阿尔金山北缘恰什坎萨依地区逆冲推覆构造的发现及其构造意义
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摘要
阿尔金山北缘恰什坎萨依地区位于北东向阿尔金走滑断裂北侧与东西向阿尔金北缘断裂夹持的区域,是区域上红柳沟-拉配泉构造带的西段。该区广泛发育火山沉积岩系,前人将其确定为奥陶系拉配泉群,并划分为下岩组(火山岩组)、中岩组(碎屑岩组)和上岩组(碳酸盐岩组)。通过野外地质调查与局部填图,在恰什坎萨依沟、沟口泉铁矿、贝壳滩等地,发现厚层碳酸盐岩以不规则顶盖状出露在较高山顶或山脊上,并与碎屑岩或火山岩呈低角度断层接触关系,构成典型的飞来峰构造。该火山岩组和碎屑岩组已被归为奥陶系,但碳酸盐岩组一直没有精确的生物地层年代依据。综合研究认为,碳酸盐岩应该属中元古界,原来的拉配泉群可能要解体。结合截切推覆构造的冰沟岩体时代,认为推覆构造形成于中—晚奥陶世。该认识与本区在中—晚奥陶世发生裂谷(弧后盆地或有限洋盆)闭合、板块碰撞的区域构造环境和演化历史吻合。
The Qiashikansayi area of Altun Mountains is located in the western segment of Hongliugou-Lapeiquan structural belt,which is bounded by the NE-trending Altun strike-slip faults to the north and EW-trending northern Altun fault. There volcanic-sedimentary rocks are well developed, which are assigned to Lapeiquan Group and divided into three formations: the lower formation(volcanic rock formation), medium formation(fragmental rock formation) and upper formation(carbonate rock formation).Based on the field study and mapping in Qiashikansayi gully, Goukouquan iron ore area and Beiketan area, the author discovered a series of thick bedded carbonate rocks as an irregular top cover outcropped at high hills or ridge of hills and contacting with fragmental rock or volcanic rock under them by lower angle fault, which constitute the typical thrust outlier structure. The volcanic rock and fragmental rock are dated as Ordovician,while the thick bedded carbonate rocks are not dated by any accurate biostratigraphic or chronologic evidence. It is very probable that thick bedded carbonate rocks may be of Meso-Proterozoic period and the Lapeiquan Group was broken up into two parts: one was a new Lapeiquan Group(only consisting of volcanic rock formation and fragmental rock formation), and the other was carbonate rocks formation of Meso-Proterozoic period. According to the age of Binggou granite body which cut off the thrust nappe structural zone, the author considers that the thrust nappe formed in Middle to Late Ordovician epoch(about 460 Ma). All these features are identical to specious tectonic setting of the closure of the Hongliugou-Lapeiquan rift(or back-arc basin or limited ocean basin) and of the collision belt of convergent plate in Middle to Late Ordo-vician epoch and their evolution history.
The Qiashikansayi area of Altun Mountains is located in the western segment of Hongliugou-Lapeiquan structural belt,which is bounded by the NE-trending Altun strike-slip faults to the north and EW-trending northern Altun fault. There volcanic-sedimentary rocks are well developed, which are assigned to Lapeiquan Group and divided into three formations: the lower formation(volcanic rock formation), medium formation(fragmental rock formation) and upper formation(carbonate rock formation).Based on the field study and mapping in Qiashikansayi gully, Goukouquan iron ore area and Beiketan area, the author discovered a series of thick bedded carbonate rocks as an irregular top cover outcropped at high hills or ridge of hills and contacting with fragmental rock or volcanic rock under them by lower angle fault, which constitute the typical thrust outlier structure. The volcanic rock and fragmental rock are dated as Ordovician,while the thick bedded carbonate rocks are not dated by any accurate biostratigraphic or chronologic evidence. It is very probable that thick bedded carbonate rocks may be of Meso-Proterozoic period and the Lapeiquan Group was broken up into two parts: one was a new Lapeiquan Group(only consisting of volcanic rock formation and fragmental rock formation), and the other was carbonate rocks formation of Meso-Proterozoic period. According to the age of Binggou granite body which cut off the thrust nappe structural zone, the author considers that the thrust nappe formed in Middle to Late Ordovician epoch(about 460 Ma). All these features are identical to specious tectonic setting of the closure of the Hongliugou-Lapeiquan rift(or back-arc basin or limited ocean basin) and of the collision belt of convergent plate in Middle to Late Ordo-vician epoch and their evolution history.
