Tibetan Uplift Research Articles

Chromosome-level genome assembly and population genomic analysis provide insights into the genetic diversity and adaption of Schizopygopsis younghusbandi on the Tibetan Plateau.

The Yarlung Tsangpo River on the Tibetan Plateau provides a unique natural environment for studying fish evolution and ecology. However, the genomes and genetic diversity of plateau fish species have been rarely reported. Schizopygopsis younghusbandi, a highly specialized Schizothoracine species and economically important fish inhabiting the Yarlung Tsangpo River, is threatened by overfishing and biological invasion. Herein, we generated a chromosome-level genome of S. younghusbandi and whole-genome resequencing data for 59 individuals from six locations of the river. The results showed that the divergence time between S. younghusbandi and other primitive Schizothoracine species was ∼4.2 Mya, coinciding with the major phase of the Neogene Tibetan uplift. The expanded gene families enriched in DNA integration and replication, ion binding and transport, energy storage, and metabolism likely contribute to the adaption of this species. The S. younghusbandi may have diverged from other highly specialized Schizothoracine species in the Zanda basin during the Pliocene epoch, which underwent major population reduction possibly due to the drastic climate change during the last glacial period. Population analysis indicated that the ancient population might have originated upstream before gradually adapting to evolve into the populations inhabiting the mid-stream and downstream regions of the Yarlung Tsangpo River. In conclusion, the chromosome-level genome and population diversity of S. younghusbandi provide valuable genetic resources for the evolution, ecology, and conservation studies of endemic fishes on the Tibetan Plateau.

No significant provenance changes in the Hoh Xil Basin, central-northern Tibetan Plateau, from the Late Cretaceous to the Early Miocene

The construction and uplift of the Tibetan Plateau has played a critical role in Cenozoic global climatic cooling due to extensive chemical weathering and establishment of the Asian monsoons. However, the models, mechanisms, and timing of Tibet's uplift remain rigorously debated. Important outstanding questions include what were surface elevations of the Tibetan Plateau prior to the Paleogene India-Asia collision and what mechanisms were responsible for the Cenozoic uplift of the central Tibetan Plateau. In this study, we integrated new detrital zircon data from the Tuotuohe Basin, a sub-basin of the Hoh Xil Basin in the central Tibetan Plateau, with paleocurrent directions, petrological textures, sedimentary facies, and eastern and western Hoh Xil Basin isotopes to investigate the source-to-sink relationship between the Tanggula Range and the Hoh Xil Basin. Any notable provenance shifts would have implications for the topographic evolution of the central and northern Tibet and proposed plateau uplift mechanisms. Our detrital zircon data from the Tuotuohe sub-basin revealed no provenance changes between ca. 37 and ca. 20 Ma. Detrital zircon data from the Tuotuohe section and the eastern and western Hoh Xil Basins, paleocurrent directions, petrologic analysis, strata characteristics, and isotopic evidence suggest that there was a single expansive Hoh Xil Basin from the Late Cretaceous to the Early Miocene. Furthermore, the Tanggula Range has been the primary source region for the Hoh Xil Basin since the Late Cretaceous. However, the Fenghuo Range may have provided a significant secondary source of detritus starting in the Late Oligocene-Early Miocene. Our results imply that there was established topographic relief in central-northern Tibet between mountainous highlands in the south and the Hoh Xil Basin in the north since the Late Cretaceous. The Tanggula Range-Hoh Xil Basin experienced surface deformation and uplift from the Late Cretaceous to ca. 40 Ma, induced by the Lhasa-Qiangtang and India-Asia collisions, after which the deformation intensity ceased by ca. 27–24 Ma. Therefore, the additional ∼1.5 km surface uplift of the Hoh Xil Basin since the Middle Miocene cannot be the result of crustal shortening. Instead, surface uplift may have been caused by the convective removal of the mantle lithosphere or magmatic inflation, which explains the sub-horizontal attitudes of the Middle Miocene Wudaoliang Formation in the region.

