1:25万斯诺乌山幅、狮泉河幅地质调查成果与进展

1:250 000 Sinuowushan and Shiquanhe Sheets in Xizang

关键词:  1:25万  地质调查  斯诺乌山幅  狮泉河幅  成果与进展  西藏

Key words:  1:250 000  geological survey  Sinuowushan Sheet  Shiquanhe Sheet  development  Xizang

摘要:

地层方面,在测区札达陆块厘定出念青唐古拉岩群;在措勤-申扎地层分区发现坚扎弄组在测区的存在,新建淌那勒组;将则弄群火山岩解体;根据化石,则弄群弧火山岩的形成时间为早白垩世;确认狮泉河蛇混岩带的形成时间是晚侏罗世—早白垩世;将才里群解体。岩石方面,在测区不同时代地层中发现火山岩系,填绘出了一系列火山机构;将中新生代深成侵入岩划分为拉轨岗日花岗岩带和冈底斯花岗岩带两个岩浆带;发现浆混岩系。构造方面,发现雅鲁藏布江结合带南北支在图区的存在;证实狮泉河带内存在洋脊蛇绿岩套,狮泉河带存在俯冲;确认班-怒带的南支向北与狮泉河带斜接。

Abstract:

The stratigraphic developments have been achieved in the geological survey within the extent of the 1:250 000 Sinuowushan and Shiquanhe Sheets in Xizang, including the delineation of the Nyainqentanglha Group Complex on the Zanda landmass, recognition of the Jianzhanong Formation in the Coqen-Xainza terrane and re-establishment of the Tangnale Formation, and subdivision of the Zenong Group volcanic rocks. The Zenong Group arc volcanic rocks indicate an Early Cretaceous age, and Shiquanhe ophiolite zone a Late Jurassic to Early Cretaceous age. The Caili Group is subdivided as well. Lithologically, the volcanic rock series can be observed in the strata of varying ages. The volcanic apparatus are mapped. The Mesozoic and Cenozoic plutonic intrusive rocks are grouped into the Lhagoi Kangri and Gangdise granite zones. The magma-mingled rock series are observed. Tectonically, there exist the northern and southern branches of the Yarlung Zangbo suture zone in these Sheets. The subduction and oceanic-ridge ophiolitic suites may be discriminated in the Shiquanhe zone. The southern branch of the Bangong-Nujiang suture zone is obliquely connected with the Shiquanhe zone in the north.