SUBVOLCANIC ZONED GRANITIC PLUTON IN THE BARTON AND WEAVER PENINSULAS, KING GEORGE ISLAND, ANTARCTICA

The subvolcanic granitic pluton in the Barton and Weaver Peninsulas, King George Island, is mainly composed of granodiorite with small volumes of gabbro, diorite and aplitic dikes. The pluton shows a vertically compositional zonation; the lower part consists of gabbro and diorite, whereas the upper...

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Bibliographic Details
Main Authors: / ナガオ ケイスケ, Jong Ik LEE, Jeong HWANG, Hyeoncheol KIM, Cheon Yun KANG, Mi Jung LEE, Keisuke NAGAO
Format: Report
Language:English
Published: Polar Research Center, Korea Ocean Research & Development Institute 1996
Subjects:
subvolcanic zoned pluton
King George Island
accumulation
primary granitic magma
Weaver
Barton
Antarc*
Antarctica
Online Access:https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2825
http://id.nii.ac.jp/1291/00002825/
https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2825&item_no=1&attribute_id=18&file_no=1
Description
Summary:The subvolcanic granitic pluton in the Barton and Weaver Peninsulas, King George Island, is mainly composed of granodiorite with small volumes of gabbro, diorite and aplitic dikes. The pluton shows a vertically compositional zonation; the lower part consists of gabbro and diorite, whereas the upper part is mainly granodiorite. Various geochemical signatures of the pluton confirm that all subunits of the pluton were formed by accumulation and fractionation in a calc-alkaline magma at a shallow level of the crust. The positive Sr and Eu anomalies as well as textural features of gabbro strongly support that gabbro was the cumulate derived from accumulation of calcic plagioclase and in situ crystallization of ferromagnesian minerals. Taking into account the geochemical features of gabbro as a cumulate, the primary magma of the pluton is considered to have been intermediate (dioritic or quartz dioritic) in composition.

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