中国石炭纪构造-地层区划与地层格架

Carboniferous tectonostratigraphic regionalization and stratigraphic framework in China

中国石炭纪构造活跃,在华北地块、扬子地块、塔里木地块等稳定块体间存在着大量造山带,尤其存在着北天山洋、南天山洋、布青山—勉略洋、金沙江洋、甘孜—理塘洋等多个洋盆中的洋板块地层,大地构造分区极为复杂。传统的地层区划主要考虑稳定的地块区,按目前的地理格局来进行地层区划划分。本文通过大地构造单元与构造演化阶段相结合,借鉴目前国内经典的大地构造划分方案,对中国石炭纪构造地层进行区划,共划分出阿尔泰—兴蒙地层大区、北准噶尔—西拉木伦地层大区、天山—北山地层大区、塔里木—阿拉善地层大区、华北地层大区、秦祁昆地层大区、扬子地层大区、华夏地层大区、北羌塘—三江地层大区、班公湖—怒江地层大区、印度地层大区等11个地层大区及若干地层区。其中阿尔泰—兴蒙地层大区位置相当于阿尔泰—兴蒙多岛弧盆系,发育洋板块地层及大量岛弧火山岩,分为阿尔泰地层区和兴安地层区;北准噶尔—西拉木伦地层大区位置相当于额尔齐斯—西拉木伦大洋盆,包括大量岛弧带地层及洋板块地层,分为北准噶尔地层区及西拉木伦地层区;天山—北山地层大区位置相当于天山—北山造山系,发育大量火山岩,分为南准噶尔地层区、北天山地层区、南天山地层区、伊犁地层区及额济纳—北山地层区;塔里木—阿拉善地层大区位置相当于塔里木陆块、塔东南—敦煌隆起及阿拉善地块,为稳定的滨浅海沉积,局部为海陆交互相沉积,分为塔里木地层区和阿拉善地层区;华北地层大区位置相当于华北陆块及贺兰山陆缘裂陷盆地,主要为稳定的海陆交互相地层,分为贺兰山地层区、华北地层区及华北地块北缘地层区,其中华北地层区缺乏密西西比亚纪地层;秦祁昆地层大区位置相当于秦祁昆造山系,分为祁连地层区、东昆仑—柴达木地层区、西昆仑地层区、秦岭地层区、南秦岭-苏鲁地层区;扬子地层大区位置相当于扬子陆块,分为盐源-丽江地层区、中上扬子地层区、下扬子地层区、湘浙赣地层区及滇黔桂地层区,主要为稳定的碳酸盐沉积,仅湘浙赣地层区见现有较多的海陆交互相沉积;华夏地层大区位置相当于武夷-云开造山系,分为粤闽地层区、粤南地层区、钦防地层区、琼北地层区、琼中南地层区及华夏地层区,除钦防地层区为一套深海-半深海硅泥质沉积外,其他地层区主要为滨浅海沉积及少量海陆交互相沉积;北羌塘-三江地层大区位置相当于北羌塘-三江多岛弧盆系,包括多个稳定的小型地块及其间的蛇绿混杂岩带,洋板块地层发育,分为可可西里-巴颜喀拉-勉略地层区、金沙江-哀牢山地层区、中甸-昌都-思茅地层区、鲜水河-甘孜-理塘地层区、北羌塘地层区及甜水海地层区;班公湖-怒江地层大区位置相当于班公湖-双湖-怒江-孟连大洋盆,主要为洋板块地层;印度地层大区位置相当于印度大陆北部被动大陆边缘,以发育冈瓦纳大陆特有的古生物化石组合及冰成岩为特征,分为冈底斯地层区、北喜马拉雅地层区及保山地层区。简单介绍了各地层大区、地层区及部分地层分区内的岩石组合、古生物组合及地层序列。结合实例提出了中国石炭纪地层格架建立的原则,对各地层区系石炭系进行了系统的地层对比,建立了其地层对比关系。

