Lithofacies palaeogeography of the Early Paleozoic black rock series in Dabashan region and their shale-gas geological significance
Xiong Guoqing1, 2, 3, Wang Jian1, 2, 3, Li Yuanyuan4, Yu Qian2, 3, Men Yupeng2, 3, Zhou Xiaolin1, 2, 3, Xiong Xiaohui2, 3, Zhou Yexin1, 2, 3, Yang Xiao1, 2, 3
1 College of Earth Science,Chengdu University of Technology,Chengdu 610059,Sichuan; 2 Chengdu Center of Geological Survey,China Geological Survey,Chengdu 610081,Sichuan; 3 Key Laboratory of Sedimentary Basin & Oil and Gas Resources,MLR,Chengdu 610081,Sichuan; 4 Shandong Institute of Geophysical & Geochemical Exploration,Jinan 250013,Shandong
Abstract：Two suites of black rock series of the Lower Cambrian Shuijingtuo Formation(the Bashan Formation to the Lujiaping Formation)and the Upper Ordovician Wufeng Formation to the Lower Silurian Longmaxi Formation were developed in the Dabashan region in the Early Paleozoic. Sedimentological research reveals that the black rock series were deposited in a passive continental margin basin in the northern margin of the Yangtze Plate. Their sedimentary environments were mainly a deep shelf due to rapid transgression during the earlier period and gradually changed into the shallow shelf with sea-level decline during the later period with some local reefs and shoals. The Early Cambrian and Late Ordovician to Early Silurian basements of the passive continental margin basin in the study area were not flat,which would result in the multi-island obstructively palaeogeographical pattern in continental margin. But their formation mechanisms are totally different. The Early Cambrian palaeogeographic pattern was inherited from graben-horst pattern of the Doushantuo Stage,and local uplift or submerged uplift remained in garben;but foreland uplift during the Late Ordovician to Early Silurian developed in passive continental margin basin in the northern margin of Yangtze Plate was related to Yangtze Plate subduction to North China Plate. The restricted stagnant ocean is more conducive to high-quality shale formation with heavy thickness,high TOC(2%~6%)and high content of brittle mineral(40%~65%),which are usually sweet target layers for shale-gas exploration,but it is necessary to enforce structural research of preservation conditions.
Xiong Guoqing,Wang Jian,Li Yuanyuan et al. Lithofacies palaeogeography of the Early Paleozoic black rock series in Dabashan region and their shale-gas geological significance[J]. JOPC, 2017, 19(6): 965-986.
