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Mountain glaciers are one of the most sensitive indicators of climate change. Reconstructing past glacier extents provides valuable insights into the climate change for specific regions where instrumental records are not enough and even absent. In the paper we mapped the outlines for 691 Little Ice Age (LIA) glaciers in terms of prominent moraines beyond contemporary glaciers in the Tanggula Mountains, central Tibetan Plateau (TP). Based on these glacier outlines, we reconstructed the ice thicknesses and surfaces for the LIA glaciers in the region. Accordingly, we calculated the equilibrium-line altitudes (ELAs) for contemporary and LIA glaciers. By comparing the ELAs between the contemporary and LIA glaciers, we estimated the LIA summer temperature decreases in different subregions of the Tanggula Mountains. Since the LIA, the ELA have risen by 35.6 ± 18.8 m, 26.1 ± 17.6 m, and 63.1 ± 38.6 m in the respective western, central, and eastern subregions of the Tanggula Mountains. Assuming no change in precipitation, the LIA summer temperature would decrease by 0.22 ± 0.12 °C, 0.14 ± 0.09 °C, and 0.34 ± 0.21 °C in the three subregions, respectively. Moreover, glaciers in the western, central, and eastern subregions have lost 13.3%, 23.9%, and 42.8% of their area, 15.4%, 25.3%, and 39.6% of their length, and 20.8%, 39.0%, and 61.0% of their volume, respectively. By compiling the LIA ELA data from previous studies, we also estimated the LIA summer temperature changes for other regions of the TP. The LIA ELA and summer temperature changes relative to the present showed a decreasing trend from the edges towards the interior on the TP. • LIA glaciers and summer climate were reconstructed at the Tanggula Mountains. • LIA summers were 0.22 ± 0.12 °C, 0.14 ± 0.09 °C, and 0.34 ± 0.21 °C cooler than present in three subregions. • Summer temperature change had a decreasing trend from the edges towards the interior on the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The early Aptian oceanic anoxic event (OAE 1a) is well known in the western Tethys, the North Atlantic and the Pacific Ocean, but has not been reported in the eastern Tethys to date. In this paper, we present bulk organic carbon isotope data and ammonite biostratigraphy of a lower Aptian succession from the Gucuo area (southern Tibet). These findings document the occurrence of the OAE 1a for the first time from the eastern Tethys. The studied sequence can be attributed to the D. forbesi and D. deshayesi ammonite zones of the lower Aptian. The δ 13 C org data can be correlated with published early Aptian carbon isotope records from the western Tethys and the Pacific. A distinctive negative carbon isotope excursion of 2.4‰ in the upper part of the section corresponds to segment C3 of the OAE 1a, and the following positive excursion correlates to segment C4. The absolute values of the carbon isotope ratio in the Gucuo area are higher than those of known sections in the western Tethys and equatorial Pacific. We suggest that diagenetic alteration is the major cause of the higher absolute values in the Gucuo area. [ABSTRACT FROM AUTHOR]

Studies of geochemical proxies, such as carbonate δ18O and TEX 86 , show that the Earth's climate has changed significantly during the Cretaceous Period. However, knowledge about the sea surface temperature (SST) history of the eastern Tethys is limited. Based on the calcareous nannofossil record of the Nirang section, Tethys Himalayas, this paper attempts to establish the biostratigraphic framework and SST evolution of the Cretaceous Period in the southern Tibet. A total of 131 species were identified from the studied succession. Twelve bioevents were recognized, allowing for early Albian to the early Campanian (CC8 to CC18 biozones) in the section. Meanwhile, a disconformity within 81–71 Ma was also identified. The SST evolution was analysed by the calcareous nannofossils modified temperature index (mTI), and the results reveal that the long-term SST changes in the Tethys Himalayas of southern Tibet experienced progressive warming from the early Albian to the early Turonian and the warm interval persisted until the early Campanian. Short-term warming and cooling events, e.g., rapid warming in the early and late Albian, subsequent cooling in the latest Albian and peak warmth at the Cenomanian–Turonian transition, are also recorded in the study area. The SST history of the Albian-Cenomanian in the eastern Tethys can be well correlated to the western Tethys (central Italy). However, the compilation of TEX 86 data indicates substantial global cooling during the Coniacian to Campanian. This study suggests that the northward drift of the Indian continent towards the equator is likely to be responsible for the sustained warmth in the Tethys Himalayas from the middle Turonian to the early Campanian. • Calcareous nannofossil biozones of Albian-early Campanian in Tethys Himalaya of southern Tibet is defined. • Based on mTI of nannofossils, long term history of Cretaceous palaeoclimate of eastern Tethys is reconstructed. • The SST history in Tethys Himalaya is controlled by changes of global palaeotemperature and regional palaeolatitude. [ABSTRACT FROM AUTHOR]

