Heavy Minerals from Paleogene Sediments, Deep Sea Drilling Project Leg 81: Their Bearing on Stratigraphy, Sediment Provenance, and the Evolution of the North Atlantic

Abstract

Five heavy mineral associations occur in the Paleocene and Eocene sediments recovered during Leg 81 of the Deep Sea Drilling Project (DSDP) in the SW Rockall area. Association 1, consisting of augite, iddingsite, and olivine, was derived from the basaltic rocks of the northern part of the Rockall Plateau. Association 2 consists of epidote group minerals, including piedmontite, and amphiboles of actinolite, actinolitic hornblende, and magnesio-hornblende compositions, and was derived from the metamorphic basement of south Greenland. Association 3 comprises garnet, augite, apatite, and edenitic and pargasitic amphiboles and has a provenance in the southern Rockall Plateau. Associations 4 (garnet, apatite, edenitic/pargasitic amphiboles) and 5 (garnet, apatite) are intrastratal solution derivatives of Association 3, with successive removal of first pyroxene and then amphibole with increasing depth of burial.Throughout the SW Rockall Plateau area there is a significant change in the spectrum of the above assemblages in the lower part of the Eocene. This change has been noted at Sites 403, 404, 553, and 555 and is defined by the last appearance of Association 2. This level therefore marks the cessation of sediment supply from southern Greenland and is the result of the final separation of Rockall and Greenland immediately prior to magnetic Anomaly 24.

Geochemical and Mineralogical Characters of the Coastal Plain Sediments of the Arabian Gulf, Kuwait

“…Mange-Rajetsky and Oberhanshi [22] demonstrated a stratigraphic trend in amphibole compositions in the Molasse of Savoy (France) which they related to progressive metamorphism of the developing Alpine source area. Morton [23] distinguished two amphibole populations in the early palaeogene sediments of the south-west Rockall plateau (NE Atlantic) on the basis of variations in Si, Mg/(Mg + Fe) and (Na + K). Twenty five amphibole grains from coastal plain deposits of the studies area were analyzed by EPMA.…”

Eocene post-rift tectonostratigraphy of the Rockall Plateau, Atlantic margin of NW Britain: Linking early spreading tectonics and passive margin response

“…Immediately prior to rifting, the siliciclastic component was partly sourced from SE Greenland, but this provenance disappeared as the early ocean basin began to widen (Morton, 1984). During the Mid-Eocene, the SW Rockall Plateau began to subside and siliciclastic material was replaced by carbonate deposits.…”

Compositions of heavy minerals in Northeastern China sandlands and provenance analysis

“…They may also provide some evaluation of source mixture and get more detailed information on lithologic compositions of source areas [10] . Many heavy mineral species are especially useful in provenance studies, such as garnet [11] , tourmaline [12] , pyroxene [13] , amphibole [14] , ilmenite [15,16] , magnetite [17] , zircon [18] and spinel [19] . In order to determine the location and estimate relative contributions of source regions of the three sandlands of northeastern China, assemblages of heavy minerals and chemical compositions of detrital garnets and tourmalines from sand samples of northeastern China sandlands are measured and compared to those from central-southern Mongolia and central Tarim to discuss whether they have similar sources.…”