PRESENT ACTIVITY: Update as of 0900 hr 17 March 2009. XCB coring from 147.6 mbsf to 157.3 mbsf. This hole was piston cored to 138.2 mbsf with 102.0 % recovery before opting to switch over to the XCB in anticipation of running into chert. Between 0430 and 0500, the drill string was flushed by circulating a volume of sea water equal to the internal displacement of the pipe. Spud Hole U1331A at 0750 hr and establish sea floor at 5127.3 mbrf (5116.2 mbsl). Piston core U1331A-1H to -11H to 100.2 with an average recovery of 101.3%. In plain language, that’s 11 ten-meter cores from Hole A (our first of three holes) at Site U1331A.
Challenge: Discuss why and how core recovery could be more than 100%. Hint: Think about the nature of the seafloor we are coring. Post your answers through the comment function below.
LOCATION: Site U1331: Hole U1331A (PEAT-1C) Preliminary Position: 12°04.089’ N, 142° 09.698’ W; Calculated Water Depth: 5127.3 mbrf/5116.2 mbsl
WEATHER: Heading: various. Wind:14-16 kt gusting 20 kt @ 075°; Seas: 6 ft @ 6 sec from 070°- 075°; Swell: 4-6 ft @ 6 sec from 045°-050°; Sea Water Temp: 25.8°C; Barometer: 1012 mb steady; Air Temp: 25°C; Heave: 3 ft; Max Pitch: 1° @ 6 sec; Max Roll: 2° @ 6-8 sec.
OPERATION PLAN (next 24-48 hours): After reaching total depth ~187 mbsf, we will log this hole with the Triple Combo and other instruments. Upon completion of the logging effort, we will offset (move over) the vessel and APC/XCB hole U1331B to ~187 mbsf.
CURRENT TIME ZONE: GMT -10 (Hawaii Time)
Photo: A single 10 meter core on the catwalk. Curator Jerry Bode (foreground) and Expedition Project Manager Adam Klaus prepare to cut the core into 150 cm sections. Credit: Bill Crawford, IODP Imaging Specialist.