1:25万日新幅、札达县幅、姜叶马幅地质调查成果与进展

1:250 000 Rixin, Zanda and Gya'nyima Sheets in Xizang

关键词:  1:25万  地质调查  日新幅  札达县幅  姜叶马幅  成果与进展  西藏

Key words:  1:250 000  geological survey  Rixin Sheet  Zanda Sheet  Gya'nyima Sheet  development  Xizang

摘要:

地层古生物方面,在北喜马拉雅地层分区,新圈定出了石器坡组、普鲁组,在测区东部划分出了石炭系亚里组、纳兴组,确定了测区内札达以东不存在该时期的局部隆起;取得了聂拉木岩群形成于古元古代的年龄信息;将雅鲁藏布江地层区的原修康群、侏罗—白垩纪地层解体;将原亚如那嘎组解体;将原打昌群进一步划分,完善了雅鲁藏布江地层区石炭纪地层系统;在阿里地区普普嘎组和聂聂雄拉组中首次发现了韦拉海扇;古新世早期浮游有孔虫动物群的发现在西藏尚属首次。岩浆岩方面,对区内冈底斯南缘火山岩浆弧带的侵入岩进行了解体,将其划分为白垩纪、古近纪、新近纪3个形成期10个填图单位的侵入体。混杂岩方面,雅鲁藏布江结合带划分为南北两个混杂岩带和札达-仲巴微陆块,在南北混杂岩带内划分了19个填图单位,其中在北带首次发现了早侏罗世混杂岩,同时发现了基质时代为古近纪的泥砂混杂岩。

Abstract:

The delineation of the strata includes the Shiqipo and Pulu Formations in the Northern Himalayan stratigraphic subprovince and the Carboniferous Yali and Naxing Formations in the eastern part of the surveyed areas. There is no evidence on the Carboniferous palaeouplifts in the area east of Zanda. The Nyalam Group Complex indicates a Palaeoproterozoic age. The disintegration of the formerly Xiukang Group and Jurassic-Cretaceous strata and formerly Yarunaga Formation, and subdivision of the formerly Dachang Group help improve the understanding of the Carboniferous stratigraphic systems in the Yarlung Zangbo stratigraphic province. The Weila Pecten is recognized for the first time in the Pupuga and Nieniexiongla Formations in the Ngari region. The early Paleocene planktonic foraminifera are also identified for the first time in Xizang. The intrusive rocks in the southern Gangdise volcanic magmatic arc zone are grouped into ten mappable intrusive unitsformed during the Cretaceous, Paleogene and Neogene, respectively. The Yarlung Zangbo suture zone is divided into northern and southern tectonic mélange zones and Zanda-Zhongba microlandmass, of which the northern and southern mélange zones may be subdivided into nineteen mappable units. The Early Jurassic mélanges and sandy and muddy melanges with the Paleogene matrix are also recognized for the first time in the northern zone.