%0 Journal Article
%T Initiation and evolution of the Bogda subduction-torn-type rift<br>论博格达俯冲撕裂型裂谷的形成与演化
%A GU LianXing
%A HU ShouXi
%A YU ChunShui
%A WU ChangZhi
%A YAN ZhengFu
%A <br>顾连兴
%A 胡受奚
%J 岩石学报
%D 2001
%I 
%X The W-E trending Bogda rift is situated between the Junggar and the Turfan-Hami Precambrian blocks. Itextends with the east and is connected with the Devono-Carboniferous Kelameili-Harlik volcanic arc at a large angle. Following the Early and Middle Carboniferous initiation of rifting, a thick sequence of terrestrial elastics with bimodel volcanites was accumulated in the Bogda basin. Rift closure took place towards the end of Middle Carboniferous or during the Late Carboniferous time. Magmatism characterised by widespread diabase with minor intermediate-acidic differenciates represents post-closure tectonic conversion from compression to extension. The eastern and western sections of the rift are distinct in their evolution history. Rifting of the eastern section was commenced during early Carboniferous and featured by volcanism dominated by basalts with minor rhyolites. Intense subsidence of this section led to a bathyal or abyssal environment, and closure of the rift was accomplished by the end of middle Carboniferous or early at the late Carboniferous time. On intense folding, rift sequence of the eastern section is overlain unconformably by the Permian strata, exhibiting "abrupt" closure of the rift. By contrast, rifting of the western section did not become prominent until middle Carboniferous epoch. Rift volcanites are dominated by dacites and rhyolites with minor basalts, and the volcanic-sedimentary sequence was accumulated in a shallow-sea environment. It was not until late Carboniferous that the western section of the rift closed. Without intense folding, rift sequence of this section passes into the overlying Permian strata through a parallel unconformity, exhibiting "gradational" closure of the rift. This rift was initiated by the tearing force induced by oblique subduction of the ancient Asian oceanic crust beneath the ancestral Junggar-Turfan-Hami continental block, and could, therefore, be designated as a subduction-torn-type rift. Conspicuously non-uniform evolution along strike is an essential feature of such a rift type.
%K Orogenic belt
%K Rift
%K Plate subduction
%K Magmatism
%K Volcanism
%K Bogda
%K Xinjiang<br>造山带
%K 裂谷
%K 板块俯冲
%K 岩浆活动
%K 火山作用
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=621CF755B1A341E5&jid=2013B5467E3054B1614CEC199353FCED&aid=8DC7178E7BF5FCAC&yid=14E7EF987E4155E6&vid=BCA2697F357F2001&iid=E158A972A605785F&sid=E513158F1BE1471F&eid=0A8675156EB60B87&journal_id=1000-0569&journal_name=岩石学报&referenced_num=58&reference_num=105