Articles | Volume 4
Sci. Dril., 4, 4–10, 2007
Sci. Dril., 4, 4–10, 2007

  01 Mar 2007

01 Mar 2007

IODP Expeditions 309 and 312 Drill an Intact Section of Upper Oceanic Basement into Gabbros

J. C. Alt1, D. A. H. Teagle2, S. Umino3, S. Miyashita4, N. R. Banerjee5, D. S. Wilson6, and the IODP Expeditions 309 and 312 Scientists, and the ODP Leg 206 Scientific Party J. C. Alt et al.
  • 1Department of Geological Sciences, University of Michigan, 1000 North University, Ann Arbor, Mich.48109-1005, USA
  • 2School of Ocean and Earth Science, National Oceanography Centre, University of Southampton, European Way, Southampton SO14-3ZH, UK
  • 3Department of Biology and Geosciences, Shizuoka University, Ohya 836, Shizuoka 422-8529, Japan
  • 4Department of Geology, Niigata University, 8050 Ikarashi, Niigata 950-2181, Japan
  • 5Dept. Earth Sciences, Univ. Western Ontario, London, ON N6A 5B7, Canada
  • 6Department of Earth Science and Marine Science Institute, University of California, Santa Barbara, Calif.93106, USA

Abstract. The Integrated Ocean Drilling Program’s (IODP) Expeditions 309 and 312 successfully completed the first sampling of an intact section of upper oceanic crust, through lavas and the sheeted dikes into the uppermost gabbros. Hole 1256D, which was initiated on the Ocean Drilling Program’s (ODP) Leg 206, now penetrates to > 1500 mbsf and > 1250 m sub-basement. The first gabbroic rocks were encountered at 1407 mbsf. Below this, the hole penetrates ~100 m into a complex zone of fractionated gabbros intruded into contact metamorphosed dikes.