【作者】 白景国；

【导师】 钟康惠；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2010， 硕士

【摘要】 矿床位于冈底斯-念青唐古拉板片中东部色日绒-巴嘎裂谷盆地南缘。矿区大比例尺填图和区域路线地质调查证实,洞中拉矿床产于色日绒-巴嘎晚古生代裂谷盆地南缘向北反转推覆构造系后部带,为典型后生铅锌多金属矿床。色日绒-巴嘎晚古生代裂谷盆地南缘向北推覆构造系,由晚古生代裂谷层系(上石炭统-下二叠统来姑组C2P1l碎屑岩夹钙质碎屑岩和上二叠统洛巴堆组P2l碳酸盐岩-碎屑岩)构成。印支期,裂谷沿松多岩组分布区碰撞关闭,一方面,导致裂谷南部原先北倾的生长断裂,不仅性质反转,而且倾向反转南倾,使松多岩组向北逆冲推覆于裂谷层系之上;另一方面,导致北侧裂谷层系发生近底拆离破裂,向北推掩形成规模宏大的斜歪-同斜倒转复式褶皱系。晚燕山早期,碰撞后松弛伸展,以及雅鲁藏布江洋北向俯冲引发的弧内伸展作用,导致中酸性岩浆、中基性岩浆(110～130Ma±)沿推覆破裂系统大规模上侵贯入推覆构造系,致使岩浆热液所及碳酸盐岩和钙质碎屑岩发生矽卡岩化、大理岩化,泥质、硅质碎屑岩发生角岩化。喜马拉雅早期,雅鲁藏布江洋关闭碰撞的远程效应,致使推覆构造系后部先存燕山晚期岩浆岩水平节理面形成轴面南倾的斜歪褶皱,并在松弛期发生中酸性岩浆侵入、喷出(40～60Ma±),伴有铅锌多金属成矿作用。喜马拉雅中期,区域性造山后伸展,推覆构造系中普遍发育中酸性岩浆脉状侵入(13～17Ma±)。色日绒-巴嘎晚古生代裂谷盆地南缘推覆构造系后缘,位于德宗-择弄-洞中拉-远朗-纳棍一线,表现为松多岩组反转掩覆于晚古生代裂谷层系或燕山晚期中酸性岩体之上,邻近的岩体普遍发育轴面南倾的节理褶皱。推覆构造系向北的影响范围,目前尚未界定,但至少抵达色日绒以北。色日绒至德宗一带,南北宽约25km范围,为一轴面南倾的复式同斜倒转背斜。转折部位于日邛朵-恩龙多一带,发育“M”型褶曲。色日绒-德宗大型复式同斜倒转背斜,南翼发育系列同斜倒转-斜歪褶皱,其中,近推覆构造系后缘的次级背斜构造常控制铅锌多金属矿体的产出,目前已发育现洞中拉、洞中松多、蒙亚啊、龙马拉、亚贵拉等铅锌多金属矿床。洞中拉矿区处于推覆构造系后部,色日绒-德宗复式背斜南翼,广泛发育晚燕山早期石英斑岩(127.4±1.9Ma,费光春等,2009)、闪长玢岩(117±1.0Ma,费光春等,2009)、花岗斑岩。需要说明的是,上述浅成侵入岩长期以来未被识别,而视为中酸性凝灰岩和玄武岩(西藏地质二队,2007),定为帕那组(E2p,1/25万门巴区幅,杨德明等,2004)。复式浅成岩体南部发育轴面南倾的斜歪节理褶皱系,并被松多岩群同斜紧闭褶皱片岩系掩覆。雁列式斜歪-同斜倒转褶皱发育的裂谷层系大部分已被岩浆吞蚀,仅有残存顶盖,主体为洛巴堆组(P2l)碳酸盐岩-碎屑岩。斜歪-同斜倒转背斜发育,伴有产状145°～175°∠50°～80°的轴面破裂系统,矿区已知矿体均成脉型产于残存顶盖褶皱轴面破裂系统中。矿化局限于碳泥质板岩屏蔽层下伏的矽卡岩化大理岩化碳酸盐岩层,突显上覆碎屑岩的屏蔽效应。Ⅱ号矿体含矿脉石英Ar-Ar等时线年龄42.2±1.7Ma(费光春等,2009),表明成矿发生于喜马拉雅早期。同时多期次浅成岩浆侵入活动的存在,不排除进一步找到斑岩型矿床的可能性。上述洞中拉铅锌多金属矿床控岩控矿构造研究,不仅对洞中拉矿床及外围找矿指明了方向,而且对冈底斯中东段色日绒-巴嘎晚古生代裂谷盆地南缘铅锌多金属找矿有重要指导意义。更多还原

