共查询到20条相似文献，搜索用时 531 毫秒
1.
《地理学报(英文版)》2017,(11)
The geomorphological evolution of the Northeastern Tibetan Plateau(NETP)could provide valuable information for reconstructing the tectonic movements of the region.And the considerable uplift and climatic changes at here,provide an opportunity for studying the impact of tectonic and monsoon climate on fluvial morphological development and sedimentary architecture of fluvial deposits.The development of peneplain-like surface and related landscape transition from basin filling to incision indicate an intense uplift event with morphological significance at around 10–17 Ma in the NETP.After that,incision into the peneplain was not continuous but a staircase of terraces,developed as a result of climatic influences.In spite of the generally persisting uplift of the whole region,the neighbouring tectonic blocks had different uplift rates,leading to a complicated fluvial response with accumulation terraces alternating with erosion terraces at a small spatial and temporal scale.The change in fluvial activity as a response to climatic impact is reflected in the general sedimentary sequence on the terraces from high-energy(braided)channel deposits(at full glacial)to lower-energy deposits of small channels(towards the end of the glacial),mostly separated by a rather sharp boundary from overlying flood-loams(at the glacial-interglacial transition)and overall soil formation(interglacial).Pronounced incision took place at the subsequent warm-cold transitions.In addition,it is hypothesized that in some strongly uplifted blocks energy thresholds could be crossed to allow terrace formation as a response to small climatic fluctuations(10~3–10~4 year timescale).Although studies of morpho-tectonic and geomorphological evolution of the NETP,improve understanding on the impacts of tectonic motions and monsoonal climate on fluvial processes,a number of aspects,such as the distribution and correlation of peneplain and the related morphological features,the extent and intensity of tectonic movements influencing the crossing of climatic thresholds,leading to terrace development,need to be studied further. 相似文献
2.
Sea level change and environmental evolution of coastal lakes in Vestfold Hills, Antarctica 
下载免费PDF全文
下载免费PDF全文 Ecological and palaeoecological studies were carried out in a series of lakes in the Vestfold Hills (68°38′S, 78°06′E) on eastern Antarctic continent. Dynamics types of the lakes in environmental geomorphology and physic chemistry, as well as features of biological community structures in different lakes were analyzed. Marine macro and micro fossils collected from the terraces and beaches surrounding these lakes and determined in 14 C radiocarbon ages to be the Late Pleistocene, were used as evidences to show the evolutionary processes of the lakes after sea level changes and transgressions since 18000 a B.P.. Basic modals of evolution for the lakes given in the paper could be regarded as not only explaining the history of environmental and ecological changes in VH lakes, and also reflecting of local environmental evolution in Antarctic region and global climate changes from past to present time. 相似文献
3.
River incision and drainage reorganization have an important impact on the site selection of many major projects including city,road and others,and are the key issues of Quaternary environmental changes.Studies of river incision and river-network adjustment have traditionally been based on extensive field evidence,such as sediment age and beheaded river system.The Buyuan River basin is a large sub-basin of the upper Lancang-Mekong,with high mountains and extremely active erosion.The latter affects the preservation of the Quaternary period sediments leading to difficulties in understanding the main evolution characteristics of the basin.This study investigates differences in the equilibrium state of the longitudinal profile,infers incision rates,and evaluates drainage divide migration timelines using the stream-power incision model,the latest morphological dating,and Chi-plots(χ–z) based on digital elevation models(DEMs) on the GIS software platform.The final results show that two significant erosion base-level decreases occurred in the Late Pleistocene at least.The incision rate of the mainstream might have been 0–2.99 mm/yr since 100 ka BP and 0–3.28 mm/yr since 46 ka BP.The Chi-values across the divides suggest that space limited(or constrained) river reorganization and that there is no severe reorganization in the basin;the imbalance of traceable erosion only exists in local areas.The main driving force for the geomorphologic evolution of the Buyuan River basin is likely climate fluctuations rather than strong tectonic uplift since the Late Pleistocene. 相似文献
4.
