上扬子区奥陶系五峰组—志留系龙马溪组沉积期火山活动对页岩有机质富集程度的影响
|
摘要
利用等时地层格架内建立的火山活动事件与海洋古生产力及氧化还原环境的对应关系,对上扬子区奥陶系五峰组—志留系龙马溪组沉积期火山活动及其对页岩有机质富集程度的影响进行研究。结果表明,研究区斑脱岩主要发育在五峰组沉积期海侵体系域(TST1)与龙马溪组沉积期海侵体系域(TST2)中,这两个体系域均对应高硅高炭的优质页岩相。根据斑脱岩发育的分段性特征,将TST1划为斑脱岩密集段,TST2划为斑脱岩稀疏段,前者斑脱岩发育频次大于1.5层/Ma且斑脱岩累计厚度比(斑脱岩厚度/页岩厚度)大于1%,后者斑脱岩发育频次小于1.5层/Ma且累计厚度比小于1%。TST1(密集段)较TST2(稀疏段)火山活动强度大且频次高,造成TST1有机质含量普遍较TST2高。剧烈且频繁的火山活动对页岩有机质富集具有双重促进作用,一方面火山灰提供营养物质促进海洋生物生产力,另一方面火山作用产生极度缺氧的环境提高有机质的埋藏量和保存率。
Based on the corresponding relationship between the paleoproductivity, redox conditions and volcanism within a isochronous stratigraphic framework, the effects of volcanic events in the Wufeng–Longmaxi period on organic abundance of shale were examined. Bentonite layers were mostly developed in the transgressive systems tract 1(TST1, Wufeng Formation) and transgressive systems tract 2(TST2, Longmaxi Formation), and the two systems tracts corresponded to favorite shale lithofacies with high silica and total organic carbon(TOC) contents. According to the stratigraphic characteristics of bentonite rich interval, TST1 is classified as the interval with dense bentonite layers with the frequency of bentonite layer(bentonite layers/time) of more than 1.5 layers/Ma and the cumulative thickness ratio of bentonite layers(thickness of bentonite layers/thickness of shale) of more than 1%; TST2 is classified as the interval with sparse bentonite layers(frequency < 1.5 layers/Ma; cumulative thickness ratio < 1%). TST1(dense interval) witnessed more intense and high-frequency volcanic activities than TST2(sparse interval), so the TST1 has higher TOC than TST2 in general. The intense and frequent volcanic activities had dual effects on organic-rich shale: on one hand, volcanic ash provided a sufficient supply of nutrients, which triggered high marine productivity; on the other hand, the extremely anoxic environment caused by volcanic activity enhanced the burial amount and preservation rate of organic matter.
Based on the corresponding relationship between the paleoproductivity, redox conditions and volcanism within a isochronous stratigraphic framework, the effects of volcanic events in the Wufeng–Longmaxi period on organic abundance of shale were examined. Bentonite layers were mostly developed in the transgressive systems tract 1(TST1, Wufeng Formation) and transgressive systems tract 2(TST2, Longmaxi Formation), and the two systems tracts corresponded to favorite shale lithofacies with high silica and total organic carbon(TOC) contents. According to the stratigraphic characteristics of bentonite rich interval, TST1 is classified as the interval with dense bentonite layers with the frequency of bentonite layer(bentonite layers/time) of more than 1.5 layers/Ma and the cumulative thickness ratio of bentonite layers(thickness of bentonite layers/thickness of shale) of more than 1%; TST2 is classified as the interval with sparse bentonite layers(frequency < 1.5 layers/Ma; cumulative thickness ratio < 1%). TST1(dense interval) witnessed more intense and high-frequency volcanic activities than TST2(sparse interval), so the TST1 has higher TOC than TST2 in general. The intense and frequent volcanic activities had dual effects on organic-rich shale: on one hand, volcanic ash provided a sufficient supply of nutrients, which triggered high marine productivity; on the other hand, the extremely anoxic environment caused by volcanic activity enhanced the burial amount and preservation rate of organic matter.
