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This paper presents a quantitative study of dinoflagellate cysts (dinocysts) and palynofacies of the Campanian–Danian marly succession at the village of Tattofte (western External Rif, northwestern Morocco). The paleoenvironmental and paleoclimatic interpretations, inferred from this palynologic analysis, are compared to coeval sequences of other areas in the Northern Hemisphere. Changes in the relative abundances of dinocyst taxa, which are paleoenvironmental indicators, throughout the section suggest a deposition in a marine inner to outer neritic setting. The upper Campanian dinocyst assemblage is characterized by the presence of outer neritic-oceanic and low productivity indicator taxa (e.g., Spiniferites spp., Odontochitina spp.) and cold-water taxa (e.g., Manumiella spp., Chantangiella spp., Laciniadinium spp.), whereas, the lower Maastrichtian assemblage is characterized by inner neritic, high productivity and warm-water indicator taxa (e.g., Palaeocystodinium spp., Andalusiella spp.). The upper Maastrichtian dinocyst assemblage displays a return to an outer neritic environment under a transgressive regime, but with a cooling pulse and a moderate productivity. However, the Cretaceous–Paleogene (K/Pg) boundary interval records remarkable changes in the relative abundances of dinocyst taxa, indicating an inner neritic (coastal) setting, which is the most proximal in the study section; such changes reflect instable paleoenvironmental conditions which may be related to global cooling periods, likely caused by the Deccan volcanism in India and/or the Chicxulub asteroid impact in Mexico at the K/Pg boundary. In the Danian, the dinocyst relative abundances indicate a gradual return to stable environmental conditions. A quantitative analysis of the kerogen plots (palynomorphs, phytoclasts and amorphous organic matter (AOM)) reveals five types of palynofacies, generally indicating oxic to suboxic marine environments. The upper Campanian and upper Maastrichtian (lowermost part) strata are characterized by a playnofacies (V), indicating a distal shelf, while the lower Maastrichtian and lower Danian (uppermost part) strata record a playnofacies (III), reflecting an intermediate inner-outer neritic environment. However, the K/Pg boundary transition is characterized by playnofacies types (I) and (II), indicating a proximal (coastal) environment.

New palaeogeographical reconstructions for the earlier Ordovician (480 Ma), and later Ordovician (450 Ma) integrate revised longitude-calibrated palaeomagnetic reconstructions and the inclusion of synthetic plate margins within the now-vanished oceanic areas. There are substantial published differences from the previous placing of some of the continents and terranes in Asia; for example, Siberia and Gondwana have previously been placed at varied distances and relative positions in relation to the Kazakh terranes, South and North China, and Tarim. But there are only minor changes for most of the world, particularly in the North American and European areas. The global distributions of benthic trilobites and brachiopods within faunal provinces and their changes through the Ordovician are plotted, including the new term Cathay-Tasman Province for some pan-equatorial brachiopod faunas from China and Australia, and key sites and provinces are shown on the revised maps. The 30 Myrs from 470 to 440 Ma (mid Ordovician to early Silurian) saw some of the most varied and changeable climates of the whole Phanerozoic culminating in the ‘Hirnantian’ ice age. Those changes in turn much affected the rates of evolution of many benthic and pelagic animal groups which were driven by both biological and environmental causes. Global cooling during the Ordovician was a prime factor by reducing sea surface temperatures which challenged life to evolve faster and more substantially than before. That cooling was driven by decreasing atmospheric CO2, for reasons that are not fully resolved, but probably included reduced sourcing (reduced continental arc activity) combined with increased silicate weathering due to the advent of land plants and perhaps the progressive exhumation of low-latitude collisional arcs. Since long-term CO2 sinks are largely controlled by palaeogeography, the general increase in the concentration of continents in the tropics during the Ordovician increased the overall global weathering.

