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1.
可可西里盆地早渐新世雅西措群沉积环境分析及古气候意义   总被引:18,自引:3,他引:15  
刘志飞  王成善 《沉积学报》2000,18(3):355-361
可可西里盆地是青藏高原腹地最大的第三纪沉积盆地,第三纪沉积地层包括早始新世 -早渐新世风火山群、早渐新世雅西措群、早中新世五道梁群。其中,雅西措群为紫红色、砖红色泥岩、含膏泥岩与紫红色粉砂岩、细砂岩韵律互层,夹白色石膏薄层和石膏结核层,沉积厚度为 6 70.0m,沉积环境主要由河流和湖泊环境组成,并以湖泊环境为主,古水流方向反映盆地沉积中心逐渐向东向北迁移。雅西措群中石膏层的突然大量出现发生在底部地层距今约32.0Ma,体现了渐新世最早期的全球变冷变干事件在青藏高原北部的记录。  相似文献   

2.
HOH XIL PIGGYBACK BASINS:IMPLICATIONS FOR PALEOGENE SHORTENING OF THE TIBETAN PLATEAU  相似文献   

3.
MASS ACCUMULATION IN THE CENOZOIC HOH XIL BASIN,NORTHERN TIBET1 BarronEJ,WashingtonWM .Theroleofgeographicvariablesinexplainingpaleoclimates:ResultsfromCretaceousclimatemodelsensitivitystudies[J] ..JournalofGeophysicalResearch ,1984 ,89:12 6 7~ 12 79. 2 HayWW ,ShawCA ,WoldCN .Mass balancedpaleogeographicreconstructions[J] ..GeologischeRundschau,1989,78( 1) :2 0 7~ 2 4 2 . 3 LiuZhifei,WangChengshan .FaciesanalysisanddepositionalprocessesofCenozoicsed…  相似文献   

4.
The Hoh Xil Basin is the largest Cenozoic sedimentary basin in the hinterland of the Tibetan Plateau. Tertiary sedimentary strata 5.8 km thick, comprising the Fenghuoshan, Yaxicuo and Wudaoliang groups, provide compelling evidence concerning the crustal shortening, erosion and peneplanation of the northern Tibetan Plateau. The basal Fenghuoshan and overlying Yaxicuo groups span the Eocene-Early Oligocene stratigraphically, and have been dated by magnetostratigraphy as 56–30 Ma old. Both groups are composed of terrigenous rocks. Provenance analysis of sandstones and conglomerates demonstrates that Permian and Triassic strata in the Tanggula Orogenic Zone in the south were the source for the Fenghuoshan Group. In contrast, the Carboniferous–Triassic strata in the Tanggula, Bairizhajia, and Heishishan-Gaoshan orogenic zones in the north, were the source for the Yaxicuo Group.During the Late Oligocene, northern Tibet underwent strong north–south crustal shortening (∼43%) and thickening. Extensive erosion, which occurred over the entire plateau surface near the end of the Oligocene, resulted in development of a peneplain surface. The latter is overlain by the Early Miocene Wudaoliang Group, composed of fresh water limestones. These are exposed both on summit surfaces, as well as on the valley floors, showing that a phase of differential uplift occurred after the deposition of the Wudaoliang Group. This post-Miocene differential uplift was due to regional extension, in a region of overall shortening. Even though we have not succeeded in obtaining conclusive data about the exact timing of phases of rapid uplift of the Tibetan Plateau, it is most likely that the major phase of uplift occurred during the Late Oligocene.  相似文献   

5.
可可西里西段羊湖盆地沉积、构造特征及其动力学意义   总被引:1,自引:0,他引:1  
对可可西里西段新生代盆地缺乏了解是导致该区新生代地质演化存在争议的重要原因.本文以沉积学和构造变形分析为主要手段,对可可西里西段羊湖盆地时代、充填序列、物源区和变形特征进行了分析,结果表明,羊湖盆地新生界沉积厚度大于1302m,主要由下部雅西错组冲积扇相碎屑岩和上部五道梁群湖泊相碳酸盐岩组成,其岩石组合和充填序列与可可西里东段具有一致性,同时古流向和碎屑锆石U-Pb年代学分析显示盆地物源来南部的羌塘地块,盆地形成演化受南部褶皱冲断带制约,盆地构造变形强烈,沿褶皱冲断带和羊湖盆地地壳分别发生51%和41%的缩短.沉积充填结构和变形特征表明,羊湖盆地与东段可可西里盆地具有相同的演化历史和性质,预示青藏高原中部在渐新世-中新世在存在一个大的、统一的可可西里盆地.  相似文献   