[1] 陈朝刚. 2016. 渝东北南大巴山前陆褶皱冲断带下古生界页岩含气量影响因素分析. 石油地质与工程,30(4): 18-22. [Chen C G. 2016. Influencing factors analysis of lower Paleozoic shale gas content in foreland fold thrust belts of south Dabashan,north-eastern Chongqing. Petroleum Geology and Engineering,30(4): 18-22] [2] 陈旭,肖承协,陈洪冶. 1987. 华南五峰期笔石动物群的分异及缺氧环境. 古生物学报,26(3): 326-344. [Chen X,Xiao C X,Chen H Z. 1987. Wufengian(Ashgillian)graptolite faunal differentiation and anoxic environment in South China. Acta Palaeontologica Sinica,26(3): 326-344] [3] 陈旭,徐均涛,成汉钧,汪明洲,陈祥荣,许安东,邓占球,伍鸿基,丘金玉,戎嘉余. 1990. 论汉南古陆及大巴山隆起. 地层学杂志,14(2): 81-116. [Chen X,Xu J T,Cheng H J,Wang M Z,Chen X R,Xu A D,Deng Z Q,Wu H J,Qiu J Y,Rong J Y. 1990. Discussion on Hannan old land and Dabashan uplift. Journal of Stratigraphy,14(2): 81-116] [4] 成汉钧,许安东,陈淑娥. 1988a. 论大巴山地区的临湘组. 西安地质学院学报,10(4): 1-11. [Cheng H J,Xu A D,Chen S E. 1988a. On Linxiang Formation in the Daba mountains. Journal of Xi’an College of Geology,10(4): 1-11] [5] 成汉钧,汪明洲,陈祥荣,许安东,陈淑娥. 1988b. 大巴山奥陶系的研究. 西安地质学院学报,10(1): 1-13. [Cheng H J,Wang M Z,Chen X R,Xu A D,Chen S E. 1988b. A study of Ordovician System in the MTS Dabashan. Journal of Xi’an College of Geology,10(1): 1-13] [6] 成汉钧,汪明洲,陈祥荣,许安东,陈淑娥. 1992. 论大巴山隆起的镇巴上升. 地层学杂志,16(3): 196-199. [Cheng H J,Wang M Z,Chen X R,Xu A D,Chen S E. 1992. Discussion on Zhenba uplift of Dabashan uplift. Journal of Stratigraphy,16(3): 196-199] [7] 成汉钧,叶俭,汪明洲. 1993. 大巴山早古生代地层. 陕西西安: 西北工业大学出版社, 1-215. [Cheng H J,Ye J,Wang M Z. 1993. Early Paleozoic Stratigraphy in Dabashan. Xi’an, Shaanxi: Xibei Industry University Press,1-215] [8] 崔楠,张烨,陆朝晖. 2017. 城口地区鲁家坪组页岩储集特征及含气性影响因素. 新疆石油地质,38(2): 176-181. [Cui N,Zhang Y,Lu C H. 2017. Shale reservoir characteristics and influencing factors on shale gas content in Lujiaping Formation of Chengkou area. Xinjiang Petroleum Geology,38(2): 176-181] [9] 范德廉,叶杰,杨瑞英,黄忠祥. 1987. 扬子地台前寒武—寒武纪界线附近的地质事件与成矿作用. 沉积学报,5(3): 81-96. [Fang D L,Ye J,Yang R Y,Huang Z X. 1987. The geological events and ore mineralization nearby the Precambrian-Cambrian boundary in Yangtze platform. Acta Sedimentologica Sinica,5(3): 81-96] [10] 高长林,刘光祥,张玉箴,吉让寿. 2003. 东秦岭—大巴山逆冲推覆构造与油气远景. 石油实验地质,25(s1): 523-531. [Gao C L,Liu G X,Zhang Y Z,Ji R S. 2003. Thrusting nappe structure and oil-gas potential in eastern Qinling and Daba Mountain. Petroleum Geology and Experiment,25(s1): 523-531] [11] 高长林,秦德余,吉让寿,殷勇. 1990. 东秦岭俯冲消减古洋壳的地球化学鉴定. 石油实验地质,12(2): 135-145. [Gao C L,Qin D Y,Ji R S,Yin Y. 1990. A geochemical determination of the subduction ocean crust in east Qinling mountains. Petroleum Geology and Experiment,12(2): 135-145] [12] 辜学达,刘啸虎. 1997. 四川省岩石地层. 湖北武汉: 中国地质大学出版社, 1-417. [Gu X D,Liu X H. 1997. Lithostratigraphy of Sichuan Province. Wuhan, Hubei: China University of Geosciences Press, 1-417] [13] 郭秀梅,王剑,杨宇宁,周业鑫,牛丙超. 2015. 渝东北地区五峰组—龙马溪组黑色页岩储集层特征. 沉积与特提斯地质,35(2): 54-59. [Guo X M,Wang J,Yang Y N,Zhou Y X,Niu B C. 2015. Black shale reservoirs from the Wufeng and Longmaxi Formations in northeastern Chongqing. Sedimentary Geology and Tethyan Geology,35(2): 54-59] [14] 郭旭升,胡东风,文治东,刘若冰. 2014. 四川盆地及周缘下古生界海相页岩气富集高产主控因素: 以焦石坝地区五峰组—龙马溪组为例. 中国地质,41(3): 893-901. [Guo X S,Hu D F,Wen Z D,Liu R B. 2014. Major factors controlling the accumulation and high productivity in marine shale gas in the Lower Paleozoic of Sichuan basin and its periphery: A case study of the Wufeng-Longmaxi Formation of Jiaoshiba area. Geology in China,41(3): 893-901] [15] 胡艳华,孙卫东,丁兴,汪方跃,凌明星,刘健. 2009. 