Extant snake faunas have their origins in the mid-Cenozoic, when colubroids replaced booid-grade snakes as the dominant species. The timing of this faunal changeover in North America and Europe based on fossils is thought to have occurred in the early Neogene, after a period of global cooling opened environments and made them suitable for more active predators. However, new fossils from the late Oligocene of Tanzania have revealed an early colubroid-dominated fauna in Africa suggesting a different pattern of faunal turnover there. Additionally, molecular divergence times suggest colubroid diversification began sometime in the Paleogene, although the exact timing and driving forces behind the diversification are not clear. Here we present the first fossil snake referred to the African clade Lamprophiinae, and the oldest fossil known of Lamprophiidae. As such, this specimen provides the only potential fossil calibration point for the African snake radiation represented by Lamprophiidae, and is the oldest snake referred to Elapoidea. A molecular clock analysis using this and other previously reported fossils as calibration points reveals colubroid diversification minimally occurred in the earliest Paleogene, although a Cretaceous origin cannot be excluded. The elapoid and colubrid lineages diverged during the period of global warming near the Paleocene-Eocene boundary, with both clades diversifying beginning in the early Eocene (proximate to the Early Eocene Climate Optimum) and continuing into the cooler Miocene. The majority of subclades diverge well before the appearance of colubroid dominance in the fossil record. These results suggest an earlier diversification of colubroids than generally previously thought, with hypothesized origins of these clades in Asia and Africa where the fossil record is relatively poorly known. Further work in these regions may provide new insights into the timing of, and environmental influences contributing to, the rise of colubroid snakes.

A comprehensive understanding of the Neogene paleoenvironmental evolution of Central Asia is important for predicting the future climatic and environmental conditions within the region. However, our understanding of the relative roles of Tibetan Plateau (TP) uplift and global cooling in driving its paleoenvironmental evolution remain elusive. Here we present two well-dated (~16–5 Ma) independent environmental magnetic records from the northern TP, together with a comprehensive analysis of other well-dated Neogene environmental magnetic datasets for ten other sites from the northern TP. The results indicate synchronous changes in magnetic parameters which we interpret as reflecting a major environmental transition in Central Asia at ~11–9 Ma, which is supported by evidence from multiple independent paleoecological and paleoclimatic studies. A major environmental transition at 11–9 Ma is also supported by the results of linear and non-linear analyses of the magnetic records of the two studied sections. Our analyses reveal that prior to ~11 Ma, the environmental fluctuations within the QB were primarily driven by insolation variations modulated by Earth orbital parameters; however, after ~11 Ma this influence faded and there was a shift from a stable environmental system, characterized by periodic fluctuations, to an unstable system with erratic fluctuations. The timing of this phase shift in the paleoenvironment of Central Asia was not related to global cooling but it coincided with extensive tectonic activity in the TP. Together with conceptual models and previous numerical simulations results, we conclude that a major shift of the dominant driver of Central Asia paleoenvironment occurred at ~11–9 Ma and that uplift of the TP, rather than global cooling, was responsible.

The ~74 ka Toba super-eruption was the largest known explosive volcanic event of the past 2.5 million years and has been held responsible for presumed dramatic global cooling and large-scale hominin extinction. The hypothesis that the Toba super-eruption resulted in human extinction outside of tropical Africa has been cited as a mechanism to support models of a Middle Pleistocene African origin for modern humans. This hypothesis has prevailed for decades and drawn the attention of researchers from many fields. Recently, this proposition has been debated or refuted because of the development of more precise dating techniques and higher-resolution geological records that provide new data to reevaluate the climatic influence of the Toba event. Relevant archaeological evidence also indicates the survival of hominin groups in Eurasia immediately after the Toba event, even in India and Sumatra, which were covered by thick deposits of volcanic ash. Here, we correlate high-resolution geological records with the most precise available ages for the Toba event (ca. 74 ka), including ice cores, stalagmites, and lake and deep-sea sediments, concluding only limited influence of the Toba super-eruption on the Earth's climate. We also assemble archaeological data demonstrating continuity of human activity before and after the Toba event, ancient DNA and fossil evidences also testify the survival of other archaic humans after the eruption. The preponderance of the evidence dictates rejection of previous “population bottleneck” hypotheses and the total replacement model for the origins of modern humans. Although the Toba super-eruption was the largest such event of the Quaternary period, it did not have a devastating impact on the Earth's climate and human activity.

