南天山库米什蛇绿混杂岩带中硅质岩的元素地球化学特征及其形成环境
-
摘要: 南天山库米什铜花山地区蛇绿混杂岩带不同岩块中的硅质岩高Al_2O_3和Al_2O_3/TiO_2,Zr、Nb、Hf、Ta和Th与Al_2O_3等陆源元素具较好正相关性,北关页岩标准化稀土模式呈现无Ce负异常(Ce/Ce~*=1.05~1.33)的典型大陆边缘硅质岩平坦稀土谱型,它们的(La/Ce)_SN=0.74~0.98,Ti/V=5.10~122.18,V/Y=0.39~6.03,均与大陆边缘硅质岩值相当,表明这些硅质岩形成在明显受陆源物质影响与大陆边缘密切相关的环境。但不同岩块硅质岩的物源区仍存在一定差异。其中,与泥岩成互层产出的红色硅质岩的Th/Sc=0.56—4.35,具Eu负异常(Eu/Eu~*=0.56~0.71)明显的较陡右倾球粒陨石标准化稀土谱型(La_N/Yb_N=3.92~7.43),与分异岩浆弧源区特征类似,可能形成在相对近陆缘的弧前盆地,其源区物质主要来自分异岩浆弧。而成夹层产出于基性熔岩中的绿色硅质岩呈现为Eu负异常较弱(Eu/Eu~*=0.72~0.93)右倾较缓的稀土谱型(La_n/Yb_n=4.15~6.69),其Th/Sc=0.57~0.87,反映有洋内弧物质加入的影响,因此它们可能形成于相对远离大陆、除有未分异基性程度较高的洋内弧物质输入外,仍受到陆缘物质影响的有限洋盆环境。根据硅质岩晚古生代初的放射虫化石推断,该地区硅质岩在晚古生代初期形成,南天山构造带已进入板块汇聚俯冲消减洋盆萎缩的发展演化阶段。
-
[1] Armstrong HA,Owen AW and Floyd JD.1999. Rear earth geochemistry of Arenig cherts from the Ballantrae Ophiolite and Leadhills Imbricate Zone,southern Scotland:Implications for origin and significance to the Caledonian Orogeny.Journal of the Geological Society,London,156:549 -560
[2] Dong YP,Wang RS,Zhou DW,et al.2001. Geochemistry and genesis of meta-mafic-ultramafic rocks from Yushugou region,north margin of the South Tianshan tectonic belt,western China.Geochimica,30(6):559 -568 (in Chinese with English abstract)
[3] Girty GH,Hanson AD,Knaack C and Johnson D.1994. Provenance determined by REE,Th and Sc analyses of metasedimentary rocks,Boyden Cave roof pendant,central Sierra Nevada,California.Journal of Sedimentary Research,64:68-73
[4] Girty GH,Ridge DL,Knaack C,Johnson D and Al-Riyami RK.1996. Provenance and depositional setting of Paleozoic chert and argillite,Sierra Nevada,California.Journal of Sedimentary Research,66(1):107-118
[5] Le Matter R W.1976. The chemical variability of some common igneous rocks.Journal of Petrology,17:589 -637
[6] Li MS,He GQ and Gao J,et al.1996. Ophiolite in Southwest Tianshan of China.In:ZhangQ (ed).Study on Ophiolites and Geodynamics.Beijing:Geological Publishing House,112-116 (in Chinese)
[7] Li CY et al.1982. Guideline book for tectonic map of Asian.Beijing:Geological Publishing House (in Chinese)
[8] Liu B and Qian YX.2003. The geological characteristics and fluid evolution in the three high-pressure metamorphic belts of eastern Tianshan.Acta Petrologica Sinica,19 (2):283-296 (in Chinese with English abstract)
[9] Ma RS,Wang CY,Ye SF,et al.1993. Tectonic framework and crustal evolution of Eastern Tianshan Mountains.Nanjing:Publishing House of Nanjing University,9 -22 (in Chinese)
[10] Murray RW,Buchholtz Ten Brink MR,Gerlach DC,Gerlach DC and Russ GP.1990. Rear earth elements as indicators of different marine depositional environments in chert and shale.Geology,88:268 -271
[11] Murray RW,Buchholtz Ten Brink M R,Gerlach DC,et al.1991. Rare earth,major,and trace elements in chert from the Franciscan Complex and Monterey Group:Assessing REE sources to finegrained marine sediments.Geochimica et Cosmochimica Acta,55:1875-1895
[12] Murray R W,Buchholtz Ten Brink MR,Gerlach DC,et al.1992. Rare earth,major,and trace element composition of Monterey and DSDP chert and associated host sediment:Assessing the influence of chemical fractionation during diagenesis.Geochimica et Cosmochimica Acta,56:2657-2671
[13] Murray RW.1994. Chemical criteria to identify the depositional environment of chert:general principles and applications.Sedimentary Geology,90:213 -232
