内蒙古锡林浩特跃进公社地区温都尔庙群年代学、地球化学特征及构造环境
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摘要
温都尔庙群为一套绢云绿泥石英片岩、绢云石英片岩、二云石英片岩、黑云斜长片麻岩、变粒岩、石英岩等的变质岩组合,形成于新元古代。LA-ICP-MS锆石U-Pb同位素定年结果显示,温都尔庙群中的岩浆热事件年龄为459.0±1.8Ma,变质年龄为898.9±5.2Ma,即锡林浩特地区存在900Ma左右的变质基底岩系。温都尔庙群片岩样品显示轻稀土元素富集的中等分异特征,并有一定的负Eu异常,其稀土元素分布模式接近于安第斯型;在微量元素原始地幔标准化图解中,出现明显的高场强元素Nb负异常,表明原岩受地壳混染作用影响;Sr/Ba平均值为0.30,小于1,基本反映了副变质岩的特点。通过岩石地球化学图解分析,认为本区温都尔庙群哈尔哈达组的原岩为沉积岩,岩性主要为砂岩和泥岩。地球化学特征及形成构造环境判别结果表明,温都尔庙群哈尔哈达组片岩原岩沉积环境为活动大陆边缘体系。
The Ondor Sum Group is a set of combined metamorphic rocks, which consist mainly of sericite chlorite schist, quartz sericite schist, two mica quartz schist, biotite plagioclase gneiss, leptynite and quartzite, and was formed in Neoproterozoic. LA-ICPMS zircon U-Pb dating results show that the age of magmatic event in the Ondor Sum Group is 459.0 ± 1.8 Ma, and the metamorphic age is 898.9±5.2 Ma, suggesting that there exists a metamorphic basement rock series of 900 Ma in Xilinhot area.The Ondor Sum Group schist samples show moderate differentiation characteristics of LREE enrichment, and have some negative anomalies of Eu, whereas the REE distribution pattern is close to the Andean type. In the normalized multi-element diagrams of primitive mantle, the high field strength element Nb has clear negative anomalies, indicating that the original rock was affected by the action of crustal contamination. The mean Sr/Ba ratio is 0.30, which is less than 1, basically reflecting the characteristics of parametamorphism. Based on the lithogeochemical analysis, it is considered that the original rocks of the Harhada Formation in the Ondor Sum Group in this area were sedimentary rocks, with the lithology being mainly sandstone and mudstone. The comprehensive geochemical characteristics and the discrimination of the tectonic environment indicate that the sedimentary environment of the Harhada Formation schist rock in the Ondor Sum Group is of an active continental margin system.
The Ondor Sum Group is a set of combined metamorphic rocks, which consist mainly of sericite chlorite schist, quartz sericite schist, two mica quartz schist, biotite plagioclase gneiss, leptynite and quartzite, and was formed in Neoproterozoic. LA-ICPMS zircon U-Pb dating results show that the age of magmatic event in the Ondor Sum Group is 459.0 ± 1.8 Ma, and the metamorphic age is 898.9±5.2 Ma, suggesting that there exists a metamorphic basement rock series of 900 Ma in Xilinhot area.The Ondor Sum Group schist samples show moderate differentiation characteristics of LREE enrichment, and have some negative anomalies of Eu, whereas the REE distribution pattern is close to the Andean type. In the normalized multi-element diagrams of primitive mantle, the high field strength element Nb has clear negative anomalies, indicating that the original rock was affected by the action of crustal contamination. The mean Sr/Ba ratio is 0.30, which is less than 1, basically reflecting the characteristics of parametamorphism. Based on the lithogeochemical analysis, it is considered that the original rocks of the Harhada Formation in the Ondor Sum Group in this area were sedimentary rocks, with the lithology being mainly sandstone and mudstone. The comprehensive geochemical characteristics and the discrimination of the tectonic environment indicate that the sedimentary environment of the Harhada Formation schist rock in the Ondor Sum Group is of an active continental margin system.
引文
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[2]内蒙古自治区地质矿产局.内蒙古自治区区域地质志[M].北京:地质出版社, 1991:725.