Study of clay mineral is one of effective methods for reconstruction of the paleoclimate and paleoenvironment. Here we represent clay mineral records from an upper Miocene–Pliocene red clay succession in the central Chinese Loess Plateau (CLP). On the basis of the existing age model, we employ X-ray diffraction and scanning electron microscopy to carry out clay mineral analyses, the results indicated that illite was the dominant clay mineral and the contents of smectite, chlorite and kaolinite were minor. From the analysis of contents of clay minerals, illite crystallinity, illite 5 A/10 A, smectite/(illite+chlorite) ratio, magnetic susceptibility, summer monsoon intensity and deep-sea δ18O values, the paleoclimatic evolution between 7.5 and 2.6 Ma can be divided into three intervals: interval I, from 7.5 to 6.9 Ma, it was cool and dry; interval II, from 6.9 to 4.1 Ma, was cool-warm oscillations; interval III, from 4.1 to 2.6 Ma, was significantly warm and humid stage of the seasonal climate conditions. The proxy records display a large amplitude transition in the later interval III, from 2.8 to 2.6 Ma, which implied an abrupt climate and environment variability. Through comparison the local and global paleoclimatic records, we found that clay minerals reflect regional paleoclimatic change superimposing global climatic records during the late Miocene–Pliocene period. We conclude that the regional tectonic activity and global cooling had affected East Asia Monsoon, which was characterized by the different temperature and precipitation in the central CLP.

Beach ridges and spits along the north-facing coast of the Chukchi Sea record paleo-storm history during the 1st millennium AD, correlative with a widespread global cooling climate episode. Northwest Alaska is a sensitive proxy owing to its absence of tectonism, glacio-isostasy, and a low rate of eustatic sea level rise. Four locales provide a regional transect and detailed chronologies: north-facing Deering and Cape Espenberg and west-facing Kotzebue and southwest facing Point Barrow. A single storm or series of storms during AD 400–600 impacted both north and south areas, while lesser intensity storms occurred across the southern region during the 11th century AD. The first millennium AD storms were as strong as or stronger than those of the 20th century, if paleo-sea level is factored in. Storm-heightened upwelling had a salubrious effect on cultures around the Chukchi Sea, leading to a florescence of whaling and walrusing.

Early Paleogene neodymium (Nd) isotopic reconstructions of ocean circulation in the Pacific suggest a bipolar mode of overturning circulation characterized by convection of deep-water masses from 70 to at least 40 Ma. This mode is fundamentally different from the “sluggish, diffusive” mode that characterizes the modern North Pacific. Therefore, major reorganization of Pacific circulation must have occurred between 40 Ma and the modern. To investigate the potential timing of such a reorganization, we present new Nd isotope data from drill sites spanning 40 to 10 Ma. Here, we use Nd isotopic analyses to identify the sources of dissolved Nd to the Pacific in order to evaluate the application of the Nd proxy for ancient water mass composition. We combine analyses of fossil fish debris, sequentially leached oxide coatings and leach residues to further refine our understanding of Nd marine geochemical cycling and to contribute new constraints on the paleoceanographic history of the Pacific. Overall, these data support previous interpretations of the convection of deep water in the Pacific sector of the Southern Ocean and surface-ventilated North Pacific Deep Water formation from ∼70 to 40 Ma. The new Nd isotope data suggest a gradual transition between 36 and 25 Ma, a time period characterized by global cooling. This transition consists of a change from North Pacific Nd isotopic signatures controlled by convection and water mass mixing to values heavily influenced by overprinting from other sources of Nd to the deep Pacific. Such a transition is consistent with a change in overturning circulation from a “Paleogene mode” to a mode dominated by sluggish diffusive mixing. After 25 Ma the data indicate a significant contribution of radiogenic dissolved Nd to the deep waters of the North Pacific. The most likely source of radiogenic dissolved Nd would have been labile volcanic ash that altered the composition of the water mass as it slowly advected through the North Pacific. A slowing of overturning circulation in the North Pacific could have resulted in diminished poleward heat transport, increasing equator to pole thermal gradients and contributing to a cooling global climate.

