scholarly journals Aridification signatures from middle–late Eocene pollen indicate widespread drying across the Tibetan Plateau after 40 Ma

2020 ◽  
Author(s):  
Qin Yuan ◽  
Natasha Barbolini ◽  
Catarina Rydin ◽  
Dong-Lin Gao ◽  
Hai-Cheng Wei ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Central Asia ◽  
Middle Eocene ◽  
Global Climate ◽  
Late Eocene ◽  
Desert Ecosystem ◽  
The Tibetan Plateau ◽  
Pollen Record ◽  
East Central ◽  
History Of

Abstract. Central Asia experienced a number of significant elevational and climatic changes during the Cenozoic, but much remains to be understood regarding the timing and driving mechanisms of these changes, as well as their influence on ancient ecosystems. Here we describe the palaeoecology and palaeoclimate of a new section from the Nangqian Basin in Tibet, northwestern China, here dated as late Lutetian–Bartonian (late middle–late Eocene) based on our palynological analyses. Located on the east-central part of the Tibetan Plateau, this section is excellently placed for better understanding the palaeoecological history of Tibet following the India-Asia collision. Our new pollen record reveals that a strongly seasonal steppe-desert ecosystem characterised by drought-tolerant shrubs, diverse ferns and an underlying component of broad-leaved forests existed in east-central Tibet during the Eocene, influenced by a southern monsoon. Warming during the Middle Eocene Climatic Optimum only prompted a temporary vegetation response, while a drying signature in our pollen record after 40 Ma demonstrates that proto-Paratethys sea retreat caused widespread long-term aridification across the plateau. To better distinguish between local climatic variation and farther-reaching drivers of Central Asian palaeoclimate and elevation, we correlated key palynological sections across the Tibetan Plateau by means of established radioisotopic ages and biostratigraphy. This new palynozonation illustrates both intra- and inter-basinal floral response to plateau uplift and global climate change during the Paleogene, and provides a framework for the age assignment of future palynological studies in Central Asia. Our work highlights the ongoing challenge of integrating various deep time records for the purpose of reconstructing palaeoelevation, indicating that a multiproxy approach is vital for unravelling the complex uplift history of the Tibetan Plateau and its resulting influence on Asian climate.

scholarly journals Aridification signatures from fossil pollen indicate a drying climate in east-central Tibet during the late Eocene

2020 ◽  
Vol 16 (6) ◽  
pp. 2255-2273
Author(s):  
Qin Yuan ◽  
Natasha Barbolini ◽  
Catarina Rydin ◽  
Dong-Lin Gao ◽  
Hai-Cheng Wei ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Central Asia ◽  
Late Eocene ◽  
Western China ◽  
Desert Ecosystem ◽  
Temporary Increase ◽  
The Tibetan Plateau ◽  
East Central ◽  
History Of ◽  
Central Tibet

Abstract. Central Asia experienced a number of significant elevational and climatic changes during the Cenozoic, but much remains to be understood regarding the timing and driving mechanisms of these changes as well as their influence on ancient ecosystems. Here, we describe the palaeoecology and palaeoclimate of a new section from the Nangqian Basin in Tibet, north-western China, dated as Bartonian (41.2–37.8 Ma; late Eocene) based on our palynological analyses. Located on the east-central part of what is today the Tibetan Plateau, this section is excellently placed for better understanding the palaeoecological history of Tibet following the Indo-Asian collision. Our new palynological record reveals that a strongly seasonal steppe–desert ecosystem characterized by drought-tolerant shrubs, diverse ferns, and an underlying component of broad-leaved forests existed in east-central Tibet during the Eocene, influenced by a southern monsoon. A transient warming event, possibly the middle Eocene climatic optimum (MECO; 40 Ma), is reflected in our record by a temporary increase in regional tropical taxa and a concurrent decrease in steppe–desert vegetation. In the late Eocene, a drying signature in the palynological record is linked to proto-Paratethys Sea retreat, which caused widespread long-term aridification across the region. To better distinguish between local climatic variation and farther-reaching drivers of Central Asian palaeoclimate and elevation, we correlated key palynological sections across the Tibetan Plateau by means of established radioisotopic ages and biostratigraphy. This new palynozonation illustrates both intra- and inter-basinal floral response to Qinghai–Tibetan uplift and global climate change during the Paleogene, and it provides a framework for the age assignment of future palynological studies in Central Asia. Our work highlights the ongoing challenge of integrating various deep time records for the purpose of reconstructing palaeoelevation, indicating that a multi-proxy approach is vital for unravelling the complex uplift history of Tibet and its resulting influence on Asian climate.