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[10]葛梦春,周文孝,于洋,等.内蒙古锡林郭勒杂岩解体及表壳岩系年代确定[J].地学前缘, 2011, 18(5):1-14.
[11]赵光,朱永峰,张勇.内蒙古锡林郭勒杂岩岩石学特征及其变质作用的P-T条件[J].岩石矿物学杂志, 2002, 21(1):40-48.
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[13]徐备,刘树文,王长秋,等.内蒙古西北部宝音图群Sm-Nd和Rb-Sr地质年代学研究[J].地质论评, 2000, 46(1):86-90.
[14]孙立新,任邦方,赵凤清,等.内蒙古锡林浩特地块中元古代花岗质片麻岩的锆石U-Pb年龄和Hf同位素特征[J].地质通报,2013, 32(2/3):327-340.
[15]杜理科,葛梦春.内蒙古锡林浩特宝音图群斜长角闪岩原岩恢复的地球化学示踪[J].新疆地质, 2010, 28(2):200-203.
[16]石玉若,刘敦一,张旗,等.内蒙古中部苏尼特左旗地区三叠纪A型花岗岩锆石SHRIMP U-Pb年龄及其区域构造意义[J].地质通报, 2007, 26(2):183-189.
[17]Wronkiewicz D J, Condie K C. Geochemistry and provenance of sediments from the Pongola Supergroup,South Africa:Evidence for a 3.0Ga-old continental craton[J]. Geochimicaet cosmochimica Acta, 1989, 53(7):1537-1549.
[18]Ludwig K R. Isoplot/EX, version 3.0 A—Geochronological Toolkit for Microsoft Excel[M]. Berkeley Geochronol Center Special Publication, 2003, 4:1-70.
[19]唐克东,颜竹筠,张允平,等.关于温都尔庙群及其构造意义[C]∥中国北方板块构造文集.沈阳:辽宁科学技术出版社, 1983:186-208.
[20]李承东,冉皞,赵利刚,等.温都尔庙群锆石的LA-MC-ICPMS U-Pb年龄及构造意义[J].岩石学报, 2012, 28(11):3705-3715.
[21]徐备,徐严,栗进,等.内蒙古西部温都尔庙群的时代及其在中亚造山带中的位置[J].地学前缘, 2016, 23(6):120-127.
[22]张臣,吴泰然.内蒙古温都尔庙群变质基性火山岩Sm-Nd, RbSr同位素年代研究[J].地质科学, 1998, 33(1):25-30.
[23]聂凤军,裴荣富,吴良士,等.内蒙古温都尔庙群变质火山-沉积岩Sm-Nd同位素研究[J].科学通报, 1994, 39(13):1211-1214.
[24]葛梦春,周文孝,于洋,等.内蒙古锡林郭勒杂岩解体及表壳岩系年代确定[J].地学前缘, 2011, 18(5):1-14.
[25]王仁民,贺高平,陈珍珍,等.变质岩原岩图解判别法[M].北京:地质出版社, 1987:1-199.
[26]周世泰.恢复变质岩原岩的一种岩石化学方法[J].辽宁地质学报, 1981, 1:184-187.
[27]徐备,陈斌.内蒙古北部华北板块与西伯利亚板块之间中古生代造山带的结构及演化[J].中国科学(D辑), 1997, 27(3):227-232.
[28]张臣,吴泰然.内蒙古苏左旗南部华北板块北缘中新元古代—古生代裂解-汇聚事件的地质记录[J].岩石学报, 2001, 17(2):199-205.
[29]唐克东.中朝板块北侧褶皱带构造演化及其成矿规律[M].北京:北京大学出版社, 1992:1-264.
[30]胡晓,许传诗,牛树银.华北地台北缘早古生代大陆边缘演化[M].北京:北京大学出版社, 1990:1-185.
[31]王继春,肖荣阁,苏士杰,等.内蒙古白云鄂博地区新元古界温都尔庙群洋壳残片特征及地质意义[J].地质找矿论丛, 2011, 26(1):51-57.