In this paper, we provide a late Miocene (Tortonian) to early Pleistocene (Gelasian) palynological record from the Eryuan Basin, Yunnan Plateau, China, to investigate plant diversity over this time. Between 7.6 and 4.3 Ma, the palynological assemblage was dominated by coniferous trees (70.2% on average), with subordinate amounts of broadleaved trees (8.8% on average). This suggests that the vegetation mainly comprised mixed forests, and that the climate was relatively warm and humid. After 4.3 Ma, the proportion of conifer pollen increased overall, and amount of cold-temperate coniferous forest Picea and Abies pollen, in particular, increased significantly (from 19.1% to 41.9%), concurrent with decreases in the pollen of broadleaved trees, shrubs, herbs, and other plant taxa. We suggest that these plant variations and overall reduced diversity may be responses to the tectonic uplift of the Yunnan Plateau and global cooling.

A large fossil leaf assemblage (>3700 specimens) is reported from the Oligocene Rio Leona Formation in the Sierra Baguales of Chilean Patagonia. The association comprises 29 species but is dominated by Nothofagus genera, which constitutes 65% of specimens. The collection can be classified as a Mixed Palaeoflora of the Austral-Antarctic association. Stratigraphic analysis of the assemblage indicates a decrease in species diversity and richness over time, which was accompanied by species turnover. Quantitative studies of foliar morphology (CLAMP, Leaf Margin Analysis) indicates cool-to-cold and dry climatic conditions, with a Mean Annual Temperature of 9.2 °C, a relatively high seasonality in temperature and precipitation, and a Mean Annual Precipitation of 931 mm. Nothofagus only became dominant in southeastern Patagonia during the Rupelian, coinciding with a marked global cooling period linked to the initiation of glaciation in Antarctica about 34 Ma. The decrease in precipitation following this event is attributed to the development of a rain shadow to the east of the rising Southern Patagonian Andes, which must have been of the order of 1000 m or more for topographic climate forcing to take effect. This contrasts with the rain shadow development east of the Andes at lower latitudes, which was mainly manifested after the middle Miocene.

Although the development of Gobi Desert in central and eastern Asia has greatly affected the regional and even the global climate, its precise origin and evolution have yet to be determined. The three preconditions for the formation of Gobi Desert are: i) a dry climate, ii) basin landforms and iii) abundant sediment production. In this study, we present a synthesis of both new and published data on the formation and evolution of Gobi Desert in central and eastern Asia. We conclude that the combined effects of mountain building, the mid-latitude westerly circulation and changes in the Asian monsoon, accompanied by global cooling, were principally responsible for the formation of modern Gobi Desert landscapes in central and eastern Asia during the late Pliocene. The arid climate in central and parts of eastern Asia probably developed in the early Cenozoic, from ~50 Ma. Related events included the collision of the Indian and Asian plates, the closure and complete retreat of the Paratethys Ocean from central Asia, and the growth of the Himalayas and the Tibetan Plateau in the Eocene through late Miocene, which blocked the water vapor supply and intensified the aridification of the Asian interior. Superimposed on the topographic changes was the process of stepwise global cooling since the early Oligocene, and in particular since the late Miocene, which controlled the formation and evolution of the Gobi Desert landscape. Global cooling weakened the Asian monsoon circulation, strengthened the westerly circulation and enhanced physical weathering processes in mountain areas, which together promoted both the aridification of the Asian interior and sediment production. These processes finally resulted in the establishment of the modern Gobi Desert landscape in the late Pliocene. We estimate that the modern Gobi Desert landscape was formed at ~2.6 Ma and was the result of the stepwise evolution of Asian topography and climate during the Cenozoic, dominated by Asian tectonic deformation and uplift, and the evolution of Asian monsoon climate and the westerly circulation, forced by global temperature change.