Paleoaltitudinal histories for the northern and southern margins of the Tibetan Plateau during the Late Cenozoic: revealed by GDGTs

2021 ◽  
Author(s):  
Chihao Chen ◽  
Yan Bai ◽  
Xiaomin Fang ◽  
Haichao Guo ◽  
Weilin Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Late Miocene ◽  
Global Climate ◽  
The Tibetan Plateau ◽  
Lake Surface ◽  
Terrestrial Organic Matter ◽  
Plant Fossils ◽  
History Of ◽  
Monsoon System ◽  
Uplift History

<p>As an important driver of global climate change during the Cenozoic, the uplift of the Tibetan Plateau (TP) has strongly influenced the origination and evolution of the Asian monsoon system, and therefore the aridification of central Asia. Over the last two decades, the application of stable isotope paleoaltimeters and the discoveries of mammal and plant fossils have greatly promoted the understanding of the uplift history of the TP. However, paleoaltitudinal reconstructions based on different paleoaltimeters have suggested differing outcomes and therefore remain controversial. Novel paleoaltimeters have therefore needed to be developed and applied to constrain the uplift history of the TP more accurately and effectively by comparing and verifying multi-proxies. Paleothermometers based on glyceryl dialkyl glycerol tetraethers (GDGTs) are widely used in terrestrial and ocean temperature reconstructions. In this study, GDGT-based paleothermometers were tentatively applied to the Gyirong Basin on the southern TP, and the Xining Basins on the northern TP, in an attempt to quantitatively reconstruct their paleoaltitudes.</p><p>Both soil and aquatic-typed branched GDGTs have been identified from Late Miocene to Mid-Pliocene (7.0-3.2 Ma) samples taken from the Gyirong Basin; their reconstructed paleotemperatures were 7.5±3.3°C and 14.2±4.5°C, respectively. The former temperature may represent the mean temperature of the terrestrial organic matter input area, while the latter may represent the lake surface temperature. The results would suggest that the lake surface of the Gyirong Basin during the Late Miocene to Mid-Pliocene was 2.5±0.8 km and that the surrounding mountains exceeded 3.6±0.6 km, implying that the central Himalayas underwent a rapid uplift of ~1.5 km after the Mid-Pliocene.</p><p>GDGT-based paleotemperature reconstructions using MBT'<sub>5ME</sub> values show that the Xining Basin dropped in temperature by ~10°C during the ~10.5-8 Ma period, exceeding that in sea surface temperatures and low-altitude terrestrial temperatures during these periods. By combining these results with contemporaneous tectonic and sedimentary records, we infer that these cooling events signaled the regional uplift with the amplitude of ~1 km of the Xining basins. Our results support that the TP was still growing and uplifting substantially since the Late Miocene, which may provide new evidence for understanding the growth, expansion and uplift patterns of the TP.</p>

scholarly journals Contrasting Evolution Patterns of Endorheic and Exorheic Lakes on the Central Tibetan Plateau and Climate Cause Analysis during 1988–2017

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1962
Author(s):  
Zhilong Zhao ◽  
Yue Zhang ◽  
Zengzeng Hu ◽  
Xuanhua Nie
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Climatic Factors ◽  
Global Climate ◽  
Rapid Expansion ◽  
Annual Precipitation ◽  
The Tibetan Plateau ◽  
Lake Area ◽  
Climate Change Research ◽  
Mean Temperature

