现代地质2000，Vol.14Issue(1)：21-28,8.
藏东南碧土带瓦浦组火山岩形成的大地构造环境
TECTONIC SETTINGS OF THE VOLCANIC ROCKS IN THE WAPU FORMATION FROM BITU ZONE,SOUTHEAST XIZANG
摘要
Abstract
The geological survey in early 90's discovered the Bitu ophiolite in southeast X izang(Tibet),which comprehends the Bitu tectono-magmatic zone a complicated oro genic collage,and named the Wapu Formation which is Late Triassic sediments inte rlayered with andesites.Our study,the first systematic work of petrochemistry o n the volcanic rocks,reveals that the Wapu Formation may include two volcanic su ites with varied tectonic settings and ages.The volcanic rocks in Wapu and Jushu i consist of,in ascending order,basalt as well as sub-ordinate basaltic andesit e,continent-erupted rhyolite,tuff and volcaniclastic rocks.The petrochemistry f eatures indicate the tectonic setting of an oceanic island,which may be one of H awaiian-type,and erupted in Early Permian-early Late Permian.The volcano-sedi mentary strata,with principal part calcareous turbidites and outcroping at Juema -Bage and Zhaxi,are products of an active continental margin:the island arc tho leiite recording a subduction of the major oceanic basin of Paleotethys in early Late Triassic.The Jushui,Xueba and other oceanic islands have been discovered i n southeast Xizang,the recognition of Wapu oceanic island supports further evide nce for the major oceanic basin of Paleotethys being an archipelago.The volcano -sedimentary rock formation comprehends a relative wide back-arc basin in earl y Late Triassic,which can be well comparable with that in southwest Yunnan:an ac tive continental margin of Mariana-type during that time.关键词
古特提斯/洋岛/活动大陆边缘/藏东南Key words
Paleotethys/oceanic island/active continental margin/so utheast Xizang分类
天文与地球科学引用本文复制引用
吴根耀,聂泽同..藏东南碧土带瓦浦组火山岩形成的大地构造环境[J].现代地质,2000,14(1):21-28,8.基金项目
国家自然科学基金重点项目(49232030和49732100) （49232030和49732100）