Nowadays, Southwestern Romania faces a large-scale aridization of the climate, revealed by the rise of temperatures and the decline of the amount of precipitations, with negative effects visible, among others, in the desiccation of forest vegetation. The present study means to identify the changes that occurred, quality-wise, in the past two decades(1990–2011) in forest vegetation in Southwestern Romania, and to establish the link between those changes and extant thermal stress in the region, whose particular features are high average annual and seasonal temperatures. In order to capture the evolution in time of climate aridization, a first step consisted in using climate data, the temperature and precipitation parameters from three weather stations; these parameters were analyzed both individually and as aridity indexes(De Martonne and UNEP). In order to quantify the changes in forest vegetation, NDVI indexes were used and analyzed, starting off from Landsat satellite images, acquired at three distinct moments in time, 1990, 2000 and 2011. In order to identify the link between the changes of NDVI index values and regional thermal stress, a yardstick of climate changes, statistical correlations were established between the peak values of average annual temperatures, represented in space, and negative changes in the NDVI index, as revealed by the change-detection analysis. The results obtained indicated there is an obvious(statistically significant) connection between thermal stress and the desiccation(degradation) of forest species in the analyzed area, with false acacia(Robinia Pseudoacacia) the main species to be impacted. 相似文献
5.
《地理学报(英文版)》2017,(6)
The Xiaohe Cemetery archaeological site(Cal.4–3.5 ka BP)is one of the most important Bronze Age sites in Xinjiang,China.Although the surrounding environment is an extremely arid desert now,abundant archaeological remains indicate that human occupation was common during certain periods in the Holocene.Field investigations and laboratory analyses of a sediment profile near the Xiaohe Cemetery indicate that while the regional environment was arid desert throughout the Holocene there were three episodes of lake formation near the site in the periods 4.8–3.5 ka BP,2.6–2.1 ka BP and 1.2–0.9 ka BP.Geomorphic and hydrological investigations reveal that a lake or lakes formed in a low-lying area when water was derived initially from the Kongque River and then shunted into the Xiaohe River basin.Low amounts of active chemical elements in lacustrine sediment between 4.8–3.5 ka BP indicate abundant and continuous water volume in the lake;the content of active chemical elements increased between 2.6–2.1 ka BP but was still at a relatively low level,suggesting a declining amount of water and diminished inflow.Between 1.2–0.9 ka BP there was a very high content of active elements,suggesting decreased water volume and indicating that the lake was stagnate.In contrast,the general climate condition shows that there had a warm-humid stage at 8–6 ka BP,a cool-humid stage at 6–2.9 ka BP and a warm-dry stage at2.9–0.9 ka BP in this region.The hydrological evolutions around Xiaohe Cemetery did not have one-to-one correspondence with climate changes.Regional comparison indicates that broad-scale climatic conditions played an important role through its influences on the water volume of the Tarim River and Kongque River.But,the formation of the lakes and their level were controlled by geomorphic conditions that influenced how much water volume could be shunted to Xiaohe River from Kongque River.Human occupation of the Xiaohe Cemetery and nearby regions during the Bronze Age and Han-Jin period(202 BC–420 AD)corresponded to the two earlier lake periods,while no human activities existed in the third lake period because of the decreased water volume. 相似文献
6.
Detecting climate change effects on forest ecosystems in Southwestern Romania using Landsat TM NDVI data 总被引：1，自引：0，他引：1
Nowadays, Southwestern Romania faces a large-scale aridization of the climate, revealed by the rise of temperatures and the decline of the amount of precipitations, with negative effects visible, among others, in the desiccation of forest vegetation. The present study means to identify the changes that occurred, quality-wise, in the past two decades （1990-2011） in forest vegetation in Southwestern Romania, and to establish the link between those changes and extant thermal stress in the region, whose particular features are high average annual and seasonal temperatures. In order to capture the evolution in time of cli- mate aridization, a first step consisted in using climate data, the temperature and precipitation parameters from three weather stations; these parameters were analyzed both individually and as aridity indexes （De Martonne and UNEP）. In order to quantify the changes in forest vegetation, NDVI indexes were used and analyzed, starting off from Landsat satellite images, acquired at three distinct moments in time, 1990, 2000 and 2011. In order to identify the link between the changes of NDVI index values and regional thermal stress, a yardstick of climate changes, statistical correlations were established between the peak values of average annual temperatures, represented in space, and negative changes in the NDVI index, as revealed by the change-detection analysis. The results obtained indicated there is an obvious （statistically significant） connection between thermal stress and the desiccation （degradation） of forest species in the analyzed area, with false acacia （Robinia Pseudoacacia） the main species to be impacted. 相似文献
7.