[14] Gao S,Ling WL,Qiu YM,et al.1999. Contrasting geochemical and Sm-Nd isotopic compositions of Archean metasediments from the Kongling high-grade terrain of the Yangtze craton:Evidence for cratonic evolution and redistribution of REE during crustal anatexis.Geochimica et Cosmochimica Acta,63:2071 -2088
[15] Sholkvitz ER.1988. Rear earth elements in the sediments of the North Atlantic Ocean,Amazon Delta,and East China Sea:Reinterpretation of terrigenous input patterns to the oceans.American Journal of Science,288:236-281
[16] Sturt BA,Thon A and Furnes H.1980. The geology and preliminary geochemistry of the Kamψy ophiolite,S.W.Norway.In:Panayiotou A (ed).Ophiolites.Nicosia Geological Survey,538 -553
[17] Wang RS,Wang Y,Li HM,et al.2000. Zircon U-Pb dating of Yushugou Terrain of high-pressure granulite facies in Southern Tianshan Mountain and its geological significance.Chinese Journal of Geochemistry,19 (1):23 -28
[18] Wang RS,Zhou DW,Wang JL et al.1999a.Study on the Yushugou granulite terrain of Variscan deep crust in southern Tianshan.Science in China (series D),29:306-313 (in Chinese)
[19] Wang RS,Zhou DW,Wang JL,et al.1999b.Study on Yushugou Ophiolite suite modified by the metamorphism of granulite facies in Southern Tianshan.Scientia Geologica Sinica,34 (2):166-176(in Chinese with English abstract)
[20] Wang ZX,Wu JY,Lu XC,et al.1990. Polycyclic tectonic evolution and metallogeny of the Tianshan Mountains.Beijing:Science Press,9 -44 (in Chinese)
[21] Wu WQ,Jiang CY and Yang F.1992. Paleozoic era crustal evolution and mineralization law in Kumishi region.Xi\'an:Shaanxi Science and Technology Publishing House,69-83 (in Chinese)
[22] Xiao WJ,Zhang LC,Qin KZ,Sun S and Li JL.2004. Paleozoic accretionary and collisional tectonics of the Eastern Tianshan (China):Implications for the continental growth of central Asia.American Journal of Science,304:370-395
[23] Yasuhiro K,Kyoko N and Yukio I.2002. Geochemistry of Late Permian to Early Triassic pelagic cherts from southwest Japan:implications for an oceanic redox change.Chemical Geology,182:15 -34
[24] Zhang C.1981. Some geological characteristics of ophiolite in Xinjiang.Geological Reviews,27:307 -314 (in Chinese with English abstract)
[25] Zhang Q and Zhou GQ.2001. Ophiolites of China.Beijing:Science Press,16-22 (in Chinese)
[26] Zhou DW,Su L,Jian P,et al.2004. Zircon U-Pb SHRIMP ages of highpressure granulite in Yushugou ophiolitic terrane in southern Tianshan and their tectonic implications.Chinese Science Bulletin,49 (13):1415-1419
[27] 董云鹏,王润三,周鼎武等.2001.南天山北缘榆树构变质基性-超基性岩的地球化学及其成因机制.地球化学,30(6):559-568
[28] 李茂松,何国琦,高峻等.1996.中国西南天山的蛇绿岩,见:张旗主编,蛇绿岩与地球动力学研究.北京:地质出版社.112-116
[29] 李春昱等.1982.亚洲大地构造图说明书.北京:地质出版社
[30] 刘斌,钱一雄.2003.东天山三条高压变质带地质特征和流体作用.岩石学报,19:283-296
[31] 马瑞士,王赐银,叶尚夫,等.1993.东天山构造格架及地壳演化.南京:南京大学出版社.9-22
[32] 王润三,王焰,李惠民等.1998.南天山榆树构高压麻粒岩地体锆石U-Pb定年及其地质意义.地球化学,27(6):517-522
[33] 王润三,周鼎武,王居里等.1999a.南天山榆树沟华力西期深地壳麻粒岩地体研究.中国科学(D辑),29:306-313
[34] 王润三,王居里,周鼎武等.1999b.南天山榆树沟遭受麻粒岩相变质改造蛇绿岩套研究.地质科学,34(2):166-176
[35] 王作勋,邬继易,吕喜朝等.1990.天山多旋回构造演化及成矿.北京:科学出版社.9-44
[36] 吴文奎,姜常义,杨复.1992.库米什地区古生代地壳演化及成矿规律.西安:陕西科学技术出版社.69-83
[37] 张驰.1981.新疆蛇绿岩某些地质特征.地质论评,27:307-314
[38] 张旗,周国庆.2001.中国蛇绿岩.北京:科学出版社.16-22
[39] 周鼎武,苏犁,简平等.2004.南天山榆树沟蛇绿岩地体中高压麻粒岩SHRIMP锆石U-Pb年龄及构造意义.科学通报,49(14):1411-1415
计量
- 文章访问数: 7223
- PDF下载数: 7052
- 施引文献: 0