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doi:10.2204/iodp.proc.308.212.2009

Data report: stress orientations from borehole breakouts, IODP Expedition 308, Ursa area, Mississippi Fan, Gulf of Mexico1

J. Casey Moore,2 Gerardo J. Iturrino,3 Peter B. Flemings,4 and Derek E. Sawyer4

Abstract

Borehole failures are a conspicuous feature of the logging-while-drilling resistivity images at Integrated Ocean Drilling Program Sites U1322 and U1324. Failures appear as irregular zones of low resistivity on opposite sides of the well bore (resembling traditional breakouts) and also as zones of high resistivity flanked by narrower low-resistivity intervals. The failures show a consistent east–west trend at both sites and with depth in each. The inferred SHmin directions are 85°–265° and 91°–271°, respectively, at Sites U1322 and U1324. SHmax at Sites U1322 and U1324 is oriented subparallel to the overall southerly slope of the Gulf of Mexico slope in this region. At Site U1322, SHmin is perpendicular to en echelon extensional fractures along the margin of a submarine landslide.

1 Moore, J.C., Iturrino, G.J., Flemings, P.B., and Sawyer, D.E., 2009. Data report: stress orientations from borehole breakouts, IODP Expedition 308, Ursa area, Mississippi Fan, Gulf of Mexico. In Flemings, P.B., Behrmann, J.H., John, C.M., and the Expedition 308 Scientists, Proc. IODP, 308: College Station, TX (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/​iodp.proc.308.212.2009

2 Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz CA 95064, USA. cmoore@pmc.ucsc.edu

3 Borehole Research Group, Lamont-Doherty Earth Observatory of Columbia University, Palisades NY 10964, USA.

4 John A. and Katherine G. Jackson School of Geosciences, University of Texas, Austin TX 78712, USA.

Initial receipt: 1 July 2008
Acceptance: 24 June 2009
Publication: 1 September 2009
MS 308-212