引文
[1]郭召杰,张志诚,王建君.阿尔金山北缘蛇绿岩带的Sm-Nd等时线年龄及其大地构造意义[J].科学通报,1998,43(18):1981-1984.
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[9]李松彬,陈柏林,陈正乐,等.阿尔金北缘喀腊大湾地区早古生代中酸性火山熔岩岩石地球化学特征及其构造环境[J].地质论评,2013,59(3):423-436.
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[11]陈柏林,陈正乐,崔玲玲,等.阿尔金喀腊大湾地区成矿构造环境初步研究[J].西北地质,2010,43(增刊):175-176.
[12]陈柏林,王永,陈正乐,等.阿尔金山喀腊大湾地区控矿构造系统研究[J].地学前缘,2015,22(4):67-77.
[13]韩凤彬,陈柏林,崔玲玲,等.阿尔金山喀腊大湾地区中酸性侵入岩SHRIMP年龄及其意义[J].岩石学报,2012,28(7):2277-2291.
[14]赵更新,毛德宝,张燕,等.阿尔金成矿带加里东期主要成矿系统[J].地质调查与研究,2007,30(2):90-97.
[15]杨屹,陈宣华,Gehrels G,等.阿尔金山早古生代岩浆活动与金成矿作用[J].矿床地质,2004,23(4):464-472.
[16]陈柏林,崔玲玲,白彦飞,等.阿尔金断裂走滑位移的新认识——来自阿尔金山东段地质找矿进展的启示[J].岩石学报,2010,26(11):3387-3396.
[17]陈柏林,王世新,祁万修,等.阿尔金北缘大平沟韧脆性变形带特征[J].岩石学报,2008,24(4):637-644.
[18]杨子江,王宗秀,王成.阿尔金山东段恰什坎萨依沟的地层新发现[J].中国地质,2012,38(5):1257-1262.
[19]新疆维吾尔自治区地质矿产局.新疆维吾尔自治区地质志[M].北京:地质出版社,1993:1-941.
[20]杨子江,马华东,王宗秀,等.阿尔金山北缘冰沟蛇绿混杂岩中辉长岩锆石SHRIMP U-Pb定年及其地质意义[J].岩石学报,2012,28(7):2269-2276.
[21]杨经绥,史仁灯,吴才来,等.北阿尔金地区米兰红柳沟蛇绿岩的岩石学特征和SHRIMP定年[J].岩石学报,2008,24(7):1567-1584.
[22]吴才来,姚尚志,曾令森,等.北阿尔金巴什考供-斯米尔布拉克花岗杂岩特征及锆石SHRIMP U-Pb定年[J].中国科学(D辑),2007,37(1):10-26.
[23]盖永生,刘良,康磊,等.北阿尔金蛇绿混杂岩中斜长花岗岩的成因及其地质意义[J].岩石学报,2015,31(9):2549-2565.
[24]陈柏林,李松彬,蒋荣宝,等.阿尔金喀腊大湾地区中酸性火山岩SHRIMP年龄及其构造环境[J].地质学报,2016,90(4):708-727.
[25]陈柏林,李丽,祁万修,等.阿尔金山喀腊大湾铁矿田地质特征与形成时代[J].矿床地质,2016,35(2):315-334.
[26]陈柏林,曹富根,赵树铭,等.大平沟地区褶皱构造及其成因初探[J].地质通报,2011,30(12):1159-1166.
(1)新疆地质局第一区域地质调查大队.巴什考供幅(J-46-Ⅶ)1∶20万区域地质调查报告.1981.
(2)新疆地质矿产局第一区域地质调查大队.新疆若羌县阿尔金山沟口泉一带1∶5万区域地质调查报告.2007.
(3)新疆地质局第一区域地质调查大队.索尔库里幅(J-46-Ⅷ)1∶20万区域地质调查报告.1981.
(4)青海省地质矿产局.鹅博梁幅(J-46-Ⅸ)1∶20万区域地质调查报告.1986.
[2]崔军文,唐哲民,邓晋福,等.阿尔金断裂系[M].北京:地质出版社,1999:1-249.
[3]刘良,车自成,王焰,等.阿尔金高压变质带的特征及其构造意义[J].岩石学报,1999,15(1):57-64.
[4]Sobel E R,Arnaud N.A possible middle Paleozoic suture in the Altun Tagh,NW China[J].Tectonics,1999,18(1):64-74.
[5]Yin A,Rumelhart P E,Butler R,et al.Tectonic history of the Altyn Tagh fault system in northern Tibet inferred from Cenozoic sedimentation[J].Geological Society of America Bulletin,2002,114(10):1257-1295.