奥陶纪—志留纪边界附近火山活动记录: 来自华南周缘钾质斑脱岩的信息. 岩石学报,25(12): 3298-3308. [Hu Y H,Sun W D,Ding X,Wang F Y,Ling M X,Liu J. 2009. Volcanic event at the Ordovician-Silurian boundary: The message from K-bentonite of Yangtze Block. Acta Petrologica Sinica,25(12): 3298-3308] [16] 黄志诚,黄钟瑾,陈智娜. 1991. 下扬子区五峰组火山碎屑岩与放射虫硅质岩. 沉积学报,9(2): 1-14. [Huang Z C,Huang Z H,Chen Z N. 1991. Volcanic rock and radiolorian silicilith of Wufeng Formation in lower Yangtze region. Acta Sedimentologica Sinica,9(2): 1-14] [17] 吉让寿,秦德余,高长林. 1990. 古东秦岭洋关闭和华北与扬子两地块的拼合. 石油实验地质,12(4): 353-365. [Ji R S,Qin D Y,Gao C L. 1990. Closing of eastern Qinling palaeoocean and collaging between the North China and Yangtze blocks. Petroleum Geology and Experiment,12(4): 353-365] [18] 姜月华,岳文浙. 1994. 华南下古生界缺氧事件与黑色页岩及有关矿产. 有色金属矿产与勘查,3(5): 272-278. [Jiang Y H,Yue W Z. 1994. Anoxic event,black shales and related mineral resources: Taking the Lower Paleozoic in southern China as example. Geological Exploration for Non-ferrous Metals,3(5): 272-278] [19] 姜月华,岳文浙,业治铮. 1993. 中国南部早寒武世磷矿类型和成因探讨. 矿物岩石地球化学通报,12(3): 159-160. [Jiang Y H,Yue W Z,Ye Z Z. 1993. Discussion on types and origin of Early Cambrian phosphate rock in southern China. Bulletin of Mineralogy,Petrology and Geochemistry,12(3): 159-160] [20] 靳凤仙,邵龙义,梁峰,吝文,李丽,赵群. 2017. 重庆地区下古生界页岩气聚集条件及有利区预测. 古地理学报,19(2): 341-352. [Jin F X,Shao L Y,Liang F,Lin W,Li L,Zhao Q. 2017. Accumulation conditions and strategic select of favorable areas of shale gas of the Lower Paleozoic in Chongqing area. Journal of Palaeogeography(Chinese Edition),19(2): 341-352] [21] 李飞,尚长健,楼章华,朱振宏,李梅,周孝鑫. 2014. 米仓—大巴山海相地层古流体地球化学特征与油气保存. 石油与天然气地质,35(3): 365-371. [Li F,Shan C J,Lou Z H,Zhu Z H,Li M,Zhou X X. 2014. Geochemical characteristics of paleofluid and hydrocarbon preservation in marine strata of Micang-Daba piedmont and its adjacent areas. Oil and Gas Geology,35(3): 365-371] [22] 李荣社. 1990. 陕西紫阳—岚皋地区志留纪岩石地层单位穿时性讨论. 陕西地质,8(2): 59-64. [Li R S. 1990. On the diachronism of the Silurian lithostratigraphic units in the Ziyang-Langao area. Geology of Shaanxi,8(2): 59-64] [23] 李双建,周雁,高波,孙冬胜. 2012. 大巴山山前带油气成藏条件与勘探方向. 地质勘探,32(6): 9-14. [Li S J,Zhou Y,Gao B,Sun D S. 2012. Hydrocarbon pooling conditions of the foothill belt of the Dabashan mountain and exploration direction. Natural Gas Industry,32(6): 9-14] [24] 李智武,刘树根,罗玉宏,刘顺,徐国强. 2006. 南大巴山前陆冲断带构造样式及变形机制分析. 大地构造与成矿学,30(3): 294-304. [Li Z W,Liu S G,Luo Y H,Liu S,Xu G Q. 2006. Structural style and deformational mechanism of southern Dabashan foreland fold-thrust belt in central China. Geotectonica et Metallogenia,30(3): 294-304] [25] 梁峰,拜文华,邹才能,王红岩,武瑾,马超,张琴,郭伟,孙莎莎,朱炎铭,崔会英,刘德勋. 2016. 渝东北地区巫溪2井页岩气富集模式及勘探意义. 