Through high-resolution research of sedimental chronology and the sediment environmental indexes,such as graininess ,minerals,magnetic parameters,pigment content organic carbon and chronology in Ds-core and Ws-core in Nansihu Lake,the authors analyze the formation cause of the Nansihu Lake and its water environmental changes,Historical documents are also analyzed here in order to reach the conclusion .Researches indicate that the Nansihu Lake came into being about 2500 aBP and its evolution succession can be divided into four stages.In this evolution process ,several scattered lakes merge into one large lake in the east of China,This process is distinctively affected by the overflow of the Yellow River,the excavation of the Grand Canal and other human activities. 相似文献
8.
Qinghai Lake and Zhuye Lake, ~400 km apart, are located in the northwest margin of the Asian summer monsoon. Water of these two lakes mostly comes from the middle and eastern parts of the Qilian Mountains. Previous studies show that the Holocene climate changes of the two lakes implied from lake records are different. Whether lake evaporation plays a role in asynchronous Holocene climate changes is important to understand the lake records. In this paper, we used modern observations beside Qinghai Lake and Zhuye Lake to test the impact factors for lake evaporation. Pan evaporation near the two lakes is mainly related to relative humidity, temperature, vapor pressure and sunshine duration. But tem-perature has different impacts to lake evaporation of the two lakes, which can affect Holocene millennial-scale lake level changes. In addition, differences in relative humidity on the millen-nial-scale would be more significant, which also can contribute to asynchronous lake records. 相似文献
9.
1960-2007年中国地表潜在蒸散发敏感性的时空变化(英文) 总被引：2，自引：0，他引：2
Potential evapotranspiration (E0), as an estimate of the evaporative demand of the atmosphere, has been widely studied in the fields of irrigation management, crop water demand and predictions in ungauged basins (PUBs). Analysis of the sensitivity of E0 to meteorological factors is a basic research on the impact of climate change on water resources, and also is important to the optimal allocation of agricultural water resources. This paper dealt with sensitivity of E0 over China, which was divided into ten drainage systems, including Songhua River basin, Liaohe River basin, Haihe River basin, Yellow River basin, Yangtze River basin, Pearl River basin, Huaihe River drainage system, Southeast river drainage system, Northwest river drainage system and Southwest river drainage system. In addition, the calculation method of global radiation in Penman-Monteith formula was improved by optimization, and the sensitivities of Penman-Monteith potential evapotranspiration to the daily maximum temperature (STmax), daily minimum temperature (STmin), wind speed (SU2), global radiation (SRs) and vapor pressure (SVP) were calculated and analyzed based on the long-term meteorological data from 653 meteorological stations in China during the period 1960-2007. Results show that: (1) the correlation coefficient between E0 and pan evaporation increased from 0.61 to 0.75. E0 had the decline trends in eight of ten drainage systems in China, which indicates that "pan evaporation paradox" commonly exists in China from 1960 to 2007. (2) Spatially, Tmax was the most sensitive factor in Haihe River basin, Yellow River basin, Huaihe River drainage system, Yangtze River basin, Pearl River basin and Southeast river drainage system, and VP was the most sensitive factor in Songhua River Basin, Liaohe River basin, Northwest river drainage system while Rs was the most sensitive factor in Southwest river drainage system. For the nation-wide average, the most sensitive factor was VP, followed by Tmax, Rs, U2 and Tmin. In addition, the changes in sensitivity coefficients had a certain correlation with elevation. (3) Temporally, the maximum values of STmax and SRs occurred in July, while the maximum values of STmin, SVP and SU2 occurred in January. Moreover, trend analysis indicates that STmax had decline trends, while STmin, SU2, SRs and SVP had increasing trends. 相似文献
10.
On paleodrainage evolution in mid-late Epipleistocene based on radar remote sensing in northeastern Ejin Banner,Inner Mongolia 总被引：2，自引：0，他引：2
WANGXinyuan GUOHuadong CHANGYueming ZHALiangsong 《地理学报(英文版)》2004,14(2):235-241
Radar remote sensing can acquire information of sub-surface covered by sand in arid area,detect surface roughness and vegetation coronet‘s layer and linear feature such as linear structure and channel sensitively. With sediment facies analysis, this paper studies the features of environmental evolution in mid-late Epipleistocene (60 ka BP-20 ka BP) in northeastem Ejin Banner. The conclusions are listed as follows: (1) The evolution of the three lakes, i.e. Gaxunnur, Sugunur and Tian‘e lakes, are dominated by faults and regional climate. (2) By analyzing sedimentary section of old Juyanze Lake,the three lakes used to be a large outflow lake before 50 ka BP in northeastem Ejin Banner, and at 50 ka BP, temperature declined rapidly in northwestem China. The event caused the lake‘s shrinkage. (3)By fault activity uplift in the northem part of old Juyan Lake and depression in the southem part, the lake‘s water followed fi‘om north to south at around 35 ka BP, old Juyanze fluvial fan was formed. At the same time, Juyan lake separated fi‘om Sugunur Lake and Wentugunr old channel was abandoned.(4) In recent 2000 years, Ruoshui River is a wandering river, sometimes it flows into Juyan lake and sometimes Sugunur and Gaxunnur lakes. Due to human activities and over exploitation, the oasis ecosystem is rapidly degenerated in 15 years (1986-2000). 相似文献
11.