引文
[1]胡艳华,周继彬,宋彪,等.中国湖北宜昌王家湾剖面奥陶系顶部斑脱岩SHRIMP锆石U-Pb定年[J].中国科学:地球科学,2008,38(1):72-77.HU Yanhua,ZHOU Jibin,SONG Biao,et al.SHRIMP zircon U-Pb dating from K-bentonite in the top of Ordovician of Wangjiawan Section,Yichang,Hubei,China[J].SCIENCE CHINA Earth Sciences,2008,51(4):493-498.
[2]吴蓝宇,胡东风,陆永潮,等.四川盆地涪陵气田五峰组-龙马溪组页岩优势岩相[J].石油勘探与开发,2016,43(2):189-197.WU Lanyu,HU Dongfeng,LU Yongchao,et al.Advantageous shale lithofacies of Wufeng Formation-Longmaxi Formation in Fuling gas field of Sichuan Basin,SW China[J].Petroleum Exploration and Development,2016,43(2):189-197.
[3]李登华,李建忠,黄金亮,等.火山灰对页岩油气成藏的重要作用及其启示[J].天然气工业,2014,34(5):56-65.LI Denghua,LI Jianzhong,HUANG Jinliang,et al.An important role of volcanic ash in the formation of shale plays and its inspiration[J].Natural Gas Industry,2014,34(5):56-65.
[4]CHEN X,FAN J X,WANG W H,et al.Stage-progressive distribution pattern of the Lungmachi black graptolitic shales from Guizhou to Chongqing,Central China[J].SCIENCE CHINA Earth Sciences,2017,60(6):1133-1146.
[5]陈旭,樊隽轩,张元动,等.五峰组及龙马溪组黑色页岩在扬子覆盖区内的划分与圈定[J].地层学杂志,2015,39(4):351-359.CHEN Xu,FAN Junxuan,ZHANG Yuandong,et al.Subdivision and delineation of the Wufeng and Lungmachi black shales in the subsurface areas of the Yangtze platform[J].Journal of Stratigraphy,2015,39(4):351-359.
[6]GRADSTEIN F M,OGG J G,SCHMITZ M D,et al.The geologic time scale 2012[M].Amsterdam:Elsevier,2012.
[7]聂海宽,金之钧,马鑫,等.四川盆地及邻区上奥陶统五峰组-下志留统龙马溪组底部笔石带及沉积特征[J].石油学报,2017,38(2):160-174.NIE Haikuan,JIN Zhijun,MA Xin,et al.Graptolites zone and sedimentary characteristics of Upper Ordovician Wufeng Formation and Lower Silurian Longmaxi Formation in Sichuan Basin and its adjacent areas[J].Acta Petrolei Sinica,2017,38(2):160-174.
[8]HUFF W D,BERGSTR?M S M,KOLATA D R,et al.The lower Silurian Osmundsberg K-bentonite,Part II:Mineralogy,geochemistry,chemostratigraphy and tectonomagmatic significance[J].Geological Magazine,2000,135(1):15-26.
[9]SU W B,HE L Q,WANG Y B,et al.K-bentonite beds and high-resolution integrated stratigraphy of the uppermost Ordovician Wufeng and the lowest Silurian Longmaxi formations in South China[J].SCIENCE CHINA Earth Sciences,2003,46(11):1121-1133.
[10]SU W B,HUFF W D,ETTENSOHN F R,et al.K-bentonite,black-shale and flysch successions at the Ordovician-Silurian transition,South China:Possible sedimentary responses to the accretion of Cathaysia to the Yangtze Block and its implications for the evolution of Gondwana[J].Gondwana Research,2009,15(1):111-130.