石油勘探与开发,43(3): 350-358. [Liang F,Bai W H,Zou C N,Wang H Y,Wu J,Ma C,Zhang Q,Guo W,Sun S S,Zhu Y M,Cui H Y,Liu D X. 2016. Shale gas enrichment pattern and exploration significance of Well WuXi-2 in northeast Chongqing,NE Sichuan Basin. Petroleum Exploration and Development,43(3): 350-358] [26] 罗志立. 1998. 四川盆地基底结构的新认识. 成都理工学院学报,25(2): 191-200. [Luo Z L. 1998. New recognition of basement in Sichuan Basin. Journal of Chengdu University of Technology,25(2): 191-200] [27] 马润华. 2008. 陕西省岩石地层. 湖北武汉: 中国地质大学出版社, 1-291. [Ma R H. 2008. Lithostratigraphy of Shaanxi Province. Wuhan, Hubei: China University of Geosciences Press, 1-291] [28] 马勇,钟宁宁,韩辉,李大华,张毅,程礼军. 2014. 糜棱化富有机质页岩孔隙结构特征及其含义. 中国科学: 地球科学,44(10): 2202-2209. [Ma Y,Zhong N N,Han H,Li D H,Zhang Y,Cheng L J. 2014. Definition and structure characteristics of pores in mylonitized organic-rich shales. Science in China: Earth Sciences,44(10): 2202-2209] [29] 毛黎光,肖安成,魏国齐,沈中延,王亮,张林,钱俊锋. 2011. 扬子地块北缘晚古生代—早中生代裂谷系统的分布及成因分析. 岩石学报,27(3): 721-731. [Mao L G,Xiao A C,Wei G Q,Shen Z Y,Wang L,Zhang L,Qian J F. 2011. Distribution and origin of Late Paleozoic-Early Mesozoic rift systems on the northern margin of the Yangtze block. Acta Petrologica Sinica,27(3): 721-731] [30] 彭小娟,胡明,马航,尹瀚翔. 2014. 渝东北页岩气下古生界储集特征研究. 复杂油气藏,7(3): 24-27. [Peng X J,Hu M,Ma H,Yin H X. 2014. Study on the characteristics of shale-gas reservoir in Lower Paleozoic in the northeast of Chongqing. Complex Hydrocarbon Reservoirs,7(3): 24-27] [31] 戎嘉余. 1984. 上扬子区晚奥陶世海退的生态地层与冰川活动的影响. 地层学杂志,8(1): 19-30. [Rong J Y. 1984. Ecostratigraphic evidence during Late Ordovician regressive and the effect of glaciation in the upper Yangtze region. Journal of Stratigraphy,8(1): 19-30] [32] 戎嘉余. 1986. 生态地层学的基础: 群落生态的研究. 见: 中国古生物学会第13、14届学术年会论文选集. 安徽合肥: 安徽科学技术出版社, 1-22. [Rong J Y. 1986. The Basis of Ecological Stratigraphy: Studies on Community Ecology. In: The Thirteenth and Fourteenth Academic Annual Meeting Selected Papers Sponsored by Palaeontological Society of China. Hefei, Anhui: Anhui Science and Technology Press, 1-22] [33] 戎嘉余,陈旭. 1987. 华南晚奥陶世的动物群分异及生物相、岩相与环境模式. 古生物学报,26(5): 507-535. [Rong J Y,Chen X. 1987. Faunal differentiation,biofacies and lithofacies pattern of Late Ordovician(Ashgillian)in South China. Acta Palaeontologica Sinica,26(5): 507-535] [34] 戎嘉余,方宗杰,周忠和,詹仁斌,王向东,袁训来. 2006. 生物的起源、辐射与多样性演变:华夏化石记录的启示. 北京: 科学出版社,1-962. [Rong J Y,Fang Z J,Zhou Z H,Zhan R B,Wang X D,Yuan X L. 2006. Originations,Radiations and Biodiversity Changes:Evidence from the Chinese Fossil Record. Beijing: Science Press, 1-962] [35] 施春华,曹剑,胡凯,韩善楚,边立曾,姚素平. 2011. 华南早寒武世黑色岩系Ni-Mo多金属矿床成因研究进展. 地质论评,57(5): 718-730. [Shi C H,Cao J,Hu K,Han S C,Bian L Z,Yao S P. 2011. A review on origin of Ni-Mo polymetallic deposits in Lower Cambrian black rock series in South China. Geological Review,57(5): 718-730] [36] 苏文博,何龙清,王永标,龚淑云,周湖云. 2002. 华南奥陶—志留系五峰组及龙马溪组底部斑脱岩与高分辨综合地层. 