Meso-Neoproterozoic Sedimentary Formation in the Southern Margin of the North China Craton and Its Geological Implications
详细信息
- 责任者：Hu Guohui (Key Laboratory of Mineralogy and Metallogeny ; Guangzhou Institute of Geochemistry ; Chinese Academy of Sciences ; Guangzhou 510640 ; China) ; Zhao Taiping
- 刊名：Acta Petrologica Sinica
- 出版年：2013
- 卷期：29(7)
- 关键词：中元古代 ; Mesoproterozoic ; 新元古代 ; Neoproterozoic Era ; 地层对比 ; stratigraphic correlation ; 华北地区 ; North China
- 页码：p.2491-2507
- 图表：7 illus., 4 tables, 100 refs.
- 分类号：1200
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
Meso-Neoproterozoic terrigenous clastic and carbonate rocks cover the metamorphic crystalline basement with angular unconformity in the southern margin of the North China Craton ( NCC) ,which can be divided into Songshan-Jishan,Mianchi-Queshan and Xiong’ershan stratigraphic provinces. The Songshan-Jishan stratigraphic province,in the northeast of the Xiong’er basin,is composed of siliceous clastic rocks. The Mianchi-Queshan province,in the northern margin of the Xiong’er basin,consists of the transitional facies of siliceous clastic-carbonate rocks. The Xiong’ershan province,in the southern margin of the basin,is mainly composed of carbonate rocks. Based on their stratigraphic and petrologic characteristics,these sedimentary sequences formed in typical fluvial-marine environment with water depth shallowing from south to north. They can be divided into low sea depth,transgression and high sea depth depositional system accordingly. The petrologic and geochemical signatures show that these sedimentary rocks sourced from post-Archean felsic components with minor basic rocks and formed in a passive continental margin during Mesoproterozoic. However,the Neoproterozoic sequences formed in sedimentary basin related to a continental arc. It implies that more crustal activities and distinct changes in tectonic settings from passive to active continental margin from Mesoproterozoic to Neoproterozoic,a possible effect of the early tectonic events of the Qinling Orogenic Belt. Laser ablation ICP-MS U-Pb dating of detrital zircons from these sedimentary sequences yields ages ranging from ca. 1. 50Ga to 2. 70Ga with most Paleoproterozoic ages ( 1. 70 ～ 2. 40Ga) and minor Archean ages,indicating the detritus mainly sourced from Paleoproterozoic geologic bodies. The youngest ages at the bottom of the sequences of ～ 1600Ma can constrain the maximum age of deposition. The pronounced age peak at ～ 1. 93Ga corresponds to the significant Early Precambrian metamorphic event of the NCC. All detrital zircons have obvious negative to moderately positive ε Hf ( t) values from - 20 to + 6,indicating the contribution of juvenile materials with positive ε Hf ( t) values and reworking of Archean crustal materials with negative ε Hf ( t) values. The Hf model ages ( t DM C ) range from 3. 8Ga to 2. 3Ga and cluster between 3. 0Ga and 2. 6Ga with a peak at ～ 2. 75Ga,implying the major crustal growth occurred at Late Archean.