摘要
详细研究了库车坳陷卡普沙良河剖面恰克马克组叠层石的形态及内部构造、微量元素、氧碳同位素特征.指出该叠层石的形成环境为咸水湖盆.从恰克马克组沉积为湖盆扩张期这一事实出发,认为叠层石的发育与干盐湖无关,而可以作为海泛存在的证据.
Stromatolites bioherm lenses 20-40 cm in diameter and 10-20 cm thick developed in the top of the lowest member Qiakemake Formation along Karpsalian section. Club-shaped columns of 3 - 7 cm in diameter with indistinct branches are similar to those discovered in Pillare limestone, Devonian, Australia. The gaps between columns are filled by debres which were derived from stromatolites. There are three kinds of fabrics within the laminae. The first is fenestral fabric, the second is laminated, and the third is the laminar calcretes. The fenestra fabric is dominant, and can be compared with that found in stromatolites from Hamelin Pool, western Australia and stromatolites from the Windjana limestone (Devonian) at Geikie Gorge. The characteristics of the stromatolites suggest that developed in a nearshore environment. Based on geochemical and isotope studies, we find that the stromatolites of Qiakemake Formation developed in an environment of saltwater encroachment.Qiakmak Formation was deposited during the extensional stage of the Tarim basin. Therefore the stromatolites in Qiakmak Formation have no relationship with a playa rather than can act as evidence for a sea-flooding. The co-existence of the lake extension with sea - flooding reveals the extensive tectonic setting of the
出处
《南京大学学报（自然科学版）》
CAS
CSCD
北大核心
2003年第1期9-16,共8页
Journal of Nanjing University（Natural Science）
基金
国家自然科学基金重点项目(49832004)
国家"九五"重点攻关项目(99-111-01-03)
关键词
塔里木盆地
库车坳陷
侏罗系
恰克马克组
叠层石
湖盆扩张
海泛事件
环境意义
Kuqa area, north flank of Tarim Basin during Late Triassic to Middle Jurassic time. The Kuqa rejuvenation foreland basin was created in Late Cenozoic.