The alpine lakes on the Tibetan Plateau (TP) are indicators of climate change. The assessment of lake dynamics on the TP is an important component of global climate change research. With a focus on lakes in the 33° N zone of the central TP, this study investigates the temporal evolution patterns of the lake areas of different types of lakes, i.e., non-glacier-fed endorheic lakes and non-glacier-fed exorheic lakes, during 1988–2017, and examines their relationship with changes in climatic factors. From 1988 to 2017, two endorheic lakes (Lake Yagenco and Lake Zhamcomaqiong) in the study area expanded significantly, i.e., by more than 50%. Over the same period, two exorheic lakes within the study area also exhibited spatio-temporal variability: Lake Gaeencuonama increased by 5.48%, and the change in Lake Zhamuco was not significant. The 2000s was a period of rapid expansion of both the closed lakes (endorheic lakes) and open lakes (exorheic lakes) in the study area. However, the endorheic lakes maintained the increase in lake area after the period of rapid expansion, while the exorheic lakes decreased after significant expansion. During 1988–2017, the annual mean temperature significantly increased at a rate of 0.04 °C/a, while the annual precipitation slightly increased at a rate of 2.23 mm/a. Furthermore, the annual precipitation significantly increased at a rate of 14.28 mm/a during 1995–2008. The results of this study demonstrate that the change in precipitation was responsible for the observed changes in the lake areas of the two exorheic lakes within the study area, while the changes in the lake areas of the two endorheic lakes were more sensitive to the annual mean temperature between 1988 and 2017. Given the importance of lakes to the TP, these are not trivial issues, and we now need accelerated research based on long-term and continuous remote sensing data.

scholarly journals Evolutionary history of zoogeographical regions surrounding the Tibetan Plateau

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Jiekun He ◽  
Siliang Lin ◽  
Jiatang Li ◽  
Jiehua Yu ◽  
Haisheng Jiang
Keyword(s):  
Tibetan Plateau ◽  
Evolutionary History ◽  
The Tibetan Plateau ◽  
Change Over Time ◽  
Deep Time ◽  
Terrestrial Vertebrates ◽  
History Of ◽  
Striking Change ◽  
Time Periods ◽  
Over Time

AbstractThe Tibetan Plateau (TP) and surrounding regions have one of the most complex biotas on Earth. However, the evolutionary history of these regions in deep time is poorly understood. Here, we quantify the temporal changes in beta dissimilarities among zoogeographical regions during the Cenozoic using 4,966 extant terrestrial vertebrates and 1,278 extinct mammal genera. We identify ten present-day zoogeographical regions and find that they underwent a striking change over time. Specifically, the fauna on the TP was close to the Oriental realm in deep time but became more similar to the Palearctic realms more recently. The present-day zoogeographical regions generally emerged during the Miocene/Pliocene boundary (ca. 5 Ma). These results indicate that geological events such as the Indo-Asian Collision, the TP uplift, and the aridification of the Asian interior underpinned the evolutionary history of the zoogeographical regions surrounding the TP over different time periods.

Paleolake salinity evolution in the Qaidam Basin (NE Tibetan Plateau) between ~42 and 29 Ma: Links to global cooling and Paratethys sea incursions

2021 ◽  
Author(s):  
Chengcheng Ye ◽  
Yibo Yang ◽  
Xiaomin Fang ◽  
Weilin Zhang ◽  
Chunhui Song ◽  
...  
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Middle Eocene ◽  
Qaidam Basin ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Driving Mechanism ◽  
The Tibetan Plateau ◽  
Early Oligocene ◽  
Global Cooling