[32]Xiao W J, Windley BF, Hao J, et al. Accretion leading to collision and the Permian Solonker suture,Inner Mongolia,China:Termination of the central Asian orogenic belt[J]. Tectonics, 2003,22:288-308.
[33]徐备, Charcet J,张福勤.内蒙古北部苏尼特左旗蓝片岩岩石学和年代学研究[J].地质科学, 2001, 36(4):424-434.
[34]初航,张晋瑞,魏春景,等.内蒙古温都尔庙群变质基性火山岩构造环境及年代新解[J].科学通报, 2013, 58(28/29):2958-2965.
[35]Bhatia M R. Pare tectonics and geochemical composition of sandstones[J]. Journal of Geology, 1983, 91(6):611-627.
[36]Roser B P, Korsch R J. Determination of tectonic setting of sandstone-mudstone suites using Si O2content and K2O/Na2O ratio[J].Journal of Geology, 1986,(5):635-650.
[37]Bhatia M R. Pare earth elemengt geochemistry of Australian Paleozoic graywackes and mudrocks:Provenance and tectonic control[J]. Sedimentary Geology, 1985, 45(1/2):97-113.
[38]Sun S S, MCDonough W F. Chemical and isotopic systematics of oceanic basalts:implications for mantle composition and processes[J].Geological Society of London, Special Publications, 1989, 42(1):313-345.
[2]内蒙古自治区地质矿产局.内蒙古自治区区域地质志[M].北京:地质出版社, 1991:725.
[3]内蒙古自治区地质矿产局.内蒙古自治区岩石地层[M].武汉:中国地质大学出版社, 1996:119-120, 137-142.
[4]孙俊俊,葛梦春,周文孝,等.内蒙古锡林浩特岩群岩相学、地球化学特征及构造环境分析[J].地学前缘, 2012, 19(5):144-155.
[5]于洋,葛梦春,周文孝,等.内蒙古锡林浩特岩群岩石学特征及变质温压条件[J].地学前缘, 2012, 19(5):136-143.
[6]周文孝,葛梦春.内蒙古锡林浩特地区中元古代锡林浩特岩群的厘定及其意义[J].地球科学——中国地质大学学报, 2013, 38(4):715-724.
[7]施光海,刘敦一,张福勤,等.中国内蒙古锡林郭勒杂岩SHRIMP锆石U-Pb年代学及意义[J].科学通报, 2003, 48(20):2187-2192.
[8]徐备,陈斌,邵济安.内蒙古锡林郭勒杂岩Sm-Nd, Rb-Sr同位素年代研究[J].科学通报, 1996, 41(2):153-155.
[9]郝旭,徐备.内蒙古锡林浩特锡林郭勒杂岩的原岩年代和变质年代[J].地质评论, 1997, 43(1):101-105.
[10]葛梦春,周文孝,于洋,等.内蒙古锡林郭勒杂岩解体及表壳岩系年代确定[J].地学前缘, 2011, 18(5):1-14.
[11]赵光,朱永峰,张勇.内蒙古锡林郭勒杂岩岩石学特征及其变质作用的P-T条件[J].岩石矿物学杂志, 2002, 21(1):40-48.
[12]吴泰然,张臣,万基虎.内蒙古温都尔庙地区温都尔庙群的形成环境和构造意义[J].高校地质学报, 1998, 4(2):168-176.
[13]徐备,刘树文,王长秋,等.内蒙古西北部宝音图群Sm-Nd和Rb-Sr地质年代学研究[J].地质论评, 2000, 46(1):86-90.
[14]孙立新,任邦方,赵凤清,等.内蒙古锡林浩特地块中元古代花岗质片麻岩的锆石U-Pb年龄和Hf同位素特征[J].地质通报,2013, 32(2/3):327-340.
[15]杜理科,葛梦春.内蒙古锡林浩特宝音图群斜长角闪岩原岩恢复的地球化学示踪[J].新疆地质, 2010, 28(2):200-203.
[16]石玉若,刘敦一,张旗,等.内蒙古中部苏尼特左旗地区三叠纪A型花岗岩锆石SHRIMP U-Pb年龄及其区域构造意义[J].地质通报, 2007, 26(2):183-189.
