unable to lower the tool beyond this depth. The FMS-Sonic tool was deployed last at 1610 hr and run successfully down to 334 mbsf, where it was blocked by another obstruction in the hole. We recorded resistivity images of the borehole, sonic velocities, and natural gamma data over this interval. The rest of the day was spent pulling the drill string out of the hole and preparing for our departure to the next site, U1388 (proposed site GC-04D).
Daily Science Report for 16 December 2011
LOCATION: Hole U1387C (36°48.3139' N, 7°43.112773' W, water depth 570 mbrf; proposed Site GC-09A)
SCIENCE UPDATE: We completed coring operations in Hole U1387C with the recovery of RCB Cores U1387C-57R to 62R from 817.6 to 870 mbsf. Core recovery was 63%. All remaining cores from Hole U1387C have been split and measured for physical and paleomagnetic properties. The lowermost 50 m of the stratigraphic section recovered at Hole U1387C consists of slightly bioturbated, greenish gray to dark greenish gray nannofossil mud to muddy nannofossil ooze. The age at the bottom of the hole (870 mbsf) is estimated to be latest Miocene. Following the end of coring operations, we began conditioning Hole U1387C for downhole logging. Hole preparation extended until the end of the day.
Daily Science Report for 15 December 2011
LOCATION: Hole U1387C (preliminary 36°48.32' N, 7°43.13' W, water depth 570 mbrf; proposed Site GC-09A)
SCIENCE UPDATE: We recovered RCB Cores U1387C-46R to 56R from 712 to 817.6 mbsf with a rate of penetration of ~9 m/hr. Core recovery was 51%. Cores U1387C-31R through 50R have been split and measured for physical and paleomagnetic properties. Sediment composition varies from silty muddy to medium sandstone with biogenic carbonate and subangular to subrounded quartz grains, to nannofossil mud and silty mud with biogenic carbonate. The age at the bottom of Core U1387C-50R is estimated to be at the Miocene/Pliocene boundary.
Daily Science Report for 14 December 2011
LOCATION: Hole U1387C (preliminary 36°48.32' N, 7°43.13' W, water depth 570 mbrf; proposed Site GC-09A)
SCIENCE UPDATE: We recovered RCB Cores U1387C-31R to 45R from 568 to 712 mbsf with a rate of penetration of ~12 m/hr. Core recovery was 64%. Our plan is to core Hole U1387C to a revised depth of 870 mbsf and then conduct downhole logging operations with the Triple combo, FMS-sonic, and VSI tool strings. The new depth, recently approved by EPSP and the TAMU Safety panel, as well as the Government of Portugal, will ensure the recovery of a complete stratigraphic record from the late Miocene to the present. Cores U1387C-15R through 30R have been split and measured for physical and paleomagnetic properties. The main lithologies remain the same: nannofossil mud, silty mud and silty sand with biogenic carbonate. Occasional turbidites are present and bioturbation ranges from sparse to moderate. The age at the bottom of Core U1387C-43R is estimated as early Pliocene. Geochemical analyses of sediment samples and interstitial water continues.
Daily Science Report for 13 December 2011
LOCATION: Hole U1387C (preliminary 36°48.32' N, 7°43.13' W, water depth 570 mbrf; proposed Site GC-09A)
SCIENCE UPDATE: Today we recovered RCB Cores U1387C-13R to 30R from 405 to 568 mbsf with a rate of penetration of ~13 m/hr. Core recovery was 81%. Cores U1387C-4R through 15R have been split and measured for physical and paleomagnetic properties. The sediment consists of nannofossil mud, silty mud with biogenic carbonate, and silty sand with biogenic carbonate. Bioturbation ranges from sparse to moderate. The age at the bottom of Core U1387C-26R is estimated at 3.6 Ma. Geochemical analyses of sediment samples and interstitial water continues at Hole U1387C.
Daily Science Report for 12 December 2011
LOCATION: Hole U1387C (preliminary 36°48.32' N, 7°43.13' W, water depth 570 mbrf; proposed Site GC-09A)
SCIENCE UPDATE: Today we recovered Cores U1387C-2R to 13R from 290 to 405 mbsf (recovery 86%). All remaining cores from Hole U1387B (-20X to 36X) and Cores U1387C-2R to 3R have been split and measured for physical and paleomagnetic properties. The sediment composition remains the same as in Hole U1387A. The age at the bottom of Core U1387C-10R is estimated at 1.6 My.