<p>Global cooling, the early uplift of the Tibetan Plateau, and the retreat of the Paratethys are three main factors that regulate long-term climate change in the Asian interior during the Cenozoic. However, the debated elevation history of the Tibetan Plateau and the overlapping climate effects of the Tibetan Plateau uplift and Paratethys retreat makes it difficult to assess the driving mechanism on regional climate change in a particular period. Some recent progress suggests that precisely dated Paratethys transgression/regression cycles appear to have fluctuated over broad regions with low relief in the northern Tibetan Plateau in the middle Eocene–early Oligocene, when the global climate was characterized by generally continuous cooling followed by the rapid Eocene–Oligocene climate transition (EOT). Therefore, a middle Eocene–early Oligocene record from the Asian interior with unambiguous paleoclimatic implications offers an opportunity to distinguish between the climatic effects of the Paratethys retreat and those of global cooling.</p><p>Here, we present a complete paleolake salinity record from middle Eocene to early Miocene (~42-29 Ma) in the Qaidam Basin using detailed clay boron content and clay mineralogical investigations. Two independent paleosalimeters, equivalent boron and Couch’s salinity, collectively present a three-staged salinity evolution, from an oligohaline–mesohaline environment in the middle Eocene (42-~34 Ma) to a mesosaline environment in late Eocene-early Oligocene (~34-~29 Ma). This clay boron-derived salinity evolution is further supported by the published chloride-based and ostracod-based paleosalinity estimates in the Qaidam Basin. Our quantitative paleolake reconstruction between ~42 and 29 Ma in the Qaidam Basin resembles the hydroclimate change in the neighboring Xining Basin, of which both present good agreement with changes of marine benthic oxygen isotope compositions. We thus speculated that the secular trend of clay boron-derived paleolake salinity in ~42-29 Ma is primarily controlled by global cooling, which regulates regional climate change by influencing the evaporation capacity in the moisture source of Qaidam Basin. Superimposed on this trend, the Paratethys transgression/regression cycles served as an important factor regulating wet/dry fluctuations in the Asian interior between ~42 and ~34 Ma.</p>

scholarly journals Late Cenozoic Denudation and Topographic Evolution History of the Lhasa River Drainage in Southern Tibetan Plateau: Insights From Inverse Thermal History Modeling

2021 ◽  
Vol 9 ◽  
Author(s):  
Dongxu Cai ◽  
Xianyan Wang ◽  
Guangwei Li ◽  
Wenbin Zhu ◽  
Huayu Lu
Keyword(s):  
Tibetan Plateau ◽  
Surface Erosion ◽  
The Tibetan Plateau ◽  
Monsoon Precipitation ◽  
Late Cenozoic ◽  
River Drainage ◽  
History Of ◽  
Southern Tibetan Plateau ◽  
Lhasa River ◽  
Topographic Evolution

The interaction of surface erosion (e.g., fluvial incision) and tectonic uplift shapes the landform in the Tibetan Plateau. The Lhasa River flows toward the southwest across the central Gangdese Mountains in the southern Tibetan Plateau, characterized by a low-relief and high-elevation landscape. However, the evolution of low-relief topography and the establishment of the Lhasa River remain highly under debate. Here, we collected thermochronological ages reported in the Lhasa River drainage, using a 3D thermokinematic model to invert both late Cenozoic denudation and relief history of the Lhasa River drainage. Our results show that the Lhasa River drainage underwent four-phase denudation history, including two-stage rapid denudation at ∼25–16 Ma (with a rate of ∼0.42 km/Ma) and ∼16–12 Ma (with a rate of ∼0.72 km/Ma). In the latest Oligocene–early Miocene, uplift of the Gangdese Mountains triggered the rapid denudation and the formation of the current main drainage of the Lhasa River. In the middle Miocene, the second stage of the rapid denudation and the high relief were associated with intense incision of the Lhasa River, which is probably due to the enhanced Asian summer monsoon precipitation. This later rapid episode was consistent with the records of regional main drainage systems. After ∼12 Ma, the denudation rate decreases rapidly, and the relief of topography in the central Gangdese region was gradually subdued. This indicates that the fluvial erosion resulting from Asian monsoon precipitation increase significantly impacts on the topographic evolution in the central Gangdese region.

Late Eocene post-collisional magmatic rocks from the southern Qiangtang terrane record the melting of pre-collisional enriched lithospheric mantle

2021 ◽  
Author(s):  
Yue Qi ◽  
Qiang Wang ◽  
Gang-jian Wei ◽  
Xiu-Zheng Zhang ◽  
Wei Dan ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Trace Element ◽  
Partial Melting ◽  
Early Cretaceous ◽  
Lithospheric Mantle ◽  
Late Eocene ◽  
The Tibetan Plateau ◽  
Mafic Rocks ◽  
Isotopic Compositions ◽  
Qiangtang Terrane