Little Ice Age (LIA), a time of global cooling widely manifested in the 14th-19th centuries, was characterized by worldwide expansion of mountain glaciers. Unfortunately, little is known about the LIA glacier changes in remote areas of continental Siberia. In this work we studied the evolution of the glaciers of the Kodar Range, southeast Siberia. These glaciers are mainly of small size (

Large tropical volcanic eruptions can cause short-term global cooling. However, little is known whether large tropical volcanic eruptions, like the one in Tambora/Indonesia in 1815, cause regional hydroclimatic anomalies. Using a tree-ring network of precisely dated Himalayan birch in the central Himalayas, we reconstructed variations in the regional pre-monsoon precipitation back to 1650 CE. A superposed epoch analysis indicates that the pre-monsoon regional droughts are associated with large tropical volcanic eruptions, appearing to have a strong influence on hydroclimatic conditions in the central Himalayas. In fact, the most severe drought since 1650 CE occurred after the Tambora eruption. These results suggest that dry conditions prior to monsoon in the central Himalayas were associated with explosive tropical volcanism. Prolonged La Nina events also correspond with persistent pre-monsoon droughts in the central Himalayas. Our results provide evidence that large tropical volcanic eruptions most likely induced severe droughts prior to monsoon in the central Himalayas.

Earth's climate transitioned from the greenhouse conditions of the Eocene to the icehouse of the Oligocene ∼34 million years ago. Global cooling was triggered by a decrease in atmospheric pCO2 and is associated with the first appearance of large, permanent ice-sheets on Antarctica. The Eocene–Oligocene transition (EOT) is marked by a large two-step increase in the δ 18 O of benthic foraminifera, reflecting a combination of cooler global temperatures and continental ice growth. We measured the hydrogen isotope composition of hydrated volcanic glasses deposited in Patagonia during the EOT to reconstruct stable isotope hydrology and associated changes in temperature during this critical climate transition. These data show changes in stable hydrogen isotope ratios that are consistent with Patagonian terrestrial mean annual temperature decreasing by ∼5 °C during the EOT before returning to 2 °C below pre-EOT values by the Early Oligocene. This is approximately synchronous with Northern Hemisphere cooling during the EOT, and indicates close coupling of temperature and atmospheric pCO2.

The Hetao region of China is noted for research on ancient humans. However, a lack of detailed records of vegetation and climate changes in this region has hindered understanding of human dispersal. We reconstructed the vegetation and climate changes during the last Pleistocene using pollen records from a continuous lacustrine sediment section in the Hetao Basin. The vegetation type was forest-steppe dominated by Pinus and Artemisia during the last interglacial periods. During the last glacial periods, the vegetation shifted to a Chenopodiaceae – Artemisia desert steppe with an Artemesia steppe between 44 and 34 ka BP. The steppe ecosystem, in the Hetao region during milder periods of the last glacial, was suitable for herbivores that may have provided sufficient prey for ancient humans. The vegetation changes indicate an altered climate characterized by colder and drier conditions that were probably influenced by global cooling and a decline of northern insolation variations from the last interglacial to glacial periods.

The Eocene is an enigmatic and interesting period due to the critical thermal events that occurred during the gradual global cooling, which have been demonstrated in the marine realm but remain poorly reported in terrestrial basins. In this study, a continuous ~404-m interval of the Middle Eocene terrestrial succession in Bohai Bay Basin, eastern China, was recovered from Well Fanye-1 in the Shengli Oilfield. This interval provides a unique record that can be used to better clarify the terrestrial sedimentary responses to astronomically forced climate changes, especially the Middle Eocene Climatic Optimum (MECO). Here, a high-resolution cyclostratigraphic framework from the lower third member (Es3l) to the upper fourth chun member (Es4cu) of the Shahejie Formation (Middle Eocene) was constructed by using magnetic susceptibility (MS) as a palaeoenvironmental proxy, in association with new paleomagnetic data. Power spectral analysis of the MS series reveal that the wavelength ratios of stratigraphic cycles are ~43.1–25:15.3–7.5:4.5–3:2.2–1.4, consistent with the period ratios of astronomical cycles. Moreover, a high-resolution astronomical time scale (ATS) for Well Fanye-1 was established by tuning the MS curves to the astronomical solution in combination with the magnetic stratigraphic framework. The method for establishing a high-resolution ATS with magnetostratigraphy and cyclostratigraphy was well applied in Well Fanye-1, making it possible to recalculate the ages in the Jiyang Depression. Finally, the terrestrial record across the MECO event was constructed and characterized based on the widespread “interbedded” argillaceous limestone. The resulting record is consistent with the time frame based on marine records and highlights the apparently primary role of the MECO event in shaping Asian paleoenvironments.