中国科学: 地球科学,32(3): 207-219. [Su W B,He L Q,Wang Y B,Gong S Y,Zhou H Y. 2002. Bentonites at the bottom of Ordovician-Silurian Wufeng and Longmaxi Formation and high-resolution stratigraphy in Southern China. Science in China: Earth Sciences,32(3): 207-219] [37] 汪明洲,成汉钧,陈祥荣,许安东. 1989. 大巴山区寒武系的研究. 西安地质学院学报,11(4): 1-9. [Wang M Z,Cheng H J,Chen X R,Xu A D. 1989. A study of Cambrian System in the MTS Dabashan. Journal of Xi’an College of Geology,11(4): 1-9] [38] 汪明洲,许安东. 1987. 陕南镇巴地区早寒武世地层: 火烧店组的建立及其地层学意义. 长春地质学院学报,17(3): 249-254. [Wang M Z,Xu A D. 1987. The establishment of Lower Cambrian Huoshaodian Formation and its significance in stratigraphy,Zhenba,southern Shaanxi. Journal of Changchun College of Geology,17(3): 249-254] [39] 汪啸风,柴之芳. 1989. 奥陶系与志留系界线处生物灭绝事件及其与铱和碳同位素异常的关系. 地质学报,63(3): 256-264. [Wang X F,Chai Z F. 1989. Terminal Ordovician mass extinction and its relationship to iridium and carbon isotope anomalies. Acta Geologica Sinica,63(3): 256-264] [40] 汪泽成,邹才能,陶士振,李军,王世谦,赵朝阳. 2004. 大巴山前陆盆地形成及演化与油气勘探潜力分析. 石油学报,25(6): 23-28. [Wang Z C,Zou C N,Tao S Z,Li J,Wang S Q,Zhao C Y. 2004. Analysis on tectonic evolution and exploration potential in Dabashan foreland basin. Acta Petrolei Sinica,25(6): 23-28] [41] 熊小辉,王剑,余谦,杨宇宁,熊国庆,牛丙超,郭秀梅,邓奇. 2015. 富有机质黑色页岩形成环境及背景的元素地球化学反演:以渝东北地区田坝剖面五峰组—龙马溪组页岩为例. 天然气工业,35(4): 25-32. [Xiong X H,Wang J,Yu Q,Yang Y N,Xiong G Q,Niu B C,Guo X M,Deng Q. 2015. Element geochemistry inversion of environment and background of organic-rich black shale formation: A case study of the Wufeng-Longmaxi black shale in the Tianba section in northeastern Chongqing. Natural Gas Industry,35(4): 25-32] [42] 徐道一,张勤文,孙亦因. 1987. 古生物大量灭绝:地质历史发展阶段划分的基本标志. 地质学报,61(3): 195-204. [Xu D Y,Zhang Q W,Sun Y Y. 1987. Biomass extinction:A fundamental indicator for major natural divisions geological history. Acta Geologica Sinica,61(3): 195-204] [43] 许靖华,奥伯亨斯利 H,高计元,孙枢,陈海泓,克雷恩比 U. 1986. 寒武纪生物爆发前的死劫难海洋. 地质科学,21(1): l-5. [Xu J H,Oberhansli H,Gao J Y,Sun S,Chen H H,U Krahenbuhl. 1986. Strangelove ocean before the Cambrian explosion. Scientia Geologica Sinica,21(1): 1-5] [44] 许志琴,卢一伦,汤耀庆, Mattauer M,Matte P, Malavieille J, Tapponnier P, Maluski H. 1986. 东秦岭造山带的变形特征及构造演化. 地质学报,60(3): 237-247. [Xu Z Q,Lu Y L,Tang Y Q, Mattauer M, Matte P, Malavieille J, Tapponnier P, Maluski H. 1986. Deformation characteristics and tectonic evolution of the eastern Qinling orogenic belt. Acta Geologica Sinica,60(3): 237-247] [45] 杨宇宁,王剑,熊国庆. 2016. 沉积环境对页岩气储集层的控制作用: 以渝东北地区五峰组—龙马溪组为例. 沉积与特提斯地质,36(3): 91-97. [Yang Y N,Wang J,Xiong G Q. 2016. Controls of sedimentary environments on shale gas reservoirs: A case study of the Wufeng and Longmaxi Formations in northeastern Chongqing. Sedimentary Geology and Tethyan Geology,36(3): 91-97] [46] 叶俭,杨友运,苏春乾,李钟秀,刘仿韩. 1992. 大巴山南坡奥陶系的沉积环境分析. 西安地质学院学报,14(2): 7-16. [Ye J,Yang Y Y,Su C Q,Li Z X,Liu F H. 1992. An analysis of sedimentary environment of the Ordovician System in the southern slope of the Daba Mountain. Journal of Xi’an College of Geology,14(2): 7-16] [47] 余川,程礼军,曾春林,汪生秀. 2014. 