6.
青藏高原北部可可西里盆地第三纪风火山群沉积环境分析   总被引:19,自引:4,他引:19  
青藏高原北部的可可西里盆地是高原腹地最大的第三纪沉积盆地,分布着沉积厚度达 4 782.8m的早始新世-早渐新世风火山群灰紫色砂岩、泥岩和砾岩,其沉积环境演化经历了四个阶段,从早期 56.0~ 52.2Ma河流为主的环境,到中期 52.2~ 4 3.1Ma的湖泊环境和 4 3.1~ 3 8.3Ma的河流与扇三角洲环境,演变到晚期 3 8.3~ 3 2.0Ma河流为主的环境。古水流方向也由北东向变为南东向,到晚期又转变为北向为主,反映盆地沉积中心逐渐向东向北迁移。这种沉积环境演化和盆地沉积中心迁移可能受青藏高原早期隆升的影响.  相似文献   

7.
可可西里盆地位于昆仑山和唐古拉山之间 ,是青藏高原腹地最大的第三纪沉积盆地 ,对于研究青藏高原早期隆升和地壳短缩过程具有重要作用 .盆地保存的始新世—渐新世早期风火山群和雅西措群主要由碎屑岩和泥岩组成 ,厚度为 5 45 2 .8m .碎屑岩的物源区分析表明 ,风火山群主要来自于南部的唐古拉造山带二叠—三叠纪地层 ,而雅西措群主要来自于南部的唐古拉、白日榨加和黑石山 -高山造山带 ,剥蚀深度加大至石炭—二叠纪地层 .它们的沉积演化过程是盆地南部造山带老第三纪构造隆升持续加强的结果 ,表明在雅西措群沉积时期青藏高原北部已经隆升至一定的高度 .  相似文献   

8.
Paleocurrent indicator data collected in field work were used to study the early Cenozoic regional paleodrainage patterns in the Hob Xil basin in northern Tibetan plateau. The paleocurrent directions of the Eocene Fenghuoshan Group obviously show that the flows were northward with a unidirectional dispersal pattern. This probably reflects the uplift of the Qiangtang terrain during the initial basin deposition period and indicates that the Tanggula Moutains occurred as topographic highlands at least in the Eocene. Paleoflows of the Oligocene Yaxicuo Group were dominantly oriented to the north and then flowed eastwards during its late deposition. This regional variability of paleodrainage patterns of the Yaxicuo Group is interpreted to record the dispersal style of sediments from transverse rivers to longitudinal river systems. It is inferred that the Oligocene uplift of the Kunlun Mountains obstructed by northward paleoflows and created longitudinal river systems parallel to the orogenic belts. The temporal and spatial changes of the paleodrainage patterns suggest that the northern boundary of the Tibetan plateau during the early Cenozoic was situated in the Hoh Xil area and its uplift has progressed northwards through time.  相似文献   

9.
PROVENANCE OF LOWER TERTIARY REDBEDS IN HOH XIL BASIN AND UPLIFT OF NORTHERN TIBET PLATEAU  相似文献   

10.
THE PALEOCURRENT PATTERN OF EARLY TERTIARY REDBEDS IN THE HOH XIL BASIN,NORTHERN TIBET PLATEAU:IMPLICATIONS FOR AN EARLY UPLIFT AND UNROOFING  相似文献   

11.
MAGNETOSTRATIGRAPHIC DATING:IMPLICATIONS FOR TERTIARY EVOLUTION OF THE HOH XIL BASIN, NORTHERN TIBET1 BGMRQ (BureauofGeologyandMineralResourcesofQinghai) .RegionalgeologyofQinghai(inChinesewithEnglishab stract) [M] .Beijing :ChinaGeolPress,1991. 2 CowardWP ,KiddWSF ,Pang,Y ,etal.Thestructureof1985TibetGeotraverse ,LhasatoGolmud.In:Sino BritishComprehensiveGeologicalExpeditionTeamoftheQinghai TibetPlateau.ThegeologicalevolutionoftheQin…  相似文献   

