1. Drilling to gabbro in intact ocean crust.
- Author
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Wilson DS, Teagle DA, Alt JC, Banerjee NR, Umino S, Miyashita S, Acton GD, Anma R, Barr SR, Belghoul A, Carlut J, Christie DM, Coggon RM, Cooper KM, Cordier C, Crispini L, Durand SR, Einaudi F, Galli L, Gao Y, Geldmacher J, Gilbert LA, Hayman NW, Herrero-Bervera E, Hirano N, Holter S, Ingle S, Jiang S, Kalberkamp U, Kerneklian M, Koepke J, Laverne C, Vasquez HL, Maclennan J, Morgan S, Neo N, Nichols HJ, Park SH, Reichow MK, Sakuyama T, Sano T, Sandwell R, Scheibner B, Smith-Duque CE, Swift SA, Tartarotti P, Tikku AA, Tominaga M, Veloso EA, Yamasaki T, Yamazaki S, and Ziegler C
- Abstract
Sampling an intact sequence of oceanic crust through lavas, dikes, and gabbros is necessary to advance the understanding of the formation and evolution of crust formed at mid-ocean ridges, but it has been an elusive goal of scientific ocean drilling for decades. Recent drilling in the eastern Pacific Ocean in Hole 1256D reached gabbro within seismic layer 2, 1157 meters into crust formed at a superfast spreading rate. The gabbros are the crystallized melt lenses that formed beneath a mid-ocean ridge. The depth at which gabbro was reached confirms predictions extrapolated from seismic experiments at modern mid-ocean ridges: Melt lenses occur at shallower depths at faster spreading rates. The gabbros intrude metamorphosed sheeted dikes and have compositions similar to the overlying lavas, precluding formation of the cumulate lower oceanic crust from melt lenses so far penetrated by Hole 1256D.
- Published
- 2006
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