Site 111

Abstract

Core samples from the above locality and depth contain Upper Paleozoic spores associated with thermally-altered organic matter, and Jurassic palynomorphs accompanied by relatively unaltered organic matter. It is concluded that the samples are of Jurassic, probably Bajocian, age (ca. 170 million years; Howarth, 1964), and that the Paleozoic fossils have been reworked.

Regional stratigraphy and subsidence of Orphan Basin near the time of breakup and implications for rifting processes

“…Existing biostratigraphic data for the nearby Cumberland B‐55 well also show missing Aptian through Turonian section (Williams, ) atop the elevated basement high. In the East Orphan Basin, extensive erosion over the Central Orphan High is confirmed by significant missing Cretaceous section at both Great Barasway F‐66 and Lona O‐55 (Chevron Canada Limited, ; Williams, ), and at DSDP Site 111 (Laughton et al ., ). In the Flemish Pass Basin, unconformities of this age have also been documented from the Mizzen wells (Fenton, ; Statoil Canada Ltd., ).…”

“…; Hart et al ., ; Williams, ), and similar sediments accumulated on Orphan Knoll above the Bajocian–Albian unconformity (Fig. ; Laughton et al ., ). Subsidence in the East Orphan Basin depocentre also may have occurred at this time, or perhaps earlier, and most of the accommodation space between AU and SU was generated above the area of thinned continental crust.…”

“…The fragmentation of the calcarenites combined with oxidation and alteration of glauconite to limonite suggests prolonged weathering of the exposed sediments on Orphan Knoll. The clasts were further rimmed by phosphate with the outer surface enriched in iron and manganese (Laughton et al ., ). Accordingly, the period of subaerial exposure was followed by a transgression during which sedimentation rates were low forming the phosphatic‐, iron‐ and manganese‐rich rim over the weathered clasts.…”

“…Accordingly, the period of subaerial exposure was followed by a transgression during which sedimentation rates were low forming the phosphatic‐, iron‐ and manganese‐rich rim over the weathered clasts. Overlying sediments comprise Maastrichtian chalks suggesting about 30 Myr of missing time (Laughton et al ., ).…”

“…Laughton et al . () described the top of the Albian–Cenomanian unit (Fig. ) as calcarenites that were fragmented and recemented into a conglomeratic unit with a chalky matrix.…”