A comparative analysis of the geochemical characteristics of sediments from the Oligocene Zhuhai Formation(32-23.8 Ma),the Miocene Zhujiang Formation(23.8-16.5 Ma),and the Hanjiang Formation(16.5—10.5 Ma) and a compr...A comparative analysis of the geochemical characteristics of sediments from the Oligocene Zhuhai Formation(32-23.8 Ma),the Miocene Zhujiang Formation(23.8-16.5 Ma),and the Hanjiang Formation(16.5—10.5 Ma) and a comprehensive analysis of the geochemical characteristics of rocks surrounding the paleo-Pearl River drainage contribute to understanding the influences of the Tibetan Plateau uplift on provenance evolution of the paleo-Pearl River.The results show that the geochemical characteristics of sediments from the Oligocene Zhuhai Formation are very different from the geochemical characteristics of sediments from the Miocene Zhujiang and Hanjiang Formations.The ∑ rare earth elements(REE) of mudstone is relatively high in the Zhuhai Formation,204.07-293.88 ppm(average 240.46 ppm),and low in the Zhujiang and Hanjiang Formations,181.32-236.73 ppm(average 203.83 ppm) and 166.84-236.65 ppm(average199.04 ppm),respectively.The chemical index of alteration(CIA) for these samples has a similar trend to the∑ REE:the CIA of the Zhuhai Formation is relatively high and the CIA of the Zhujiang and Hanjiang Formations is relatively low.The uplift of the Tibetan Plateau is crucial to the westward expansion of the paleo-Pearl River drainage.展开更多
The siliciclastic sediments of the uppermost section of 185 mcd(meters composite depth) from ODP Site 1146 on the northern continental slope of the South China Sea(SCS) were partitioned according to their sources usin...The siliciclastic sediments of the uppermost section of 185 mcd(meters composite depth) from ODP Site 1146 on the northern continental slope of the South China Sea(SCS) were partitioned according to their sources using end-member modeling on grain-size data. The goal was to evaluate the evolution of the East Asian monsoon over the past 2 million years. The siliciclastic sediments were described as hybrids of four end-members, EM1, EM2, EM3, and EM4, with modal grain sizes of 8–22 μm, 2–8 μm, 31–125 μm, and 4–11 μm, respectively. EM1 and EM3 are interpreted as eolian dust and EM2 and EM4 as fluvial mud. The ratio of eolian dust to fluvial mud((EM1+EM3)/(EM2+EM4)) is regarded as an indicator of the East Asian monsoon. The variation in this ratio not only shows periodical oscillations consistent with oxygen isotope stages, but also exhibits a phased increasing trend corresponding with the phased uplifts of the Tibetan Plateau, indicating that the evolution of the East Asian Monsoon was controlled not only by glacial-interglacial cycles, but also by the phased uplifts of the Tibetan Plateau during the Quaternary.展开更多
[Objective]The aim was to study the influence of Qinghai-Tibet Plateau uplift on regional climate in China.[Method] Trough relevant study of Qinghai-Tibet Plateau and its surrounding movement,the tectonic movement of ...[Objective]The aim was to study the influence of Qinghai-Tibet Plateau uplift on regional climate in China.[Method] Trough relevant study of Qinghai-Tibet Plateau and its surrounding movement,the tectonic movement of the Qinghai-Tibet Plateau and its surrounding areas,especially the case of the impact caused by plateau phased uplift were studied based on paleomagnetic measurements.[Result]The increasing Qinghai-Tibet Plateau led to obvious transition from dry to cold in northwest China and it became dry quickly,which led to loess accumulation,replacement of vegetation types and human activity.Meanwhile,it was dry,and there was certain degree of climate changes in the area.[Conclusion] Qinghai-Tibet Plateau had far-reaching significance on basic climate characteristics in northwest China.展开更多
In southern Asia, there are three large-scale wave-like mountains ranging from the Tibetan Plateau westward to the Iranian Plateau and the Armenian Plateau. On the southern side between plateaus, there are the Indian ...In southern Asia, there are three large-scale wave-like mountains ranging from the Tibetan Plateau westward to the Iranian Plateau and the Armenian Plateau. On the southern side between plateaus, there are the Indian Peninsula and the Arabian Peninsula. What dynamic mechanisms form the directional alignment of the three plateaus with the two peninsulas remains a mystery. In the early stages of the Earth’s geological evolution, the internal structure of the Earth was that the center was a solid core, and the outmost layer was a thin equatorial crust zone separated by two thick pristine continents in polar areas, while the middle part was a deep magma fluid layer. Within the magma fluid layer, thermal and dynamic differences triggered planetary-scale vertical magma cells and led to the core-magma angular momentum exchange. When the core loses angular momentum and the magma layer gains angular momentum, the movement of upper magma fluids to the east and the tropical convergence zone (TCZ) drives the split and drift of two thick pristine continents, eventually forming the current combination of these plateaus and peninsulas and their wave-like arrangement along the east-west direction. Among them, the horizontal orthogonal convergence (collision) of upper magma fluids from the two hemispheres excited the vertical shear stress along the magma TCZ, which is the dynamic mechanism of mountain uplifts on the north side and plate subductions on the south side. To confirm this mechanism, two examples of low-level winds are used to calculate the correspondence between cyclone/anticyclonic systems generated by the orthogonal collision of airflows along the atmospheric TCZ and satellite-observed cloud systems. Such comparison can help us revisit the geological history of continental drift and orogeny.展开更多
Making full use of modern analytical and testing techniques to explore and establish new indexes or methods for extracting paleoseawater geochemical information from sediments will help to reconstruct the sedimentary ...Making full use of modern analytical and testing techniques to explore and establish new indexes or methods for extracting paleoseawater geochemical information from sediments will help to reconstruct the sedimentary paleoenvironment in different research areas.The connection between the subsidence of the South China Sea basin and the uplift of the Tibetan Plateau has been a scientific concern in recent decades.To explore the information on the sedimentary paleoenvironment,provenance changes and uplift of Tibetan Plateau contained in core sediments(debris),we selected core samples from Well LS33 in the Qiongdongnan Basin,South China Sea,and analyzed the contents of typical elements(Al,Th,and rare earth elements)that can indicate changes in provenance and the Sr isotopic compositions,which can reveal the geochemical characteristics of the paleoseawater depending on the type of material(authigenic carbonate and terrigenous detritus).The results show the following:(1)during the late Miocene,the Red River transported a large amount of detrital sediments from the ancient continental block(South China)to the Qiongdongnan Basin.(2)The authigenic carbonates accurately record changes in the 87Sr/86Sr ratios in the South China Sea since the Oligocene.These ratios reflect the semi-closed marginal sea environment of the South China Sea(relative to the ocean)and the sedimentary paleoenvironment evolution process of the deep-water area of the Qiongdongnan Basin from continental to transitional and then to bathyal.(3)Since the Neogene,the variations in the 87Sr/86Sr ratio in the authigenic carbonates have been consistent with the variations in the uplift rate of the Tibetan Plateau and the sediment accumulation rate in the Qiongdongnan Basin.These consistent changes indicate the complex geological process of the change in the rock weathering intensity and terrigenous Sr flux caused by changes in the uplift rate of the Tibetan Plateau,which influence the Sr isotope composition of seawater.展开更多