[11]谢尚克,汪正江,王剑,等.湖南桃源郝坪奥陶系五峰组顶部斑脱岩LA-ICP-MS锆石U-Pb年龄[J].沉积与特提斯地质,2012,32(4):65-69.XIE Shangke,WANG Zhengjiang,WANG Jian,et al.LA-ICP-MSzircon U-Pb dating of the bentonites from the uppermost part of the Ordovician Wufeng Formation in the Haoping section,Taoyuan,Hunan[J].Sedimentary Geology&Tethyan Geology,2012,32(4):65-69.
[12]罗华,何仁亮,潘龙克,等.湖北宣恩县麻阳寨晚奥陶-早志留世龙马溪组斑脱岩LA-ICP-MS锆石U-Pb年龄及其地质意义[J].资源环境与工程,2016,30(1):547-550.LUO Hua,HE Renliang,PAN Longke,et al.LA-ICP-MS Zircon U-Pb age and its significance of late Ordovician-early Silurian Longmaxi Bentonite[J].Resources Environment&Engineering,2016,30(1):547-550.
[13]申宝剑,仰云峰,腾格尔,等.四川盆地焦石坝构造区页岩有机质特征及其成烃能力探讨:以焦页1井五峰-龙马溪组为例[J].石油实验地质,2016,38(4):480-488.SHEN Baojian,YANG Yunfeng,TENGER,et al.Characteristics and hydrocarbon significance of organic matter in shale from the Jiaoshiba structure,Sichuan Basin:A case study of the Wufeng-Longmaxi formations in well Jiaoye1[J].Petroleum Geology and Experiment,2016,38(4):480-488.
[14]戎嘉余,詹仁斌.奥陶纪末集群灭绝后腕足动物复苏的主要源泉:论先驱型生物的分类[J].中国科学:地球科学,1999,29(3):232-239.RONG Jiayu,ZHAN Renbin.Chief sources of brachiopod recovery from the end Ordovician mass extinction with special references to progenitors[J].SCIENCE CHINA Earth Sciences,1999,42(5):553-560.
[15]ALGEO T J,MAYNARD J B.Trace-element behavior and redox facies in core shales of Upper Pennsylvanian Kansas-type cyclothems[J].Chemical Geology,2004,206(3/4):289-318.
[16]TRIBOVILLARD N,ALGEO T J,LYONS T,et al.Trace-metals as paleoredox and paleoproductivity proxies:An update[J].Chemical Geology,2006,232(1/2):12-32.
[17]MA Y Q,MA J F,LU Y C,et al.Geochemistry and sedimentology of the Lower Silurian Longmaxi mudstone in southwestern China:Implications for depositional controls on organic matter accumulation[J].Marine and Petroleum Geology,2016,75:291-309.
[18]OLGUN N,DUGGEN S,ANDRONICO D,et al.Possible impacts of volcanic ash emissions of Mount Etna on the primary productivity in the oligotrophic Mediterranean Sea:Results from nutrient-release experiments in seawater[J].Marine Chemistry,2013,152(2):32-42.
[19]LANGMANN B,ZAK?EK K,HORT M,et al.Volcanic ash as fertiliser for the surface ocean[J].Atmospheric Chemistry&Physics,2010,10(8):3891-3899.
[20]DUGGEN S,CROOT P L,SCHACHT U,et al.Subduction zone volcanic ash can fertilize the surface ocean and stimulate phytoplankton growth:Evidence from biogeochemical experiments and satellite data[J].Geophysical Research Letters,2007,34(1):95-119.
[21]KIMURA H,WATANABE Y.Oceanic anoxia at the PrecambrianCambrian boundary[J].Geology,2001,29(11):995-998.
[22]ROSS D J K,BUSTIN R M.Investigating the use of sedimentary geochemical proxies for paleoenvironment interpretation of thermally mature organic-rich strata:Examples from the Devonian-Mississippian shales,Western Canadian Sedimentary Basin[J].Chemical Geology,2009,260(1/2):1-19.
