四川省会理县河口地区辉绿岩体的锆石SHRIMP U-Pb年龄及其地质意义
|
摘要
普遍认为,扬子地台西缘前震旦系基底存在结晶基底和褶皱基底的双层(或三层)结构,河口群作为结晶基底与褶皱基底之间的过渡层位,其归属及形成时代仍存在争议。对河口群的深入研究,有助于深化认识扬子地台西缘基底结构的特点及演化过程。通过对会理县河口地区侵入于河口群中辉绿岩体的锆石SHRIMP U-Pb测年,获得1710±8 Ma(MSWD=1.11)的锆石U-Pb年龄,表明河口群的形成时代要早于这个年龄。大量的同位素数据证明,河口群主要形成于1817~1710 Ma,为古元古代晚期。本文的研究成果,对认识整个扬子地台西缘的构造格架与演化历史具有重要的意义。
It has been widely believed that a double layer structure(or three layer) of crystallization basement and folding basement occurs over the Pre-Sinian basement in the western margin of Yangtze block,with the Hekou Group as the transitional sequence between two basements,but its attribute and formation time have long been in dispute.Advanced study of Hekou Group would have important implications for understanding of the feature and evolution of the basement structure of the western margin of Yangtze block.Here we reported 13 groups of zircon SHRIMP U-Pb ages from the diabase that intruded into the Hekou Group,and obtained 1710±8 Ma concordant U-Pb age,which indicates that the Hekou Group formed earlier than that age.A large voluminous of isotopic evidence by previous studies shows that the Hekou Group should formed during 1817~1710 Ma,which suggests the Late Paleoproterozoic.The age of the diabase reported in this study,has confined the upper limited age of Hekou Group,and has great significance in further understanding of the tectonic patterns and evolutionary history of the western margin of the Yangtze terrane.
It has been widely believed that a double layer structure(or three layer) of crystallization basement and folding basement occurs over the Pre-Sinian basement in the western margin of Yangtze block,with the Hekou Group as the transitional sequence between two basements,but its attribute and formation time have long been in dispute.Advanced study of Hekou Group would have important implications for understanding of the feature and evolution of the basement structure of the western margin of Yangtze block.Here we reported 13 groups of zircon SHRIMP U-Pb ages from the diabase that intruded into the Hekou Group,and obtained 1710±8 Ma concordant U-Pb age,which indicates that the Hekou Group formed earlier than that age.A large voluminous of isotopic evidence by previous studies shows that the Hekou Group should formed during 1817~1710 Ma,which suggests the Late Paleoproterozoic.The age of the diabase reported in this study,has confined the upper limited age of Hekou Group,and has great significance in further understanding of the tectonic patterns and evolutionary history of the western margin of the Yangtze terrane.
引文
[1]云南省地质局第一区测队.1966.中华人民共和国1∶20万区域地质测量报告永仁幅.
[2]四川省地质局第一区测队.1970.中华人民共和国1∶20万区域地质测量报告会理幅.
[3]四川省地质局攀西地质大队区调二队.1994.中华人民共和国1∶5万区域地质测量报告河口幅.
[4]耿元生,杨崇辉,王新社,杜利林,任留东,周喜文.2005.扬子地台西缘变质基底演化研究.地质调查研究报告.
陈岳龙,罗照华,赵俊香,李志宏,张宏飞,宋彪.2004.从锆石SHRI MP年龄及岩石地球化学特征论四川冕宁康定杂岩的成因.中国科学(D辑),34(8):687~697.
陈智梁,陈世瑜,周铭魁.1987.扬子地块西部边缘地质构造演化.重庆:重庆出版社,1~172.
程裕淇.1994.中国区域地质概论.北京:地质出版社,1~517.
杜利林,耿元生,杨崇辉,王新社,任留东,周喜文,石玉若,杨铸生.2005.扬子地块西缘盐边群玄武质岩石地球化学特征及SHRI MP锆石U-Pb年龄.地质学报,79(6):805~813.
杜利林,耿元生,杨崇辉,王新社,周喜文,任留东,王彦斌,杨铸生.2007.扬子地台西缘康定群的再认识:来自地球化学和年代学证据.地质学报,81(11):1562~1577.
耿元生,杨崇辉,王新社,任留东,杜利林,周喜文.2007.扬子地台西缘结晶基底的时代.高校地质学报,13(3):429~441.
耿元生,杨崇辉,王新社,杜利林,任留东,周喜文.2008.扬子地台西缘变质基底演化.北京:地质出版社,1~215.
辜学达,刘啸虎.1997.四川省岩石地层.武汉:中国地质大学出版社,1~417.
简平,程裕淇,刘敦一.2001.变质锆石成因的岩相学研究--高级变质岩U-Pb年龄解释的基本依据.地学前缘,8(3):183~191.
阚泽忠,乔正福.1999.四川会理-河口地区褶皱基底的双层结构.四川地质学报,19(3):204~209.
李复汉,覃嘉铭.1980."康滇地轴"金沙江两岸的前震旦系.西南地质科技情报,(3):116~136.