Diverse rock types and contrasting geochemical compositions of post-collisional mafic rocks across the Tibetan Plateau indicate that the underlying enriched lithospheric mantle is heterogeneous; however, how these enriched mantle sources were formed is still debated. The accreted terranes within the Tibetan Plateau experienced multiple stages of evolution. To track the geochemical characteristics of their associated lithospheric mantle through time, we can use mantle-derived magmas to constrain the mechanism of mantle enrichment. We report zircon U-Pb ages, major and trace element contents, and Sr-Nd isotopic compositions for Early Cretaceous and late Eocene mafic rocks in the southern Qiangtang terrane. The Early Cretaceous Baishagang basalts (107.3 Ma) are characterized by low K2O/Na2O (<1.0) ratios, arc-like trace element patterns, and uniform Sr-Nd isotopic compositions [(87Sr/86Sr)i = 0.7067−0.7073, εNd(t) = −0.4 to −0.2]. We suggest that the Baishagang basalts were derived from partial melting of enriched lithospheric mantle that was metasomatized by subducted Bangong−Nujiang oceanic material. We establish the geochemistry of the pre-collisional enriched lithospheric mantle under the southern Qiangtang terrane by combining our data with those from other Early Cretaceous mafic rocks in the region. The late Eocene (ca. 35 Ma) post-collisional rocks in the southern Qiangtang terrane have low K2O/Na2O (<1.0) ratios, and their major element, trace element, and Sr-Nd isotopic compositions [(87Sr/86Sr)i = 0.7042−0.7072, εNd(t) = −4.5 to +1.5] are similar to those of the Early Cretaceous mafic rocks. Based on the distribution, melting depths, and whole-rock geochemical compositions of the Early Cretaceous and late Eocene mafic rocks, we argue that the primitive late Eocene post-collisional rocks were derived from pre-collisional enriched lithospheric mantle, and the evolved samples were produced by assimilation and fractional crystallization of primary basaltic magma. Asthenosphere upwelling in response to the removal of lithospheric mantle induced the partial melting of enriched lithospheric mantle at ca. 35 Ma.

scholarly journals Comparison of satellite-based evapotranspiration estimates over the Tibetan Plateau

2016 ◽  
Vol 20 (8) ◽  
pp. 3167-3182 ◽  
Author(s):  
Jian Peng ◽  
Alexander Loew ◽  
Xuelong Chen ◽  
Yaoming Ma ◽  
Zhongbo Su
Keyword(s):  
Tibetan Plateau ◽  
Vegetation Index ◽  
Water Cycle ◽  
Global Climate ◽  
Spatial Scales ◽  
Accurate Estimation ◽  
The Tibetan Plateau ◽  
North West ◽  
Comparison Results ◽  
Normalised Difference Vegetation Index

Abstract. The Tibetan Plateau (TP) plays a major role in regional and global climate. The understanding of latent heat (LE) flux can help to better describe the complex mechanisms and interactions between land and atmosphere. Despite its importance, accurate estimation of evapotranspiration (ET) over the TP remains challenging. Satellite observations allow for ET estimation at high temporal and spatial scales. The purpose of this paper is to provide a detailed cross-comparison of existing ET products over the TP. Six available ET products based on different approaches are included for comparison. Results show that all products capture the seasonal variability well with minimum ET in the winter and maximum ET in the summer. Regarding the spatial pattern, the High resOlution Land Atmosphere surface Parameters from Space (HOLAPS) ET demonstrator dataset is very similar to the LandFlux-EVAL dataset (a benchmark ET product from the Global Energy and Water Cycle Experiment), with decreasing ET from the south-east to north-west over the TP. Further comparison against the LandFlux-EVAL over different sub-regions that are decided by different intervals of normalised difference vegetation index (NDVI), precipitation, and elevation reveals that HOLAPS agrees best with LandFlux-EVAL having the highest correlation coefficient (R) and the lowest root mean square difference (RMSD). These results indicate the potential for the application of the HOLAPS demonstrator dataset in understanding the land–atmosphere–biosphere interactions over the TP. In order to provide more accurate ET over the TP, model calibration, high accuracy forcing dataset, appropriate in situ measurements as well as other hydrological data such as runoff measurements are still needed.