Daily Science Report for 11 December 2011
LOCATION: Hole U1387B (preliminary 36°48.3246' N, 7°43.1278' W, water depth 570 mbrf)
Hole U1387C (preliminary 36°48.32' N, 7°43.13' W, water depth 570 mbrf) (Proposed Site GC-09A)
SCIENCE UPDATE: Cores U1387B-25X to 36X advanced from 223.6 to 338.4 mbsf with a recovery of 95%. XCB coring stopped shallower than planned to switch to RCB coring with the aim to improve core quality. The XCB biscuiting disturbance is pervasive in the deeper cores from Hole U1387A and the same is expected in Hole U1387B. After pulling the drillstring out of the hole and offsetting the vessel 20 m south of Hole U1387B, we lowered the underwater camera to conduct a pre-spud inspection of the seafloor before starting Hole U1387C. No obstructions were observed. The underwater camera system was recovered, and Hole U1387C was spudded with the RCB at 1850 hr at a water depth of 569.8 mbrf. The plan is to drill ahead without recovery to 290 mbsf and then start RCB coring from there down to 784 mbsf. By midnight, the RCB bit was at ~220 mbsf. Cores U1387A-29X to 38X and U1387B-1H to 19X have been split and consist of nannofossil mud, silty mud with biogenic carbonate and silty sand with biogenic carbonate. The age at the bottom of Core U1387B-36X is estimated at 1.6 My.
Daily Science Report for 10 December 2011
LOCATION: Site U1387 (Proposed Site GC-09A; preliminary 36°48.32' N, 7°43.14' W, water depth 570 mbrf)
SCIENCE UPDATE: Cores U1387A-33XH to 38X advanced from 295.2 to 352.4 mbsf with a recovery of 100%. Having reached our depth objective in Hole U1387A, we pulled out of the hole, offset the vessel 20 m east, and lowered the underwater camera to survey the seafloor and ensure it was free of obstructions before beginning operations in Hole U1387B. No obstructions were observed. Cores U1387B-1H to 5H advanced from 0 to 46.9 mbsf with a recovery of 103%. Once APC refusal was reached, the coring system was switched to the extended core barrel (XCB) and coring operations continued. Cores U1387B-6X to 24X advanced from 47 to 176.7 mbsf with a recovery of 97%. Cores U1387A-10X to 28X have been split and consist of nannofossil mud and silty mud with biogenic carbonate. The age at the bottom of Hole U1387A is estimated at 1.6 My. A meeting was held to present the scientific results from Site U1386.
Daily Science Report for 9 December 2011
LOCATION: Site U1387 (Proposed Site GC-09A; preliminary 36°48.32' N, 7°43.14' W, water depth 570 mbrf)
SCIENCE UPDATE: Today we started coring Hole U1387A. Cores U1387A-1H to 6H advanced from 0 to 48 mbsf with a recovery of 102%. Once APC refusal was reached, the coring system was switched to the extended core barrel (XCB) and coring operations continued. Cores U1387A-7X to 32X advanced from 48 to 295.2 mbsf with a recovery of 97%. The sediment in Cores U1387A-1H to 9X consists of moderately bioturbated nannofossil mud, silty mud with biogenic carbonate, and silty sand with biogenic carbonate. All cores up to Core U1387A-16X have been measured for physical properties. Geochemical analyses of sediment material and interstitial water continue.
Daily Science Report for 8 December 2011
LOCATION: Site U1386 (Proposed Site GC-01A; final 36°49.68' N, 7°45.32' W, water depth 572 mbrf)
and Site U1387 (Proposed Site GC-09A; preliminary 36°48.32' N, 7°43.14' W, water depth 578 mbrf)
SCIENCE UPDATE: Logging operations continued today in Hole U1386C with the deployment of the FMS-Sonic tool string, which provides resistivity images of the borehole, sonic velocities, and natural gamma data. The tool string was run successfully down to 375 mbsf, where it was blocked by an obstruction in the hole. Following the marine mammal protection protocol, the vertical seismic profile (VSP) experiment was conducted during daylight. Data were recorded upward from 368 mbsf. Logging operations ended in the early afternoon, thus completing operations at Site U1386. The vessel was offset 2.2 nmi on a bearing of 128° to Site U1387 (GC-09A). The day ended with the deployment of the camera system to conduct a survey of the seafloor to ensure that it is free of obstructions before coring operations begin at Hole U1387A.
Daily Science Report for 7 December 2011
LOCATION: Site U1386 (Proposed Site GC-01A; final 36°49.68' N, 7°45.32' W, water depth 572 mbrf)
SCIENCE UPDATE: Cores U1386C-17R and 18R penetrated from 510 to 526 mbsf yielding 82% of core recovery. This concluded coring operations at Site U1386. Cores U1386C-16R to 18R consist of calcareous silty mud, sandy silt, silty sand, and medium to coarse sand with biogenic carbonate, including several shell-rich layers. The age at the bottom of Hole U1386C is late Miocene. Following the end of coring operations, the hole was displaced with mud in preparation for logging. The triple combo logging tool string was rigged up and successfully lowered to the bottom of the hole (526 mbsf), and the first pass up to the seafloor was finished before midnight. Spectral gamma ray, caliper, and resistivity were recorded over the entire interval. The tool string was modified to include both the new and old resistivity tools, to compare results from both.