Tectonic movements and climate changes are two main controllers on the development of landform. In order to reconstruct the history of the evolution of the landform in the Fenhe drainage basin during middle-late Quaternary comprehensively, this paper has provided a variety of geomorphological and geologic evidences to discuss how tectonic movements and climate changes worked together to influence the landform processes. According to the features of the lacustrine and alluvial terraces in this drainage basin, it is deduced that it was the three tectonic uplifts that resulted in the three great lake-regressions with an extent of about 40-60 m and the formation of the three lacustrine terraces. The times when the tectonic uplifts took place are 0.76 MaBP, 0.55 MaBP and 0.13 MaBP respectively, synchronous with the formation of paleosol units S8, S5 and S1 respectively. During the intervals between two tectonic uplifts when tectonic movement was very weak, climate changes played a major role in the evolution of the paleolakes and caused frequent fluctuations of lake levels. The changes of the features of lacustrine sediment in the grabens show the extent of such fluctuations of lake level is about 2-3 m. 相似文献
12.
汾河流域地貌发育对构造运动和气候变化的响应 总被引：12，自引：0，他引：12
自中更新世中晚期以来，由于构造运动及气候变化，在汾河流域系列盆地中无论是地貌还是沉积都出现了相应的变化。根据对系列盆地中普遍发育的三级冲湖积台地的成因分析，发现发生于0.76MaBP,0.55MaBP及0.13MaBP的3次大幅度区域构造抬升是导致古湖盆湖退，三级台地形成的根源，根据对太原盆地东南边缘的一台地-洪山台地湖积层的分析，发现在相邻两次构造抬升之间的构造相对稳定期，气候变化完全控制着湖盆的演化，由第四纪气候的干湿变化对象太原盆地这样大的湖盆，一般只引起不大于4.5m的湖面升降，与构造抬升引起的湖面变动相差甚大，作为影响河湖地貌发育的2个主导因素，构造运动是主要的，气候变化只是在构造稳定期才突出地显示其影响。 相似文献
13.
贵州高原北部发育平缓丘丛和深切峰丛2种喀斯特地貌组合,保存于喀斯特山间盆地的河流阶地对区域地貌演化具有指示意义。本文根据阶地发育特征和光释光（OSL）测年,分析阶地形成的时代和动力,结合区域地质背景,探讨构造抬升和河流侵蚀对黔北喀斯特地貌演化的驱动作用。结果显示,绥阳盆地T1阶地时代18.8~8.2 ka,T2时代144.4~104.1 ka;旺草盆地T1年龄为5.5 ka,T2年龄为45.1 ka。绥阳盆地阶地以漫滩相沉积物为主,旺草盆地阶地则多切割了白云岩基岩。分析认为,气候条件影响了阶地的沉积过程,但差异性构造抬升应为区域河流阶地差异发育的主要因素。阶地测年显示,旺草盆地的河流平均下切速率明显高于绥阳盆地,表明芙蓉江流域构造抬升和河流下切强度明显高于洋川河。在差异性构造抬升和河流侵蚀综合作用下,北部大娄山区形成了深切的喀斯特峰丛-峡谷地貌,南部乌江中游流域则发育以平坦盆地和宽缓丘丛为主的地貌组合。 相似文献
14.
中昆仑山区距今一万七千年以来湖面波动研究 总被引：3，自引：0，他引：3
根据湖盆地貌、湖泊沉积物分析,本文指出:中昆仑山区的封闭湖泊17000年以来湖面在总体下降过程中,出现了3期相对高湖面,近期湖泊仍在收缩咸化,未来仍将继续达一趋势。 相似文献
15.
