华南西部新元古代中期沉积盆地性质及其动力学分析——来自桂北丹洲群的沉积学制约  

An Analysis on Property and Dynamics of the Middle Neoproterozoic Sedimentary Basin in the Western of South China;Constraint from the Sedimentary Data of Danzhou Group in Northern Guangxi

作　　者：杨菲[1,2] 汪正江[1] 王剑[1] 杜秋定[1] 邓奇[1,3] 伍浩[1,3] 周小琳[1] 

机构地区：[1]国土资源部成都地质矿产研究所,成都610082 [2]山东科技大学研究生院,山东青岛266510 [3]中国地质科学院研究生部,北京100037

出　　处：《地质论评》2012年第5期854-864,共11页Geological Review

基　　金：国家自然科学重点基金资助项目(批准号41030315);国家自然科学基金资助项目(批准号41072088);中国地质调查局基础研究项目(编号1212011121111)的成果

摘　　要：在桂北,新元古代丹洲群出露在九万大山至越城岭一带,为一套角度不整合在中——新元古界四堡群变质岩系之上,整合于南华冰期沉积之下的浅变质/未变质沉积岩夹火山岩组合。本文通过对罗城黄金丹洲群剖面的沉积相及沉积序列研究表明:白竹组至合桐组为冲洪积相(移地滨岸相)、三角洲相、浅海陆棚相、碳酸盐缓坡(台地)、深水陆棚相(或欠补偿盆地相)等沉积组合,拱洞组为深水浊积岩、浅海陆棚相沉积组合,晚期为滨浅海相或三角洲相组合。综合剖面沉积相、沉积层序以及其中多幕式的火山—岩浆活动等沉积记录分析,作者认为与新元古代新生沉积盆地开启相伴的双模式的、同期的、一系列大火成岩省的形成,沉积盆地早期的海侵上超和饥饿沉积,晚期差异沉降和快速充填,以及与盆地演化阶段相伴的幕式火山岩浆活动等一系列事实与弧陆碰撞模式是相矛盾的,丹洲群及其相当层位地层应为裂谷盆地充填序列,其盆地演化的阶段性可能是地幔柱幕式活动的沉积响应。The mid-Neoproterozoic Danzhou Group outcropped across the Jiuwandashan Mountains and the Yuecheng Mountains in Northern Guangxi. The Danzhou Group, which consisted of low metamorphic or normal sedimentation inter-bedded with igneous rocks, overlay the Metamorphite series of the Sibao Group with unconfomity; and underlay the Nanhua glacial deposition with conformity. Writers characterized the sedimentary facies and depositional sequences of the Danzhou Group at the Huangjin section, Luocheng County, northern Guangxi. From the bottom to the top, the Baizhu Formation and Hetong Formation were composed of five kinds of facies, alluvial-fluvial facies （ immigrating beach facies） , delta facies, shallow shelf facies, carbonate ramp （ or platform） , deep shelf facies （ or starved basin facies）, respectively. The Gongdong Formation contained deep water turbidite and shallow shelf facies from bottom to top, and lately developed delta facies. Based on the comprehensive analysis of sedimentary facies and sedimentary succession, and eombined with depositional record of volcanic activity, it is believed that the oecurenee of the bimodal large igneous-rock provinces （LIPs） which accompanied with the onset of sedimentary basin, transgression overlap and starve deposition in early stage, and differential subsidence and quickly filling in late stage, and episodic voleano-magmatie activity with the basin evolution, were all contradictory to the arc-continent collision model. The Danzhou Group and its equivalences were an early filling succession of rift basin, and the phases of the basin evolution should be a sedimentary response to mantle plume episodic activities.

关 键 词：桂北 新元古代中期 丹洲群 沉积序列 裂谷盆地 地幔柱活动 

分 类 号：P534.3[天文地球—古生物学与地层学] P512.2[天文地球—地质学]