[6]陈宣华,Gehrels G E,王小凤,等.阿尔金山北缘花岗岩的形成时代及其构造环境探讨[J].矿物岩石地球化学通报,2003,22(4):294-298.
[7]张建新,孟繁聪,于胜尧,等.北阿尔金HP/LT蓝片岩和榴辉岩的Ar-Ar年代学及其区域构造意义[J].中国地质,2007,34(4):558-564.
[8]刘永顺,辛后田,周世军,等.阿尔金山东段拉配泉地区前寒武纪及古生代构造演化[J].北京:地质出版社,2010:1-211.
[9]李松彬,陈柏林,陈正乐,等.阿尔金北缘喀腊大湾地区早古生代中酸性火山熔岩岩石地球化学特征及其构造环境[J].地质论评,2013,59(3):423-436.
[10]刘兵.阿尔金山喀腊达坂一带火山成因块状硫化物型铅锌矿床地质特征及找矿前景[J].西北地质,2014,47(4):264-268.
[11]陈柏林,陈正乐,崔玲玲,等.阿尔金喀腊大湾地区成矿构造环境初步研究[J].西北地质,2010,43(增刊):175-176.
[12]陈柏林,王永,陈正乐,等.阿尔金山喀腊大湾地区控矿构造系统研究[J].地学前缘,2015,22(4):67-77.
[13]韩凤彬,陈柏林,崔玲玲,等.阿尔金山喀腊大湾地区中酸性侵入岩SHRIMP年龄及其意义[J].岩石学报,2012,28(7):2277-2291.
[14]赵更新,毛德宝,张燕,等.阿尔金成矿带加里东期主要成矿系统[J].地质调查与研究,2007,30(2):90-97.
[15]杨屹,陈宣华,Gehrels G,等.阿尔金山早古生代岩浆活动与金成矿作用[J].矿床地质,2004,23(4):464-472.
[16]陈柏林,崔玲玲,白彦飞,等.阿尔金断裂走滑位移的新认识——来自阿尔金山东段地质找矿进展的启示[J].岩石学报,2010,26(11):3387-3396.
[17]陈柏林,王世新,祁万修,等.阿尔金北缘大平沟韧脆性变形带特征[J].岩石学报,2008,24(4):637-644.
[18]杨子江,王宗秀,王成.阿尔金山东段恰什坎萨依沟的地层新发现[J].中国地质,2012,38(5):1257-1262.
[19]新疆维吾尔自治区地质矿产局.新疆维吾尔自治区地质志[M].北京:地质出版社,1993:1-941.
[20]杨子江,马华东,王宗秀,等.阿尔金山北缘冰沟蛇绿混杂岩中辉长岩锆石SHRIMP U-Pb定年及其地质意义[J].岩石学报,2012,28(7):2269-2276.
[21]杨经绥,史仁灯,吴才来,等.北阿尔金地区米兰红柳沟蛇绿岩的岩石学特征和SHRIMP定年[J].岩石学报,2008,24(7):1567-1584.
[22]吴才来,姚尚志,曾令森,等.北阿尔金巴什考供-斯米尔布拉克花岗杂岩特征及锆石SHRIMP U-Pb定年[J].中国科学(D辑),2007,37(1):10-26.
[23]盖永生,刘良,康磊,等.北阿尔金蛇绿混杂岩中斜长花岗岩的成因及其地质意义[J].岩石学报,2015,31(9):2549-2565.
[24]陈柏林,李松彬,蒋荣宝,等.阿尔金喀腊大湾地区中酸性火山岩SHRIMP年龄及其构造环境[J].地质学报,2016,90(4):708-727.
[25]陈柏林,李丽,祁万修,等.阿尔金山喀腊大湾铁矿田地质特征与形成时代[J].矿床地质,2016,35(2):315-334.
[26]陈柏林,曹富根,赵树铭,等.大平沟地区褶皱构造及其成因初探[J].地质通报,2011,30(12):1159-1166.
(1)新疆地质局第一区域地质调查大队.巴什考供幅(J-46-Ⅶ)1∶20万区域地质调查报告.1981.
(2)新疆地质矿产局第一区域地质调查大队.新疆若羌县阿尔金山沟口泉一带1∶5万区域地质调查报告.2007.
(3)新疆地质局第一区域地质调查大队.索尔库里幅(J-46-Ⅷ)1∶20万区域地质调查报告.1981.
(4)青海省地质矿产局.鹅博梁幅(J-46-Ⅸ)1∶20万区域地质调查报告.1986.