[23]严德天,陈代钊,王清晨,等.扬子地区奥陶系-志留系界线附近地球化学研究[J].中国科学:地球科学,2009,39(3):285-299.YAN Detian,CHEN Daizhao,WANG Qingchen,et al.Geochemistry study across the Ordovician-Silurian boundary on the Yangtze Platform,South China[J].SCIENCE CHINA Earth Sciences,2009,52(1):38-54.
[24]GENIN A,LAZAR B,BRENNER S.Vertical mixing and coral death in the Red Sea following the eruption of Mount Pinatubo[J].Nature,1995,377(6549):507-510.
[25]PAYNE J L,TURCHYN A V,PAYTAN A,et al.Calcium isotope constraints on the end-Permian mass extinction[J].Proceedings of the National Academy of Sciences of the United States of America,2010,107(19):8543-8548.
[26]殷鸿福,宋海军.古、中生代之交生物大灭绝与泛大陆聚合[J].中国科学:地球科学,2013,43(10):1539-1552.YIN Hongfu,SONG Haijun.Mass extinction and Pangea integration during the Paleozoic-Mesozoic transition[J].SCIENCE CHINAEarth Sciences,2013,56(11):1791-1803.
[27]MIKNIGHT D M,FEDER G L,STILES E A.Toxicity of volcanic-ash leachate to a blue-green alga.Results of a preliminary bioassay experiment[J].Environmental Science&Technology,1981,15(3):362-364.
[28]王玉满,董大忠,黄金亮,等.四川盆地及周边上奥陶统五峰组观音桥段岩相特征及对页岩气选区意义[J].石油勘探与开发,2016,43(1):42-50.WANG Yuman,DONG Dazhong,HUANG Jinliang,et al.Guanyinqiao Member lithofacies of the Upper Ordovician Wufeng Formation around the Sichuan Basin and the significance to shale gas plays,SW China[J].Petroleum Exploration and Development,2016,43(1):42-50.
[29]GONG Q,WANG X D,ZHAO L S,et al.Mercury spikes suggest volcanic driver of the Ordovician-Silurian mass extinction[J].Scientific Reports,2017,7(1):1-7.
[30]JONES D S,MARTINI A M,FIKE D A,et al.A volcanic trigger for the Late Ordovician mass extinction?Mercury data from south China and Laurentia[J].Geology,2017,45(7):631-634.
[2]吴蓝宇,胡东风,陆永潮,等.四川盆地涪陵气田五峰组-龙马溪组页岩优势岩相[J].石油勘探与开发,2016,43(2):189-197.WU Lanyu,HU Dongfeng,LU Yongchao,et al.Advantageous shale lithofacies of Wufeng Formation-Longmaxi Formation in Fuling gas field of Sichuan Basin,SW China[J].Petroleum Exploration and Development,2016,43(2):189-197.
[3]李登华,李建忠,黄金亮,等.火山灰对页岩油气成藏的重要作用及其启示[J].天然气工业,2014,34(5):56-65.LI Denghua,LI Jianzhong,HUANG Jinliang,et al.An important role of volcanic ash in the formation of shale plays and its inspiration[J].Natural Gas Industry,2014,34(5):56-65.
[4]CHEN X,FAN J X,WANG W H,et al.Stage-progressive distribution pattern of the Lungmachi black graptolitic shales from Guizhou to Chongqing,Central China[J].SCIENCE CHINA Earth Sciences,2017,60(6):1133-1146.
[5]陈旭,樊隽轩,张元动,等.五峰组及龙马溪组黑色页岩在扬子覆盖区内的划分与圈定[J].地层学杂志,2015,39(4):351-359.CHEN Xu,FAN Junxuan,ZHANG Yuandong,et al.Subdivision and delineation of the Wufeng and Lungmachi black shales in the subsurface areas of the Yangtze platform[J].Journal of Stratigraphy,2015,39(4):351-359.
[6]GRADSTEIN F M,OGG J G,SCHMITZ M D,et al.The geologic time scale 2012[M].Amsterdam:Elsevier,2012.
