GEOCHEMICAL FEATURES OF THE VOLCANIC ROCKS OF LINZIZONG GROUP IN CHUOQIN BASIN
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摘要: 青藏高原措勤盆地新生代火山活动十分强烈,以古近纪林子宗群火山岩为代表,主要分布在盆地中央隆起带的冈底斯构造岩浆岩带中,在北部坳陷带中仅有零星分布。林子宗群火山岩主要由安山岩、流纹岩、中酸性熔岩和火山碎屑岩组成。岩石化学研究表明属钙碱-高钾钙碱系列;岩石地球化学研究表明,林子宗群火山岩具岛弧火山岩特点,为喜马拉雅板片与冈底斯-念青唐古拉板片碰撞作用的产物。Abstract: Violent volcanic eruption occurred in the Chuoqin Basin of Qinghai-Tibetan Plateau during Cenozoic era, resulting in volcanic rocks consisting of andesite, rhyolite, intemediate-acid lava flow and pyroclastics known as the Linzizong Group which are distributed mainly in the Gangdise tectono-volcanic belt of the central uplift in the Chuoqin Basin but sparsely scattered in the north depression. Petrochemical study suggests the volcanics are of calc-alkalic to high potassium calc-alkalic suite; Geochemical study indicates that they are akin to the island are type formed by collision of the Himalayian plate with the Gangdis-Nianqing Tangula plate.
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Key words:
- Qinghai-Tibetan Plateau /
- Cuoqin Basin /
- Volcanic rock /
- Tectonic setting
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