Geological structure of Barton Peninsula and Weaver Peninsula, Maxwell bay King George Island (south Shetland Islands, west Antarctica)

• Autorzy: Birkenmajer K.
• Języki publikacji: EN

Abstrakty

EN

The rock-units of group rank occur at Barton and Weaver penisulas, King George Island (South Shetland Islands, West Antarctica): the Cardozo Cove GRoup (the oldest), the Wegger Peak Group, and the Admiralty Bay Group. The Cardozo Cove Group (CCG) represents a stratiform volcanic-volcaniclastic complex, predominantly andesite and basaltic-andesite lavas, alernating with tuffs and volcanic agglomerates. The rocks are strongly altered due to widespread propylitic and argillic alterations. Hovever, Plant-imprints are locally preservatived in terrestrial-type sediment interlayers. The CCG rocks were strongly folded, locally also low-angle thrust, before the WPG plutonic intrusion wich reset their radiametric ages. The Wegger Peak Group (WPG) is represented by two moderate-scale, and one small-scale, calc-alkaline plutonic intrusions of granodiorite to diorite to quartz-gabbro composition. The Noel Hill pluton (vertical dyke or sill) and the North Spit pluton (vertical sill) probably represent the same intrusive body, displaced by a left-lateral strike-slip fault running along Marian Cove. Radiometric dates plot in two groups: the older one, 63.4-60.6 Ma (Paleocene), probably represents true geological age of the pluton; the younger group, 53-42.1 Ma (Eocene), could be an effect of resetting of older radiometric ages by successive thermal events, mainly at 44 Ma (Middle Eocene). The admiralty Bay Group (ABG) is represented by uncommon hypabyssal intrusions (basalt and andesite): a moderate-size plug, several small dykes and sills. They all post-ddate the CCG and the WPG rocks,thus they are late Middle Eocene or younger in age.

Słowa kluczowe

EN

magmatic rocks; Tertiary

PL

zachodnia Antarktyka; skała magmowa; trzeciorzęd

• Wydawca: Centrum Upowszechniania Nauki PAN
• Czasopismo: Bulletin of the Polish Academy of Sciences. Earth Sciences
• Rocznik: 1998
• Tom: Vol. 46, nr 3-4
• Strony: 191--209
• Opis fizyczny: bibliogr. 44 poz., rys., tab.

Twórcy

autor

Birkenmajer K.

• Instytut Nauk Geologicznych Polskiej Akademii Nauk 32-002 Kraków, ul Senacka 2