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滇西哀牢山断裂带构造岩块变质变形特征及其演化

发布时间:2018-07-25 15:20
【摘要】:云南省三江地区一直以来都是地学界各个领域专家研究的热点地区,其中哀牢山断裂带是青藏高原东南缘的一条重要线性构造。因其独特的线形延伸,复杂而多期的构造演化,以及构造带东西两侧地质演化明显差异,再加上新生代以来作为印度板块-欧亚板块碰撞调节及复合的重要场所,使该构造带成为长期以来被地质学界广泛关注和研究的构造带之一。哀牢山断裂带位处特提斯三江造山带东南缘处于板块构造结合部,构造背景复杂,多级别、多期次的构造形迹发育。研究区位于哀牢山断裂带北段,构造带总体上呈北北西-南南东展布,为一条北西段和南东段侧较宽,中段相对较窄的狭长构造变形带。哀牢山断裂带分布于南涧图幅的马鞍山-洪水井-梅子箐-阿扎鲁小村-团田山一带,是扬子板块楚雄盆地与兰坪-思茅盆地的分界线。它与东西两侧之中生界地层均为断层接触,其上仅有零星新近系地层不整合覆盖。由三条断裂和两个变质带组成。三条断裂从北东至南西断裂分别为红河断裂、哀牢山断裂和阿墨江断裂。两个变质带为深变质带和浅变质带,深变质带被红河断裂和哀牢山断裂所夹持,浅变质带位于哀牢山断裂和阿墨江断裂间。前人将处于哀牢山北段的哀牢山岩群由东向西依次划分为阿龙岩组、清水河岩组和小羊街岩组,将哀牢山南段的哀牢山岩群划分为乌都坑组、凤港组、阿龙组、小羊街组。该构造域经历了前古特提斯阶段、古特提斯阶、新特提斯阶段及陆内演化阶段。尤其是古生代-新生代时期,扬子陆块西缘的离解、碰撞拼贴及陆内会聚作用,包括岩石圈伸展作用、收缩作用、推覆作用和分层撤离作用,其地质构造演化历史漫长而复杂。哀牢山岩群的变形-变质作用十分强烈,尤以韧性变形表现显著,岩石糜棱岩化现象普遍。岩群中早期形成的结晶片理、片麻理已经全面取代原生层理,且多期次变形现象明显,因此,目前所见到的“层状”构造已不能代表原岩建造特征。因而,哀牢山岩群已无层序可言。大河边岩组经历了澄江运动、海西-印支运动、喜马拉雅运动的构造变形、变质作用及改造,岩石中早期平卧褶皱发生再褶现象,形成直立或斜歪褶皱,并伴生轴面劈理,置换早期的面理构造。中二叠世至晚二叠世时,沉积了中二叠统坝溜组碳酸盐岩(P2b)和上二叠统羊八寨组(P3y)三角洲相含煤建造。随着洋壳的向西推挤以及弧后盆地的扩张,盆地内的古生界地层均遭受了变形变质作用。产生了程度不等的低绿片岩相区域低温动力变质。在伸展构造背景下,形成了区域性透入面理以及片理面上出现拉伸线理,面理中发育平卧褶皱及斜卧褶皱,它们是形成于中浅部构造层次,热流的上涌使岩石发生明显的热变质作用。根据研究区的地质概况并结合区域地质资料进行综合分析,大致可以将研究区构造演化分为三个阶段,即洋盆形成,洋盆闭合,陆陆碰撞。洋盆形成时间为晚泥盆世-早二叠世。洋盆闭合时间为晚早二叠世晚期-中三叠世晚期,包括两个阶段:俯冲消减,弧后盆地的形成阶段;洋壳闭合,弧后前陆盆地的形成阶段。陆陆碰撞时间为晚三叠世至古近纪。
[Abstract]:The Sanjiang area of Yunnan province has always been a hot area of expert research in various fields of the geosciences. The Ailaoshan fault zone is an important linear structure in the southeastern margin of the Qinghai Tibet Plateau. Because of its unique linear extension, complex and multi phase tectonic evolution, and the obvious difference in geological evolution between the two sides of the tectonic belt and the Cenozoic era, it is added to the Cenozoic era. As an important place for the collision regulation and recombination of the India plate Eurasia plate, the tectonic belt has been one of the tectonic belts which have been widely concerned and studied by the geologists for a long time. The southeastern edge of the Sanjiang orogenic belt at the Ailao Mountain fault zone is in the plate tectonic junction, and the structure of the tectonic back is complex, multilevel and multistage. The study area is located in the northern section of the Ailao Mountain fault zone. The tectonic belt is generally north north west to South East. It is a narrow and narrow structural deformation zone with a wide side in the North West and the South East section and relatively narrow in the middle section. The Ailao Mountain fault zone is located in the Ma'anshan flood well of Nanjian - Maizi - Al - Al - Al - Al - Tsau small village - tutian area, and the Yangtze plate Chuxiong The dividing line between the basin and the Lanping Simao basin, which is in contact with the Mesozoic strata on both sides of the East and West, has only the unconformable cover of the sporadic Neogene strata. It consists of three faults and two metamorphic belts. The three faults are Honghe fault, Ailaoshan fault, and a Mojiang fault, respectively, from the North East to the South West fault. Two metamorphic belts are deep. The metamorphic belt and the epic metamorphic belt