In this paper, we examine the Early to Middle Holocene evolution of a prominent group of ground-water fed lakes in the southeastern hinterland of the Badain Jaran Desert (BJD) of northwest China. Specifically, we describe a sediment profile record from the Taoerlegetu (TR) palaeolake basin using multiple proxies of total organic carbon (TOC), total nitrogen (TN), C/N ratio, δ13C org , grain size and mineral composition based on a well-dated trench profile. As C/N values suggest that sedimentary organic matter mainly originated from aquatic plants, δ13Corg values can be used as a qualitative proxy for water level because aquatic plants in different biotopes (water depth) have different δ13C values. Our results show that from 10.9 to 9.1 cal kyr B.P., water level rose slowly, and aquatic macrophytes occupied the lake basin. From 9.1 to 5.5 cal kyr B.P., water level reached an even higher level and phytoplankton replaced macrophytes as the major contributor to organic matter. The humid episode of the lakes in the hinterland of the BJD in the early Holocene might be related to the increased groundwater supply from the northeast region of the Tibet Plateau. These findings are consistent with earlier studies of lacustrine and peat sediments found in periphery of the modern lake group, which indicate that their geographic extent may have been larger in the past. A relative drought period recorded in the studied succession from 8.5 to 8.0 cal kyr B.P. marks an interval of reduced ground-water transport from the Tibet Plateau. This interval probably corresponds to the "8.2 ka cold event" and provides evidence that this widespread climate episode influenced groundwater processes across inland Asia. • The δ13C org value could be used as a qualitative indicator for the change of water level. • Lakes in the hinterland of the Badain Jaran Desert shows different evolution progress with these in the edge. • The main water source of lakes in the hinterland of the BJD in the Early Holocene comes from the Tibet Plateau. [ABSTRACT FROM AUTHOR]

The uplift of the Tibetan Plateau has been widely associated with India-Asia continental collision during the Cenozoic. However, recent studies have proposed that a proto-Tibetan Plateau in central Tibet was elevated during the late Mesozoic. This paper improves that understanding by focusing on the Cretaceous terrestrial strata in the Gerze area of central Tibet. Our studies suggest that the Qushenla Formation in the Nare area contains alluvial fan conglomerate intercalated with rhyolitic ignimbrite and vesicular rhyolite. Zircon U Pb dating of rhyolitic ignimbrite (103.9 ± 1.4 Ma) and two granitoid boulders of conglomerate (106.0 ± 1.6 and 106.1 ± 1.5) indicate that the Qushenla Formation was deposited during the late Albian. The compositions of the Qushenla Formation conglomerate were dominated by hypabyssal intrusions on the southern Qiangtang terrane, which recorded a rapid uplift and denudation process in the late Albian, accompanied by intense volcanic eruptions. The second set of terrestrial strata is the Upper Cretaceous Jingzhushan Formation alluvial fan-braided river deposits, which can be divided into a lower conglomerate member (Member 1) and a upper sandstone member (Member 2). The large amount of bioclastic limestone fragments in the Member 1 show that they come from the Upper Cretaceous Langshan Formation in the central and northern Lhasa subterranes. While in the Member 2, abundant limestone debris, detrital zircon yielding Jurassic–Cretaceous ages with ε Hf (t) values between −18.6 and + 8.4, and occurrence of volcanic and ancient zircon grains indicate a volcanic-sedimentary source located in the central and northern Lhasa subterranes, with some input from the Bangong-Nujiang suture zone. This suggests that the central and northern Lhasa subterranes experienced rapid crustal uplift in the Late Cretaceous, thus ending the marine sedimentary environment since the Jurassic. Based on the temporal and spatial sedimentary characteristics of the Qushenla and Jingzhushan formations as well as the regional data, our integrated study suggests that the central plateau (Lhasa and southern Qiangtang terranes) experienced a complex uplift history during the Aptian-Turonian, with southwards stepwise growth in time and space. Furthermore, the uplift mechanism of the central plateau is complex, which was controlled by the diachronous closure of the Bangong-Nujiang Tethyan Ocean from east to west during the Early Cretaceous, and by the far-field forces associated with northwards subduction of the Neo-Tethys Ocean during the Late Cretaceous. [Display omitted] • There are two sets of Cretaceous terrestrial strata in the Gerze area. • Gerze area had a residual sea retreat southwards during Aptian-Turonian. • Central Tibet experienced a dual diachronic uplift of E–W and N S in Aptian-Cenomanian • We suggest that the early uplift process of central Tibet was phased. [ABSTRACT FROM AUTHOR]

