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Number of results: 13
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Keywords Antarctic geology

Abstract

Admiralty Bay, which is the largest embayment on King George Island (South Shetland Islands, West Antarctica) has been geologically mapped by the present author between 1977 and 1979. The following rock-complexes have been distinguished: 1) evoic stratiform complex of andesitic and rhyolitic lavas and sediments (Martel Inlet Group and Cardozo Cove Group: probably Upper Jurassic); 2) Andean intrusions represented by gabbroic and dioritic dykes with associated pyrite-mineralization (Wegger Peak Group: approximately Cretaceous-Tertiery boundary); 3) Tertiary stratiform complex of basaltic and andesitic lavas and interstratified sediments, altogether more than 2700 m thick (King Island Supergroup: probably Eocene — Middle Miocene); 4) late Tertiary intrusive complex of basaltic and andesitic dykes and plugs (Admiralty Bay Group: probably boundary of Miocene and Pliocene); 5) late Tertiary effusives: olivine basalts, andesites etc., and sediments, about 600 m thick (Kraków Icefield Supergroup: Pliocene and ?earfy Pleistocene), with well preserved traces of two subsequent glaciations; 6) Quaternary intrusions (Cape Syrezol Group), Pleistocene) and effusives (Penguin Island Group: Holocene), mainly olivine basalts, related to opening of the Bransfield rift. An outline of structural history of King George Island is also presented.
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Abstract

Studies of Quaternary sediments of South Spitsbergen (Hornsund, Bellsund and northern Billefjorden regions) focus on their occurrence, origin and chronostratigraphy. Methods and results of geological mapping are described. Glacial, glaciofluvial, glaciolacustrine and aeolian sedimentary environments, rock glaciers, taluses and raised marine beaches are presented. Mutual relations of these sediments as well as their radiocarbon and thermoluminescence datings made chronostratigraphy of Late Quaternary glacial episodes possible. Results of preliminary neotectonic studies are also presented, the same as works on periglacial phenomena, chemical weathering and tundra vegetation. Key significance of the studies for the Quaternary evolution of the Arctic and for better recognition of geodynamic phenomena of Pleistocene glaciations in Poland (Tatra and Sudeten Mts included) is underlined.
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Abstract

Rocks of the Legoupil Formation in the Cape Legoupil area were folded about a N70E oriented axis. Later these rocks were affected only by brittle deformation which occurred in four stages: (1) jointing — set I, (2) dyking, (3) faulting and, (4) jointing — set II. Both, folding and subsequent brittle deformation, are hardly compatible with the Mesozoic-Cenozoic eastward subduction of the ancient Pacific ocean crust.
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Abstract

Cockburn Island is one of the most historically significant places on the Antarctic continent. The isle was first surveyed in early 1843 during Captain James Ross’ famous expedition, but the early explorers failed to recognise its geological and palaeontological significance. Cockburn Island is exceptional for it has the only succession of Upper Cretaceous, Eocene and Miocene–Pliocene rocks on the continent, which is now known to contain an admirable and diverse fossil record of fauna and flora. These fossil assemblages are providing exciting new information on the evolutionary history of Antarctica. At least 22 species of Late Cretaceous macroinvertebrates and vertebrates have been recognised, whereas the Eocene record is slightly more diverse at 28 macroinvertebrate taxa recorded. The Pliocene macrofossil record is depauperate atsome 11 species, butmicrofossils (diatoms, ostracods, foraminifera) are represented by at least 94 taxa. The palaeoecologic and palaeobiogeographic significance of fossil assemblages is explored in this paper. Further, a checklist of fossils is presented herein, for the first time, as is a bibliography of the geology and palaeontology of the island.
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Abstract

Geological investigations of the 4th Polish Geodynamic Expedition to West Antarctica, summer 1990/91, covered the following topics: volcanological studies and mapping at Deception Island; stratigraphic, palaeonotological and sedimentological studies, and mapping of Tertiary glacial and glacio-marine strata on King George Island; sedimentological and mesostructural studies, and mapping at Hurd Peninsula, Livingston Island; and palaeontological sampling of Jurassic (Mount Flora Formation) and Trinity Peninsula Group deposits at Hope Bay, Trinity Peninsula.
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Abstract

Geological investigations of the 3rd Polish Geodynamic Expedition to West Antarctica, 1987—1988, covered the following topics: sedimentological and mesostructural studies of the Trinity Peninsula Group (?Carboniferous — Triassic) at Hope Bay, Cape Legoupil and Andvord Bay, Antarctic Peninsula, and at South Bay. Livingston Island (South Shetland Islands); late Mesozoic plant-bearing terrestrial sediments at Hope Bay; Antarctic Peninsula Volcanic Group, Andean-type plutons and systems of acidic and basic dykes (Upper Cretaceous and ?Tertiary) at Trinity Peninsula and around Gerlache Strait (Arctowski Peninsula, Anvers and Brabant islands); basalts and hyaloclastites within Tertiary glacigenic successions of King George Island; volcanic succession of the Deception Island caldera.
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Abstract

Plastic rocks can creep, therefore the knowledge of the rheological properties of the drilled formations is an important element of the drilling process and when choosing borehole designs. These properties of plastic formations also influence the way in which appropriate drilling technology and drilling mud properties are selected. The article presents the effect of basic rheological parameters of salt from the Fore-Sudetic Monocline deposit on the drilling of boreholes in the mining area of KGHM Polska Miedź, which in the future can be used as a good drilling practice to improve the safety and efficiency of drilling. The process of drilling in plastic rocks may be hindered. Salt is a plastic rock and in the analyzed rock mass it is deposited at a considerable depth. The caprock exerts big loads on it, beside the temperature in the deposit intensifies the rheological properties of the rock. The creep process causes that the borehole contracts, therefore the knowledge about the rheological properties of the drilled rock is very important for establishing the safe time in which the well may remain uncased. The paper is devoted to the influence of basic rheological parameters of salt bed in the Fore-Sudetic Monocline on the process of drilling of a borehole in the area of KGHM Polska Miedź as these data can be used in drilling practice in the future.
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Abstract

The lithospheric transect South Shetland Islands (SSI) — Antarctic Peninsula (AP) includes: the Shetland Trench (subductional) and the adjacent portion of the SE Pacific oceanic crust; the South Shetland Microplate (younger magmatic arc superimposed on continental crust); the Bransfield Rift and Platform (younger back-arc basin); the Trinity Horst (older magmatic arc superimposed on continental crust); the Gustav Rift (Late Cenozoic) and James Ross Platform (older back-arc basin). Deep seismic sounding allowed to trace the Moho discontinuity at about 30 km under South Shetlands and at 38—42 km in the northern part of Antarctic Peninsula (Trinity Horst), under typical continental crust. Modified crust was recognized under Bransfield Strait. Geological interpretation based on deep seismic refraction and multichannel reflection soundings, and surface geological data, is presented.
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Abstract

The Slyngfjellet Conglomerate which occurs at the base of the Upper Proterozoic Sofiebogen Group in South Spitsbergen had formed predominantly as a debris-flow deposit, with subordinate contribution by fluvial and probably lacustrine sediments. There is no evidence for glacial conditions at the time of formation of the conglomerate, the latter being much older than the latest Proterozoic Varangian glaciation tillites elsewhere in Svalbard. The Slyngfjellet Conglomerate originally filled buried valleys eroded by rivers in block-faulted and uplifted western margin of the Mid-Proterozoic Torellian Basin.
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