渝东北地区下古生界页岩含气性主控因素分析. 断块油气田,2(3): 296-300. [Yu C,Cheng L J,Zeng C L,Wang S X. 2014. Main controlling factor analysis on gas-bearing property of Lower Paleozoic shale in northeastern Chongqing Region. Fault-Block Oil and Gas Field,2(3): 296-300] [48] 余谦,牟传龙,张海全,谭钦银,许效松,闫剑飞. 2011. 上扬子北缘震旦纪—早古生代沉积演化与储集层分布特征. 岩石学报,27(3): 672-680. [Yu Q,Mou C L,Zhang H Q,Tan Q Y,Xu X S,Yan J F. 2011. Sedimentary evolution and reservoir distribution of northern Upper Yangtze plate in Sinian-Early Paleozoic. Acta Petrologica Sinica,27(3): 672-680] [49] 张国伟. 1988. 秦岭造山带的形成及其演化. 陕西西安: 西北大学出版社,1-192. [Zhang G W. 1988. The Formation and Its Evolution of Qinling Orogenic Belt. Xi’an, Shaanxi: Northwest University Press,1-192] [50] 张国伟,张本仁,袁学诚,肖庆辉. 2001. 秦岭造山带与大陆动力学. 北京: 科学出版社,1-855. [Zhang G W,Zhang B R,Yuan X C,Xiao Q H. 2001. Qinling Orogenic Belt and Geodynamics. Beijing: Science Press,1-855] [51] 张国伟,张宗清,董云鹏. 1995. 秦岭造山带主要构造岩石地层单元的构造性质及其大地构造意义. 岩石学报,11(2): 101-114. [Zhang G W,Zhang Z Q,Dong Y P. 1995. Nature of main tectono-lithostratigraphic units of the Qinling orogen: Implications for the tectonic evolution. Acta Petrologica Sinica,11(2): 101-114] [52] 周业鑫,丁俊,余谦,王剑,门玉澎,熊国庆,熊小辉,邓奇. 2017. 渝东北地区观音桥段沉积与有机碳同位素特征及其区域对比. 地质学报,91(5): 1097-1107. [Zhou Y X,Ding J,Yu Q,Wang J,Men Y P,Xiong G Q,Xiong X H,Deng Q. 2017. Sedimentary and organic carbon isotopic characteristics of the Kuanyinchiao Member in northern Chongqing and its regional correlation. Acta Geologica Sinica,91(5): 1097-1107] [53] 朱瑜,张帆,李少荣. 2016. 渝东北下寒武统水井沱组陆棚相黑色页岩沉积演化特征. 地质科学,51(3): 961-977. [Zhu Y,Zhang F,Li S R. 2016. The sedimentary evolution characteristics of continental shelf facies black shale of Lower Cambrian Shuijingtuo Formation in Northeast Chongqing. Chinese Journal of Geology,51(3): 961-977] [54] 朱兆玲,葛梅钰,许汉奎,刘应楷,李豫忠,苏良友. 1977. 四川城口地区早古生代地层. 地层古生物,5: 1-64. [Zhu Z L,Ge M Y,Xu H K,Liu Y K,Li Y Z,Su L Y. 1977. The Early Paleozoic stratigraphy in Chengkou region,Sichuan. Stratigraphic Paleontology,5: 1-64] [55] Fan D L. 1984. The Lower Cambiran Black Shale Series and the Iridium Anomaly in South China,Development in Geoscience. Beijing: Science Press,215-224. [56] Jiang S Y,Chen Y Q,Ling H F,Yang J H,Feng H Z,Ni P. 2006. Trace-and rare-earth element geochemistry and Pb-Pb dating of black shales and intercalated Ni-Mo-PGE-Au sulfide ores in Lower Cambrian strata,Yangtze Platform,South China. Mineralium Deposita,41(5): 453-467. [57] Sheehan P M. 1973. The relationship of Late Ordovician glaciation to the Ordovician-Silurian changeover in North American brachiopod faunas. Lethia,6: 147-154. [58] Zhang G W,Dong Y P,Lai S C,Guo A L,Meng Q R,Liu S F,Cheng S Y,Yao A P,Zhang Z Q,Pei X Z,Li S Z. 2004. Mianlue tectonic zone and Mianlue suture zone on southern margin of Qinling-Dabie orogenic belt. Science China: Series D,47(4): 300-316.
