scholarly journals New Magnetic Constraints on Early‐Middle Miocene Uplift of the Liupan Shan, Northeastern Margin of the Tibetan Plateau

2019 ◽  
Vol 20 (3) ◽  
pp. 1340-1357 ◽  
Author(s):  
Jiabin Wu ◽  
Licheng Guo ◽  
Shangfa Xiong ◽  
Shiqi Wang ◽  
Zihua Tang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Middle Miocene ◽  
The Tibetan Plateau ◽  
Liupan Shan

scholarly journals Evolution of the Yangtze River network, southeastern Tibet: Insights from thermochronology and sedimentology

Lithosphere ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 3-18
Author(s):  
Loraine Gourbet ◽  
Rong Yang ◽  
Maria Giuditta Fellin ◽  
Jean-Louis Paquette ◽  
Sean D. Willett ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Yangtze River ◽  
Middle Miocene ◽  
Strike Slip ◽  
The Tibetan Plateau ◽  
Fluvial Incision ◽  
Upper Yangtze River ◽  
Southeastern Margin ◽  
The Upper Yangtze River ◽  
Southeastern Tibet

Abstract We performed apatite and zircon (U-Th)/He dating on a granitic pluton that has been offset by ∼10 km by motion on the sinistral strike-slip Xiangcheng fault in SW Sichuan, SE Tibetan plateau, where the Shuoqu River incises a deep valley before joining the upper Yangtze River. Mean ZHe cooling ages range from 49.5 ± 2.2 Ma to 68.6 ± 6.0 Ma. Samples located above 3870 m yield mean apatite (U-Th)/He ages ranging from 30.6 ± 1.4 Ma to 40.6 ± 2.7 Ma, whereas samples at lower elevations range from 9.8 ± 1.3 Ma to 14.6 ± 2.7 Ma. In the same region, Cenozoic continental sediments are exposed on the flanks of deep valleys. They consist of unsorted conglomerates and sandstones that partly fill a paleotopography. The sediments were deposited during an episode of rapid sedimentation, followed by incision that varies between 0.5 and 1.2 km. Thermal and exhumational modeling of the granite thermochronometric data indicates rapid cooling during the middle Miocene that was likely related to fluvial incision. Our findings suggest that the upper Yangtze River and its tributary (Shuoqu) were connected by the middle Miocene. Our modeling also supports the idea that the exhumation pattern during the Cenozoic in the southeastern margin of the Tibetan Plateau is spatially and temporally heterogeneous.

scholarly journals Late Cenozoic continuous aridification in the western Qaidam Basin: evidence from sporopollen records

2013 ◽  
Vol 9 (2) ◽  
pp. 1485-1508 ◽  
Author(s):  
Y. F. Miao ◽  
X. M. Fang ◽  
F. L. Wu ◽  
M. T. Cai ◽  
C. H. Song ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Middle Miocene ◽  
Qaidam Basin ◽  
East Asian ◽  
The Tibetan Plateau ◽  
Late Cenozoic ◽  
Plateau Uplift ◽  
Western Qaidam Basin ◽  
Global Cooling ◽  
Tibetan Plateau Uplift

Abstract. Cenozoic climate changes in inner Asia provide a basis for understanding linkages between global cooling, the Tibetan Plateau uplift, and possibly the development of the East Asian monsoon. Based on the compiled palynological results from the western Qaidam Basin, this study reconstructed an 18 Ma record of changing vegetation and paleoclimates since the middle Miocene. Thermophilic taxa percentages were highest between 18 and 14 Ma and decreased after 14 Ma, corresponding closely with the Middle Miocene Climatic Optimum (MMCO) between 18 and 14 Ma and the following global climatic cooling. After 3.6 Ma, the thermophilic taxa percentages further decreased, showing the inevitable relations with the ice-sheets enlargement in the North Hemisphere. During the same period of time, the increase in xerophytic taxa percentages and decrease in conifers percentages imply aridification in both the basin and surrounding mountains since 18 Ma. These results indicate that global cooling mainly controlled the climate change from a relative warm-wet stage to a cold-dry stage during the late Cenozoic at the western Qaidam Basin, and that the Tibetan Plateau uplift also contributed in contrast to the East Asian summer monsoon.