Geologists agree that the collision of the Indian and Asian plates caused uplift of the Tibet Plateau.However,controversy still exists regarding the modes and mechanisms of the Tibetan Plateau uplift.Geology has recor...Geologists agree that the collision of the Indian and Asian plates caused uplift of the Tibet Plateau.However,controversy still exists regarding the modes and mechanisms of the Tibetan Plateau uplift.Geology has recorded this uplift well in the Qaidam Basin.This paper analyzes the tectonic and sedimentary evolution of the western Qaidam Basin using sub-surface seismic and drill data. The Cenozoic intensity and history of deformation in the Qaidam Basin have been reconstructed based on the tectonic developments,faults growth index,sedimentary facies variations,and the migration of the depositional depressions.The changes in the sedimentary facies show that lakes in the western Qaidam Basin had gone from inflow to still water deposition to withdrawal.Tectonic movements controlled deposition in various depressions,and the depressions gradually shifted southeastward.In addition,the morphology of the surface structures in the western Qaidam Basin shows that the Cenozoic tectonic movements controlled the evolution of the Basin and divided it into(a) the southern fault terrace zone, (b) a central Yingxiongling orogenic belt,and(c) the northern fold-thrust belt;divided by the XI fault (Youshi fault) and Youbei fault,respectively.The field data indicate that the western Qaidam Basin formed in a Cenozoic compressive tectonic environment caused by the India—Asia plate collision. Further,the Basin experienced two phases of intensive tectonic deformation.The first phase occurred during the Middle Eocene—Early Miocene(Xia Ganchaigou Fm.and Shang Ganchaigou Fm.,43.8—22 Ma),and peaked in the Early Oligocene(Upper Xia Ganchaigou Fm.,31.5 Ma).The second phase occurred between the Middle Miocene and the Present(Shang Youshashan Fm.and Qigequan Fm., 14.9—0 Ma),and was stronger than the first phase.The tectonic—sedimentary evolution and the orientation of surface structures in the western Qaidam Basin resulted from the Tibetan Plateau uplift,and recorded the periodic northward growth of the Plateau.Recognizing this early tectonic—sedimentary evolution supports the previous conclusion that northern Tibet responded to the collision between India and Asia shortly after its initiation.However,the current results reveal that northern Tibet also experienced another phase of uplift during the late Neogene.The effects of these two stages of tectonic activity combined to produce the current Tibetan Plateau.展开更多
On the basis of a newly-constructed record of magnetic susceptibility （SUS） and the depositional rate change of eolian loess-red clay sequences in the last 7.2 Ma BP from the Loess Plateau, together with a compariso...On the basis of a newly-constructed record of magnetic susceptibility （SUS） and the depositional rate change of eolian loess-red clay sequences in the last 7.2 Ma BP from the Loess Plateau, together with a comparison of a record of δ<sup>18</sup>O values from the equatorial East Pacific Ocean and eolian Quartz flux variations from the North Pacific Ocean, the evolutionary process of the Late Cenozoic Great Glaciation in the Northern Hemisphere can be divided into three stages: the arrival stage around 7.2—3.4 Ma BP, the initial stage at about 3.4—2.6 Ma BP, and the Great Ice Age since 2.6 Ma BP. The evolution of the East Asian monsoon is characterized by paired winter and summer monsoons, and it is basically composed of the initial stage of weak winter and summer monsoons, the transitional stage of simuhaneous increase in intensity of winter and summer monsoons, and the prevailing stage of strong winter and weak summer monsoons, or weak winter and strong summer monsoons. The Late Cenozoic global tectonic展开更多
A global atmospheric general circulation model has been used to perform eleven idealized numerical experiments, i.e., TP00, TP10, ···, TP100, corresponding to different percentages of the Tibetan Platea...A global atmospheric general circulation model has been used to perform eleven idealized numerical experiments, i.e., TP00, TP10, ···, TP100, corresponding to different percentages of the Tibetan Plateau altitude. The aim is to explore the sensitivity of East Asian climate to the uplift and expansion of the Tibetan Plateau under the reconstructed boundary conditions for the mid-Pliocene about 3 Ma ago. When the plateau is progressively uplifted, global annual surface temperature is gradually declined and statistically significant cooling signals emerge only in the Northern Hemisphere, especially over and around the Tibetan Plateau, with larger magnitudes over land than over the oceans. On the contrary, annual surface temperature rises notably over Central Asia and most parts of Africa, as well as over northeasternmost Eurasia in the experiments TP60 to TP100. Meanwhile, the plateau uplift also leads to annual precipitation augmentation over the Tibetan Plateau but a reduction in northern Asia, the Indian Peninsula, much of Central Asia, parts of western Asia and the southern portions of northeastern Europe. Additionally, it is found that an East Asian summer monsoon system similar to that of the present initially exists in the TP60 and is gradually intensified with the continued plateau uplift. At 850 hPa the plateau uplift induces an anomalous cyclonic circulation around the Tibetan Plateau in summertime and two anomalous westerly currents respectively located to the south and north of the Tibetan Plateau in wintertime. In the mid-troposphere, similar-to-modern spatial pattern of summertime western North Pacific subtropical high is only exhibited in the experiments TP60 to TP100, and the East Asian trough is steadily deepened in response to the progressive uplift and expansion of the Tibetan Plateau.展开更多
By observing, measuring the fluvial sediment grain size of mid-western segment of the Qilianshan Range and studying the correlation between the grain size and uplift of the plateau, we model the correlation. These mod...By observing, measuring the fluvial sediment grain size of mid-western segment of the Qilianshan Range and studying the correlation between the grain size and uplift of the plateau, we model the correlation. These models are applied to the Laojunmiao section and the process curve of the uplift of the northern Tibetan Plateau against age from 8.35 Ma is illustrated here. The process curve shows that the northern Tibetan Plateau surface has uplifted from the mean altitude of 900-3700 m since 8.35 MaBP. From 8.35 to 3.1 MaBP, the Tibetan Plateau uplifted slowly, uplifted amplitude is small, the total range is 420 m. From 3.1 MaBP up to now, the Tibetan Plateau uplifted tempestuously, showing that the uplift accelerated obviously later. It uplifted totally 2400 m. About 0.9 Ma ago, the northern Tibetan Plateau surface had uplifted to over 3000 m a.s.l., showing that the Tibetan Plateau surface had reached the cryosphere; and the mountain peaks had uplifted to more than 4000 m altitude, suggesting that展开更多
As one of the most important geological events in Cenozoic era,the uplift of the Tibetan Plateau(TP)has had profound influences on the Asian and global climate and environment evolution.During the past four decades,ma...As one of the most important geological events in Cenozoic era,the uplift of the Tibetan Plateau(TP)has had profound influences on the Asian and global climate and environment evolution.During the past four decades,many scholars from China and abroad have studied climatic and environmental effects of the TP uplift by using a variety of geological records and paleoclimate numerical simulations.The existing research results enrich our understanding of the mechanisms of Asian monsoon changes and interior aridification,but so far there are still a lot of issues that need to be thought deeply and investigated further.This paper attempts to review the research on the influence of the TP uplift on the Asian monsoon-arid environment,summarize three types of numerical simulations including bulk-plateau uplift,phased uplift and sub-regional uplift,and especially to analyze regional differences in responses of climate and environment to different forms of tectonic uplifts.From previous modeling results,the land-sea distribution and the Himalayan uplift may have a large effect in the establishment and development of the South Asian monsoon.However,the formation and evolution of the monsoon in northern East Asia,the intensified dryness north of the TP and enhanced Asian dust cycle may be more closely related to the uplift of the main body,especially the northern part of the TP.In this review,we also discuss relative roles of the TP uplift and other impact factors,origins of the South Asian monsoon and East Asian monsoon,feedback effects and nonlinear responses of climatic and environmental changes to the plateau uplift.Finally,we make comparisons between numerical simulations and geological records,discuss their uncertainties,and highlight some problems worthy of further studying.展开更多