are held by the Honghe fault and Ailao Mountain fault. The epic metamorphic belt is located between the Ailao Mountain Fault and the Mojiang fault. The Ailao Mountain groups in the northern section of the Ailao Mountain are divided from east to west to the Longyan formation, the Qingshui River rock group and the Xiao Yang Street rock group, and the Ailao Mountain groups in the southern section of Ailao Mountain are divided into a group of Ailao Mountains. The tectonic domain experienced the former Gut Tis stage, the ancient Tethys stage, the new Tethys stage and the intracontinental evolution stage, especially in the Paleozoic and Cenozoic era, especially in the western margin of the Yangtze block, the collision collage and the intracontinental convergence, including lithospheric extension, contraction and nappe. The evolution history of the geological structure is long and complicated. The deformation and metamorphism of the Ailao rock group is very strong, especially the ductile deformation is remarkable, and the rock mylonitization is common. The early formation of the crystalline schism in the group of rock groups has completely replaced the primary bedding, and the multistage deformation phenomenon is obvious, therefore, at present, The "lamellar" structure can not represent the characteristics of the original rock formation. Therefore, the Ailaoshan rock group has no sequence. The Dahe edge rock group experienced the Chengjiang movement, the Hercynian Indo branch movement, the tectonic deformation, metamorphism and transformation of the Himalaya movement, and the early pleat of the flat pleat in the rocks, forming erect or oblique folds, accompanied by the formation of the crease. During the Middle Permian to late Permian, the Middle Permian carbonate rock (P2b) and the upper two stack of sheep eight village (P3y) Delta were deposited in the Middle Permian to the Late Permian, and the Paleozoic strata in the basin were deformable and metamorphosed as the oceanic crust pushed westward and the back arc basin expanded. Under the background of extensional tectonics, there is a regional penetration surface and a stretch line on the surface, and the horizontal folds and slumping folds are developed in the surface. They are formed in the middle and shallow structures, and the upwelling of heat flow causes the rock to have obvious thermal metamorphism. The geological survey and comprehensive analysis of the regional geological data can be divided into three stages, namely the formation of the oceanic basin, the closure of the ocean basin and the continental collision. The formation time of the oceanic basin is late Devonian Early Permian. The closing time of the oceanic basin is late Early Permian to the late middle three fold period, including two stages: subduction. Subduction, the formation stage of the back arc basin, the closure of oceanic crust and the formation stage of the back arc foreland basin. The land collision time is from late three to Paleogene.
【学位授予单位】:成都理工大学
【学位级别】:硕士
【学位授予年份】:2015
【分类号】:P542

【参考文献】

相关期刊论文 前1条

1 张志斌,刘发刚,包佳凤;哀牢山造山带构造演化[J];云南地质;2005年02期



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