排序方式: 共有28条查询结果,搜索用时 15 毫秒
1.
谭少华 《西南科技大学学报》1995,(4)
通过对变质岩区地层特征的分析,认为在变质地层中存在着大量的结晶片理、变形分异条带与片麻理条带、构造透镜体、顺层褶皱及近水平韧性剪切带,其分别为纵向构造置换或横向构造置换的结果。为多期变形的产物。在这些地区开展构造测量需考虑采用构造—地层学方法。此工作方法可进一步指导对变质岩老矿山的重新认识与评价。 相似文献
2.
探讨酒西盆地古近纪沉积与阿尔金左行走滑断裂的关系。通过对酒西盆地西部红柳峡剖面古近系火烧沟组、白杨河组进行系统的沉积学和年代学分析表明:火烧沟组的砾石成分主要以中-低级变质岩和沉积岩为主,到了白杨河组则转变为以岩浆岩为主;古水流方向主体来自西部-西北部;室内砂岩碎屑鉴定结果显示古近系砂岩的碎屑成分全部落入再旋回造山带物源区;碎屑锆石U-Pb年龄测定结果表现出新元古代和中元古代2个主要的年龄峰值。综合对比酒西盆地周缘的物源区,初步认为阿尔金地体为火烧沟组和白杨河组主要的物源供给区。结合前人对阿尔金左行走滑断裂的研究,表明自渐新世以后阿尔金地体才离开酒西盆地,进一步确定阿尔金断裂带最大左行走滑量450km。 相似文献
3.
4.
We applied zircon fission-track analysis to outcrop and borehole samples to study the Mesozoic cooling history of the Bachu Uplift, the Central Uplift of the Tarim Basin. Zircon fission-track (ZFT) ages of 182 Ma – 249 Ma are younger than the sample depositional ages indicating substantial post burial thermal annealing and can effectively reveal cooling events in the Bachu Uplift. The strong correlation between single grain ZFT age and U content indicates that most of the zircon grains represent ages that have been partially annealed and so the age is not directly indicative of the time of cooling. The youngest ZFT age populations with modal peak ages of 151 ± 8 Ma (Well HT1 samples), 126 ± 6 Ma (Well T1 samples) and 192 ± 10 Ma (Xiaohaizi Reservoir profile samples) from the decomposition of the ZFT single-grain ages represent the onset of cooling events in the Bachu Uplift, which were related to the collisions of the Qiangtang Terrane and Lhasa Block with the southern margin of the Eurasia continent, respectively. This study provides new insights into the tectonic and sedimentary evolution of the Tarim Basin and even Central Asia by constraining the higher temperature (c. 250–180 °C) part of the basin thermal history. 相似文献
5.
High-pressure (HP) metamorphic terrane in the Tongbai orogen comprises two HP slices (I and II) and a tectonic m61ange zone in the northeast and a blueschist-greenschist zone in the southwest. HP slice I is represented by the northern and southern eclogite zones on the two sides of the Tongbaishan antiform. HP slice II is represented by retrograded eclogite-bearing metamorphic en- claves in Cretaceous gneissic granites in the Tongbai Complex. U-Pb, Lu-Hf, Rb-Sr and 4Ar/39Ar multichronometric data indi- cate that the peak metamorphism of HP slice I took place at -255 Ma, whereas the metamorphic ages of HP slice II are as young as 232-220 Ma. By contrast, the tectonic melange zone near the suture was metamorphosed at -256 Ma. Such a diachroneity of dif- ferent slices across the direction of the orogen in the Hong'an-Dabie-Sulu HP/UHP terrane is ubiquitous, and it can be interpreted by a syn-subduction detachment/exhumation model. Furthermore, the metamorphic age of HP slice I in the Tongbai orogen is older than that of the equivalent HP slice in the Hong'an orogen by ~15 Ma, suggesting that the diachroneity may have also ex- isted along the direction of the orogen. A seesaw-type subduction/exhumation model is proposed to explain this age disparity and the subduction of the South China Block becomimg shallower towards the west. 相似文献
6.
王振荣 《成都理工大学学报(自然科学版)》1996,(1)
攀枝花-西昌地区位于扬子板块的西南缘。文章运用地体学说,根据断裂、沉积建造、岩浆活动和地球物理等标志的地体解析方法,将其划分为六大地体。并探讨了晋宁期以来,各地体拼合和离散的历史。研究表明该区在地质历史中构造面貌是不断变化的,是一典型的拼贴构造。 相似文献
7.
马家常 《徐州师范大学学报(自然科学版)》1998,(3)
麦钦乌拉山南坡出露的荒草坡群,曾被认为是东准噶尔晚古生代岛弧褶皱带的基底.本文研究表明,该套地层的诸方面特征与阿尔泰地区的奥陶系和志留系地层可以对比,实际上,荒草坡群是东准噶尔晚古生代构造带中的早古生代地体,是从西伯利亚活动陆缘裂解出来的大陆碎决. 相似文献
8.
9.
GAO Tianshan CHEN Jiangfeng XIE Zhi YANG Shenghong & YU Gang School of Earth Space Sciences University of Science Technol-ogy of China Hefei China 《科学通报(英文版)》2004,49(20):2198-2204
Abundantbasic-ultrabasicbodiescropoutintheDabie-Suluultrahighpressure(UHP)metamorphicbeltandoccurasgroupandband.Muchresearchworkhasbeencarriedoutonthebasic-ultrabasicbodiesandmadeagreatprogressespeciallyonmineralogy.ThediscoveryofmineralassemblagesofUHPmetamorphismandexsolvedlamellaesuggestthattherocksmaycomefromthedeepmantleorwasonceemplacedintotheshallowlevelofthecrustandthensubductedtothemantledepthsduringsub-ductionofthecrust[1—13].However,theiroriginandtec-tonicsettingarestillacontrov… 相似文献
10.
Rodinia裂解与华南微板块形成和演化 总被引:3,自引:0,他引:3
介绍了Rodinia研究的历史、现状及主要进展,分析了华南相关地块在Rodinia中的位置以及从Rodinia到Pangea的演化历程.分析结果表明,扬子陆块从Rodinia裂离后,其间在Gondwana形成时,可能发生过湘桂地体、云开地体、浙闽地体、保山地体和腾冲地体的碰撞拼贴造山作用过程.在古特提斯演化阶段,这些地体随古特提斯洋的开启而与扬子陆块裂离,并逐渐形成多岛洋的构造格局,之后又随Pangea的形成而再次与扬子陆块碰撞拼贴增生.因此,Rodinia,Gondwana,Pangea等的形成、裂解和裂离后地体的拼贴增生是认识华南大地构造格局和演化的关键之一.Rodinia应该是华南大地构造研究值得重视的重要课题. 相似文献