Increased primary mineral dissolution control on a terrestrial silicate lithium isotope record during the middle Miocene Climate Optimum

Lithium isotopes have great potential to fractionate at subaerial environment, so they are promising proxies for tracing chemical weathering history. However, it remains uncertain how to relate lithium isotopic compositions (δ7Li) in sediments to silicate weathering and past climate in terrestrial setting. To tackle this question, we choose the warm and wet middle Miocene climate optimum (MMCO, 17–14 Ma) with large climate variation amplitude and the following cold and dry middle Miocene climate cooling period (MMCC, 14–11 Ma) with damped climatic variation amplitude, as two climate contrasting intervals to study lithium isotopes and content ([Li]) variations of terrestrial mudrocks. Our study site is located at the eastern Qaidam Basin of the northeastern Tibetan Plateau and the precipitation pattern of this part of the basin is similar to the Chinese Loess Plateau over the two studied intervals. The study site is suitable for clarifying link between climate and δ7Li variations because previous studies have demonstrated no provenance shift over the studied interval and short transport distance from source to the study site suggests little chemical weathering over the transportation process. Both δ7Li and [Li] values show larger amplitude over the MMCO (spanning from −1.2 to 3.2 ‰ and from 32.8 to 93.9 ug/g, respectively) than the MMCC interval (−1.8 to 1.2 ‰ and 41.7–80.8 ug/g, respectively), consistent with general feature of global and Chinese Loess Plateau climate. However, δ7Li data are higher over the MMCO in comparison with the MMCC, contrary to expectation of more lithium isotope fractionation at warm interval. We interpret the more positive δ7Li values over the MMCO using increased ratio of primary mineral dissolution over secondary mineral precipitation. Qaidam mudrock and benthic Li records show complementary changes, suggesting their possible link. Furthermore, past research reveals lack of focused uplift of the northeastern Tibetan Plateau over the studied 18–11 Ma. So we conclude that global climate, rather than Tibetan uplift, played an important role in modulating inland Qaidam Basin climate variations over the middle Miocene and that increased chemical weathering over warm climate can lead to a small magnitude of lithium isotope fractionation. Therefore, interpreting chemical weathering history, and hence climate, using lithium isotope data in terrestrial setting requires considering relative importance of primary mineral dissolution versus secondary mineral precipitation.

Expansion/shrinkage history of the Paratethys Sea during the Eocene: New insights from eolian Red Clay records in the Altyn Mountains, northern China

Uplift of the Tibetan Plateau, expansion/shrinkage of the Paratethys Sea, and global climate are three major forcings for central-east Asian climatic and environmental variations during the Cenozoic. However, knowledge of expansion/shrinkage history of the Paratethys Sea is much less well known in comparison with the other two forcings. Here, we present a first multiple-parameter environmental magnetic and diffuse reflectance spectroscopy study of the Eocene eolian Red Clay deposits (∼51–40 Ma) in the Xorkol Basin of the northeastern Tibetan Plateau, which is near the easternmost maximum boundary of the Eocene Paratethys Sea. The first detailed Eocene expansion/shrinkage history of the Paratethys Sea was reconstructed based on the hematite content of the Eocene Red Clay, which shows remarkable consistency with the previous low-resolution Paratethys Sea paleowater depth record in the southwestern Tarim Basin. These results demonstrate that the Paratethys Sea experienced a three-stage (shrinkage-expansion-shrinkage) evolution between ∼51 and 40 Ma, with boundaries at ∼46.2 and 42 Ma. Superimposed on this framework, the Paratethys Sea experienced four times of rapid shrinkages at the expansion phase (shows 400-kyr cycles) during ∼44–42 Ma modulated by eccentricity forcings. These new results are of great significance to evaluate respective role of Tibetan uplift, global climate, and Paratethys Sea area variations in Asian climate and environmental change over the Eocene.

Northward Shift of the Northern Hemisphere Westerlies in the Early to Late Miocene and Its Links to Tibetan Uplift

AbstractDespite the importance of the westerlies to the global climate system, we still know little about their long‐term evolution and possible orographic controls during the late Cenozoic because of the lack of sedimentary records with precise chronological control. Eolian deposition in the North Pacific preserved past information about the westerlies, the major wind system delivering Asian dust to the Pacific. A continuous, high‐resolution eolian flux record since 23 Ma was reconstructed from sediments at Deep Sea Drilling Project Site 296 in the North Pacific. Combined with dust flux at Ocean Drilling Program Site 1208, variations in their difference indicated a northwards shift of the westerlies during 23‒9 Ma and a relatively stable state since then. We suggest that Tibetan uplift since the early Miocene began to drive the poleward shift of the westerlies until 9 Ma, after which the westerlies remained relatively stable over Asia on million‐year timescales.