scholarly journals Present-day strain accumulation in the Liupan Shan area, northeastern margin of the Tibetan Plateau by GPS observations

2019 ◽  
Vol 30 (1) ◽  
pp. 51-62
Author(s):  
Guojie Meng ◽  
Xiaoning Su ◽  
Wanzhen Xu ◽  
Chieh-Hung Chen ◽  
Kai-Chien Cheng ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Strain Accumulation ◽  
Gps Observations ◽  
Liupan Shan

scholarly journals Intensified aridity in the Qaidam Basin during the Middle Miocene: constraints from ostracod, stable isotope, and weathering records

2017 ◽  
Vol 54 (3) ◽  
pp. 242-256 ◽  
Author(s):  
Bowen Song ◽  
Junliang Ji ◽  
Chaowen Wang ◽  
Yadong Xu ◽  
Kexin Zhang
Keyword(s):  
Stable Isotope ◽  
Tibetan Plateau ◽  
Chemical Weathering ◽  
Middle Miocene ◽  
Qaidam Basin ◽  
Global Climate ◽  
The Tibetan Plateau ◽  
Tectonic Events ◽  
Regional Tectonic ◽  
Climate Evolution

The thick and continuous Cenozoic successions in the Qaidam Basin provide an excellent paleoclimate archive. Here, we focus on the ostracod fauna, stable isotope records, and paleoweathering indices from a well-dated Cenozoic sedimentary section in the Qaidam Basin, to develop an understanding of Middle Miocene aridification in central Asia. Microfossil analyses suggest that the ostracod species diversity decreased suddenly after 13.3 Ma, and that the dominant ostracod genus shifted from Ilyocypris to Cyprideis. Stable isotope data from ostracod valves have displayed abrupt positive shifts of 3.75‰ in δ18O values and 5.28‰ in δ13C values since 13.3 Ma. The chemical index of weathering (CIW) and K2O/Na2O ratios decrease markedly after 13.3 Ma, reflecting a significant decrease in chemical weathering intensity. These combined and consistent observations suggest that the Qaidam Basin has experienced increased aridification since 13.3 Ma. The dating was obtained directly from previous magnetostratigraphic studies and can be correlated accurately with global climate evolution and regional tectonic events. A comparison of these results with global paleoclimatic records and previous geologic studies of the Tibetan Plateau revealed that global cooling, rather than uplift of the Tibetan Plateau, played a key role in the drying of the Qaidam Basin at approximately 13 Ma.

Middle Miocene climate transition in the Tibetan Plateau: identification and significance

2021 ◽  
pp. 1-20
Author(s):  
Shijun Song ◽  
Lei Huang ◽  
Yongshu Zhang ◽  
Qi Zhang ◽  
Fei Zhou ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Central Asia ◽  
Middle Miocene ◽  
Gamma Ray ◽  
Qaidam Basin ◽  
The Tibetan Plateau ◽  
Fine Grained ◽  
Climatic Optimum ◽  
Mixed Sediments ◽  
Climate Transition

Abstract The Middle Miocene Climatic Optimum is known for abrupt events during the global cooling trend of the past 20 Ma. Its identification in the Tibetan Plateau can help explain the cause of the critical Middle Miocene climate transition in Central Asia. In this study, fine-grained mixed sediments widely distributed in the Miocene Qaidam Lake in the northern Tibetan Plateau were used as a sensitive indicator for palaeoclimate. Their geochemical characteristics were investigated, together with an analysis of 2600 m long successive gamma-ray logging data from the whole JS2 drillcore, to understand the mid-Miocene climate transition in the Tibetan Plateau. By comparing the gamma-ray curve of the mixed sediments with global temperature, the Middle Miocene Climatic Optimum event can be easily identified. Further, the detailed petrological features and geochemical data of lacustrine fine-grained mixed sediments from a 400 m drillcore show oxidizing, high-sedimentation rate and brackish-saline water conditions in a semi-arid climate during the Middle Miocene period, demonstrating a dryer climate in the Qaidam Basin than in the monsoon-sensitive regions in Central Asia. These fine-grained mixed sediments have recorded climate drying before 15.3 Ma that represents a climatic transition within the Middle Miocene Climatic Optimum; increasing carbonate-rich mixed sediments, decreasing algal limestone layers and decreasing lacustrine organic matter are indicators of this transition. Regional tectonic events include the retreat of the Paratethys from Central Asia at ∼15 Ma and the synchronous tectonic reorganization of the Altyn-Tagh fault system and the northeastern Tibetan Plateau. We find that global climate change is the primary factor affecting the overall characteristics and changes of the Neogene climate in the Qaidam Basin, including the occurrence of the Middle Miocene Climatic Optimum and the cooling and drying tendency, while the regional events are a secondary factor.