Frequent tectonic activities occurred in the Carboniferous.Between the stable tectonic units,such as the North China Craton,the Yangtze Craton and the Tarim Craton,there are numerous orogenic belts.Particularly in the fossil oceanic basins,various ocean plate strata are widely distributed,which include the North Tianshan Ocean,the South Tianshan Ocean,the Buqingshan-Mianlue Ocean,the Jinshajiang Ocean and the Ganzi-Litang Ocean.Thus the tectonic subdivision of China is extremely complex.The traditional stratigraphic regionalization mainly refers to the distribution of stable blocks,and the stratigraphic regions are divided according to the recent geographic framework.In this contribution,we reestablished the Carboniferous tectonostratigraphic framework of China.According to tectonic units and evolution stages,and in reference to the Chinese classical tectonic subdivision and by authors’own definition,there are 11 tectonostratigraphic super regions:Altai-Xing’an-Mongolia,North Junggar-Xar Moron,Tianshan-Beishan,Tarim-Alxa,North China,Qinling-Qilian-Kunlun,Yangtze,Cathaysia,North Qiangtang-Sanjiang,Bangonghu-Nujiang and India.Among the tectonostratigraphic super regions,Altai-Xing’an-Mongolia approximately overlaps with the Altai-Xing’an-Mongolia arc-basin system.It contains numerous ocean plate strata and arc-related magmatism and could be divided into the Altai and Xing’an stratigraphic regions.The location of North Junggar-Xar Moron is similar to the Erqis-Xar Moron paleo-oceanic basin.This super region comprises abundant arc-related strata and ocean plate strata,and it could be divided into the North Junggar and Xar Moron stratigraphic regions.Tianshan-Beishan occupies the same territory as the Tianshan-Beishan orogenic system.It possesses several stratigraphic regions,including South Junggar,North Tianshan,South Tianshan,Yili and Ejin-Beishan,and is characterized by considerable volcanic rocks.The location of Tarim-Alxa is equivalent to the Tarim Block,the southeastern Tarim-Dunhuang Uplift and the Alxa Block.This super region contains widespread stable coastal to neritic deposits and locally distributed paralic sediments.It could be divided into the Tarim and Alxa stratigraphic regions.North China overlaps with the North China Craton and Helanshan continental margin rift.It comprises the Helanshan,North China and north-marginal North China stratigraphic regions and is mainly occupied by the paralic strata.Moreover,Mississippian strata are absent in the North China stratigraphic region.The Qinling-Qilian-Kunlun super region occupies a similar territory as the Qinling-Qilian-Kunlun orogenic belt.It possesses several stratigraphic regions,involving Qilian,Eastern Kunlun-Qaidam,Western Kunlun,Qinling and Southern Qinling-Sulu.The Yangtze super region overlaps with the Yangtze Craton.It is divided into several units,including Yanyuan-Lijiang,middle to upper Yangtze,lower Yangtze,Xiang-Zhe-Gan and Dian-Qian-Gui stratigraphic regions.Stable carbonate sediments occupy most of the Carboniferous outcrops,and the paralic strata are only preserved in the Xiang-Zhe-Gan stratigraphic region.Cathaysia takes a large territory of the Wuyi-Yunkai orogenic system.Some stratigraphic regions including Yue-Min,southern Yue,Qinfang,Northern Qiong,Middle-Southern Qiong and Cathaysia are identified in this super region.Except for Qinfang,which contains shemipelagic to pelagic,siliceous and argillaceous sediments,other stratigraphic regions are dominated by coastal-neritic sediments and rare paralic deposits.North Qiangtang-Sanjiang overlaps with the North Qiangtang-Sanjiang archipelagic arc-basin system.It comprises multiple micro-blocks,with ophiolitic mélange distributed between the blocks.This super region is characterized by the widespread ocean plate strata and divided into several stratigraphic regions,including Hoh Xil-Bayan Har-Mianlue,Jinshajiang-Ailaoshan,Zhongdian-Changdu-Simao,Xianshuihe-Ganzi-Litang,Northern Qiangtang and Tianshuihai.The territory of Bangonghu-Nujiang could be regarded as the Bangong Lake-Shuanghu-Nujiang-Menglian oceanic basin.The Carboniferous sediments in this super region are dominated by ocean plate strata.The India super region coincides with the passive margin distributed along the northern margin of the Indian Craton.It is characterized by the preservation of particular paleontological assemblages and glacial sediments located in the Gondwana,and could be divided into the Gangdise,Northern Himalaya and Baoshan stratigraphic regions.Various lithostratigraphic,paleontologic assemblages and stratigraphic successions in each stratigraphic super region,region or subregion are briefly introduced.The standards for the establishment of the Carboniferous stratigraphic framework in China are proposed,and correlation of strata is suggested based on the systematic stratigraphic correlation of Carboniferous in each region.