Insights into evolution of a rift basin: Provenance of the middle Eocene-lower Oligocene strata of the Beibuwan Basin, South China Sea from detrital zircon

Investigating rift basins and their provenance is difficult because their tectonic framework is continuously evolving. The Beibuwan Basin in the South China Sea is a typical rift basin that shares many characteristics of major rift basins worldwide. We present new detrital zircon UPb ages from the Beibuwan basin and, by combining with published data from surrounding drainages, are able to define its potential sources and to investigate its provenance evolution from the middle Eocene-lower Oligocene. Detrital zircon age spectra from distinct structural units and formations of the rift basin reveal spatial-temporal differences in provenance. In the middle-upper Eocene, a similar age pattern with major peaks at 263–253 Ma and 450–416 Ma is preserved across the basin and suggests that sediment was uniformly derived from the Yunkai Massif and Hainan Island. In contrast, during the lower Oligocene the basin displays markedly diverse ages with peaks at 250–243, 416, 756, 967–945, 1096–1084 Ma. The increase of Neoproterozoic zircons in the lower Oligocene stratum suggests that a major change in provenance occurred, most likely associated with the reorganization of the paleo-Pearl River along its central reaches due to a topography reversal associated with the uplift of Tibet and the onset of seafloor spreading in the South China Sea. Our spatial analysis of ages indicates that during the lower Oligocene, the detrital input varied across the basin. Rifting processes in the Beibuwan Basin generated multiple isolated depocenters separated by intra-basinal highs. The basin's architecture greatly affected sediment routing, with structural highs serving as barriers to sediment transport. Sediment provenance in the Beibuwan Basin is primarily controlled by drainage evolution and isolated depocenters associated with an evolving topography, processes which are relevant to the evolution of rift basins globally.

Has the Tibetan Plateau risen in the Early/Mid-Miocene? Constraints from plate-motion reconstructions and seismicity of the Indian Ocean lithosphere

SUMMARYMagnetization records and seismic stratigraphy of the Indian Ocean lithosphere indicate that the Early/Mid-Miocene onset of diffuse contractional deformation coincided with slowdowns of the Indian and Capricorn plate motions. At present day, such deformation is evidenced by the seismicity of the Indian Ocean floor. Deformation onset and past plate-motion slowdowns have been interpreted as consequences of a sudden uplift of the Tibetan Plateau by 1–2 km, as this—following previous estimates—would generate a tectonically significant force between 4 × 1012 and 8 × 1012 N m−1. However, this view remains at odds with palaeoaltimetry estimates from geological and geochemical data, which indicate no increase in plateau altitude throughout the Miocene. Here, I use well-established models of viscous/brittle dynamics in inverse mode in order to constrain the amount of force that should be delivered by the Tibetan region to the Indian tectonic setting in order to explain the observations above. Results constrain such a force within the range from 4.3 × 1011 to 3.5 × 1012 N m−1. By comparison with previous estimates of the force associated with topography increase, these analyses suggest that the Early/Mid-Miocene onset of contractional deformation and plate-motion slowdowns within the Indian Ocean require minimal uplift of the Tibet Plateau of a few hundred metres. The seemingly contradicting inferences on Early/Mid-Miocene Tibetan uplift that come from geophysical and geological/geochemical observations can be reconciled by noting that the required uplift amount is less than what is resolvable by modern palaeoaltimetry techniques.

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

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.