scholarly journals Phylogenetic surveys on the newt genus Tylototriton sensu lato (Salamandridae, Caudata) reveal cryptic diversity and novel diversification promoted by historical climatic shifts

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4384 ◽  
Author(s):  
Bin Wang ◽  
Kanto Nishikawa ◽  
Masafumi Matsui ◽  
Truong Quang Nguyen ◽  
Feng Xie ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Middle Miocene ◽  
Gene Tree ◽  
The Tibetan Plateau ◽  
Indochina Peninsula ◽  
Glacial Cycles ◽  
Ancestral Area ◽  
Mountain Ranges ◽  
Climatic Transition ◽  
Asian Monsoons

Global climatic transitions and Tibetan Plateau uplifts are hypothesized to have profoundly impacted biodiversity in southeastern Asia. To further test the hypotheses related to the impacts of these incidents, we investigated the diversification patterns of the newt genus Tylototriton sensu lato, distributed across the mountain ranges of southeastern Asia. Gene-tree and species-tree analyses of two mitochondrial genes and two nuclear genes revealed five major clades in the genus, and suggested several cryptic species. Dating estimates suggested that the genus originated in the early-to-middle Miocene. Under different species delimitating scenarios, diversification analyses with birth-death likelihood tests indicated that the genus held a higher diversification rate in the late Miocene-to-Pliocene era than that in the Pleistocene. Ancestral area reconstructions indicated that the genus originated from the northern Indochina Peninsula. Accordingly, we hypothesized that the Miocene Climatic Transition triggered the diversification of the genus, and the reinforcement of East Asian monsoons associated with the stepwise uplifts of the Tibetan Plateau promoted the radiation of the genus in southeastern Asia during the Miocene-to-Pliocene period. Quaternary glacial cycles likely had limited effects on speciation events in the genus, but mainly had contributions on their intraspecific differentiations.

scholarly journals Paleoaltimetry reconstructions of the Tibetan Plateau: progress and contradictions

2015 ◽  
Vol 2 (4) ◽  
pp. 417-437 ◽  
Author(s):  
Tao Deng ◽  
Lin Ding
Keyword(s):  
Stable Isotopes ◽  
Tibetan Plateau ◽  
Late Miocene ◽  
Middle Miocene ◽  
Isotopic Fractionation ◽  
Climatic Changes ◽  
The Tibetan Plateau ◽  
Geodynamic Evolution ◽  
The Past ◽  
Future Work

Abstract Over the last two decades, many quantitative paleoaltimetry reconstructions of the Tibetan Plateau have been published, but they are still preliminary and controversial, although several approaches have been combined paleontology and geochemistry, including vertebrate, plant, and pollen fossils as well as oxygen, carbon, and hydrogen isotopes. The Tibetan Plateau is the youngest and highest plateau on Earth, and its paleoaltimetry reconstructions are crucial to interpret its geodynamic evolution and to understand the climatic changes in Asia. Uplift histories of the Tibetan Plateau based on different proxies differ considerably, and two viewpoints are pointedly opposing on the paleoaltimetry estimations of the Tibetan Plateau. One viewpoint is that the Tibetan Plateau did not strongly uplift to reach its modern elevation until the Late Miocene, but another one, mainly based on stable isotopes, argues that the Tibetan Plateau formed early during the Indo-Asian collision and reached its modern elevation in the Paleogene or by the Middle Miocene. With either a geochemical or paleontological approach, the present is used as the key to the past. However, there are great difficulties because modern processes of isotopic fractionation and species for creature distribution are not easily precisely determined. In addition, the climatic and environmental backgrounds of past geological times have massive differences from the present, and associated adjustments are influenced by many human factors. In the future work, the applications of multidisciplinary comprehensive methods and cross-checks of their results will be productive, and we look forward to achieving more reliable estimates for paleoelevations of the Tibetan Plateau.

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