Monsoon and arid regions in the Asia-Africa-Australia(A-A-A) realm occupy more than 60% of the total area of these continents. Geological evidence showed that significant changes occurred to the A-A-A environments of ...Monsoon and arid regions in the Asia-Africa-Australia(A-A-A) realm occupy more than 60% of the total area of these continents. Geological evidence showed that significant changes occurred to the A-A-A environments of the monsoon and arid regions, the land-ocean configuration in the Eastern Hemisphere, and the topography of the Tibetan Plateau(TP) in the Cenozoic. Motivated by this background, numerical experiments for 5 typical geological periods during the Cenozoic were conducted using a coupled ocean-atmosphere general circulation model to systemically explore the formations and evolutionary histories of the Cenozoic A-A-A monsoon and arid regions under the influences of continental drift and plateau uplift. Results of the numerical experiments indicate that the timings and causes of the formations of monsoon and arid regions in the A-A-A realm were very different. The northern and southern African monsoons existed during the mid-Paleocene, while the South Asian monsoon appeared in the Eocene after the Indian Subcontinent moved into the tropical Northern Hemisphere. In contrast, the East Asian monsoon and northern Australian monsoon were established much later in the Miocene. The establishment of the tropical monsoons in northern and southern Africa, South Asia, and Australia were determined by both the continental drift and seasonal migration of the Inter-Tropical Convergence Zone(ITCZ), while the position and height of the TP were the key factor for the establishment of the East Asian monsoon. The presence of the subtropical arid regions in northern and southern Africa,Asia, and Australia depended on the positions of the continents and the control of the planetary scale subtropical high pressure zones, while the arid regions in the Arabian Peninsula and West Asia were closely related to the retreat of the Paratethys Sea. The formation of the mid-latitude arid region in the Asian interior, on the other hand, was the consequence of the uplift of the TP.These results from this study provide insight to the important roles played by the earth's tectonic boundary conditions in the formations and evolutions of regional climates during geological times.展开更多
Multi-stage uplift of the Tibetan Plateau during the Cenozoic implies a complex geodynamic process. In this paper, we review main geodynamic models for the uplift of the plateau, and, in particular, analyze the spatio...Multi-stage uplift of the Tibetan Plateau during the Cenozoic implies a complex geodynamic process. In this paper, we review main geodynamic models for the uplift of the plateau, and, in particular, analyze the spatio-temporal framework of the Cenozoic deformation structures, which are closely related to the deep geodynamic mechanism for the plateau uplift. From this perspective, significant change of the deformation regime over the Tibetan Plateau occurred by the middle-late Miocene, while thrust and thrust-folding system under NS compression was succeded by extension or stress-relaxation. Meanwhile, a series of large-scale strike-slip faults commenced or was kinemtically reversed. Based on a systematic synthesis of the structure deformation, magmatism, geomorphological process and geophysical exploration, we propose a periodical model of alternating crustal compression and extension for episodic uplift of the Tibetan Plateau.展开更多
The distribution of the Mountain ranges, Plateau as well as the distribution of continents and oceans on the earth’s surface are the embodies of the structure and heat states of the materials at the deep crust and of...The distribution of the Mountain ranges, Plateau as well as the distribution of continents and oceans on the earth’s surface are the embodies of the structure and heat states of the materials at the deep crust and of the tectonic stress of regions. There should be a prevalent corresponding between terrestrial height and the texture, thermal and stress states of lithosphere. However, there is no a general consensus on what extent different factors affecting the height of a terrain should be up to now, and this is very apparent for the models of plateau uplifting.1\ Debates on the compensatory depth of crustal equilibrium\;Based on a previous equilibrium model, Woollard(1969) set up an equation to show the relation among the crustal thickness ( D \-m), the depth of Mohorovicic discontinuity(M)and height above sea level( H):D \-m=33.2+8.5 H (km). By this equation it is implied that equilibrium compensation has been reached at the depth of Mohorovicic discontinuity for the height of a terrain. As Woollard (1970)described, there is no evidence to show that mass distribution beneath the Mohorovicic discontinuity ever played an important roles in the equilibrium compensation of the crust.展开更多
Through a comprehensive study of magnetostratigraphy and sedimentology of several basins in the northeastern Tibetan Plateau, we reveal that the study area mainly experienced six tectonic uplift stages at approximatel...Through a comprehensive study of magnetostratigraphy and sedimentology of several basins in the northeastern Tibetan Plateau, we reveal that the study area mainly experienced six tectonic uplift stages at approximately 52 Ma, 34–30 Ma, 24–20 Ma, 16–12 Ma, 8–6 Ma, and 3.6–2.6 Ma. Comprehensive analyses of pollen assemblages from the Qaidam, Linxia, Xining, and West Jiuquan Basins show that the northeastern Tibetan Plateau has undergone six major changes in vegetation types and climate: 50–40 Ma for the warm-humid forest vegetation, 40–23 Ma for the warm-arid and temperate-arid forest steppe vegetation, 23–18.6 Ma for the warm-humid and temperatehumid forest vegetation, 18.6–8.5 Ma for the warm-humid and cool-humid forest steppe vegetation, 8.6–5 Ma for the temperate sub-humid savanna steppe vegetation, and 5–1.8 Ma for the cold-arid steppe vegetation. Comprehensive comparisons of tectonic uplift events inferred from sedimentary records, climatic changes inferred from pollen, and global climate changes show that in the northeastern Tibetan Plateau the climate in the Paleogene at low altitude was mainly controlled by the global climate change, while that in the Neogene interval with high altitude landscapes of mountains and basins is more controlled by altitude and morphology.展开更多
The latest sharp uplift of the Tibetan Plateau and adjacent mountains occurred at the end of the early Pleistocene. The uplift of the Plateau resulted from Late Mesozoic--Cenozoic compressional structure due to the su...The latest sharp uplift of the Tibetan Plateau and adjacent mountains occurred at the end of the early Pleistocene. The uplift of the Plateau resulted from Late Mesozoic--Cenozoic compressional structure due to the subduction of the Indian Plate beneath the Asian continent. This event definitively effected the formation of basin-mountain relief, Cenozoic basin deformation, large scale aridity and desertification of western China. The Australasian meteorites impact event happened ca. 0.8 Ma ago, located in the triangle area of the Indian Ocean ridge (20°S/67°E). The impact may have resulted in an acceleration of speeding of the Indian Ocean ridge pushing the Indian Plate to subduct rapidly northward. Thus, the impact event can give reasonable explanation for the dynamic background of the latest rapid uplift of the Tibetan Plateau and the continental deformation of western China and even of the Middle Asia.展开更多