[17]Wronkiewicz D J, Condie K C. Geochemistry and provenance of sediments from the Pongola Supergroup,South Africa:Evidence for a 3.0Ga-old continental craton[J]. Geochimicaet cosmochimica Acta, 1989, 53(7):1537-1549.
[18]Ludwig K R. Isoplot/EX, version 3.0 A—Geochronological Toolkit for Microsoft Excel[M]. Berkeley Geochronol Center Special Publication, 2003, 4:1-70.
[19]唐克东,颜竹筠,张允平,等.关于温都尔庙群及其构造意义[C]∥中国北方板块构造文集.沈阳:辽宁科学技术出版社, 1983:186-208.
[20]李承东,冉皞,赵利刚,等.温都尔庙群锆石的LA-MC-ICPMS U-Pb年龄及构造意义[J].岩石学报, 2012, 28(11):3705-3715.
[21]徐备,徐严,栗进,等.内蒙古西部温都尔庙群的时代及其在中亚造山带中的位置[J].地学前缘, 2016, 23(6):120-127.
[22]张臣,吴泰然.内蒙古温都尔庙群变质基性火山岩Sm-Nd, RbSr同位素年代研究[J].地质科学, 1998, 33(1):25-30.
[23]聂凤军,裴荣富,吴良士,等.内蒙古温都尔庙群变质火山-沉积岩Sm-Nd同位素研究[J].科学通报, 1994, 39(13):1211-1214.
[24]葛梦春,周文孝,于洋,等.内蒙古锡林郭勒杂岩解体及表壳岩系年代确定[J].地学前缘, 2011, 18(5):1-14.
[25]王仁民,贺高平,陈珍珍,等.变质岩原岩图解判别法[M].北京:地质出版社, 1987:1-199.
[26]周世泰.恢复变质岩原岩的一种岩石化学方法[J].辽宁地质学报, 1981, 1:184-187.
[27]徐备,陈斌.内蒙古北部华北板块与西伯利亚板块之间中古生代造山带的结构及演化[J].中国科学(D辑), 1997, 27(3):227-232.
[28]张臣,吴泰然.内蒙古苏左旗南部华北板块北缘中新元古代—古生代裂解-汇聚事件的地质记录[J].岩石学报, 2001, 17(2):199-205.
[29]唐克东.中朝板块北侧褶皱带构造演化及其成矿规律[M].北京:北京大学出版社, 1992:1-264.
[30]胡晓,许传诗,牛树银.华北地台北缘早古生代大陆边缘演化[M].北京:北京大学出版社, 1990:1-185.
[31]王继春,肖荣阁,苏士杰,等.内蒙古白云鄂博地区新元古界温都尔庙群洋壳残片特征及地质意义[J].地质找矿论丛, 2011, 26(1):51-57.
[32]Xiao W J, Windley BF, Hao J, et al. Accretion leading to collision and the Permian Solonker suture,Inner Mongolia,China:Termination of the central Asian orogenic belt[J]. Tectonics, 2003,22:288-308.
[33]徐备, Charcet J,张福勤.内蒙古北部苏尼特左旗蓝片岩岩石学和年代学研究[J].地质科学, 2001, 36(4):424-434.
[34]初航,张晋瑞,魏春景,等.内蒙古温都尔庙群变质基性火山岩构造环境及年代新解[J].科学通报, 2013, 58(28/29):2958-2965.
[35]Bhatia M R. Pare tectonics and geochemical composition of sandstones[J]. Journal of Geology, 1983, 91(6):611-627.
[36]Roser B P, Korsch R J. Determination of tectonic setting of sandstone-mudstone suites using Si O2content and K2O/Na2O ratio[J].Journal of Geology, 1986,(5):635-650.
[37]Bhatia M R. Pare earth elemengt geochemistry of Australian Paleozoic graywackes and mudrocks:Provenance and tectonic control[J]. Sedimentary Geology, 1985, 45(1/2):97-113.
[38]Sun S S, MCDonough W F. Chemical and isotopic systematics of oceanic basalts:implications for mantle composition and processes[J].Geological Society of London, Special Publications, 1989, 42(1):313-345.