Dinoflagellate cyst and pollen/spore abundance and preservation of ODP Leg 188 sites
Sites 1165 and 1167 were drilled on the continental slope and rise seaward of Prydz Bay, East Antarctica. The sediments penetrated are glacigene and independently dated as Neogene age (early Miocene and younger) using diatoms, radiolarians, nannofossils, and paleomagnetic data. In this depositional...
| Main Authors: | , |
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| Format: | Other/Unknown Material |
| Language: | English |
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PANGAEA
2004
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| Subjects: | |
| Online Access: | https://doi.pangaea.de/10.1594/PANGAEA.780398 https://doi.org/10.1594/PANGAEA.780398 |
| Summary: | Sites 1165 and 1167 were drilled on the continental slope and rise seaward of Prydz Bay, East Antarctica. The sediments penetrated are glacigene and independently dated as Neogene age (early Miocene and younger) using diatoms, radiolarians, nannofossils, and paleomagnetic data. In this depositional setting, most, though not all, palynomorphs recovered are not in situ but have been recycled from older sequences. However, a number of dinoflagellate cyst taxa recovered from Site 1165 support a Neogene age, although their stratigraphic distribution requires further study. They include species referable to the genera Batiacasphaera, Protoellipsodinium, cf. Cymatiosphaera, and Svalbardella. Fossil pollen and spores recovered from Site 1165 include a spore species that appears to be diagnostic of early Miocene sediments encountered in the Cape Roberts Project drill hole CRP-1 in the Ross Sea. The presence of this species, referred to as Coptospora sp. b, strengthens the case that some other spore and pollen species may be in situ, and that a woody tundra vegetation of shrubby gymnosperms and Southern Beech (Nothofagus) survived in East Antarctica into Miocene time. Recycled plant microfossils range in age from Permian and Early Jurassic to late Eocene and Oligocene. Permian taxa are most abundant on the continental shelf (Site 1167), implying that this component was transported in lithified sediments as part of the coarse bed load. Possible source beds are present in the Prince Charles Mountains. Cretaceous-Paleogene microfossils are more abundant on the continental rise (Site 1165). Early Jurassic taxa, present at both sites, reflect close floristic links between East Antarctica, southwestern Australia, and India during the Mesozoic. Beds of this age are known from the Mac.Robertson Shelf, west of Prydz Bay. Late Cretaceous taxa reflect Turonian-?Santonian sediments; these are known from Sites 1166 and 742 within Prydz Bay. Relative abundance data for Site 1167 are consistent with a simple glacial unroofing model in ... |
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