Multiproxy records in middle–late Miocene sediments from the Wushan Basin: Implications for climate change and tectonic deformation in the northeastern Tibetan Plateau

AbstractTo help understand the relationship between global cooling and Tibetan uplift in the middle to late Miocene, multiple proxy data including carbonate stable isotope records, magnetic susceptibility, and sediment color references were obtained from a magnetostratigraphic section (14.5–6.0 Ma) of the Wushan Basin along the northeastern margin of the Tibetan Plateau. New proxies identify two phase changes that may have been controlled by global cooling and tectonic deformation at this time. During 14.5–13.2 Ma, positive shifts of ∼2.0‰ in δ18O and δ13C, an increase in lightness (L*), and a decrease in redness (a*) suggest gradually increasing aridity. Relatively high δ18O and δ13C values and low a*/L* and magnetic susceptibility values continue until ca. 10 Ma, when δ18O and δ13C significantly decrease and redness as well as magnetic susceptibility significantly increase. The negative shifts in δ18O and δ13C and increases in redness and magnetic susceptibility at 10 Ma are consistent with coeval basin environment and provenance changes. Combining these data with basin analysis, we suggest that global cooling was the dominant factor and Tibetan uplift was the subordinate factor for the middle Miocene aridification of the Wushan Basin. In contrast, the contribution of Tibetan uplift was dominant and global climate change was subordinate in the late Miocene basin paleogeographic reorganization.

Nature and Evolution of Crust in Southern Lhasa, Tibet: Transformation From Microcontinent to Juvenile Terrane

AbstractThe nature and pre‐Cenozoic evolution history of crust in southern Lhasa, which is crucial for our understanding of Indo‐Asian continental collision and Tibetan uplift during the Cenozoic, remains controversial due to a “missing” pre‐Mesozoic magmatic record. In this contribution, we report petrological and geochemical data for newly identified Paleozoic bimodal magmatism in the Zhengga area of southern Tibet. The magmatism comprises Late Devonian‐Early Carboniferous (366–353 Ma) amphibolite and two‐mica gneissic granite. The protoliths of the Zhengga amphibolite were gabbro and diorite with low SiO2 and high MgO, Cr, and Ni contents with high εNd(t) values of +3.3 to +8.0, variable and positive zircon εHf(t) of +0.9 to +11.2, and low zircon δ18O of 5.7 ± 0.2‰. These protoliths are proposed to have formed by decompression melting of asthenosphere during intracontinental back‐arc extension. In contrast, the granite has relatively high SiO2 and low MgO contents with much lower εNd(t) of −8.6 to −7.3, variable and negative zircon εHf(t) of −10.4 to −1.3, and high zircon δ18O of 9.4 ± 0.2‰ values and was most likely derived from an ancient metasedimentary source. This magma subsequently underwent recharge with minor amounts mafic magma followed by fractional crystallization of K‐feldspar in middle‐upper crust (~10–20 km) magma chambers. Using our new data, in combination with Nd‐Hf isotopes, we present the first comprehensive picture of crustal evolution in southern Lhasa. The southern Lhasa sub‐block is likely to have been a microcontinent that underwent extensive Phanerozoic crustal reworking and growth, rather than a Mesozoic‐Early Tertiary juvenile accretionary arc terrane.

Patterns of niche diversification in south-east Asian crocodile newts

Niche conservatism underlies the process of speciation in amphibians on the global scale. However, high tropical diversity is partly attributable to niche shifts within evolutionary lineages. Crocodile newts (genera Echinotriton and Tylototriton) are a monophyletic group endemic to south-east Asia, and are one of the few lineages of urodeles that appear in tropical regions. Here, we examined the patterns of ecological diversification within the crocodile newts based on 207 records of 23 species. The niche space was described according to topographic, climatic variables (temperature, rainfall, and seasonality) and forest cover. Our analysis showed that the occurrence of most of these species was strongly associated with the precipitation regime and seasonality. The diversification patterns of the crocodile newts are complex, showing both conservatism and divergence. These patterns can be related to the Tibetan uplift phase during the Neogene, resulting in the emergence of new montane habitats and subsequent changes in the palaeo-drainage system and climate. The range of ecological diversification within a lineage is possibly the result of several interacting processes, including environmental heterogeneity, the regional climatic history, and physiological constraints on species.

Advent of Strong South Asian Monsoon by 20 Million Years Ago

AbstractThe monsoonal paleoclimate of India has been critical for understanding the tectonic history of Himalayan and Tibetan uplift over the past 60 My. Monsoonal circulation in deep time has been...

History of Asian eolian input to the Sea of Japan since 15 Ma: Links to Tibetan uplift or global cooling?