12.
青藏高原沱沱河盆地渐新-中新世沉积环境分析   总被引:13,自引:0,他引:13  
沱沱河盆地保存着青藏高原内部至今发现最完整的渐新世至中新世连续沉积记录,由渐新世雅西措群(31.3~23.8Ma)和早中新世五道梁群(23.8~21.8Ma)组成,总厚度2393m。雅西措群主要为紫红色、砖红色砂岩、粉砂岩与泥岩韵律互层,五道梁群为一套内陆湖泊相泥灰岩、内碎屑灰岩和叠层石灰岩沉积。沱沱河盆地渐新-中新世沉积环境经历了3个阶段的演化:(1)早渐新世,以河流环境为主,古水流以北向为主,反映古气候条件比较干燥;(2)中晚渐新世,以湖泊环境为主,古水流以东北向为主,古气候条件相对温暖潮湿;(3)晚渐新世至早中新世,主要为湖泊环境,古水流转为南向,沉积岩性由雅西措群项部的砂泥岩互层为主转变为五道梁群的泥灰岩为主,反映当时的物源区发生重大转变,构造活动趋于稳定,古气候条件由温暖潮湿转为干燥。沱沱河盆地渐新-中新世气候和构造活动历史对于研究青藏高原早期隆升作用和全球气候变化都有重要意义。  相似文献   

13.
Miocene marl is the most widespread Tertiary stratigraphic record in the northern Tibet Plateau, termed the Wudaoliang Group in the Hoh Xil region and the correlative Suonahu Formation in the Qiangtang region. The uniform marl overlies red beds of the Eocene-Oligocene Fenghuoshan Group. The Wudaoliang Group is generally 100-400 m thick, but the thickest strata are 700-1300 m, located in the Haidinghu (Maiding Lake) and Tuotuohe (Tuotuo River) regions respectively. Based on observations from eight measured sections and outcrops, the thin-bedded marl, which varies in colour from grey-white to light brown-grey, is explained as a large-scale or serial lacustrine deposit stretching throughout northern Tibet.The Wudaoliang Group commonly crops out on geographic lowland at an average elevation of 4600 m above sea level within the mountain chains, showing concordant summit levels, e.g. the Fenghuoshan and Bairizhajia Mountains. These mountains with a flat ridge are considered to be remains of the palaeo-planati  相似文献   

14.
Sedimentological, cyclic-stratigraphic, paleomagnetic, and clay-mineralogical studies on the early Oligocene Yaxicuo Group in the Hoh Xil Basin, the largest Cenozoic sedimentary basin in the hinterland of the Tibetan Plateau, provide abundant information of paleoclimate changes. A 350-m thick section in the middle-lower Yaxicuo Group was analyzed to reveal the climatic history that occurred in the Hoh Xil region during the early Oligocene interval 31.30-30.35 Ma, dated with the paleomagnetic chronostratigraphy. The results indicate that add and cold climate dominated the Hoh Xil region during the early Oligocene in general, being related to the global cooling and drying events that occurred in the earliest Oligocene. Within this period, relatively warm and wet climate accompanied by strong tectonic activity occurred in the 31.05-30.75 Ma interval; while add and cold climate and relatively inactive tectonics occurred in the 31.30-31.05 and 30.75-30.35 Ma intervals. Furthermore, spectral analyses of high-temporal resolution paleoclimatic records show orbital periods including eccentricity, obliquity, and precession. It is concluded that paleoclimate changes during the early Oligocene in the Hoh Xil region were forced by both tectonic activity and orbital periods.  相似文献   

15.
Sedimentological, cyclic-stratigraphic, paleomagnetic, and clay-mineralogical studies on the early Oligocene Yaxicuo Group in the Hoh Xil Basin, the largest Cenozoic sedimentary basin in the hinterland of the Tibetan Plateau, provide abundant information of paleoclimate changes. A 350-m thick section in the middle-lower Yaxicuo Group was analyzed to reveal the climatic history that occurred in the Hoh Xil region during the early Oligocene interval 31.30-30.35 Ma, dated with the paleomagnetic chronostratigraphy. The results indicate that arid and cold climate dominated the Hoh Xil region during the early Oligocene in general, being related to the global cooling and drying events that occurred in the earliest Oligocene. Within this period, relatively warm and wet climate accompanied by strong tectonic activity occurred in the 31.05-30.75 Ma interval; while arid and cold climate and relatively inactive tectonics occurred in the 31.30-31.05 and 30.75-30.35 Ma intervals. Furthermore, spectral analyses of hig  相似文献   