Climatic and tectonic controls on the fluvial morphology of the Northeastern Tibetan Plateau (China)
The geomorphological evolution of the Northeastern Tibetan Plateau (NETP) could provide valuable information for reconstructing the tectonic movements of the region. And the considerable uplift and climatic changes at here, provide an opportunity for studying the impact of tectonic and monsoon climate on fluvial morphological development and sedimentary architecture of fluvial deposits. The development of peneplain-like surface and related landscape transition from basin filling to incision indicate an intense uplift event with morphological significance at around 10–17 Ma in the NETP. After that, incision into the peneplain was not continuous but a staircase of terraces, developed as a result of climatic influences. In spite of the generally persisting uplift of the whole region, the neighbouring tectonic blocks had different uplift rates, leading to a complicated fluvial response with accumulation terraces alternating with erosion terraces at a small spatial and temporal scale. The change in fluvial activity as a response to climatic impact is reflected in the general sedimentary sequence on the terraces from high-energy (braided) channel deposits (at full glacial) to lower-energy deposits of small channels (towards the end of the glacial), mostly separated by a rather sharp boundary from overlying flood-loams (at the glacial-interglacial transition) and overall soil formation (interglacial). Pronounced incision took place at the subsequent warm-cold transitions. In addition, it is hypothesized that in some strongly uplifted blocks energy thresholds could be crossed to allow terrace formation as a response to small climatic fluctuations (103–104 year timescale). Although studies of morpho-tectonic and geomorphological evolution of the NETP, improve understanding on the impacts of tectonic motions and monsoonal climate on fluvial processes, a number of aspects, such as the distribution and correlation of peneplain and the related morphological features, the extent and intensity of tectonic movements influencing the crossing of climatic thresholds, leading to terrace development, need to be studied further. 相似文献
16.
K. E. Lezzar J.-J. Tiercelin M. DE Batist† A. S. Cohen‡ T. Bandora† § P. VAN Rensbergen† C. LE Turdu W. Mifundu¶ J. Klerkx 《Basin Research》1996,8(1):1-28
Abstract We present here the initial results of a high-resolution (sparker) reflection seismic survey in Northern Lake Tanganyika, East African Rift system. We have combined these results with data from earlier multichannel reflection seismic and 5-kHz echosounding surveys. The combination of the three complementary seismic investigation methods has allowed us to propose a new scenario for the late Aliocene to Recent sedimentary evolution of the North Tanganyika Basin. Seismic sequences and regional tectonic information permit us to deduce the palaeotopography at the end of each stratigraphic sequence. The basin history comprises six phases interpreted to be responses to variations in regional tectonism and/or climate. Using the reflection seismic-radiocarbon method (RSRM), the minimum ages for the start of each phase (above each sequence boundary) are estimated to be: ?7.4 Ma, ? 1.1 Ma, ?393–363 ka, ?295–262 ka, ? 193–169 ka, ?40–35 ka. Corresponding lowstand lake elevations below present lake level for the last five phases are estimated to have been: ?650–700 m, ?350 m, ?350 m, ?250 m and ? 160 m, respectively. The latest phase from ?40–35 ka until the present can be subdivided into three subphases separated by two lowstand periods, dated at ?23 ka and ? 18 ka. From the late Miocene until the mid Pleistocene, large-scale patterns of sedimentation within the basin were primarily controlled by tectonism. In contrast, from the mid Pleistocene to the present, sedimentation in Lake Tanganyika seems to have responded dramatically to climatic changes as suggested by repeated patterns of lake level fluctuations. During this period, the basin infill history is characterized by the recurrent association of three types of deposits: ‘basin fill’ accumulations; lens-shaped ‘deep lacustrine fans’; and ‘sheet drape’ deposits. The successive low-lake-level fluctuations decreased in intensity with time as a consequence of rapid sedimentary filling under conditions of declining tectonic subsidence. The climate signal has thus been more pronounced in recent sedimentary phases as tectonic effects have waned. 相似文献
17.
Tectono-sedimentary evolution of active extensional basins 总被引：28，自引：3，他引：25
We present conceptual models for the tectono-sedimentary evolution of rift basins. Basin architecture depends upon a complex interaction between the three-dimensional evolution of basin linkage through fault propagation, the evolution of drainage and drainage catchments and the effects of changes in climate and sea/lake level. In particular, the processes of fault propagation, growth, linkage and death are major tectonic controls on basin architecture. Current theoretical and experimental models of fault linkage and the direction of fault growth can be tested using observational evidence from the earliest stages of rift development. Basin linkage by burial or breaching of crossover basement ridges is the dominant process whereby hydrologically closed rifts evolve into open ones. Nontectonic effects arising from climate, sea or lake level change are responsible for major changes in basin-scale sedimentation patterns. Major gaps in our understanding of rift basins remain because of current inadequacies in sediment, fault and landscape dating. 相似文献
18.