We present high-resolution analyses of clay mineral assemblages combined with analysis of Sr–Nd–Pb isotopic compositions of the <2 μm silicate fraction of sediments from Integrated Ocean Drilling Program (IODP) Site U1430 in the southern Sea of Japan, in order to trace the sources of clay minerals and reconstruct proxy records of past changes in Asian eolian input to the basin since 15 Ma. The clay mineral assemblages at IODP Site U1430 mainly consist of smectite (∼51%) and illite (∼36%), with minor kaolinite (∼7%) and chlorite (∼6%). Provenance analysis suggests that the fine-grained sediment at the study site is a two end-member mixture of eolian dust from Central Asia and fluvial input from the Japanese islands. The Central Asian end member supplied illite-rich and high 87Sr/86Sr and low εNd(0) eolian dust to the study site by wind, while the Japanese end member, characterized by young volcanic rocks, contributed smectite-rich, low 87Sr/86Sr and high εNd(0) weathering products via rivers. The ratio of illite/smectite and εNd(0) values of clay-sized silicate sediments at Site U1430 were used as proxies for tracing the changing strength of central Asian eolian input to the Sea of Japan, and thus reconstruct the aridification history of its source region. Our study presents for the first time a continuous, high-resolution record that highlights the four-step drying of Central Asia that occurred at ∼11.8 Ma, 8 Ma, 3.5 Ma and 1.2 Ma. Considered the nature and timing of major climatic and tectonic events in Asia, we conclude that the strengthened aridification of Central Asia starting at ∼11.8 Ma was possibly driven by the combined effect of Tibetan surface uplift and global cooling, whereas the rapid drying at ∼8 Ma was caused primarily by the uplift of the northern Tibetan Plateau. In contrast, global cooling, overwhelming the influence of Tibetan Plateau uplift, has become the primary control on Central Asia aridification since ∼3.5 Ma.

Extreme aridification since the beginning of the Pliocene in the Tarim Basin, western China

Mid-latitude Central Asia is characterized by an extreme arid landscape. Among the Central Asian deserts, the Taklimakan Desert is the largest shifting sand desert which is located in the rain shadow of the Tibetan Plateau and of the other central Asian high mountains. The formation of this desert is important for placing widespread aridification into a regional tectonic context at the western end of the Himalayan-Tibetan orogen. However, there still exists considerable controversy regarding the timing of desert formation, thus impeding our understanding of the climatic effects of the Tibetan uplift and regional environmental changes. Here we report new biostratigraphic age control and multiple high-resolution climatic records from the center of the Taklimakan Desert. Our results reveal dramatic environmental changes at ~5Ma, suggesting that an extremely dry climate has prevailed since the beginning of the Pliocene, which is consistent with findings from a high-resolution borehole record about 670km to the east in the same basin. The two records combined demonstrate that an extremely dry environment prevailed in the entire Tarim Basin from approximately 5Ma. This was related to the reduced transport of water vapor by westerlies in response to the retreat of the Paratethys Ocean driven by global climatic cooling, and the closed oceanic water-vapor pathway between the Pamir and the Tian Shan ranges driven by the ongoing India-Eurasia collision.

Bumblebees take the high road: climatically integrative biogeography shows that escape from Tibet, not Tibetan uplift, is associated with divergences of present‐day Mendacibombus

Many claims that uplift of the Qinghai‐Tibetan plateau (QTP) drove the divergences of extant high‐elevation biota have recently been challenged. For Mendacibombus bumblebees, high‐elevation specialists with distributions centred on the QTP, we examine broader explanations. We extend integrative biogeography to cover multiple contributing factors by using a framework of sequential filters: 1) molecular evidence from four genes is used to estimate phylogenetic relationships, with time calibration from a published estimate; 2) spatial evidence from current distributions is combined with the phylogeny and constrained by a model of short‐distance dispersal along mountain corridors to estimate ancestral distributions by both S‐DIVA and S‐DEC analysis; 3) geological evidence from the literature is used to constrain when high mountain ranges were uplifted to become potential corridors; and 4) climatological evidence from Mendacibombus niche‐evolution reconstructions and from palaeoclimate simulations is used to constrain when habitat was suitable in key gaps within corridors. Explanations for Mendacibombus distributions can be identified that require only short‐distance dispersal along mountain corridors, commensurate with the limited dispersal ability observed for bumblebees. These explanations depend on the timing of uplift of mountain ranges, regional climate change, and climate‐niche evolution. The uplift of the QTP may have contributed to the initial Oligocene divergence of the common ancestor of Mendacibombus from other bumblebees, but for the first two thirds of the history of Mendacibombus, only a single lineage has present‐day descendants. Divergence of multiple extant Mendacibombus lineages coincided with the Late Miocene–Pliocene uplift of externally connecting mountains, combined with regional climate cooling. These changes provided greater connectivity of suitable habitat, allowing these bumblebees to disperse out of the western QTP via new high bridges, escaping along the mountain corridors of the Tian Shan and Hindu Kush ranges, reaching eventually far to the west (Iberian Peninsula) and to the north‐east (Kamchatka).

