FN Archimer Export Format PT J TI The ocean-continent boundary off the western continental margin of Iberia: Crustal structure west of Galicia Bank BT AF WHITMARSH, Robert B WHITE, Robert S HORSEFIELD, Susan J SIBUET, Jean-Claude RECQ, Maurice LOUVEL, Veronique AS 1:1;2:2;3:2;4:3;5:4;6:3,5; FF 1:;2:;3:;4:;5:;6:; C1 SOUTHAMPTON OCEANOG CTR, CHALLENGER DIV SEAFLOOR PROC, EUROPEAN WAY, SOUTHAMPTON, HANTS, ENGLAND. UNIV CAMBRIDGE, DEPT EARTH SCI, BULLARD LABS, CAMBRIDGE CB3 OEZ, ENGLAND. IFREMER, CTR BREST, F-29280 PLOUZANE, FRANCE. UNIV BRETAGNE OCCIDENTALE, UFR SCI & TECH, F-29275 BREST, FRANCE. INST PHYS GLOBE STRASBOURG, ECOLE & OBSERV PHYS GLOBE, F-67084 STRASBOURG, FRANCE. C2 NOC, UK UNIV CAMBRIDGE, UK IFREMER, FRANCE UBO, FRANCE IPGP, FRANCE IN WOS Ifremer jusqu'en 2018 IF 2.68 TC 134 TU CNRS UNIVERSITE STRASBOURG UR https://archimer.ifremer.fr/doc/00281/39255/43277.pdf LA English DT Article CR ZEEGASC2 BO L'Atalante AB A seismic refraction transect across the Galicia Bank continental margin shows that the original continental crust thins westward from 17 to 2 km immediately east of a margin-parallel peridotite ridge (PR). immediately west of the PR, oceanic crust is only 2.5-3.5 km thick, but farther west (oceanward) it thickens to 7 km. The PR caps a similar to 60-km-wide lens-shaped serpentinized peridotite body underlying both thinned continental and thin oceanic crust. When superimposed on a reflection time version of the velocity model, the S reflector is clearly intracrustal at its east end. Westward, S cuts down to lower crustal levels, eventually coinciding with the top of the serpentinized peridotite lens (original crust-mantle boundary). These observations render almost impossible the seafloor exposure of the PR by S acting as a top-to-the-west detachment fault. Numerical models of melting and borehole subsidence information constrain our rifting model. The easternmost continental crust experienced a total stretching factor of 4.3 (most likely in two stages); it probably occurred over similar to 25 m.y., with the highest Fate of stretching at the beginning of the main earlier rift phase (Valanginian; 141-135 Ma). The 3 (4.7) km thick continental crust (depending on whether serpentinized peridotite is assigned to crust or mantle), which may include melt products, requires stretching factors 6 more than 11 (7) and a rift duration of more than 25 (13) m.y. The thin oceanic crust immediately west of the PR is explained by conductive cooling of the mantle during the long prebreakup stretching phase, which temporarily caused reduced melting immediately after breakup. PY 1996 PD DEC SO Journal Of Geophysical Research-solid Earth SN 0148-0227 PU Amer Geophysical Union VL 101 IS B12 UT A1996VX66300040 BP 28291 EP 28314 DI 10.1029/96JB02579 ID 39255 ER EF