The Annecy lacustrine depression lies in a tectonic transverse valley of structural origin, linking the present day towns of Annecy and Ugine and bounded by the Bauges and Bornes massifs. Only the last two major glacial periods are represented in the stratigraphic and geomorphic evidence from the area, but its successive glaciations that have been largely responsible for the form of the valley within which the present day lake lies. Of particular importance were the lobes of the Arve glacier, one shaping the depression from the south-east; the other from the north. The retreat of the glaciers left behind a more extensive precursor of the present day Lac d'Annecy, which latter constitutes the residual body of open water after lake level lowering, partial infilling and drainage diversions within the catchment. The drainage basin of the extended lake formed shortly after the last glacial maximum (LGM) in the region. Its extent can be determined from field sampling and coring and its elevation can be established at 460 m above present day sea level. The present day lake is more isolated, since the Fier river, to the north, no longer drains into it. To the southeast, the course of the Chaise river has also been diverted, leaving the lake's drainage basin reduced to half its post-LGM size. The major paleogeographical events in the Late-Quaternary evolution of the basin are described in chronological sequence. 相似文献
19.
Numerical modelling of Quaternary terrace staircase formation in the Ebro foreland basin,southern Pyrenees,NE Iberia 下载免费PDF全文
下载免费PDF全文 Kurt Martin Stange Ronald T. Van Balen Daniel Garcia‐Castellanos Sierd Cloetingh 《Basin Research》2016,28(1):124-146
The southern foreland basin of the Pyrenees (Ebro basin) is an exorheic drainage basin since Late Miocene times. Remnants of an early exorheic Ebro drainage system are not preserved, but morphology provides evidence for the Pliocene–Quaternary drainage development. The incision history of the Ebro system is denoted by (i) extensive, low gradient pedimentation surfaces which are associated with the denudation of the southern Pyrenean piedmont around the Pliocene–Quaternary transition and (ii) deeply entrenched Quaternary river valleys. Presumably since the Middle Pleistocene fluvial incision intensified involving the formation of extensive terrace staircase in the Ebro basin. Terrace exposure dating in major Ebro tributary rivers indicates climate‐triggered terrace formation in response to glacial–interglacial climate and glacier fluctuations in the Pyrenean headwaters. The overall (semi)parallel longitudinal terrace profiles argue for progressive base level lowering for the whole Ebro drainage network. The landscape evolution model, TISC, is used to evaluate climatic, tectonic and base level scenarios for terrace staircase formation in the Ebro drainage system. Model simulations are compared with morpho‐climatic, tectonic and chronologic data. Results show that climatic fluctuations cause terrace formation, but the incision magnitudes and convergent terrace profiles predicted by this climate model scenario are not consistent with the (semi)parallel terraces in the Ebro basin. A model including previous (late Pliocene) uplift of the lower Ebro basin results in rapid base‐level lowering and erosion along the drainage network, small late stage incision magnitudes and terrace convergence, which are not in agreement with observations. Instead, continuous Quaternary uplift of both the Pyrenees and the Ebro foreland basin triggers (semi)parallel terrace staircase formation in southern Pyrenean tributary rivers in consistency with the observed longitudinal terrace profiles and Middle–Late Pleistocene incision magnitudes. Forward model simulations indicate that the present Ebro drainage system is actively incising, providing further evidence for uplift. 相似文献
20.
《地理学报(英文版)》2017,(11)
There are a series of basins in the Fenwei Graben.Field survey found that there took place several paleolake regressions or intensive stream down-incisions in all basins during the Mid-Late Quaternary.The lowest and oldest paleosol/loess units overlying three of the lacustrine terraces or alluvial ones and some paleomagenetism data from the lacustrine sediment indicate that the onset times of three paleolake regressions or intensive stream down-incisions are synchronous with the formation of L_9,L_6 and L_2 respectively in the Weihe Basin,S_8,S_5 and S_1 respectively in the Linfen-Taiyuan-Xingding Basins,and L_8,L_5 and L_1 respectively in the Datong Basin.The difference in the onset time of each lake regressions or intensive stream down-incision in different basins reveals that the farther the basin is from the Tibetan Plateau,the later it took place.Taking these field facts and the former research results in terms of the regional tectonic movement into account,it is inferred that the tectonic movement of the Tibetan Plateau most probably controlled such geomorphological-sedimentary evolution in the graben. 相似文献