Cyprininae phylogeny revealed independent origins of the Tibetan Plateau endemic polyploid cyprinids and their diversifications related to the Neogene uplift of the plateau.

Origin and diversification of the Tibetan polyploid cyprinids (schizothoracins) may help us to explore relationships between diversification of the cyprinids and the Tibetan Plateau uplift. Cyprininae phylogeny was analyzed using mitochondrial and nuclear DNA sequences to trace origins of polyploidy and diversifications of schizothoracins. Ancestral states reconstruction for ploidy levels indicated that the Cyprininae was diploid origin and the schizothoracin clades tetraploid origins. There were two diversification rate shifts along with diversification of the cyprinine fishes in response to the Tibetan uplift. The unusual diversification shifts were located to branches subtending the clades of Tibetan polyploid cyprinids. Our analyses suggested that (i) phylogeny of Cyprininae recovered two independent origins of the Tibetan polyploidy schizothoracins; (ii) diversifications of the schizothoracins were closely related to the Neogene uplift of the Tibetan plateau in the following ways: the relatively ancient Late Oligocene-Middle Miocene adaptive radiation may be associated with the uplift of the southern Tibet and Himalaya; the Middle Miocene-Early Pleistocene lineage-specific diversification broadly coincident with major phase of the Neogene Tibetan uplift; and the most recent Pleistocene diversification shift in Schizothorax closely coincident with the successive Kunlun-Huanghe and Gonghe movements of the Tibetan uplift and the glaciation-induced climate oscillations on the plateau.

Unlinking erosion from uplift in Tibet

Geomorphology![Figure][1] The Parlung River in Eastern Tibet PHOTO(FROM TOP): MATCOVITCH-NATAN ET AL. ; ZHANGZHUGANG/WIKICOMMONS Conventional wisdom suggests that the locations of gorges or “knickpoints” along the edges of large plateaus remain fixed because erosion drives tectonic uplift. Nowhere should this be more evident than the rapidly uplifting and eroding Tibetan plateau. However, King et al. found evidence for slow migration of a major knickpoint along the Parlung River in eastern Tibet. They used a new method with exceptional time resolution for determining regional cooling rates called multi–OSL (optically stimulated luminescence) thermochronology. It appears that the Parlung knickpoint is steadily moving upstream as a response to tectonic uplift that is unrelated to the local erosion rates. Science , this issue p. [800][2] [1]: pending:yes [2]: /lookup/doi/10.1126/science.aaf2637

Available data point to a 4‐km‐high Tibetan Plateau by 40 Ma, but 100 molecular‐clock papers have linked supposed recent uplift to young node ages

AbstractThe aims of this study were to synthesize data on the orogeny of the Tibetan Plateau (TP), with a focus on its elevation since the collision of the Eurasian and Indian plates, and to review the arguments in 100 phylogeny‐cum‐biogeography papers that have linked young inferred divergence times to recent TP uplift phases. I surveyed the literature on the geological history of the TP, focusing on different types of data used to infer its past height. I also tabulated the supposed TP history (and supporting references) in papers since 1998. Since the early 1990s, evidence from tectonics, isotopes, fossils and climate simulations increasingly indicates that the TP has been 4–5 km high since the mid‐Eocene. The data also indicate that the Indian summer monsoon, South‐east Asian summer monsoon, and Central Asian winter monsoon arose at different times and are unrelated to Tibetan uplift. A growing number of studies by biologists, however, are linking node ages between 0.5 and 15 Ma to specific (author‐dependent) uplift phases of the TP citing geological papers that are outdated or miscited. Biogeography of the TP thus currently appears to be in a self‐created bubble that encloses hundreds of authors and referees. Our understanding of the biogeography of Tibet requires up‐to‐date interpretation of its geological history and more fieldwork on local ecological habitat diversity, the plateau's history during the Pleistocene and the distribution of possible refugia.