16.
Understanding the Cenozoic vertical-axis rotation in the Tibetan Plateau is crucial for continental dynamic evolution. Paleomagnetic and rock magnetic investigations were carried out for the Oligocene and Miocene continental rocks of the Hoh Xil basin in order to better understand the tectonic rotations of central Tibet. The study area was located in the Tongtianhe area located in the southern part of the Hoh Xil basin and northern margin of the Tanggula thrust system in central-northern Tibet. A total of 160 independently oriented paleomagnetic samples were drilled from the Tongtianhe section for this study. The magnetic properties of magnetite and hematite have been recognized by measurements of magnetic susceptibility vs. temperature curves and unblocking temperatures. The mean directions of the Oligocene Yaxicuo Group in stratigraphic coordinates(Declination/Inclination = 354.9°/29.3°, k = 33.0, α_(95) = 13.5°, N =5 Sites) and of the Miocene Wudaoliang Group in stratigraphic coordinates(Declination/Inclination = 3.6°/36.4°, k = 161.0, α_(95) = 9.7°, N =3 Sites) pass reversal tests, indicating the primary nature of the characteristic magnetizations. Our results suggested that the sampled areas in the Tuotuohe depression of the Hoh Xil basin have undergone no paleomagnetically detectable rotations under single thrusting from the Tanggula thrust system. Our findings, together with constraints from other tectonic characteristics reported by previous paleomagnetic studies, suggest tectonic rotations in the Cuoredejia and Wudaoliang depressions of the Hoh Xil basin were affected by strike-slip faulting of the Fenghuo Shan-Nangqian thrust systems. A closer examination of geological data and different vertical-axis rotation magnitudes suggest the tectonic history of the Hoh Xil basin may be controlled by thrust and strike-slip faulting since the Eocene.  相似文献   

17.
在系统分析青藏高原新生代98个残留盆地类型、形成构造背景、岩石地层序列的基础上, 对青藏高原古新世—始新世、渐新世、中新世及上新世构造岩相古地理演化特征进行了讨论: (1)古新世—始新世: 松潘—甘孜和冈底斯带为大面积构造隆起蚀源区.塔里木东部、柴达木、羌塘、可可西里地区主体表现为大面积的构造压陷湖盆-冲泛平原沉积.高原西部和南部为新特提斯海.(2)渐新世: 冈底斯—喜马拉雅和喀喇昆仑大范围沉积缺失, 指示上述地区大面积隆升.沿雅江自东向西古河形成(大竹卡砾岩).西昆仑和松潘—甘孜地区仍为隆起蚀源区.塔里木、柴达木、羌塘、可可西里地区主体表现为大面积构造压陷湖盆沉积.塔里木西南部为压陷盆地滨浅海沉积.渐新世末塔里木海相沉积结束.(3)中新世: 约23 Ma时高原及周边不整合面广布, 标志高原整体隆升.塔里木、柴达木及西宁—兰州、羌塘、可可西里等地区主体表现为大面积的构造压陷湖盆沉积; 约18~13 Ma高原及周边出现中新世最大湖泊扩张期.约13~10 Ma期间, 藏南南北向断陷盆地形成, 是高原隆升到足够高度开始垮塌的标志.(4)上新世: 除可可西里—羌塘、塔里木、柴达木等少数大型湖盆外, 大部分地区为隆起剥蚀区.由于上新世的持续隆升和强烈的断裂活动, 使大型盆地的基底抬升被分割为小盆地, 湖相沉积显著萎缩, 进入巨砾岩堆积期, 是高原整体隆升的响应.高原从古近纪的东高西低格局, 经历了新近纪全区的不均衡隆升和坳陷, 最终铸就了西高东低的地貌格局, 青藏作为一个统一的高原发生了重大的地貌反转事件.   相似文献   

