Provenance Analysis of the Sperm Bluff Formation, southern Victoria Land, Antarctica
Beacon Supergroup rocks of probable Devonian age, containing conglomerate clasts of lithologies unknown in outcrop in southern Victoria Land (SVL) occur in the St Johns Range to Bull Pass Region, SVL, Antarctica. The Lower Taylor Group sedimentary rocks, herein called the Sperm Bluff Formation, unco...
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| Format: | Other/Unknown Material |
| Language: | English |
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University of Canterbury. Geological Sciences
2005
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| Online Access: | http://hdl.handle.net/10092/1497 https://doi.org/10.26021/6770 |
| Summary: | Beacon Supergroup rocks of probable Devonian age, containing conglomerate clasts of lithologies unknown in outcrop in southern Victoria Land (SVL) occur in the St Johns Range to Bull Pass Region, SVL, Antarctica. The Lower Taylor Group sedimentary rocks, herein called the Sperm Bluff Formation, unconformably rest on the regionally extensive Kukri Erosion Surface that truncates local basement. The basement complex includes three Plutonic Suites, Dry Valley (DV) 1a, DVIb and DV2 of the Granite Harbour Intrusives that intrude metasedimentary rocks of the Koettlitz Group. Allibone et al. (1993b) suggested a SVL terrane accretion event may have occurred about the same time as accretion of a terrane known as the Bowers terrane in northern Victoria Land (NVL) based on changing chemistry of the CambroOrdovician granitoids. Further, it is suggested that conglomerate clasts of the Sperm Bluff Formation may have been derived from this postulated terrane (Allibone et al., 1993b; and Turnbull et al., 1994). Following extensive fieldwork provenance studies and basin analysis of the sedimentary Sperm Bluff Formation are used here to test these ideas. The Sperm Bluff Conglomerate of Turnbull et al. (1994) is re-interpreted as the Sperm Bluff Formation and described using a lithofacies-based approach. The Sperm Bluff Formation is divided into six lithofacies including 1) Conglomerate Lithofacies; 2) Pebbly Sandstone Lithofacies; 3) Crossbedded Sandstone Lithofacies; 4) Parallelbedded Lithofacies; 5) Low-angle Crossbedded Lithofacies; and 6) Interbedded Siltstone/Sandstone Lithofacies. The intimate field association of the Conglomerate, Pebbly Sandstone and Crossbedded Sandstone Lithofacies ties them to the Conglomerate Lithofacies Association whereas the other three units are independent. The Conglomerate Lithofacies Association is interpreted to represent a wavedominated deltaic environment, based on the presence of broad channels, pervasive crossbedding, paleocurrent and trace fossil data. Both Parallel-bedded and Low-angle ... |
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