Reconstructing the evolution of the Sumdo Paleo-Tethyan Ocean (SPTO) is important for understanding the transition from the Paleo-Tethyan system to the Neo-Tethyan system. The existence of the SPTO is inferred from the presence of an (ultra-)high pressure metamorphic belt and dismembered ophiolite bodies that separate the southern Lhasa and northern Lhasa terrane. This paper presents new geochronological and geochemical data for the Luobadui Formation in the Lhasa terrane. The geochemical difference between the Lower Luobadui volcanics and the Upper Luobadui volcanics suggests a source transition from a depleted mantle source to an enriched mantle source, which indicates continental-arc subduction. The integrated geological evidence suggests that the SPTO initially opened during the late Carboniferous (ca. 304 Ma), as verified by the earliest record of oceanic crust. Our new data for the Luobadui volcanic rocks, together with the metamorphic and sedimentary records, support northward subduction of the SPTO lithosphere beneath North Lhasa, most likely starting during the Early Permian (ca. 275 Ma) and lasting until the Middle Permian (ca. 260 Ma). The main closure of the SPTO occurred during Middle–Late Triassic (ca. 240–220 Ma), as recorded by medium-pressure metamorphism and syn -collisional magmatism. The Wilson cycle of the SPTO is hereby reconstructed, providing significant insights into the amalgamation of the Tibetan Plateau. • The arc volcanic rocks from Luobadui Formation formed mainly during 275–260 Ma. • The Luobadui sedimentary detritus was sourced from the Lhasa terrane. • The Wilson cycle of the Sumdo Paleo-Tethys Ocean was reconstructed. [ABSTRACT FROM AUTHOR]

The Wenbudangsang section is a newly discovered continuous succession of marine carbonates that straddles the Permian–Triassic boundary (PTB), extending from the late Permian to the earliest Triassic (Induan). The section is located in the Wenbudangsang area of Geji County, northern Tibet, and tectonically sits within the northern Gangdise Stratigraphic division. Conodonts are abundant throughout this section, except being comparatively rare and less diverse in the Permian strata below the distinctive PTB Clay Bed. The conodonts are mainly represented by Hindeodus–Isarcicella Pa elements, Neogondolella Pa elements, and ramiform elements, with few Neospathodus Pa elements present at the top of the section. Two conodont zonal successions have thus been determined based on Hindeodus–Isarcicella and Neogondolella species. The Hindeodus–Isarcicella succession includes the uppermost Permian Hindeodus julfensis Zone, Hindeodus praeparvus Zone, and the lowermost Triassic Hindeodus parvus Zone, Isarcicella staeschei Zone, Isarcicella isarcica Zone, and Hindeodus postparvus Zone. The Neogondolella succession consists of the upper Permian Neogondolella changxingensis–Neogondolella deflecta–Neogondolella postwangi Zone, Neogondolella yini–Neogondolella zhangi Zone, Neogondolella meishanensis Zone, the Neogondolella taylorae Zone that crosses the PTB, and the lowermost Triassic Neogondolella krystyni Zone and Neogondolella prediscreta n. sp. Zone. The top of the section is defined by the Neospathodus kummeli Zone and Neospathodus cristagalli Zone. Two new species, Hindeodus microdentatus n. sp. and N. prediscreta n. sp., are established and described in this paper. The PTB conodont successions recognised in the new Wenbudangsang section have been closely correlated herein with other well-known PTB sections: the GSSP Meishan section of South China, sections in Abadeh in Iran, and sections at Spiti in India. Importantly, the conodont faunas from Wenbudangsang now provide an opportunity to effectively correlate the PTB hindeodid and gondolellid zonal schemes given the high abundance of both assemblages, which is unique to this section. [ABSTRACT FROM AUTHOR]