[7]聂海宽,金之钧,马鑫,等.四川盆地及邻区上奥陶统五峰组-下志留统龙马溪组底部笔石带及沉积特征[J].石油学报,2017,38(2):160-174.NIE Haikuan,JIN Zhijun,MA Xin,et al.Graptolites zone and sedimentary characteristics of Upper Ordovician Wufeng Formation and Lower Silurian Longmaxi Formation in Sichuan Basin and its adjacent areas[J].Acta Petrolei Sinica,2017,38(2):160-174.
[8]HUFF W D,BERGSTR?M S M,KOLATA D R,et al.The lower Silurian Osmundsberg K-bentonite,Part II:Mineralogy,geochemistry,chemostratigraphy and tectonomagmatic significance[J].Geological Magazine,2000,135(1):15-26.
[9]SU W B,HE L Q,WANG Y B,et al.K-bentonite beds and high-resolution integrated stratigraphy of the uppermost Ordovician Wufeng and the lowest Silurian Longmaxi formations in South China[J].SCIENCE CHINA Earth Sciences,2003,46(11):1121-1133.
[10]SU W B,HUFF W D,ETTENSOHN F R,et al.K-bentonite,black-shale and flysch successions at the Ordovician-Silurian transition,South China:Possible sedimentary responses to the accretion of Cathaysia to the Yangtze Block and its implications for the evolution of Gondwana[J].Gondwana Research,2009,15(1):111-130.
[11]谢尚克,汪正江,王剑,等.湖南桃源郝坪奥陶系五峰组顶部斑脱岩LA-ICP-MS锆石U-Pb年龄[J].沉积与特提斯地质,2012,32(4):65-69.XIE Shangke,WANG Zhengjiang,WANG Jian,et al.LA-ICP-MSzircon U-Pb dating of the bentonites from the uppermost part of the Ordovician Wufeng Formation in the Haoping section,Taoyuan,Hunan[J].Sedimentary Geology&Tethyan Geology,2012,32(4):65-69.
[12]罗华,何仁亮,潘龙克,等.湖北宣恩县麻阳寨晚奥陶-早志留世龙马溪组斑脱岩LA-ICP-MS锆石U-Pb年龄及其地质意义[J].资源环境与工程,2016,30(1):547-550.LUO Hua,HE Renliang,PAN Longke,et al.LA-ICP-MS Zircon U-Pb age and its significance of late Ordovician-early Silurian Longmaxi Bentonite[J].Resources Environment&Engineering,2016,30(1):547-550.
[13]申宝剑,仰云峰,腾格尔,等.四川盆地焦石坝构造区页岩有机质特征及其成烃能力探讨:以焦页1井五峰-龙马溪组为例[J].石油实验地质,2016,38(4):480-488.SHEN Baojian,YANG Yunfeng,TENGER,et al.Characteristics and hydrocarbon significance of organic matter in shale from the Jiaoshiba structure,Sichuan Basin:A case study of the Wufeng-Longmaxi formations in well Jiaoye1[J].Petroleum Geology and Experiment,2016,38(4):480-488.
[14]戎嘉余,詹仁斌.奥陶纪末集群灭绝后腕足动物复苏的主要源泉:论先驱型生物的分类[J].中国科学:地球科学,1999,29(3):232-239.RONG Jiayu,ZHAN Renbin.Chief sources of brachiopod recovery from the end Ordovician mass extinction with special references to progenitors[J].SCIENCE CHINA Earth Sciences,1999,42(5):553-560.
[15]ALGEO T J,MAYNARD J B.Trace-element behavior and redox facies in core shales of Upper Pennsylvanian Kansas-type cyclothems[J].Chemical Geology,2004,206(3/4):289-318.
[16]TRIBOVILLARD N,ALGEO T J,LYONS T,et al.Trace-metals as paleoredox and paleoproductivity proxies:An update[J].Chemical Geology,2006,232(1/2):12-32.
