Drilling to Gabbro in Intact Ocean Crust

Douglas S. Wilson , Damon A. H. Teagle , Jeffrey C. Alt , Neil R. Banerjee , Susumu Umino , Sumio Miyashita , Gary D. Acton , Ryo Anma , Samantha R. Barr , Akram Belghoul , Julie Carlut , David M. Christie , Rosalind M. Coggon , Kari M. Cooper , Carole Cordier (1) , Laura Crispini , Sedelia Rodriguez Durand , Florence Einaudi , Laura Galli , Yongjun Gao , Jörg Geldmacher , Lisa A. Gilbert , Nicholas W. Hayman , Emilio Herrero-Bervera , Nobuo Hirano , Sara Holter , Stephanie Ingle , Shijun Jiang , Ulrich Kalberkamp , Marcie Kerneklian , Jürgen Koepke , Christine Laverne , Haroldo L. Lledo Vasquez , John Maclennan , Sally Morgan , Natsuki Neo , Holly J. Nichols , Sung-Hyun Park , Marc K. Reichow , Tetsuya Sakuyama , Takashi Sano , Rachel Sandwell , Birgit Scheibner , Chris E. Smith-Duque , Stephen A. Swift , Paola Tartarotti , Anahita A. Tikku , Masako Tominaga , Eugenio A. Veloso , Toru Yamasaki , Shusaku Yamazaki , Christa Ziegler

1 LDO - Domaines Océaniques

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.

Domaines: Pétrographie

Douglas S. Wilson, Damon A. H. Teagle, Jeffrey C. Alt, Neil R. Banerjee, Susumu Umino, et al.. Drilling to Gabbro in Intact Ocean Crust. Sciencemag, 2006, 312 (5776), pp.1016-1020. ⟨10.1126/science.1126090⟩. ⟨hal-00114324⟩