地质论评
地質論評
지질론평
GEOLOGICAL REVIEW
2015年
1期
195-206
,共12页
白建科%李智佩%徐学义%孙吉明%牛亚卓
白建科%李智珮%徐學義%孫吉明%牛亞卓
백건과%리지패%서학의%손길명%우아탁
火山-沉积序列%后碰撞伸展环境%石炭纪%伊犁地区%西天山
火山-沉積序列%後踫撞伸展環境%石炭紀%伊犛地區%西天山
화산-침적서렬%후팽당신전배경%석탄기%이리지구%서천산
volcanic-sedimentary succession%post-collision extensional setting%Carboniferous%Ili area%western Tianshan
新疆西天山伊犁地区作为中天山微板块的一部分，呈“倒三角形”被缝合带或断裂带所围限。其上广泛出露的石炭纪火山—沉积岩系，是研究西天山石炭纪盆地性质和天山古生代造山作用演化过程最为直接的载体。本文通过对石炭纪火山—沉积剖面的岩石组合、地层序列、构造环境及盆地演化过程研究表明：伊犁地区石炭纪火山—沉积岩与下伏地层（前寒武纪结晶基底或前石炭纪褶皱基底）之间呈广泛的区域性角度不整合接触；火山—沉积岩系由下到上可以划分为2个序列，分别对应于盆地伸展—裂陷演化的两个旋回：序列Ⅰ：大哈拉军山组底部扇三角洲相、向上出现2次爆发相—喷溢相的火山喷发旋回，阿克沙克组底部扇三角洲相，向上过渡为滨浅海相—开阔台地相；序列Ⅱ：伊什基里克组由下到上由3次爆发相—喷溢相的火山喷发旋回构成，东图津河组为浅海陆棚相。西天山伊犁地区石炭纪火山—沉积序列反映了后碰撞伸展环境下的裂谷盆地充填演化过程。
新疆西天山伊犛地區作為中天山微闆塊的一部分，呈“倒三角形”被縫閤帶或斷裂帶所圍限。其上廣汎齣露的石炭紀火山—沉積巖繫，是研究西天山石炭紀盆地性質和天山古生代造山作用縯化過程最為直接的載體。本文通過對石炭紀火山—沉積剖麵的巖石組閤、地層序列、構造環境及盆地縯化過程研究錶明：伊犛地區石炭紀火山—沉積巖與下伏地層（前寒武紀結晶基底或前石炭紀褶皺基底）之間呈廣汎的區域性角度不整閤接觸；火山—沉積巖繫由下到上可以劃分為2箇序列，分彆對應于盆地伸展—裂陷縯化的兩箇鏇迴：序列Ⅰ：大哈拉軍山組底部扇三角洲相、嚮上齣現2次爆髮相—噴溢相的火山噴髮鏇迴，阿剋沙剋組底部扇三角洲相，嚮上過渡為濱淺海相—開闊檯地相；序列Ⅱ：伊什基裏剋組由下到上由3次爆髮相—噴溢相的火山噴髮鏇迴構成，東圖津河組為淺海陸棚相。西天山伊犛地區石炭紀火山—沉積序列反映瞭後踫撞伸展環境下的裂穀盆地充填縯化過程。
신강서천산이리지구작위중천산미판괴적일부분，정“도삼각형”피봉합대혹단렬대소위한。기상엄범출로적석탄기화산—침적암계，시연구서천산석탄기분지성질화천산고생대조산작용연화과정최위직접적재체。본문통과대석탄기화산—침적부면적암석조합、지층서렬、구조배경급분지연화과정연구표명：이리지구석탄기화산—침적암여하복지층（전한무기결정기저혹전석탄기습추기저）지간정엄범적구역성각도불정합접촉；화산—침적암계유하도상가이화분위2개서렬，분별대응우분지신전—렬함연화적량개선회：서렬Ⅰ：대합랍군산조저부선삼각주상、향상출현2차폭발상—분일상적화산분발선회，아극사극조저부선삼각주상，향상과도위빈천해상—개활태지상；서렬Ⅱ：이십기리극조유하도상유3차폭발상—분일상적화산분발선회구성，동도진하조위천해륙붕상。서천산이리지구석탄기화산—침적서렬반영료후팽당신전배경하적렬곡분지충전연화과정。
The Ili area,as a part of the Central Tianshan micro-continent,is a inverse-triangular area bordered by sutures and zones in the Tianshan belt.Carboniferous volcanic—sedimentary rocks widely outcropping in Ili area is the most direct carrier in the study of Carboniferous basin properties of western Tianshan and Paleozoic orogenic evolution of Tianshan.According to the rock assemblage,stratigraphic sequence,tectonic setting and basin evolution of the Carboniferous volcanic—sedimentary section,we can draw the following conclusions:there is a wide regional angular unconformity between the Lower Carboniferous and its underlying strata (the Precambrian crystalline basemen or pre-Carboniferous folded basement ). From bottom to top, Carboniferous volcanic—sedimentary rocks can be divided into two sequences respectively corresponding to two cycles of extensional—rift evolution in the basin.SequenceⅠconsists of Dahalajunshan Formation with fan delta facies in the bottom,upward transition as two cycles from volcano explosive facies to effusive facies and Akeshake Formation with fan delta facies in the bottom,upward transition as from shore—shallow sea facies to open platform facies.SequenceⅡconsists of Yishijilike Formation with three cycles by volcano explosive facies to effusive facies and Dongtujinhe Formation with neritic shelf facies.It is believed that the fill sequences in Carboniferous volcanic—sedimentary basin reflected the process of rift basin filling and evolution in post-collision extensional setting.