Geology and hydrocarbon accumulations in the deepwater of the northwestern South China Sea—with focus on natural gas

The deepwater of the northwestern South China Sea is located in the central to southern parts of the Qiongdongnan Basin (QDN Basin), which is a key site for hydrocarbon exploration in recent years. In this study, the authors did a comprehensive analysis of gravity-magnetic data, extensive 3D seismic survey, cores and cuttings, paleontology and geochemical indexes, proposed the mechanism of natural gas origin, identified different oil and gas systems, and established the model of hydrocarbon accumulations in the deep-water region. Our basin tectonic simulation indicates that the evolution of QDN Basin was controlled by multiple-phased tectonic movements, such as Indochina-Eurasian Plate collision, Tibetan Uplift, Red River faulting and the expansion of the South China Sea which is characterized by Paleogene rifting, Neogene depression, and Eocene intensive faulting and lacustrine deposits. The drilling results show that this region is dominated by marineterrestrial transitional and neritic-bathyal facies from the early Oligocene. The Yacheng Formation of the early Oligocene is rich in organic matter and a main gas-source rock. According to the geological-geochemical data from the latest drilling wells, Lingshui, Baodao, Changchang Sags have good hydrocarbon-generating potentials, where two plays from the Paleogene and Neogene reservoirs were developed. Those reservoirs occur in central canyon structural-lithologic trap zone, Changchang marginal trap zone and southern fault terrace of Baodao Sag. Among them, the central canyon trap zone has a great potential for exploration because the various reservoirforming elements are well developed, i.e., good coal-measure source rocks, sufficient reservoirs from the Neogene turbidity sandstone and submarine fan, faults connecting source rock and reservoirs, effective vertical migration, late stage aggregation and favorable structural–lithological composite trapping. These study results provide an important scientific basis for hydrocarbon exploration in this region, evidenced by the recent discovery of the significant commercial LS-A gas field in the central canyon of the Lingshui Sag.

Evolution of deepwater sedimentary environments and its implication for hydrocarbon exploration in Qiongdongnan Basin, northwestern South China Sea

Over the past several years, a number of hydrocarbon reservoirs have been discovered in the deepwater area of Qiongdongnan Basin, northwestern South China Sea. These oil/gas fields demonstrate that the evolution of the deepwater sedimentary environment are controlling the formation and distribution of large-scale clastic reservoirs. Integration between seismic and borehole data were necessary to best clarify the distribution and quality of these deepwater reservoirs. Geochemical and paleobiological evidence from discrete samples was also applied to document specific information regarding the sedimentary environment. Results show that the Qiongdongnan Basin has existed as a thriving marine environment since Oligocene, when several rifting depressions developed throughout the entire Qiongdongnan Basin. Triggered by the faults activities, several distinct provenances supplied the coarse sediments, transporting and depositing them in deep parts of the rifting depressions. A fan delta system then formed nearby the source in the deeper area of these rifting depressions. The sedimentary environment of Qiongdongnan gradiationally became deepwater since early Miocene. Consequently, abundances of sediments were transported from Hainan Island and Southern Uplift, and then sunk into the basin center. The submarine fans revealed by many boreholes in this area verified them as good reservoir. Because the area reached its lowest sea level at late Miocene and the Southern Uplift subsidenced under sea level, not providing any sediment, so that the carbonate mesa and biorhythms characteristic of this area also developed during this period. In the west part of Qiongdongnan Basin, sediments transported from Vietnam increased in response to the Tibetan Uplift. Consequently, a central canyon developed along the center of Qiongdongnan Basin, which has been confirmed by several boreholes as a favorable hydrocarbon reservoir. The clarification of the deepwater sedimentary environment’s evolution is potentially highly beneficial to future hydrocarbon exploration in the deepwater area of Qiongdongnan Basin.