李复汉,覃嘉铭,申玉连,玉福星,周国富,潘杏南,李兴振.1988.康滇地区的前震旦系.重庆:重庆出版社,1~396.
李泽琴,王奖臻,刘家军,李朝阳,杜安道,刘玉平,叶琳.2003.拉拉铁氧化物-铜-金-钼-稀土矿床Re-Os同位素年龄及其地质意义.地质找矿论丛,18(1):39~42.
刘肇昌.1996.扬子地台西缘构造演化与成矿.成都:电子科技大学出版社,1~267.
吕世琨,戴恒贵.2001.康滇地区建立昆阳群(会理群)层序的回顾和重要赋矿层位的发现.云南地质,20(1):1~24.
邱华宁,孙大中,朱炳泉,常向阳.1997.东川铜矿床同位素地球化学研究:ⅡPb-Pb,40Ar-39Ar法成矿年龄测定.地球化学,26(2):39~45.
沈其韩,耿元生,宋彪,万渝生.2005.华北和扬子陆块及秦岭-大别造山带地表和深部太古宙基底的新信息.地质学报,79(5):616~627.
四川省地质矿产局.1991.四川省区域地质志.北京:地质出版社,1~662.
四川省区域地层表编写组.1978.西南地区区域地层表:四川省分册.北京:地质出版社,1~672.
宋彪,张玉海,万渝生,简平.2002.锆石SHRI MP样品靶制作、年龄测定及有关现象讨论.地质论评,48(增刊):26~30.
宋彪,张拴宏,王彦斌,赵越.2006.锆石SHRI MP年龄测定数据处理时系统偏差的避免--标准锆石分段校正的必要性.岩矿测试,25(1):9~14.
孙志明,尹福光,关俊雷,刘建辉,李军敏,耿全如,王立全.2009.云南东川地区昆阳群黑山组凝灰岩锆石SHRI MP U-Pb年龄及其地层学意义.地质通报,28(7):898~900.
吴根耀.2006.从关键地质事件看华南的前寒武系划分.地层学杂志,30(3):271~286.
吴元保,郑永飞.2004.锆石成因矿物学研究及其对U-Pb年龄解释的制约.科学通报,49(16):1589~1604.
尹福光,孙志明,白建科.东川-滇中地区中元古代地层格架.地质论评(待刊).
尹福光,孙志明,张璋.会理-东川地区元古宙地层-构造格架.地层学杂志(待刊).
袁海华,张树发,张平.1985.攀西裂谷岩浆岩同位素地质年代学初步研究.见:张云湘主编.中国攀西裂谷论文集(1).北京:地质出版社,241~257.
袁海华,张树发,张平.1986.康滇地轴结晶基底的时代归属.成都地质学院学报,13(4):64~70.
袁海华,张树发,张平.1987.康滇地轴基底时代的初步轮廓.见:张云湘主编.中国攀西裂谷论文集(2).北京:地质出版社,51~60.
袁海华.1988.答《谈康滇地轴部分年代研究资料的可靠性》一文.成都地质学院学报,15(2):108~114.
曾良鍷.1997.川西南地区前震旦系群、组级地层单位的命名与沿革.四川地质学报,17(4):253~256.
张洪刚,李承炎.1984.四川的前震旦系--前震旦纪地层总结研究报告.成都:四川省地质矿产局地质矿产科研所出版社,1~151.
Greentree M R,Li Zhengxiang,Li Xianhua,Wu Huaichun.2006.Late Mesoproterozoic to earliest Neoproterozoic basin record of the Sibao orogenesis in western South China and relationship tothe assembly of Rodinia.Precambrian Research,151:79~100.
Greentree M R,Li Zhengxiang.2008.The oldest known rocks insouth-western China:SHRI MP U-Pb magmatic crystallizationage and detrital provenance analysis of the Paleoproterozoic Dahongshan Group.Journal of Asian Earth Sciences,33:289~302.
Simon L H,Nigel M K.2007.Zircon:tiny but timely.Elements,3(1):13~18.
[2]四川省地质局第一区测队.1970.中华人民共和国1∶20万区域地质测量报告会理幅.
[3]四川省地质局攀西地质大队区调二队.1994.中华人民共和国1∶5万区域地质测量报告河口幅.
[4]耿元生,杨崇辉,王新社,杜利林,任留东,周喜文.2005.扬子地台西缘变质基底演化研究.地质调查研究报告.
陈岳龙,罗照华,赵俊香,李志宏,张宏飞,宋彪.2004.从锆石SHRI MP年龄及岩石地球化学特征论四川冕宁康定杂岩的成因.中国科学(D辑),34(8):687~697.
陈智梁,陈世瑜,周铭魁.1987.扬子地块西部边缘地质构造演化.重庆:重庆出版社,1~172.
程裕淇.1994.中国区域地质概论.北京:地质出版社,1~517.
杜利林,耿元生,杨崇辉,王新社,任留东,周喜文,石玉若,杨铸生.2005.扬子地块西缘盐边群玄武质岩石地球化学特征及SHRI MP锆石U-Pb年龄.地质学报,79(6):805~813.
