摘要
扬子陆核北崆岭地区孔子河-樟村坪一带的"马槽园群"被认为是崆岭地区唯一出露的青白口纪沉积记录,对探讨扬子陆块在Rodinia超大陆中的位置及汇聚与裂解过程具有重要意义.通过对其进行岩石学、沉积学和碎屑锆石年代学研究,并与紧密伴存的南沱组进行对比,结果表明:"马槽园群"与南沱组的空间分布、砾石大小、分选、磨圆等特征相似,都体现了快速混杂堆积特点;最年轻锆石年龄限定"马槽园群"沉积时代晚于786Ma,南沱组则在657~635Ma之间,两者具有相似的碎屑锆石年龄谱特征.由此表明北崆岭地区的这套杂砾岩为新元古代冰碛岩,可与区域上南沱组对比,同属Marinoan冰期产物,而不能以马槽园群称之;其沉积物源来自于邻近崆岭杂岩、黄陵花岗岩和神农架群.
The ＂Macaoyuan Group＂in Kongzihe-Zhangcunping area,regarded as the sole sediment of Qingbaikou Period in North Kongling area,plays an important role to understanding the convergence and cracking of Rodinia Supercontinent.Here,new petrology,sedimentology,and detrital zircon chronology studies are conducted on 12 sections in Kongzihe-Zhangcunping area.The＂Macaoyuan Group＂is similar with the Nantuo Formation in the distribution and gravel features.The U-Pb ages of detridal zircon indicate the＂Macaoyuan Group＂is younger than 786 Ma,and the Nantuo Formation is constrained between657 Ma and 635 Ma.The new findings indicate that the diamictite of＂Macaoyuan Group＂in North Kongling area is Neoproterozoic tillite,most likely time-equivalent to the Nantuo Formation.The sediment provenance is from the Kongling Group,Shennongjia Group and Huangling granite.
作者
赵小明
安志辉
邱啸飞
吴年文
魏运许
胡昆
赵雨溪
Zhao Xiaoming;An Zhihui;Qiu Xiaofei;Wu Nianwen;Wei Yunxu;Hu Kun;Zhao Yuxi(Wuhan Center of China Geological Survey,Wuhan 430205,China;Key Laboratory for Paleontology and Coevolution of Life and Environment,China Geological Survey,Wuhan 430205,Ct~ina;Institute of Geological Survey,China University of Geoscicences,Wuhan 430074,China;College of Energy,Chengdu University of Technology,Chengdu 610059,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2018年第9期3324-3336,共13页
Earth Science
基金
中国地质调查局项目(Nos.121201009000161427,DD20160029)
国家自然科学基金项目(No.41530104)
关键词
马槽园群
南沱组
碎屑锆石
物源
北崆岭地区
地层学
Maeaoyuan Group
Nantuo Formation
detrital zircon
sediment provenance
North Kongling area
stratigraphy.