Daily Science Report for 6 December 2011
LOCATION: Site U1386 (Proposed Site GC-01A; preliminary 36°49.69' N, 7°45.33' W, water depth 572 mbrf)
SCIENCE UPDATE: We recovered Cores U1386C-6R to 16R, from 405 to 510 mbsf, with 54% recovery. The sediment composition is calcareous silty mud, sandy silt and silty sand with biogenic carbonate, and medium to coarse sand with biogenic carbonate. Based on biostratigraphic markers, the age at the base of Core U1386C-16R is over 4 My.
Daily Science Report for 5 December 2011
LOCATION: Site U1386 (Proposed Site GC-01A; preliminary 36°49.69' N, 7°45.33' W, water depth 572 mbrf)
SCIENCE UPDATE: Today we started RCB drilling Hole U1386C. By midnight, we had drilled without coring from the seafloor to 320 mbsf. However, we did take two cores in this interval (Core U1386C-2R, 165 to 174.6 m, 40% recovery; Core U1386C-4R, 205 to 214.6 m, 93% recovery) to try to fill in short gaps in APC cores recovered from Holes U1386A and U1386B. We will continue RCB drilling without coring to ~405 m and RCB core from there to 526 m. The scientific teams continued to describe and examine the cores and samples recovered at this site and to work on the site reports.
Daily Science Report for 4 December 2011
LOCATION: Site U1386 (Proposed Site GC-01A; preliminary 36°49.69' N, 7°45.33' W, water depth 572 mbrf)
SCIENCE UPDATE: We recovered XCB Cores U1386B-39X to -50X (350.1 to 464.9 mbsf) with a recovery of 81.5%. A damaged cutting shoe was retrieved on Core U1386B-49X. Prior to cutting Core 50X the sinker bars were withdrawn from the drill string to enhance circulation to the bit. There was a 20-bbl sweep circulated at 455.4 mbsf. After cutting Core U1386B-50X we were unable to recover the core barrel which was stuck in the BHA. The core barrel was finally retrieved by the coring line after two attempts with the wireline jars. Examination of the recovered hardware indicated that the spacer sub was damaged and the cutting shoe was missing and presumed jammed in the throat of the bit. Therefore, we were unable to continue coring in this hole because of the hardware failure. The plan is to pull out of the hole, make up the RCB coring assembly and continue operations in a new hole. The scientific teams continued to describe and examine the cores recovered at the site and to work on the site reports.
Daily Science Report for 3 December 2011
LOCATION: Site U1386 (Proposed Site GC-01A; preliminary 36°49.69' N, 7°45.33' W, water depth 572 mbrf)
SCIENCE UPDATE: Today we recovered Cores U1386B-20X to 38X from 168 to 350 mbsf with 100% recovery. Because of the good recovery and performance of the XCB coring system, the plan is to continue coring Hole U1386B to the total depth of 526 mbsf without changing to the rotary core barrel system. Description and measurement of physical and magnetic properties have been completed for Cores 1H to 19X from Hole U1386B. The age at the bottom of Core U1386B-41X (380 mbsf) is between 1.1 and 1.21 Ma. Geochemical analyses of sediment and interstitial water from Site U1385 were completed.
Daily Science Report for 2 December 2011
LOCATION: Site U1386 (Proposed Site GC-01A; preliminary 36°49.69' N, 7°45.33' W, water depth 572 mbrf)
SCIENCE UPDATE: This morning we completed operations in Hole U1386A with the retrieval of three more cores (U1386A-37X to 39X) from 320.5 to 349.3 mbsf (97% recovery). Hole U1386B was offset 20 m east of Hole U1386A and by midnight we recovered Cores U1386B-1H to 19X (0-167.9 mbsf, 101.6% recovery). The coring system was switched to the XCB after Core U1368B-18H advanced only 4.7 m indicating that the formation became too stiff to piston core. Description and measurement of physical and magnetic properties have been completed for all cores from Hole U1386A and are ongoing for Hole U1386B. The age at the bottom of Hole U1386A (349 mbsf) is between 1.1 and 1.21 Ma. Geochemical analyses of sediment material and interstitial water continues. The science party presented the scientific results from Site U1385.
Daily Science Report for 1 December 2011
LOCATION: Site U1386 (Proposed Site GC-01A; preliminary 36°49.69' N, 7°45.33' W, water depth 572 mbrf)
SCIENCE UPDATE: Today we continued coring Hole U1386A. Cores U1386A-17H to 21H advanced from 144 to 183 mbsf with a recovery of 102%. Once APC refusal was reached, the coring system was switched to the extended core barrel (XCB) and coring operations continued. Cores U1386A-22X to 36X advanced from 183 to 320.5 mbsf with a recovery of 100%. We have approximately three more XCB cores until we reach our target depth of 350 m for Hole U1386A. Non-magnetic core barrels were used for all APC cores. The main lithologies in Cores Hole U1386A-1H to 20H consist of dark grey to olive grey nannofossil mud and calcareous silty sand. Description and measurement of physical and magnetic properties of the cores, as well as geochemical analyses of interstitial water and sediment material are ongoing. An age of ~1 My has been assigned to the bottom of Core U1386A-36X.
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