The southeast margin of Tibet plateau mainly consists of the Western Yunnan plateau (WYP). The uplift and denudation at the southeast margin of Tibet plateau can be represented by that of the WYP. Based on the uplift ...The southeast margin of Tibet plateau mainly consists of the Western Yunnan plateau (WYP). The uplift and denudation at the southeast margin of Tibet plateau can be represented by that of the WYP. Based on the uplift of ancient plantain surface, river terrace and sedimentary response in peripheral basins of the WYP, suggest that the WYP experienced a rapid uplift and denudation in Quaternary. The WYP have been uplifted about 610～700m, and eroded away about 1095～1600m since Quaternary, average denudation rate reach 0 68～0 94mm/a. Uplift rates in different time interval were calculated according to river terrace. Relations between WYP and Tibetan plateau are discussed further..The Yinggehai basin located at the south termination of the Red River fault, it is the younger (mainly Neogene) pull\|apart basin, which developed at releasing bend of the Red River right\|lateral wrench fault. Since the Neogene, the subsidence center of the Yinggehai basin shifted southward and, connected with the Southeast Hainan basin. Both basins collected large amounts of the Holocene and Quaternary deposits of marine origin. They are peripheral marine basin of the WYP.. Silicate clastic sediments in both basins have been large supported from the WYP into both basins through the Red River system. The total volumes derived from the WYP in the Neogene and Quaternary is 2 8004×10 14 t(1 and 5 1206×10 14 t. The sedimentation rate in Yinggehai basin rose from 0 52mm/a in the Neogene to 1 39mm/a in the Quaternary. The facts that accumulation volume and sedimentation rate rose greatly after the Neogene, suggested a rapid uplift in the WYP. The rapid uplift was responsible for the unconformity between the Neogene and Quaternary. Elevation of ancient planation surface,and river terrace supported the rapid uplift of the WYP also. The ancient planation surface was elevated from 2500～2600m to 3000～3200m during Quaternary, seven terraces in Tue can be traced through the field area in elevation from 20 5m to 612m above the modern river surface in the Lancang River. The Jinsha River also incised into bed rocks about 700m in Shigu. All the facts suggest that southeast margin of Tibet plateau rose rapidly; the plateau was elevated about 610～700m in the Quaternary.展开更多
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 l...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. The continuous uplift and intensive taphrogeny in the plateau divided the original large basin into small basins, deposition of lacustrine facies decreased considerably, and boulderstone accumulated, indicating a response to the overall uplift of the plateau. Here, we discuss the evolution of tectonic lithofacies paleogeography in Cenozoic and its response to the tectonic uplift of the Qinghai-Tibet Plateau in relation to the above characteristics. We have recognized five major uplift events, which occurred during 58-53 Ma, 45-30 Ma, 25-20 Ma, 13-7 Ma, and since 5 Ma. The results presented here indicate that the paleogeomorphic configurations of the Qinghai-Tibet Plateau turned over during the late Miocene, with high elevations in the east during the pre-Miocene switching to high contours in the west at the end of Miocene.展开更多
The uplift of Qing—Zang (Qinghai—Tibet) plateau was the most important event in the late Cenozoic, which deeply influenced the environments of the World, especially those of China. Since the uplift is so important a...The uplift of Qing—Zang (Qinghai—Tibet) plateau was the most important event in the late Cenozoic, which deeply influenced the environments of the World, especially those of China. Since the uplift is so important and complex that it has been become the research focus of earth science. Nevertheless, the initial time and evolution process of the uplift is still controversial.1\ The initial time of the uplift\;Qing\|Zang plateau is a union geological\|geomorphic unit, which is composed of several geological\|structural units. Each geological\|structural unit has itself exchange history of sea\|continent (basin\|mountain); the exchange time of the different parts differs. Therefore, the initial time of some part of the plateau is not the uplift time of the whole plateau. The plateau is the highland with high height above sea level, little relief of the top, large area and steep boundary. The plateau plane is the paleo\|peneplain, which was formed by the uplift of the plateau after the peneplanation. Therefore, the initial time of the uplift should be counted from the time that the peneplain had been formed.展开更多
In northern Qinghai\|Tibet plateau there are developed Cenozoic volcanic rocks. They constitute a trachybasalt\|shoshonite\|latite\|trachydacite assemblage. According to the forming ages, three Cenozoic volcanic rock ...In northern Qinghai\|Tibet plateau there are developed Cenozoic volcanic rocks. They constitute a trachybasalt\|shoshonite\|latite\|trachydacite assemblage. According to the forming ages, three Cenozoic volcanic rock lithozones can be distinguished in the northern part of the plateau. Cenozoic volcanic rocks and muscovite/two\|mica granites forming the three belts in pairs represent the northern and southern margins of the plateau in different periods. In fact, the tectonic setting of the northern part of the Qinghai\|Tibet plateau is significantly different from that of the southern part—Himalayas. The southern part has experienced subduction and continent\|continent collision. There are developed the Cenozoic S\|type granites (muscovite/two\|mica granites) there. But the northern part is characterized by Cenozoic basaltic magmatism which obviously comes from the upper mantle. Slight doming of the upper mantle is recognized underneath the northern part of the plateau, which is the result of resistance of the Tarim plate to the north direction\|sense movement of the Tibetan plate. And at the same time, the uplift machanism shows that the formation of the Qinghai\|Tibet plateau involved three orogenic stages (35-23 Ma, 23-10 Ma and <2 Ma) of uplift in the vertical direction and extension in the horizontal direction with the Gangdise\|Qiangtang orogenic belt as its core.展开更多
基金supported by the National Major Scientific and Technological Special Project during the Twelfth Fiveyear Plan Period(Grant No.2011ZX05023-002)
文摘A comparative analysis of the geochemical characteristics of sediments from the Oligocene Zhuhai Formation(32-23.8 Ma),the Miocene Zhujiang Formation(23.8-16.5 Ma),and the Hanjiang Formation(16.5—10.5 Ma) and a comprehensive analysis of the geochemical characteristics of rocks surrounding the paleo-Pearl River drainage contribute to understanding the influences of the Tibetan Plateau uplift on provenance evolution of the paleo-Pearl River.The results show that the geochemical characteristics of sediments from the Oligocene Zhuhai Formation are very different from the geochemical characteristics of sediments from the Miocene Zhujiang and Hanjiang Formations.The ∑ rare earth elements(REE) of mudstone is relatively high in the Zhuhai Formation,204.07-293.88 ppm(average 240.46 ppm),and low in the Zhujiang and Hanjiang Formations,181.32-236.73 ppm(average 203.83 ppm) and 166.84-236.65 ppm(average199.04 ppm),respectively.The chemical index of alteration(CIA) for these samples has a similar trend to the∑ REE:the CIA of the Zhuhai Formation is relatively high and the CIA of the Zhujiang and Hanjiang Formations is relatively low.The uplift of the Tibetan Plateau is crucial to the westward expansion of the paleo-Pearl River drainage.