[17]MA Y Q,MA J F,LU Y C,et al.Geochemistry and sedimentology of the Lower Silurian Longmaxi mudstone in southwestern China:Implications for depositional controls on organic matter accumulation[J].Marine and Petroleum Geology,2016,75:291-309.
[18]OLGUN N,DUGGEN S,ANDRONICO D,et al.Possible impacts of volcanic ash emissions of Mount Etna on the primary productivity in the oligotrophic Mediterranean Sea:Results from nutrient-release experiments in seawater[J].Marine Chemistry,2013,152(2):32-42.
[19]LANGMANN B,ZAK?EK K,HORT M,et al.Volcanic ash as fertiliser for the surface ocean[J].Atmospheric Chemistry&Physics,2010,10(8):3891-3899.
[20]DUGGEN S,CROOT P L,SCHACHT U,et al.Subduction zone volcanic ash can fertilize the surface ocean and stimulate phytoplankton growth:Evidence from biogeochemical experiments and satellite data[J].Geophysical Research Letters,2007,34(1):95-119.
[21]KIMURA H,WATANABE Y.Oceanic anoxia at the PrecambrianCambrian boundary[J].Geology,2001,29(11):995-998.
[22]ROSS D J K,BUSTIN R M.Investigating the use of sedimentary geochemical proxies for paleoenvironment interpretation of thermally mature organic-rich strata:Examples from the Devonian-Mississippian shales,Western Canadian Sedimentary Basin[J].Chemical Geology,2009,260(1/2):1-19.
[23]严德天,陈代钊,王清晨,等.扬子地区奥陶系-志留系界线附近地球化学研究[J].中国科学:地球科学,2009,39(3):285-299.YAN Detian,CHEN Daizhao,WANG Qingchen,et al.Geochemistry study across the Ordovician-Silurian boundary on the Yangtze Platform,South China[J].SCIENCE CHINA Earth Sciences,2009,52(1):38-54.
[24]GENIN A,LAZAR B,BRENNER S.Vertical mixing and coral death in the Red Sea following the eruption of Mount Pinatubo[J].Nature,1995,377(6549):507-510.
[25]PAYNE J L,TURCHYN A V,PAYTAN A,et al.Calcium isotope constraints on the end-Permian mass extinction[J].Proceedings of the National Academy of Sciences of the United States of America,2010,107(19):8543-8548.
[26]殷鸿福,宋海军.古、中生代之交生物大灭绝与泛大陆聚合[J].中国科学:地球科学,2013,43(10):1539-1552.YIN Hongfu,SONG Haijun.Mass extinction and Pangea integration during the Paleozoic-Mesozoic transition[J].SCIENCE CHINAEarth Sciences,2013,56(11):1791-1803.
[27]MIKNIGHT D M,FEDER G L,STILES E A.Toxicity of volcanic-ash leachate to a blue-green alga.Results of a preliminary bioassay experiment[J].Environmental Science&Technology,1981,15(3):362-364.
[28]王玉满,董大忠,黄金亮,等.四川盆地及周边上奥陶统五峰组观音桥段岩相特征及对页岩气选区意义[J].石油勘探与开发,2016,43(1):42-50.WANG Yuman,DONG Dazhong,HUANG Jinliang,et al.Guanyinqiao Member lithofacies of the Upper Ordovician Wufeng Formation around the Sichuan Basin and the significance to shale gas plays,SW China[J].Petroleum Exploration and Development,2016,43(1):42-50.
[29]GONG Q,WANG X D,ZHAO L S,et al.Mercury spikes suggest volcanic driver of the Ordovician-Silurian mass extinction[J].Scientific Reports,2017,7(1):1-7.
[30]JONES D S,MARTINI A M,FIKE D A,et al.A volcanic trigger for the Late Ordovician mass extinction?Mercury data from south China and Laurentia[J].Geology,2017,45(7):631-634.