18.
We have studied the evolution of the tectonic lithofacies paleogeography of Paleocene–Eocene, Oligocene, Miocene, and Pliocene of the Qinghai–Tibet Plateau by compiling data regarding the type, tectonic setting, and lithostratigraphic sequence of 98 remnant basins in the plateau area. Our results can be summarized as follows. (1) The Paleocene to Eocene is characterized by uplift and erosion in the Songpan–Garzê and Gangdisê belts, depression (lakes and pluvial plains) in eastern Tarim, Qaidam, Qiangtang, and Hoh Xil, and the Neo-Tethys Sea in the western and southern Qinghai–Tibet Plateau. (2) The Oligocene is characterized by uplift in the Gangdisê–Himalaya and Karakorum regions (marked by the absence of sedimentation), fluvial transport (originating eastward and flowing westward) in the Brahmaputra region (marked by the deposition of Dazhuka conglomerate), uplift and erosion in western Kunlun and Songpan–Garzê, and depression (lakes) in the Tarim, Qaidam, Qiangtang, and Hoh Xil. The Oligocene is further characterized by depressional littoral and neritic basins in southwestern Tarim, with marine facies deposition ceasing at the end of the Oligocene. (3) For the Miocene, a widespread regional unconformity (ca. 23 Ma) in and adjacent to the plateau indicates comprehensive uplift of the plateau. This period is characterized by depressions (lakes) in the Tarim, Qaidam, Xining–Nanzhou, Qiangtang, and Hoh Xil. Lacustrine facies deposition expanded to peak in and adjacent to the plateau ca. 18–13 Ma, and north–south fault basins formed in southern Tibet ca. 13–10 Ma. All of these features indicate that the plateau uplifted to its peak and began to collapse. (4) Uplift and erosion occurred during the Pliocene in most parts of the plateau, except in the Hoh Xil–Qiangtang, Tarim, and Qaidam.  相似文献   

19.
系统分析青藏高原新生代中新世50余个沉积盆地的类型、构造背景、岩石地层序列,对青藏高原中新世构造岩相古地理演化特征进行分析和探讨。中新世,青藏高原海相沉积已经全面退出,全部转为陆相沉积,约23Ma时高原及周边不整合面广布,标志高原整体隆升。塔里木、柴达木及西宁-兰州、羌塘、可可西里等地区主体表现为大面积的构造压陷湖盆沉积。约17.2Ma左右,阿尔金山显著隆升,使柴达木盆地西叉沟一带再无生物礁灰岩出现,且在盆地西部出现了短暂的沉积间断。这一时期,柴达木盆地西部开始进入湖退期,而东南部则快速湖进;同时,大约17.7Ma索尔库里山间盆地初始凹陷形成。另外,高原腹地五道梁-沱沱河盆地受南部唐古拉山的挤压抬升,在16Ma左右结束了五道梁组的沉积,在可可西里—唢呐湖一带则再次凹陷接受唢呐湖组沉积,形成高原腹地的大型压陷湖盆。13~10Ma期间,藏南南北向断陷盆地的形成,是高原隆升到足够高度开始垮塌的标志;约8Ma以来,高原东北部几乎所有湖盆均进入湖退期,普遍出现冲积扇、辫状河和水下扇砂砾岩堆积。  相似文献   

20.
青海可可西里自石炭纪以来经历了复杂的构造演化和地表过程,形成了集高山、宽谷、夷平面、冰川、热泉、河流和湖泊等地貌元素为一体的高原高寒地貌,同时还包括了蛇绿混杂岩带、活动断裂带、地震遗迹和火山遗迹等地质元素。在调研前人研究资料和实地野外考察基础之上,根据IUCN(2005)提出的13类地质主题分类标准将区内的地质遗迹分为地质构造、火山和地热遗迹、山脉、地层剖面、河流和湖泊、现代冰川、冰期遗迹7类,共计60余处地质遗迹点。可可西里地质遗迹对重建古特提斯构造域、研究天然地震机制、青藏高原北部隆升过程及全球气候变化均具有重要的意义。基于可可西里区内地质遗迹和前人资料恢复出可可西里石炭纪以来经历了8个构造演化阶段。  相似文献   

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