西藏改则县拉果错蛇绿岩的构造属性
发布时间：2018-10-30 20:32
【摘要】：狮泉河 阿索 嘉黎蛇绿混杂岩带是青藏高原一条重要的构造带，它与班公湖 怒江缝合带的演化密切相关，均是青藏高原中部新特提斯洋演化的产物。而拉果错蛇绿岩是狮泉河 阿索 嘉黎蛇绿混杂岩带中出露最完整的蛇绿岩组合之一，关于它的地球化学研究较为薄弱，它的成因及其构造环境不清楚，时代也存在着争议。 本文选择了拉果错蛇绿岩中相伴生产出的斜长花岗岩和堆晶辉长岩作为重点研究对象，，开展了野外勘查及剖面的测制，对蛇绿岩进行了岩石学，地球化学、锆石LA-ICP-MS U-Pb定年及Lu-Hf同位素的研究，结合区域地层和岩浆岩等相关资料，探讨拉果错蛇绿岩的构造属性。 拉果错斜长花岗岩和辉长岩野外呈整合接触产出，地球化学表明二者具有同源性，具有与E-MORB相似的稀土配分形式和微量特征；Lu-Hf同位素显示岩浆源区为亏损地幔，由多种组分组成，可能来源于DDM和EM2二组分混合的地幔源区；斜长花岗岩和辉长岩的锆石LA-ICP-MS U-Pb定年分别获得了184.1±0.79Ma和183.5±2.2Ma的谐和年龄，代表了蛇绿岩的消减时代。研究表明狮泉河 阿索 嘉黎蛇绿混杂岩带属于班公湖-怒江缝合带的一个组成部分，拉果错蛇绿岩形成于洋内弧后盆地环境。
[Abstract]:The Asuo Jiali ophiolite melange belt in Shiquanhe River is an important tectonic belt in the Qinghai-Xizang Plateau. It is closely related to the evolution of the Bangong Lake Nu River suture zone and is the product of the evolution of the NeoTethys Ocean in the central part of the Tibetan Plateau. The Lago Luo ophiolite is one of the most complete ophiolite assemblages in the Shiquanhe Asuo Jiali ophiolite melange belt. Its geochemical research is relatively weak, its genesis and tectonic environment are not clear, and the age is controversial. In this paper, the plagioclase granites and heap-grained gabbro produced in the Lago Ophiolite are selected as the main research objects, the field exploration and profile survey are carried out, and the petrology and geochemistry of the ophiolite are carried out. LA-ICP-MS U-Pb dating and Lu-Hf isotopic studies of zircon, combined with regional stratigraphy and magmatic data, are used to study the tectonic properties of the Lago dislocation ophiolite. In the field, Laguocao clinopyrofeldite and gabbro show integrated contact. Geochemistry shows that the two have homology, similar rare earth partition form and trace characteristics as E-MORB. Lu-Hf isotopes show that the magmatic source region is a depleted mantle, which is composed of a variety of components and may originate from the mantle source where DDM and EM2 are mixed. The LA-ICP-MS U-Pb dating of zircon from plagioclase granite and gabbro is 184.1 卤0.79Ma and 183.5 卤2.2Ma, respectively, which represents the subduction age of ophiolite. The study shows that the Asuo Jiali ophiolite melange belt in Shiquanhe River belongs to an integral part of the Bangonghu-Nujiang suture zone, and the Laguoco ophiolite formed the inner back-arc basin environment of Yu Yang.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P583
本文编号：2301102
[Abstract]:The Asuo Jiali ophiolite melange belt in Shiquanhe River is an important tectonic belt in the Qinghai-Xizang Plateau. It is closely related to the evolution of the Bangong Lake Nu River suture zone and is the product of the evolution of the NeoTethys Ocean in the central part of the Tibetan Plateau. The Lago Luo ophiolite is one of the most complete ophiolite assemblages in the Shiquanhe Asuo Jiali ophiolite melange belt. Its geochemical research is relatively weak, its genesis and tectonic environment are not clear, and the age is controversial. In this paper, the plagioclase granites and heap-grained gabbro produced in the Lago Ophiolite are selected as the main research objects, the field exploration and profile survey are carried out, and the petrology and geochemistry of the ophiolite are carried out. LA-ICP-MS U-Pb dating and Lu-Hf isotopic studies of zircon, combined with regional stratigraphy and magmatic data, are used to study the tectonic properties of the Lago dislocation ophiolite. In the field, Laguocao clinopyrofeldite and gabbro show integrated contact. Geochemistry shows that the two have homology, similar rare earth partition form and trace characteristics as E-MORB. Lu-Hf isotopes show that the magmatic source region is a depleted mantle, which is composed of a variety of components and may originate from the mantle source where DDM and EM2 are mixed. The LA-ICP-MS U-Pb dating of zircon from plagioclase granite and gabbro is 184.1 卤0.79Ma and 183.5 卤2.2Ma, respectively, which represents the subduction age of ophiolite. The study shows that the Asuo Jiali ophiolite melange belt in Shiquanhe River belongs to an integral part of the Bangonghu-Nujiang suture zone, and the Laguoco ophiolite formed the inner back-arc basin environment of Yu Yang.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P583
【参考文献】
相关期刊论文 前10条
1 李才;龙木错-双湖-澜沧江板块缝合带与石炭二叠纪冈瓦纳北界[J];长春地质学院学报;1987年02期
2 胡承祖;狮泉河—古昌—永珠蛇绿岩带特征及其地质意义[J];成都地质学院学报;1990年01期
3 林文第,陈德泉;藏北改则—色哇地区的蛇绿岩特征[J];成都地质学院学报;1990年02期
4 李武显,李献华;蛇绿岩中的花岗质岩石成因类型与构造意义[J];地球科学进展;2003年03期
5 莫宣学,董国臣,赵志丹,周肃,王亮亮,邱瑞照,张风琴;西藏冈底斯带花岗岩的时空分布特征及地壳生长演化信息[J];高校地质学报;2005年03期
6 徐平,吴福元,谢烈文,杨岳衡;U-Pb同位素定年标准锆石的Hf同位素[J];科学通报;2004年14期
7 张玉修;张开均;黎兵;汪洋;魏庆国;唐显春;;西藏改则南拉果错蛇绿岩中斜长花岗岩锆石SHRIMP U-Pb年代学及其成因研究[J];科学通报;2007年01期
8 郑来林,耿全如,董翰,欧春生,王小伟;波密地区帕隆藏布残留蛇绿混杂岩带的发现及其意义[J];沉积与特提斯地质;2003年01期
9 樊帅权;史仁灯;丁林;刘德亮;黄启帅;王厚起;;西藏改则蛇绿岩中斜长花岗岩地球化学特征、锆石U-Pb年龄及构造意义[J];岩石矿物学杂志;2010年05期
10 潘桂棠;莫宣学;侯增谦;朱弟成;王立全;李光明;赵志丹;耿全如;廖忠礼;;冈底斯造山带的时空结构及演化[J];岩石学报;2006年03期
本文编号：2301102
本文链接：https://www.wllwen.com/kejilunwen/diqiudizhi/2301102.html
