Geochronology of selected andesitic lavas from the King George Bay area (SE King George Island)

• Autorzy: Pańczyk M. , Nawrocki J.
• Języki publikacji: EN

Abstrakty

EN

Volcanic rocks from the Lions Rump area, which are the basement for a sequence of glaciomarine sediments of the Polonez Cove Formation, and lava flows from the Turret Point–Three Sisters Point area were sampled for thermogeochronological and palaeomagnetic investigations. Generally, andesitic lavas from King George Bay area consist mainly of clinopyroxene (Ti-augite) orthopyroxene (hyperstene) and plagioclase phenocrysts. The groundmass comprises mostly plagioclase laths, clinopyroxene, titanomagnetite and rare orthopyroxene crystals. However, the modal content, size, shape and distribution of phenocrysts are variable and specific for each sample. The Ar-Ar plateaus ages calculated for lavas from the Lions Rump area are very homogenous and point to middle Eocene age (Lutetian, ~44.5 Ma). The similar and consistent ages for volcanic basement for that area excluded the thesis about separate tectonic evolution of the Warszawa and Kraków blocks at least since the middle Eocene. The lavas from Turret Point and Three Sister Point are younger and were emplaced during the late Eocene (Bartonian/Priabonian: 37.3 š0.4 Ma and Priabonian: 35.35 š0.15 Ma, respectively). The results of isotopic investigations are consistent with magnetic polarities of the rocks indicating that the samples from the Lions Rump area are coeval with the lower part of the C20 polarity chron whereas the sample from Turret Point can be correlated with the upper part of the C17 polarity chron

Słowa kluczowe

EN

West Antarctica; Eocene; 40Ar-39Ar dating; magnetostratigraphy; volcanic rocks

• Wydawca: Państwowy Instytut Geologiczny - Państwowy Instytut Badawczy
• Czasopismo: Geological Quarterly
• Rocznik: 2011
• Tom: Vol. 55, No. 4
• Strony: 323--334
• Opis fizyczny: Bibliogr. 28 poz., rys., tab., wykr.

Twórcy

autor

Pańczyk M.

autor

Nawrocki J.

• Polish Geological Institute - National Research Institute, Rakowiecka 4, PL-00-975 Warszawa, Poland,