基金Funding for this research was provided by the National Natural Science Foundation of China (NSFC), grant number 40576034
文摘The siliciclastic sediments of the uppermost section of 185 mcd(meters composite depth) from ODP Site 1146 on the northern continental slope of the South China Sea(SCS) were partitioned according to their sources using end-member modeling on grain-size data. The goal was to evaluate the evolution of the East Asian monsoon over the past 2 million years. The siliciclastic sediments were described as hybrids of four end-members, EM1, EM2, EM3, and EM4, with modal grain sizes of 8–22 μm, 2–8 μm, 31–125 μm, and 4–11 μm, respectively. EM1 and EM3 are interpreted as eolian dust and EM2 and EM4 as fluvial mud. The ratio of eolian dust to fluvial mud((EM1+EM3)/(EM2+EM4)) is regarded as an indicator of the East Asian monsoon. The variation in this ratio not only shows periodical oscillations consistent with oxygen isotope stages, but also exhibits a phased increasing trend corresponding with the phased uplifts of the Tibetan Plateau, indicating that the evolution of the East Asian Monsoon was controlled not only by glacial-interglacial cycles, but also by the phased uplifts of the Tibetan Plateau during the Quaternary.
文摘[Objective]The aim was to study the influence of Qinghai-Tibet Plateau uplift on regional climate in China.[Method] Trough relevant study of Qinghai-Tibet Plateau and its surrounding movement,the tectonic movement of the Qinghai-Tibet Plateau and its surrounding areas,especially the case of the impact caused by plateau phased uplift were studied based on paleomagnetic measurements.[Result]The increasing Qinghai-Tibet Plateau led to obvious transition from dry to cold in northwest China and it became dry quickly,which led to loess accumulation,replacement of vegetation types and human activity.Meanwhile,it was dry,and there was certain degree of climate changes in the area.[Conclusion] Qinghai-Tibet Plateau had far-reaching significance on basic climate characteristics in northwest China.
文摘In southern Asia, there are three large-scale wave-like mountains ranging from the Tibetan Plateau westward to the Iranian Plateau and the Armenian Plateau. On the southern side between plateaus, there are the Indian Peninsula and the Arabian Peninsula. What dynamic mechanisms form the directional alignment of the three plateaus with the two peninsulas remains a mystery. In the early stages of the Earth’s geological evolution, the internal structure of the Earth was that the center was a solid core, and the outmost layer was a thin equatorial crust zone separated by two thick pristine continents in polar areas, while the middle part was a deep magma fluid layer. Within the magma fluid layer, thermal and dynamic differences triggered planetary-scale vertical magma cells and led to the core-magma angular momentum exchange. When the core loses angular momentum and the magma layer gains angular momentum, the movement of upper magma fluids to the east and the tropical convergence zone (TCZ) drives the split and drift of two thick pristine continents, eventually forming the current combination of these plateaus and peninsulas and their wave-like arrangement along the east-west direction. Among them, the horizontal orthogonal convergence (collision) of upper magma fluids from the two hemispheres excited the vertical shear stress along the magma TCZ, which is the dynamic mechanism of mountain uplifts on the north side and plate subductions on the south side. To confirm this mechanism, two examples of low-level winds are used to calculate the correspondence between cyclone/anticyclonic systems generated by the orthogonal collision of airflows along the atmospheric TCZ and satellite-observed cloud systems. Such comparison can help us revisit the geological history of continental drift and orogeny.
基金The National Science and Technology Major Project under contract No.2011ZX05025-002-03the Project of China National Offshore Oil Corporation(CNOOC)Limited under contract No.CCL2013ZJFNO729the National Natural Science Foundation of China under contract No.41530963.
文摘Making full use of modern analytical and testing techniques to explore and establish new indexes or methods for extracting paleoseawater geochemical information from sediments will help to reconstruct the sedimentary paleoenvironment in different research areas.The connection between the subsidence of the South China Sea basin and the uplift of the Tibetan Plateau has been a scientific concern in recent decades.To explore the information on the sedimentary paleoenvironment,provenance changes and uplift of Tibetan Plateau contained in core sediments(debris),we selected core samples from Well LS33 in the Qiongdongnan Basin,South China Sea,and analyzed the contents of typical elements(Al,Th,and rare earth elements)that can indicate changes in provenance and the Sr isotopic compositions,which can reveal the geochemical characteristics of the paleoseawater depending on the type of material(authigenic carbonate and terrigenous detritus).The results show the following:(1)during the late Miocene,the Red River transported a large amount of detrital sediments from the ancient continental block(South China)to the Qiongdongnan Basin.(2)The authigenic carbonates accurately record changes in the 87Sr/86Sr ratios in the South China Sea since the Oligocene.These ratios reflect the semi-closed marginal sea environment of the South China Sea(relative to the ocean)and the sedimentary paleoenvironment evolution process of the deep-water area of the Qiongdongnan Basin from continental to transitional and then to bathyal.(3)Since the Neogene,the variations in the 87Sr/86Sr ratio in the authigenic carbonates have been consistent with the variations in the uplift rate of the Tibetan Plateau and the sediment accumulation rate in the Qiongdongnan Basin.These consistent changes indicate the complex geological process of the change in the rock weathering intensity and terrigenous Sr flux caused by changes in the uplift rate of the Tibetan Plateau,which influence the Sr isotope composition of seawater.