The Silurian conodont biozonation has been well established in many areas of the world, but not yet in China. The Nyalam region of southern Xizang (Tibet) is one of the best locations for studying Silurian conodonts in China. In this paper, we establish five conodont biozonal units from the Pulu Formation: the Ozarkodina sagitta sagitta Biozone, the Kockelella crassa Biozone, the Kockelella variabilis variabilis – Ancoradella ploeckensis Zonal Group, the Polygnathoides siluricus Biozone, and the " Ozarkodina " eosteinhornensis s.l. interval Biozone. We assign the Pulu Formation to the Llandovery (upper Telychian) to Pridoli stages based on the conodonts as well as the graptolites from underlying strata. The Silurian conodont species in the Nyalam region are widely distributed in the strata from the Laurussia and Gondwana, which indicates the cosmopolitan characteristic of the conodont fauna from the Wenlock to Pridoli epochs was caused by the circulation of ocean currents. • Five conodont biozonal units from Wenlock to Pridoli were identified in the Nyalam region. • Pulu Formation in the Nyalam region is Telychian to Pridoli in age. • Silurian conodont fauna in the Nyalam region have a cosmopolitan characteristic. [ABSTRACT FROM AUTHOR]

Abstract: Long-term high-resolution climate proxies are essential for understanding climate variability on the Tibetan Plateau (TP), where few long-term climate records are available. In this paper, we describe a summer (August) temperature reconstruction over the period 1385–2002 based on a tree-ring width chronology of Balfour spruce (Picea likiangensis var. balfouriana) on the southeastern TP created using the Regional Curve Standardization method. The reconstruction explains 44.7% of the variance in the instrumental temperature records during the calibration period (1962–2002), and captures temperature variability over a broad region of the TP. Warmer than average Augusts were found during the periods 1446–1494, 1509–1522, 1553–1567, 1797–1812, 1845–1905 and 1918–2002. Cooler than average Augusts occurred from 1385–1416, 1426–1445, 1495–1508, 1523–1552, 1568–1686, 1695–1718, 1725–1796, 1813–1844 and 1906–1917. A warming trend in the 20th century was unprecedented during the past six centuries. The reconstruction closely matched other tree-ring summer temperature reconstructions from neighboring regions, as well as patterns from ice-core δ18O data, and fluctuated in synchrony with Northern Hemisphere temperature reconstructions. [Copyright &y& Elsevier]