Bibliografia

• 1.BARKER P. F. (1982) - The Cenozoic subduction history of the Pacific margin of the Antarctic Peninsula: ridge crest-trench interactions. J. Geol. Soc. London, 139: 787-801.
• 2.BARKER P. F. and BURRELL J. (1977) - The opening of Drake Passage. Marine Geol., 25: 15-34.
• 3.BARKER P. F. and DALZIELI. W. D. (1983) - Progress in geodynamics in the Scotia Arc region. In: Geodynamics of the Eastern Pacific Region (ed. R. Cabre). Caribbaen and Scotia Arcs. Geodyn. Ser., 9: 137-170.
• 4.BIRKENMAJER K. (1980) - Discovery of Pliocene glaciation on King George Island, South Shetland Islands (West Antarctica). Bull. Pol. Acad. Sc. Ser. Sc. Terre., 27: 59-67.
• 5.BIRKENMAJER K. (1981) - Geological relations at Lions Rump. King George Island (South Shetland Island, Antarctica). Stud. Geol. Pol., 72: 75-87.
• 6.BIRKENMAJER K. (1982) - Pliocene tyllite-bearing succession of King George Island (South Shetland Islands, Antarctica). Stud. Geol. Pol., 74: 7-72.
• 7.BIRKENMAJER K. (1983) - Late Cenozoic phases of block-faulting on King George Island (South Shetland Island, West Antarctica). Bull. Acad. Pol. Sc. Ser. Sc. Terre., 30: 21-32.
• 8.BIRKENMAJER K. and GAZDZICKI A. (1986) -Age of the Pecten conglomerate on King George Island, West Antarctica. Bull. Pol. Acad. Sc. Earth Sc., 34:219-226.
• 9.BIRKENMAJER K., NARĘBSKI W., NICOLETTI M. and PETRUCCIANI C. (1983) - K-Ar ages of "Jurassic volcanics" and "Andean" intrusions of King George Island South Shetland Islands (West Antarctica). Bull. Acad. Pol. Sc., Ser. Sc. Terre, Sc., 30 (3-4): 121-131.
• 10.BIRKENMAJER K., SOLIANI E. jr. and KAWASHITA K. (1989) - Geochronology of Tertiary glaciations on King George Island, West Antarctica. Bull. Pol. Acad. Sc. Earth Sc., 37: 27-48.
• 11.DALRYMPLE G. B. and LAMPHERE M. A. (1971) - 40Ar/39Ar technique of K/Ar dating: a comparison with the conventional technique. Earth Planet. Sc. Lett., 12: 300-308.
• 12.GRADSTEIN F. M., OGG J. G. and SMITH A. (2004) - Geological Time Scale 2004. Cambridge University Press, Cambridge.
• 13.KIRSCHVINK J. L. (1980) - The least square line and plane and the analysis of paleomagnetic data. Geoph. J. Royal Astronomical Soc., 62: 699-718.
• 14.KRETZ R. (1983) - Symbols for rock-forming minerals. Am. Miner., 68: 277-279.
• 15.Le MAITRE R. W., BATEMAN P., DUDEK A., KELLER J., LAMEYRE J., Le BAS M., SABINE P. A., SCHMID R., SORENSEN H., STRECKEISEN A., WOOLEY A. R. and ZANETTIN B. (1989) - A classification of igneous rocks and glossary of terms. Recomendations of the International Union of Geological Sciences Subcomission on the Systematics of Igneous Rocks. Blackwell, Oxford.
• 16.LAWVER L. A., GAHAGAN L. M. and COFFIN M. F. (1992) - The development of paleoseaways around Antarctica. Am. Geoph. Union Publ. Antarctic Res. Ser., 56: 7-30.
• 17.LEWANDOWSKI M., WERNER T. and NOWOŻYŃSKI K. (1997) -PCA - a package of Fortran programs for paleomagnetic data analysis. Instit. Geoph., Pol. Acad. Sc., Manuscript.
• 18.LIVERMORE R., NANKIVELL A., EAGLES G. and MORRIS P. (2005) -Paleogene opening of Drake Passage. Earth Planet. Sc. Lett., 236: 459_470.
• 19.NAWROCKI J., PAŃCZYK M. and WILLIAMS I. S. (2010) - Isotopic ages and palaeomagnetism of selected magmatic rocks from King George Island (Antarctic Peninsula). J. Geol. Soc. London., 167: 1063-1079.
• 20.NAWROCKI J., PAŃCZYK M. and WILLIAMS I. S. (2011) - Isotopic ages of selected magmatic rocks from King George Island (West Antarctica) controlled by magneto stratigraphy. Geol. Quart., 55 (4) 301-322.
• 21.PANKHURST R. J. and SMELLIE J. L. (1983) - K-Ar geochronology of the South Shetland Islands. Lesser Antarctica: apparent lateral migration of Jurassic to Quaternary island arc volcanism. Earth Planet. Sc. Lett., 66: 214-222.
• 22.PAULO A. and TOKARSKI A. K. (1982) - Geology of the Turret Point -Three Sisters Point area, King George Island (South Shetland Islands, Antarctica). Stud. Geol. Pol., 74: 39-79.
• 23.PORĘBSKI S. J. and GRADZIŃSKI R. (1987) - Depositional history of the Polonez Cove Formation (Oligocene), King George Island. West Antarctica: a record of continental glaciation shallow-marine sedimentation and contemporaneous volcanism. Stud. Geol. Pol., 97: 7-62.
• 24.PUDEŁKO R. (2008) - Two new topographic maps for sites of scientific interest on King George Island, West Antarctica. Pol. Polar Res., 29: 291-297.
• 25.SMELLIE J. L., PANKHURST R. J., THOMSON M. R. A. and DAVIES R. E. S. (1984) - The geology of the South Shetland Islands. VI. Stratigraphy, geochemistry and evolution. Br. Antarct. Surv. Sc. Rep., 87.
• 26.TROEDSON A. L. and SMELLIE J. L. (2002) - The Polonez Cove Formation of King George Island, Antarctica: stratigraphy, facies and implications for mid-Cenozoic cryosphere development. Sedimentology, 49: 277-301.
• 27.WILLAN R. C. R. and KELLEY S. P. (1999) - Mafic dyke swarms in the South Shetland Islands volcanic arc: unraveling multiepisodic magmatism related to subduction and continental rifting. J. Geoph. Res., 104:23051-23068.
• 28.ZIJDERVELD J. D. A. (1967) - AC demagnetization of rocks: analysis of results. In: Methods in paleomagnetism (eds. D. W. Collinson et al.): 254-287. Elsevier, New York.