基金co-supposed by the Knowledge Innovation Program of the Chinese Academy of Sciences(No.KZCX2-EW-ON112)Open Fund of Key Laboratory of Petroleum Resources Research of the Chinese Academy of Sciences(No.KFJJ2010-07)
文摘Geologists agree that the collision of the Indian and Asian plates caused uplift of the Tibet Plateau.However,controversy still exists regarding the modes and mechanisms of the Tibetan Plateau uplift.Geology has recorded this uplift well in the Qaidam Basin.This paper analyzes the tectonic and sedimentary evolution of the western Qaidam Basin using sub-surface seismic and drill data. The Cenozoic intensity and history of deformation in the Qaidam Basin have been reconstructed based on the tectonic developments,faults growth index,sedimentary facies variations,and the migration of the depositional depressions.The changes in the sedimentary facies show that lakes in the western Qaidam Basin had gone from inflow to still water deposition to withdrawal.Tectonic movements controlled deposition in various depressions,and the depressions gradually shifted southeastward.In addition,the morphology of the surface structures in the western Qaidam Basin shows that the Cenozoic tectonic movements controlled the evolution of the Basin and divided it into(a) the southern fault terrace zone, (b) a central Yingxiongling orogenic belt,and(c) the northern fold-thrust belt;divided by the XI fault (Youshi fault) and Youbei fault,respectively.The field data indicate that the western Qaidam Basin formed in a Cenozoic compressive tectonic environment caused by the India—Asia plate collision. Further,the Basin experienced two phases of intensive tectonic deformation.The first phase occurred during the Middle Eocene—Early Miocene(Xia Ganchaigou Fm.and Shang Ganchaigou Fm.,43.8—22 Ma),and peaked in the Early Oligocene(Upper Xia Ganchaigou Fm.,31.5 Ma).The second phase occurred between the Middle Miocene and the Present(Shang Youshashan Fm.and Qigequan Fm., 14.9—0 Ma),and was stronger than the first phase.The tectonic—sedimentary evolution and the orientation of surface structures in the western Qaidam Basin resulted from the Tibetan Plateau uplift,and recorded the periodic northward growth of the Plateau.Recognizing this early tectonic—sedimentary evolution supports the previous conclusion that northern Tibet responded to the collision between India and Asia shortly after its initiation.However,the current results reveal that northern Tibet also experienced another phase of uplift during the late Neogene.The effects of these two stages of tectonic activity combined to produce the current Tibetan Plateau.
基金Project supported by the foundation of Chinese Academy of Sciences (Grant No. KZ951-A1-402)the State Science and Technology Committee (Grant No. 95-pre-40)the Chinese Nature Science Foundation (Grant No. 49672140)
文摘On the basis of a newly-constructed record of magnetic susceptibility （SUS） and the depositional rate change of eolian loess-red clay sequences in the last 7.2 Ma BP from the Loess Plateau, together with a comparison of a record of δ<sup>18</sup>O values from the equatorial East Pacific Ocean and eolian Quartz flux variations from the North Pacific Ocean, the evolutionary process of the Late Cenozoic Great Glaciation in the Northern Hemisphere can be divided into three stages: the arrival stage around 7.2—3.4 Ma BP, the initial stage at about 3.4—2.6 Ma BP, and the Great Ice Age since 2.6 Ma BP. The evolution of the East Asian monsoon is characterized by paired winter and summer monsoons, and it is basically composed of the initial stage of weak winter and summer monsoons, the transitional stage of simuhaneous increase in intensity of winter and summer monsoons, and the prevailing stage of strong winter and weak summer monsoons, or weak winter and strong summer monsoons. The Late Cenozoic global tectonic
基金the Chinese Academy of Sciences under Grant Nos. KZCX2-YW-205 and KZCX3-SW-229the National NaturalScience Foundation of China under Grant Nos. 40505017and 40775052.
文摘A global atmospheric general circulation model has been used to perform eleven idealized numerical experiments, i.e., TP00, TP10, ···, TP100, corresponding to different percentages of the Tibetan Plateau altitude. The aim is to explore the sensitivity of East Asian climate to the uplift and expansion of the Tibetan Plateau under the reconstructed boundary conditions for the mid-Pliocene about 3 Ma ago. When the plateau is progressively uplifted, global annual surface temperature is gradually declined and statistically significant cooling signals emerge only in the Northern Hemisphere, especially over and around the Tibetan Plateau, with larger magnitudes over land than over the oceans. On the contrary, annual surface temperature rises notably over Central Asia and most parts of Africa, as well as over northeasternmost Eurasia in the experiments TP60 to TP100. Meanwhile, the plateau uplift also leads to annual precipitation augmentation over the Tibetan Plateau but a reduction in northern Asia, the Indian Peninsula, much of Central Asia, parts of western Asia and the southern portions of northeastern Europe. Additionally, it is found that an East Asian summer monsoon system similar to that of the present initially exists in the TP60 and is gradually intensified with the continued plateau uplift. At 850 hPa the plateau uplift induces an anomalous cyclonic circulation around the Tibetan Plateau in summertime and two anomalous westerly currents respectively located to the south and north of the Tibetan Plateau in wintertime. In the mid-troposphere, similar-to-modern spatial pattern of summertime western North Pacific subtropical high is only exhibited in the experiments TP60 to TP100, and the East Asian trough is steadily deepened in response to the progressive uplift and expansion of the Tibetan Plateau.
基金the National Key Basic Research Project on the Tibetan Plateau (Grant No. G1998040809), the Hundred Talents Project of the CAS and the Project on Sci-Techology Research.