杜利林,耿元生,杨崇辉,王新社,周喜文,任留东,王彦斌,杨铸生.2007.扬子地台西缘康定群的再认识:来自地球化学和年代学证据.地质学报,81(11):1562~1577.
耿元生,杨崇辉,王新社,任留东,杜利林,周喜文.2007.扬子地台西缘结晶基底的时代.高校地质学报,13(3):429~441.
耿元生,杨崇辉,王新社,杜利林,任留东,周喜文.2008.扬子地台西缘变质基底演化.北京:地质出版社,1~215.
辜学达,刘啸虎.1997.四川省岩石地层.武汉:中国地质大学出版社,1~417.
简平,程裕淇,刘敦一.2001.变质锆石成因的岩相学研究--高级变质岩U-Pb年龄解释的基本依据.地学前缘,8(3):183~191.
阚泽忠,乔正福.1999.四川会理-河口地区褶皱基底的双层结构.四川地质学报,19(3):204~209.
李复汉,覃嘉铭.1980."康滇地轴"金沙江两岸的前震旦系.西南地质科技情报,(3):116~136.
李复汉,覃嘉铭,申玉连,玉福星,周国富,潘杏南,李兴振.1988.康滇地区的前震旦系.重庆:重庆出版社,1~396.
李泽琴,王奖臻,刘家军,李朝阳,杜安道,刘玉平,叶琳.2003.拉拉铁氧化物-铜-金-钼-稀土矿床Re-Os同位素年龄及其地质意义.地质找矿论丛,18(1):39~42.
刘肇昌.1996.扬子地台西缘构造演化与成矿.成都:电子科技大学出版社,1~267.
吕世琨,戴恒贵.2001.康滇地区建立昆阳群(会理群)层序的回顾和重要赋矿层位的发现.云南地质,20(1):1~24.
邱华宁,孙大中,朱炳泉,常向阳.1997.东川铜矿床同位素地球化学研究:ⅡPb-Pb,40Ar-39Ar法成矿年龄测定.地球化学,26(2):39~45.
沈其韩,耿元生,宋彪,万渝生.2005.华北和扬子陆块及秦岭-大别造山带地表和深部太古宙基底的新信息.地质学报,79(5):616~627.
四川省地质矿产局.1991.四川省区域地质志.北京:地质出版社,1~662.
四川省区域地层表编写组.1978.西南地区区域地层表:四川省分册.北京:地质出版社,1~672.
宋彪,张玉海,万渝生,简平.2002.锆石SHRI MP样品靶制作、年龄测定及有关现象讨论.地质论评,48(增刊):26~30.
宋彪,张拴宏,王彦斌,赵越.2006.锆石SHRI MP年龄测定数据处理时系统偏差的避免--标准锆石分段校正的必要性.岩矿测试,25(1):9~14.
孙志明,尹福光,关俊雷,刘建辉,李军敏,耿全如,王立全.2009.云南东川地区昆阳群黑山组凝灰岩锆石SHRI MP U-Pb年龄及其地层学意义.地质通报,28(7):898~900.
吴根耀.2006.从关键地质事件看华南的前寒武系划分.地层学杂志,30(3):271~286.
吴元保,郑永飞.2004.锆石成因矿物学研究及其对U-Pb年龄解释的制约.科学通报,49(16):1589~1604.
尹福光,孙志明,白建科.东川-滇中地区中元古代地层格架.地质论评(待刊).
尹福光,孙志明,张璋.会理-东川地区元古宙地层-构造格架.地层学杂志(待刊).
袁海华,张树发,张平.1985.攀西裂谷岩浆岩同位素地质年代学初步研究.见:张云湘主编.中国攀西裂谷论文集(1).北京:地质出版社,241~257.
袁海华,张树发,张平.1986.康滇地轴结晶基底的时代归属.成都地质学院学报,13(4):64~70.
袁海华,张树发,张平.1987.康滇地轴基底时代的初步轮廓.见:张云湘主编.中国攀西裂谷论文集(2).北京:地质出版社,51~60.
袁海华.1988.答《谈康滇地轴部分年代研究资料的可靠性》一文.成都地质学院学报,15(2):108~114.
曾良鍷.1997.川西南地区前震旦系群、组级地层单位的命名与沿革.四川地质学报,17(4):253~256.
张洪刚,李承炎.1984.四川的前震旦系--前震旦纪地层总结研究报告.成都:四川省地质矿产局地质矿产科研所出版社,1~151.
Greentree M R,Li Zhengxiang,Li Xianhua,Wu Huaichun.2006.Late Mesoproterozoic to earliest Neoproterozoic basin record of the Sibao orogenesis in western South China and relationship tothe assembly of Rodinia.Precambrian Research,151:79~100.
Greentree M R,Li Zhengxiang.2008.The oldest known rocks insouth-western China:SHRI MP U-Pb magmatic crystallizationage and detrital provenance analysis of the Paleoproterozoic Dahongshan Group.Journal of Asian Earth Sciences,33:289~302.
Simon L H,Nigel M K.2007.Zircon:tiny but timely.Elements,3(1):13~18.
目录