New Noctuidae species from China (Lepidoptera, Noctuoidea)

Zootaxa ◽  
2011 ◽  
Vol 2896 (1) ◽  
pp. 46
Author(s):  
P. GYULAI ◽  
L. RONKAY ◽  
A. SALDAITIS
Keyword(s):  
New Species ◽  
Tibetan Plateau ◽  
Central Asia ◽  
New Taxa ◽  
Light Trapping ◽  
Himalayan Region ◽  
Research Centre ◽  
The Tibetan Plateau ◽  
The Third ◽  
High Diversity

Collecting expeditions to China's Sichuan, Gansu and Qinghai provinces were conducted by the third author, along with Alessandro and Irene Floriani, during June 2009, April 2010 and July 2010. Light trapping yielded numerous noctuid moths including four new species, described herein. These new taxa reflect the high diversity of some genera (Hada, Billberg, 1820 ; Palaeamathes, Boursin, 1954) in SW China, and the biogeographical connections of the Tibetan Plateau to Central Asia (Lacanobia kitokia sp. n., L. contrastata (Bryk, 1942), L. mongolica Behounek, 1993, L. kirghisa Gyulai & Ronkay, 1998) and to the Himalayan Region (Palaeamathes serrulata sp. n. is close to P. harpegnoma (Hreblay & Ronkay, 1998). Acronyms for personal and institutional collections are as follows: AFM—Alessandro Floriani (Milan, Italy); ASV—Aidas Saldaitis (Vilnius, Lithuania); BJ—Janos Babics (Budapest, Hungary); DNK—Danny Nilsson (Kalvehave, Denmark); GRB—Gabor Ronkay (Budapest, Hungary); GBG/ZSM—Gottfried Behounek (Grafing, Germany) / Zoologische Staatssammlung, München (Germany); GYP—Peter Gyulai (Miskolc, Hungary); HHP – Henri Hoppe (Klein Pravtshagen, Germany); NRCV—Nature Research Centre (Vilnius, Lithuania); WSM—Wolfgang Speidel (München, Germany).

The tectonic evolution of the Tibetan Plateau

1988 ◽  
Vol 327 (1594) ◽  
pp. 379-413 ◽  
Keyword(s):  
Tibetan Plateau ◽  
Late Jurassic ◽  
Middle Eocene ◽  
Late Triassic ◽  
The Tibetan Plateau ◽  
Peninsular India ◽  
Lhasa Terrane ◽  
Lateral Extrusion ◽  
Palaeomagnetic Data ◽  
Normal Thickness

The Tibetan Plateau, between the Kunlun Shan and the Himalayas, consists of terranes accreted successively to Eurasia. The northernmost, the Songban Ganzi Terrane, was accreted to the Kunlun (Tarim-North China Terrane) along the Kunlun-Qinling Suture during the late Permian. The Qiangtang Terrane accreted to the Songban-Ganzi along the Jinsha Suture during the late Triassic or earliest Jurassic, the Lhasa Terrane to the Qiangtang along the Banggong Suture during the late Jurassic and, finally, Peninsular India to the Lhasa Terrane along the Zangbo Suture during the Middle Eocene. The Kunlun Shan, Qiangtang and Lhasa Terranes are all underlain by Precambrian continental crust at least a billion years old. The Qiangtang and Lhasa Terranes came from Gondwanaland. Substantial southward ophiolite obduction occurred across the Lhasa Terrane from the Banggong Suture in the late Jurassic and from the Zangbo Suture in the latest Cretaceous-earliest Palaeocene. Palaeomagnetic data suggest successive wide Palaeotethyan oceans during the late Palaeozoic and early Mesozoic and a Neotethys which was at least 6000 km wide during the mid-Cretaceous. Thickening of the Tibetan crust to almost double the normal thickness occurred by northward-migrating north-south shortening and vertical stretching during the mid-Eocene to earliest Miocene indentation of Asia by India; Neogene strata are almost flat-lying and rest unconformably upon Palaeogene or older strata. Since the early Miocene, the northward motion of India has been accommodated principally by north south shortening both north and south of Tibet. From early Pliocene to the Present, the Tibetan Plateau has risen by about two kilometres and has suffered east-west extension. Little, if any, of the India Eurasia convergence has been accommodated by eastward lateral extrusion.

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