文摘By observing, measuring the fluvial sediment grain size of mid-western segment of the Qilianshan Range and studying the correlation between the grain size and uplift of the plateau, we model the correlation. These models are applied to the Laojunmiao section and the process curve of the uplift of the northern Tibetan Plateau against age from 8.35 Ma is illustrated here. The process curve shows that the northern Tibetan Plateau surface has uplifted from the mean altitude of 900-3700 m since 8.35 MaBP. From 8.35 to 3.1 MaBP, the Tibetan Plateau uplifted slowly, uplifted amplitude is small, the total range is 420 m. From 3.1 MaBP up to now, the Tibetan Plateau uplifted tempestuously, showing that the uplift accelerated obviously later. It uplifted totally 2400 m. About 0.9 Ma ago, the northern Tibetan Plateau surface had uplifted to over 3000 m a.s.l., showing that the Tibetan Plateau surface had reached the cryosphere; and the mountain peaks had uplifted to more than 4000 m altitude, suggesting that
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB03020601)the National Basic Research Program of China(2010CB833406)the National Natural Science Foundation of China(41290255 and 41075067)
文摘As one of the most important geological events in Cenozoic era,the uplift of the Tibetan Plateau(TP)has had profound influences on the Asian and global climate and environment evolution.During the past four decades,many scholars from China and abroad have studied climatic and environmental effects of the TP uplift by using a variety of geological records and paleoclimate numerical simulations.The existing research results enrich our understanding of the mechanisms of Asian monsoon changes and interior aridification,but so far there are still a lot of issues that need to be thought deeply and investigated further.This paper attempts to review the research on the influence of the TP uplift on the Asian monsoon-arid environment,summarize three types of numerical simulations including bulk-plateau uplift,phased uplift and sub-regional uplift,and especially to analyze regional differences in responses of climate and environment to different forms of tectonic uplifts.From previous modeling results,the land-sea distribution and the Himalayan uplift may have a large effect in the establishment and development of the South Asian monsoon.However,the formation and evolution of the monsoon in northern East Asia,the intensified dryness north of the TP and enhanced Asian dust cycle may be more closely related to the uplift of the main body,especially the northern part of the TP.In this review,we also discuss relative roles of the TP uplift and other impact factors,origins of the South Asian monsoon and East Asian monsoon,feedback effects and nonlinear responses of climatic and environmental changes to the plateau uplift.Finally,we make comparisons between numerical simulations and geological records,discuss their uncertainties,and highlight some problems worthy of further studying.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41690115 & 41572150)the Strategic Priority Research Program (A) of Chinese Academy of Sciences (Grant No. XDA20070103)+1 种基金supported by the U.K. National Centre for Atmospheric Science-Climate (NCAS-Climate) at the University of Readingsupported by the University of San Diego (FRG # 2017-18)
文摘Monsoon and arid regions in the Asia-Africa-Australia(A-A-A) realm occupy more than 60% of the total area of these continents. Geological evidence showed that significant changes occurred to the A-A-A environments of the monsoon and arid regions, the land-ocean configuration in the Eastern Hemisphere, and the topography of the Tibetan Plateau(TP) in the Cenozoic. Motivated by this background, numerical experiments for 5 typical geological periods during the Cenozoic were conducted using a coupled ocean-atmosphere general circulation model to systemically explore the formations and evolutionary histories of the Cenozoic A-A-A monsoon and arid regions under the influences of continental drift and plateau uplift. Results of the numerical experiments indicate that the timings and causes of the formations of monsoon and arid regions in the A-A-A realm were very different. The northern and southern African monsoons existed during the mid-Paleocene, while the South Asian monsoon appeared in the Eocene after the Indian Subcontinent moved into the tropical Northern Hemisphere. In contrast, the East Asian monsoon and northern Australian monsoon were established much later in the Miocene. The establishment of the tropical monsoons in northern and southern Africa, South Asia, and Australia were determined by both the continental drift and seasonal migration of the Inter-Tropical Convergence Zone(ITCZ), while the position and height of the TP were the key factor for the establishment of the East Asian monsoon. The presence of the subtropical arid regions in northern and southern Africa,Asia, and Australia depended on the positions of the continents and the control of the planetary scale subtropical high pressure zones, while the arid regions in the Arabian Peninsula and West Asia were closely related to the retreat of the Paratethys Sea. The formation of the mid-latitude arid region in the Asian interior, on the other hand, was the consequence of the uplift of the TP.These results from this study provide insight to the important roles played by the earth's tectonic boundary conditions in the formations and evolutions of regional climates during geological times.
基金supported by the National Special Project on the Tibetan Plateau of the China Geological Survey (1212011121261, 1212010610103)the National Natural Science Foundation of China (Nos. 41202144, 40902060)
文摘Multi-stage uplift of the Tibetan Plateau during the Cenozoic implies a complex geodynamic process. In this paper, we review main geodynamic models for the uplift of the plateau, and, in particular, analyze the spatio-temporal framework of the Cenozoic deformation structures, which are closely related to the deep geodynamic mechanism for the plateau uplift. From this perspective, significant change of the deformation regime over the Tibetan Plateau occurred by the middle-late Miocene, while thrust and thrust-folding system under NS compression was succeded by extension or stress-relaxation. Meanwhile, a series of large-scale strike-slip faults commenced or was kinemtically reversed. Based on a systematic synthesis of the structure deformation, magmatism, geomorphological process and geophysical exploration, we propose a periodical model of alternating crustal compression and extension for episodic uplift of the Tibetan Plateau.
文摘The distribution of the Mountain ranges, Plateau as well as the distribution of continents and oceans on the earth’s surface are the embodies of the structure and heat states of the materials at the deep crust and of the tectonic stress of regions. There should be a prevalent corresponding between terrestrial height and the texture, thermal and stress states of lithosphere. However, there is no a general consensus on what extent different factors affecting the height of a terrain should be up to now, and this is very apparent for the models of plateau uplifting.1\ Debates on the compensatory depth of crustal equilibrium\;Based on a previous equilibrium model, Woollard(1969) set up an equation to show the relation among the crustal thickness ( D \-m), the depth of Mohorovicic discontinuity(M)and height above sea level( H):D \-m=33.2+8.5 H (km). By this equation it is implied that equilibrium compensation has been reached at the depth of Mohorovicic discontinuity for the height of a terrain. As Woollard (1970)described, there is no evidence to show that mass distribution beneath the Mohorovicic discontinuity ever played an important roles in the equilibrium compensation of the crust.
基金supported by Foundation of Geological Survey of China (no. 1212011121261)the State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (no. GBL11307)
文摘Through a comprehensive study of magnetostratigraphy and sedimentology of several basins in the northeastern Tibetan Plateau, we reveal that the study area mainly experienced six tectonic uplift stages at approximately 52 Ma, 34–30 Ma, 24–20 Ma, 16–12 Ma, 8–6 Ma, and 3.6–2.6 Ma. Comprehensive analyses of pollen assemblages from the Qaidam, Linxia, Xining, and West Jiuquan Basins show that the northeastern Tibetan Plateau has undergone six major changes in vegetation types and climate: 50–40 Ma for the warm-humid forest vegetation, 40–23 Ma for the warm-arid and temperate-arid forest steppe vegetation, 23–18.6 Ma for the warm-humid and temperatehumid forest vegetation, 18.6–8.5 Ma for the warm-humid and cool-humid forest steppe vegetation, 8.6–5 Ma for the temperate sub-humid savanna steppe vegetation, and 5–1.8 Ma for the cold-arid steppe vegetation. Comprehensive comparisons of tectonic uplift events inferred from sedimentary records, climatic changes inferred from pollen, and global climate changes show that in the northeastern Tibetan Plateau the climate in the Paleogene at low altitude was mainly controlled by the global climate change, while that in the Neogene interval with high altitude landscapes of mountains and basins is more controlled by altitude and morphology.