【Abstract】 The dong zhong la ore deposit located in middle east of Tibet Gan gdise zone ,it is explored in recent years as a lead zinic polymetallic Ore deposits.The deposit located in the south margin of se ri rong–ga ba rift basin in middle east of Gan gdise-Nyanqêntanglha plate .the plotting scale in the deposit area and the route of this area had confirmed that the dong zhong la ore deposit form from the south margin towards north overturned nappe structure system of se ri rong–ga ba Neopaleozoic rift basin ,it is a typical Secondary lead-zinc polymetallic deposits.Dong zhong la ore deposit in south margin towards north overturned nappe structure system of serirong–baga Neopaleozoic rift basin, combined by eopaleo-oic rift valley system (UpperCarboniferous-lower PermianC2P1lclastic mingled calcarneyte and pperPermianseries luobadui P2l carbonatite-clastic rock), Indosiian, ift valley along the areal area Songduo Group Complex shut up because of collision , on one side ,resulting in the south of rift valley northward growth fault.not only character over-turned, but also trend over-turned toward southern , forced the Songduo Group Complex nappe structure on the top of rift valley system .on the other hand, forced the northern rift valley system occur the bottom burst,northward overridden and formed the large scale With inclined overturned fold drape.the Early stage of late Yanshan period. After the collision ,it slack stretch ,and Brahmaputra northward subduction extensional reactivation,it made the mediosilicic -acid magma and medium-basic magma (110-130Ma±)along over-turned fracture system in large scale rising and eructating injection nappe structure system.it forced magma hydrothermalism and carbonatite、calcarneyte occurred skarnization、marbleization、tonhaltig、siliciclastic rocks occurred the hornstone lithification. The early Himalayan period,the remote effection of Brahmaputra closed collision .forced the back of the over-turned structure-ystem ,and at the slack period occurred the medium acid magma intruded,erupted(40-60Ma±),accompanied with lead zinc polyvalent metallization. The middle period of Himalayan, regional orogenetic stretch to back. Among the nappe structure system mediosilicic-acid magma vein intrusion are prospect growth(13-17Ma±).Se ri rong–ga ba Neopaleozoic south margin of rift basin back margin,located in de zong-ze nong-dong zhong la-yuan lang-na gun,it showed us that Songduo Group Complex over-turned and overridden at Neopaleozoic rift basin system or the upper of late Yanshanian medium acid rock. the adjacent rock normaly grow the axial surface trend to south of the joint drape.the region in north of nappe structure system effected, It did not have the defined bounds,but it can reach the north of se ri rong at least .the region of se ri rong to de zong , the distance between south and north is about 25km ,it is a axial surface trend to south fold and overturned anticline .the part of turning located in qiong duo aand en longduo ,growing as the typeof“M”fold. se ri rong to de zong large scale compound inclined reversal anticline, the south wing grow series inclined reversal-inclined fold, thereinto,the secondary anticline of the back marign of nappe structure system,it also controlled lead-zinc polymetallic deposit. now we had found lead zinic polymetallic Ore deposits of dong zhong la、dongzhsongduo、long ma la、meng ya a .The dong zhong la ore field located in back of nappe structure system, Se Ri Rong to De Zong compound anticline south wing , broadly growing the late Yanshanian quartz porphyry(127.4±1.9Ma,Fei Guang chun etc,2009),porphyrite(117±1.0Ma,Fei guang chun etc,2009)、granite porphyry. we need give a special explanation. Igneous rocks never recognized for a long time. But it refer to the medium acid tuff and basalt(the second geology team of tibet,2007),named after(P2l)Carbonate- clasolite. Inclined folds, accompanied with the occurrence of 145°～175°∠50°～80°axial plane fracture system,orefield has found ore body formed vein shape produced on the top of fold axial plane fracture. Mineralization is confined in skarnization and marbleization carbonate under the carbonaceous slate shielding layer. the clasolite prominence shielding effect. TheⅡbody includes veiny quartz Ar-Ar isochron age 42.2±1.7Ma(Fei Guang chun etc,2009),it indicates metallogenesis occurred in the early Himalaya.at the same time ,the existingof polyphase hypabyssal magma intrusion activities. We did not get rid of we will find the possibility of porphyre deposit existed.The study of ore-controlling structure in lead zinic polymetallic Ore deposits in Tibet Maizhokunggar County, not only make a clear direction to Dongzhongla and outside deposit, but also have a important significant to lead zinic polymetallic Ore deposits in south margin of se ri rong–ga ba rift basin in middle east of Gan gdise-Nyanqêntanglha zone.更多还原