Dredged Rocks from the Armorican and Celtic Margins

This report presents the preliminary results of the study of rocks and sediments obtained by dredging during four cruises of the R/V Jean Charcot and R/V Le Suroît during a cooperative program between CNEXO and CEPM (CH 58 : April 1975 ; SU 01 : December 1975 ; CH 66 : February 1976 ; and CH 67 : March 1976). A bathymetric map of the margins under study, as well as the location of the 27 dredges considered in this report, are presented in Figures 1 and 2, respectively. [NOT CONTROLLED OCR

56. Morphology and Basement Structures of the Goban Spur Continental Margin (Northeastern Atlantic) and the Role of the Pyrenean Orogeny

A new bathymetric map, based mainly on Seabeam data, has been established for the Goban Spur area during a postcruise survey of DSDP Leg 80. Using both Seabeam data and a new series of eight seismic profiles obtained perpen-dicular to the continental margin, we have constructed a new detailed structural map of the Goban Spur continental margin which clearly reveals Caledonian and Variscan trends. Both the thinning of the Goban Spur continental crust, from Early Cretaceous (late Cimmerian phase) to middle Albian time, and subsequent widening of the adjacent oceanic domain, from middle Albian to Campanian time, resulted from tensional movements in a N70 ° direction which fol-lowed Caledonian trends. During the rifting phase, the tops of the tilted fault blocks remained close to sea level. The rapid subsidence of the margin seems to have occurred in the early Albian during the last stage of rifting. Eocene intraplate deformation affected the whole Goban Spur continental margin, but is particularly evident at the Pastouret Ridge, a reactivated oceanic fracture zone. The oceanic domain underwent a slight intraplate compression, which fractured the old oceanic crust through its entire thickness, probably along previous zones of weakness, such as fracture zones