| The Characteristics and Mechanism of Island-Arc Volcanism on the Central and Southern Fildes Peninsula, King George Island, Antarctica |
| |
| 摘 要： | The volcanic rock series on the Fildes Peninsula is the product of the later subduction of the Pacific platebeneath the Antarctic plate. It consists mainly of basalt, basaltic andesite and andesite with minor dacite. Itsisotopic ages range from 64.6±1 to 43±2 Ma, belonging to Palaeocene to Eocene. Volcanism in the area maybe divided into two phases. The contents of major oxides, rare earth elements (REE) and trace elements in vol-canic rocks formed in different phases show regular changes, which are mainly related to the rock associationsof these phases. Isotope geochemical studies indicate that the primitive magma in the area originating by par-tial melting in the upper mantle underwent fractional crystallization and ascended to the high-level (shallow)magma chamber. Before eruption the primitive basalt-andesitic magma was subjected to differentiation in thehigh-level magma chamber, forming zones of derivative magmas of different compositions. In various phasesmagma-conducting faults experienced periodic extension and cut through various derivative magma zones indifferent parts of the peninsula, leading to the eruption of magmas of different compositions on the surface andthe formation of volcanic rock associations of corresponding compositions.
|
The Characteristics and Mechanism of Island-Arc Volcanism on the Central and Southern Fildes Peninsula,King George Island,Antarctica |
| |
| Authors: | Li Zhaonai Liu Xiaohan Shang Ruxiang |
| |
| Abstract: | Abstract The volcanic rock series on the Fildes Peninsula is the product of the later subduction of the Pacific plate beneath the Antarctic plate. It consists mainly of basalt, basaltic andesite and andesite with minor dacite. Its isotopic ages range from 64.6 ± 1 to 43 ± 2 Ma, belonging to Palaeocene to Eocene. Volcanism in the area may be divided into two phases. The contents of major oxides, rare earth elements (REE) and trace elements in volcanic rocks formed in different phases show regular changes, which are mainly related to the rock associations of these phases. Isotope geochemical studies indicate that the primitive magma in the area originating by partial melting in the upper mantle underwent fractional crystallization and ascended to the high-level (shallow) magma chamber. Before eruption the primitive basalt-andesitic magma was subjected to differentiation in the high-level magma chamber, forming zones of derivative magmas of different compositions. In various phases magma-conducting faults experienced periodic extension and cut through various derivative magma zones in different parts of the peninsula, leading to the eruption of magmas of different compositions on the surface and the formation of volcanic rock associations of corresponding compositions. |
| |
| Keywords: | |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《Acta Geologica Sinica》浏览原始摘要信息 |
| 点击此处可从《Acta Geologica Sinica》下载免费的PDF全文 |
|