基金Supported by Projects of NSFC (Nos. 40872127, 40572135)
文摘The latest sharp uplift of the Tibetan Plateau and adjacent mountains occurred at the end of the early Pleistocene. The uplift of the Plateau resulted from Late Mesozoic--Cenozoic compressional structure due to the subduction of the Indian Plate beneath the Asian continent. This event definitively effected the formation of basin-mountain relief, Cenozoic basin deformation, large scale aridity and desertification of western China. The Australasian meteorites impact event happened ca. 0.8 Ma ago, located in the triangle area of the Indian Ocean ridge (20°S/67°E). The impact may have resulted in an acceleration of speeding of the Indian Ocean ridge pushing the Indian Plate to subduct rapidly northward. Thus, the impact event can give reasonable explanation for the dynamic background of the latest rapid uplift of the Tibetan Plateau and the continental deformation of western China and even of the Middle Asia.
文摘The southeast margin of Tibet plateau mainly consists of the Western Yunnan plateau (WYP). The uplift and denudation at the southeast margin of Tibet plateau can be represented by that of the WYP. Based on the uplift of ancient plantain surface, river terrace and sedimentary response in peripheral basins of the WYP, suggest that the WYP experienced a rapid uplift and denudation in Quaternary. The WYP have been uplifted about 610～700m, and eroded away about 1095～1600m since Quaternary, average denudation rate reach 0 68～0 94mm/a. Uplift rates in different time interval were calculated according to river terrace. Relations between WYP and Tibetan plateau are discussed further..The Yinggehai basin located at the south termination of the Red River fault, it is the younger (mainly Neogene) pull\|apart basin, which developed at releasing bend of the Red River right\|lateral wrench fault. Since the Neogene, the subsidence center of the Yinggehai basin shifted southward and, connected with the Southeast Hainan basin. Both basins collected large amounts of the Holocene and Quaternary deposits of marine origin. They are peripheral marine basin of the WYP.. Silicate clastic sediments in both basins have been large supported from the WYP into both basins through the Red River system. The total volumes derived from the WYP in the Neogene and Quaternary is 2 8004×10 14 t(1 and 5 1206×10 14 t. The sedimentation rate in Yinggehai basin rose from 0 52mm/a in the Neogene to 1 39mm/a in the Quaternary. The facts that accumulation volume and sedimentation rate rose greatly after the Neogene, suggested a rapid uplift in the WYP. The rapid uplift was responsible for the unconformity between the Neogene and Quaternary. Elevation of ancient planation surface,and river terrace supported the rapid uplift of the WYP also. The ancient planation surface was elevated from 2500～2600m to 3000～3200m during Quaternary, seven terraces in Tue can be traced through the field area in elevation from 20 5m to 612m above the modern river surface in the Lancang River. The Jinsha River also incised into bed rocks about 700m in Shigu. All the facts suggest that southeast margin of Tibet plateau rose rapidly; the plateau was elevated about 610～700m in the Quaternary.
基金supported by the Foundation of Geological Survey of China (Nos.1212011121261,1212010733802)the National Natural Science Foundation (No.40921062)
文摘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. The continuous uplift and intensive taphrogeny in the plateau divided the original large basin into small basins, deposition of lacustrine facies decreased considerably, and boulderstone accumulated, indicating a response to the overall uplift of the plateau. Here, we discuss the evolution of tectonic lithofacies paleogeography in Cenozoic and its response to the tectonic uplift of the Qinghai-Tibet Plateau in relation to the above characteristics. We have recognized five major uplift events, which occurred during 58-53 Ma, 45-30 Ma, 25-20 Ma, 13-7 Ma, and since 5 Ma. The results presented here indicate that the paleogeomorphic configurations of the Qinghai-Tibet Plateau turned over during the late Miocene, with high elevations in the east during the pre-Miocene switching to high contours in the west at the end of Miocene.
基金This study was supported jointly by the National Natural Science Foundation grant 40572134 the Land and Resources Survey project ＂Environmental Evolution Sequence of Tertiary Major Paleolakes on the Qinghai- Tibet Plateau＂ （Ke[2003]007-02）.
文摘The uplift of Qing—Zang (Qinghai—Tibet) plateau was the most important event in the late Cenozoic, which deeply influenced the environments of the World, especially those of China. Since the uplift is so important and complex that it has been become the research focus of earth science. Nevertheless, the initial time and evolution process of the uplift is still controversial.1\ The initial time of the uplift\;Qing\|Zang plateau is a union geological\|geomorphic unit, which is composed of several geological\|structural units. Each geological\|structural unit has itself exchange history of sea\|continent (basin\|mountain); the exchange time of the different parts differs. Therefore, the initial time of some part of the plateau is not the uplift time of the whole plateau. The plateau is the highland with high height above sea level, little relief of the top, large area and steep boundary. The plateau plane is the paleo\|peneplain, which was formed by the uplift of the plateau after the peneplanation. Therefore, the initial time of the uplift should be counted from the time that the peneplain had been formed.
文摘In northern Qinghai\|Tibet plateau there are developed Cenozoic volcanic rocks. They constitute a trachybasalt\|shoshonite\|latite\|trachydacite assemblage. According to the forming ages, three Cenozoic volcanic rock lithozones can be distinguished in the northern part of the plateau. Cenozoic volcanic rocks and muscovite/two\|mica granites forming the three belts in pairs represent the northern and southern margins of the plateau in different periods. In fact, the tectonic setting of the northern part of the Qinghai\|Tibet plateau is significantly different from that of the southern part—Himalayas. The southern part has experienced subduction and continent\|continent collision. There are developed the Cenozoic S\|type granites (muscovite/two\|mica granites) there. But the northern part is characterized by Cenozoic basaltic magmatism which obviously comes from the upper mantle. Slight doming of the upper mantle is recognized underneath the northern part of the plateau, which is the result of resistance of the Tarim plate to the north direction\|sense movement of the Tibetan plate. And at the same time, the uplift machanism shows that the formation of the Qinghai\|Tibet plateau involved three orogenic stages (35-23 Ma, 23-10 Ma and <2 Ma) of uplift in the vertical direction and extension in the horizontal direction with the Gangdise\|Qiangtang orogenic belt as its core.
