Geochemical Features, Age, and Tectonic Significance of the Kekekete Mafic-ultramafic Rocks, East Ku

来源 :Acta Geologica Sinica(English Edition) | 被引量 : 0次 | 上传用户:skyedge228
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
The Kekekete mafic-ultramafic rocks are exposed in the Kekesha-Kekekete-Dawate area,which are in the eastern part of the East Kunlun Orogenic Belt.It outcrops as tectonic slices intruding tectonically in the Paleoproterozoic Baishahe Group and the Paleozoic Nachitai Group.The Kekekete mafic and ultramafic rocks is located near the central fault in East Kunlun and lithologically mainly consists of serpentinite,augite peridotite,and gabbro.The LA-ICP-MS zircon U-Pb age of the gabbro is 501±7 Ma,indicating that Kekekete mafic-ultramafic rocks formed in the Middle Cambrian.This rock assemblage is relatively poor in SiO2 and(Na2 O+K2 O) but rich in MgO and SFeO.The chondrite-normalized REE patterns of the gabbro dip slightly to the right;the primitive mantle and MORBnormalized spidergrams of trace elements show enrichment of large-ion lithophile elements(Cs,Rb,Ba,etc.) and no differentiation of high field strength elements.The general dominance of E-MORB features and the geochemical characteristics of OIB suggest that the Kekekete mafic-ultramafic rocks formed in an initial oceanic basin with slightly enriched mantle being featured by varying degrees of mixing of N-MORB depleted mantle and a similar-OIB-type source.From a comprehensive study of the previous data,the author believes that the tectonic history of the East Kunlun region was controlled by a geodynamic system of rifting and extension in the late stages of the Neoproterozoic to early stages of the Early Paleozoic and this formed the paleo-oceanic basin or rift system now represented by the ophiolites along the central fault in East Kunlun,the Kekekete mafic-ultramafic rocks and Delisitan ophiolite. The Kekekete mafic-ultramafic rocks are exposed in the Kekesha-Kekekete-Dawate area, which are in the eastern part of the East Kunlun Orogenic Belt. Tit outcrops as tectonic slices intruding tectonically in the Paleoproterozoic Baishahe Group and the Paleozoic Nachitai Group. The Kekekete mafic and ultramafic rocks are located near the central fault in East Kunlun and lithologically mainly consists of serpentinite, augite peridotite, and gabbro. The LA-ICP-MS zircon U-Pb age of the gabbro is 501 ± 7 Ma, indicating that Kekekete mafic -ultramafic rocks formed in the Middle Cambrian. This rock assemblage is relatively poor in SiO2 and (Na2 O + K2 O) but rich in MgO and SFeO. The chondrite-normalized REE patterns of the gabbro dip slightly to the right; the primitive mantle and MORBnormalized spidergrams of trace elements show enrichment of large-ion lithophile elements (Cs, Rb, Ba, etc.) and no differentiation of high field strength elements. The general dominance of E-MORB features and the geochemical charac teristics of OIB suggest that the Kekekete mafic-ultramafic rocks formed in an initial oceanic basin with slightly enriched mantle being featured by varying degrees of mixing of N-MORB depleted mantle and a similar-OIB-type source. For a comprehensive study of the previous data, the author believes that the tectonic history of the East Kunlun region was controlled by a geodynamic system of rifting and extension in the late stages of the Neoproterozoic to early stages of the Early Paleozoic and this formed the paleo-oceanic basin or rift system now represented by the ophiolites along the central fault in East Kunlun, the Kekekete mafic-ultramafic rocks and Delisitan ophiolite.
其他文献
由南京华东工学院王其祥副教授发明的序列脉冲激光瞬态全息摄影仪(专利号85105775),日前荣获中国专利局和联合国世界产权组织联合颁发的中国首届十大专利发明创造金奖。序列
在乙醇溶液中采用快速反应相转移法,分别以n(油溶性茶多酚)∶n(As3+)=2∶1、4∶1、6∶1,pH=4.0,反应温度40~45℃,反应时间15 h的条件,合成了油溶性茶多酚砷,产率59%。配合物
5月29日至30日,自治区建设厅厅长宋继东赶赴四川绵竹市,深入灾区一线,看望慰问广西建设系统救援队,并实地研究部署下一步的支援工作。宋继东厅长在详细考察灾区过渡安置房建
数名美貌女子相继被害,探案小组发现,凶手是一个专杀放荡女子的连环杀手。法租界巡捕房洪涛警长遭遇炸弹袭击,万幸只受轻伤。顺着炸弹的线索,探案小组找到凶手何东来。此人当
<正>"冷战"问题是人教版必修1《两极世界的形成》一课的重点问题,关于这一问题,笔者在进一步涉猎有关"冷战"问题的研究后,基于历史复杂性的视域,发现在政治地理学领域,学者们
5月22日,在映秀镇,阿坝州工商局局长斯卫平在指挥部前安排运送灾民出山。地震发生时,绵竹市剑南工商所干部胡安蓉在成都住院,她不顾术后伤口疼痛,用住院费购买一车救灾物资赶
请下载后查看,本文暂不支持在线获取查看简介。 Please download to view, this article does not support online access to view profile.
期刊
3月份,“中美电影新政”将进口分账大片名额提升至34部,还没来得及细细品味其中的苦与涩,就遭遇与好莱坞的火拼,结果国产电影几乎全军覆没,两岸三地电影人忍不住共同表态:“
以通俗的标准,他们是三个好男人:事业成功、收入丰厚,夫妻和睦、生活幸福。说事业成功,指他们都是公司老总,小有身家、小有名气;说家庭美满,指他们作为一个个有血有肉的普通
请下载后查看,本文暂不支持在线获取查看简介。 Please download to view, this article does not support online access to view profile.