The paleogeographic evolution of the Lhasa Block in northern Tibet during the Permian has been a contentious issue during the past decades. Several pioneering studies have highlighted the significance of faunas and their paleobiogeography in this block. In this paper, a new Middle Permian foraminiferal fauna is documented from the Xiala Formation in the Zhabuye area in the central Lhasa Block. This fauna is characterized by the presence of the Shanita - Hemigordiopsis foraminiferal assemblage, with its age to be the early Midian (Wordian) based on the coexisting fusulines Neoschwagerina craticulifera (Schwager), N. cheni Sheng and Kahlerina tenuitheca Wang, Sheng and Zhang. A review of the Shanita - Hemigordiopsis assemblage globally confirms that the age of this assemblage ranges from the late Murgabian to the Midian rather than extending into the Dzhulfian as previously recognized. This assemblage is widely distributed on the Cimmerian microcontinents and Gondwanan margin, but absent from the South China and Indochina blocks, which were approximately at the same latitude with Turkey in equatorial regions. Such a distribution pattern is better explained by the influence of oceanic currents flowing from equatorial regions to the Gondwanan margin along the Neotethys Ocean. It further suggests that the Neotethys Ocean may have opened by the Middle Permian to facilitate oceanic currents. • The age of Shanita-Hemigordiopsis foraminiferal assemblage is Middle Permian. • The distribution of Shanita is controlled by oceanic currents along Neotethys Ocean. • The Neotethys Ocean opened before the Middle Permian. [ABSTRACT FROM AUTHOR]

In this paper, we review evidence for a major biotic turnover across the Oligocene/Miocene in the Tibetan Plateau region. Based on the recent study of six well-preserved fossil sites from the Cenozoic Lunpola and Nima basins in the central Tibetan Plateau, we report a regional changeover from tropical/subtropical ecosystems in the Late Oligocene ecosystem (26–24 Ma) to a cooler, alpine biota of the Early Miocene (23–18 Ma). The Late Oligocene fossil biota, comprising of fish (climbing perch), insects and plants (palms), shows that the hinterland of the Tibetan Plateau was a warm lowland influenced by tropical humidity from the Indian Ocean. In the Early Miocene, the regional biota became transformed, with the evolution and diversification of the endemic primitive snow carp. Early Miocene vegetation was dominated by temperate broad-leaved forest with abundant conifers and herbs under a cool climate, and mammals included the hornless rhinoceros, Plesiaceratherium , a warm temperate taxon. This dramatic ecosystem change is due to a cooling linked to the uplift of Tibetan region, from a Late Oligocene paleo-elevation of no greater than 2300 m a.s.l. in the sedimentary basin to a paleo-elevation of about 3000 m a.s.l. Another factor was the Cenozoic global climatic deterioration toward to an ice-house world. • The Tibetan uplift had a profound impact on the evolution of terrestrial ecosystems. • The Oligocene subtropical ecosystem was replaced by a Miocene cooler biota in Tibet. • The Late Oligocene biota showed that the Tibetan hinterland was a warm lowland. • The Early Miocene biota eventually culminated in the present ecosystem of Tibet. • This dramatic ecosystem change is due to the cooling effect of the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The Lhasa Terrane of Tibet is critical to understanding Early Triassic crustal convergence of Gondwana and Eurasia. However, its palaeo-position during this period remains obscure. This paper considers the disputed tectonic nature of the Lhasa Terrane during Triassic time. The debate has taken the form of two schools of thought regarding the Lhasa Terrane. One holds that the terrane was a stable carbonate platform during Triassic time. The opposing view maintains that the Lhasa Terrane occupied a compressional orogenic belt. These contrasting explanations stem mainly from the absence of a sedimentary record, especially in the southern part of the Lhasa Terrane of Tibet. We report on results of a biostratigraphic investigation of a dolomite unit considered to be of Guadalupian age in the Comai area, southern Lhasa Terrane. This work yielded the ellisonid conodont species Pachycladina rendona n. sp. Wu and Ji suggesting an Early Triassic age and a low latitude depositional setting of the dolomite. Further, these findings favor correlation of the dolomite with the upper member of the Upper Permian to Lower Triassic Mujiuco Formation. Results of the present study, especially the newly collected Pachycladina fauna, suggest that the Lhasa Terrane was an element of a low-latitude carbonate platform that had separated from Gondwana during the Early Triassic. It is hoped that our findings will promote further research of the Triassic sedimentary history and paleogeographic evolution of the Lhasa Terrane. • The ellisonid Pachycladina fauna has been recovered from the southern Lhasa Terrane. • The Pachycladina fauna places the Lhasa Terrane at low latitude during the Induan. • The western Lhasa Terrane was a carbonate platform setting during the Early Triassic. [ABSTRACT FROM AUTHOR]