Eocene age of the Baranowski Glacier Group at Red Hill, King George Island, West Antarctica

• Published in: Polish Polar Research
• Main Authors: Mozer Anna, Pécskay Zoltán, Krajewski Krzysztof P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Polish Academy of Sciences 2015
• Subjects: Antarctica; King George Island; Red Hill; Eocene; volcanogenic succession; K-Ar dating; flora; Geology; QE1-996.5; Antarctic; Antarctic Peninsula; West Antarctica; South Shetland Islands; Bransfield Strait; Admiralty Bay; Baranowski Glacier; Zamek; Llano Point; Antarc*; Polar Research
• Online Access: https://doi.org/10.1515/popore-2015-0022; https://doaj.org/article/41dd8e2fe8d24fbd9c538a87f04cdc35

Radiometric and geochemical studies were carried out at Red Hill in the southern part of King George Island (South Shetland Islands, northern Antarctic Peninsula) on the Bransfield Strait coast. The rock succession at Red Hill has been determined to represent the Baranowski Glacier Group that was previously assigned a Late Cretaceous age. Two formations were distinguished within this succession: the lower Llano Point Formation and the upper Zamek Formation. These formations have stratotypes defined further to the north on the western coast of Admiralty Bay. On Red Hill the Llano Point Formation consists of terrestrial lavas and pyroclastic breccia; the Zamek Formation consist predominantly of fine to coarse tuff, pyroclastic breccia, lavas, tuffaceous mud-, silt-, and sandstone, locally conglomeratic. The lower part of the Zamek Formation contains plant detritus (Nothofagus, dicotyledonous, thermophilous ferns) and numerous coal seams (vitrinitic composition) that confirm the abundance of vegetation on stratovolcanic slopes and surrounding lowlands at that time. Selected basic to intermediate igneous rocks from the succession have been analysed for the whole-rock K-Ar age determination. The obtained results indicate that the Red Hill succession was formed in two stages: (1) from about 51–50 Ma; and (2) 46–42 Ma, i.e. during the Early to Middle Eocene. This, in combination with other data obtained from other Baranowski Glacier Group exposures on western coast of Admiralty Bay, confirms the recently defined position of the volcano-clastic succession in the stratigraphic scheme of King George Island. The new stratigraphic position and lithofacies development of the Red Hill succession strongly suggest its correlation with other Eocene formations containing fossil plants and coal seams that commonly occur on King George Island.