The Ordovician–Silurian (O–S) transition was a period of dramatic climatic, environmental, and biological change. Numerous studies have documented the Late Ordovician glacial or mass extinction interval, but the Early Silurian has received significantly less attention. This study presents a U-Pb zircon age data and organic carbon isotope (δ13Corg) records from the Upper Ordovician to Lower Silurian succession of South China to better constrain carbon isotope perturbations and to evaluate their possible causes and relationships to paleoenvironmental change during Early Silurian time. A volcanic ash bed located at the top of the organic-rich Lower Silurian Longmaxi Formation yields a 206Pb/238U zircon age of 440 ± 3 Ma (MSWD = 1.4), which is consistent with the Rhuddanian–Aeronian (R–A) boundary age. The newly acquired age is similar to that documented an ash bed in Scotland (439.57 ± 1.13 Ma) perhaps indicating synchronous volcanism. The δ13Corg values show a negative excursion in the organic-rich lower Longmaxi Formation that is interrupted by a positive excursion in the organic-lean upper part of the unit. The positive excursion begins immediately above the dated ash bed thus assigning it to the R–A boundary. The documented δ13Corg trend is comparable to those of other sections throughout the world, and is suggestive of a global perturbation of carbon cycle. The negative δ13Corg excursion of the Rhuddanian stage was coeval with deposition of organic-rich shale under anoxic/euxinic conditions, whereas the subsequent positive δ13Corg excursion coincided with a change to suboxic conditions that could have diminished organic matter preservation. We propose that the negative δ13Corg excursion could be considered as the defining isotopic characteristic of the Rhuddanian oceanic anoxic event (Rhuddanian OAE). Results of the present study in tandem with published age data from the Guanyinqiao Bed immediately below the base of the Longmaxi Formation suggest that the negative δ13Corg excursion and associated Rhuddanian OAE persisted for approximately 3 Myr. This relatively long-lived event reflects a sustained addition of isotopically light carbon into the atmosphere-ocean system, possibly related to the release of volcanic CO2. The enhanced burial of organic carbon in association with the Rhuddanian OAE could have removed the substantial 12C from the carbon reservoir and lowered atmospheric pCO2 thus resulting in a subsequent positive δ13C excursion and global cooling at the R-A boundary.

Cenozoic basin sediments around the Tibetan Plateau are valuable archives that can be used to reveal long-term interactions among tectonics, climate and weathering. However, the reconstruction of silicate weathering histories in this tectonically active region is consistently hindered by the presence of frequently embedded conglomerate and sandstone in the long sedimentary sequences. Here, we present detailed geochemical compositions of the clay components of the sediments in the Huaitoutala section (ca. 15.3–1.8 Ma) of the northeastern Qaidam Basin to reconstruct the chemical weathering history of the catchment since the Middle Miocene. Major element ratio proxies reveal evidence of four stages of change: from ca. 15.3 to 12.6 Ma, in which the clay components are characterized by relatively high Chemical Index of Alteration (CIA) values (75–88, average = 81) but low mobile/immobile oxide ratios (e.g., K2O/Al2O3, Na2O/Al2O3 and CaO/Al2O3), thus indicating the occurrence of intense chemical weathering conditions; from ca. 12.6 to 6.6 Ma, in which decreasing CIA values, together with increasing mobile/immobile oxide ratios, suggesting that a long-term decrease in silicate weathering intensity occurred in the source area; from 6.6 to 2.6 Ma, in which the clay components in the sediments exhibit persistently low CIA values (66–81, average = 76.8) and high oxide ratios, which are indicative of mild to moderate chemical weathering; and since 2.6 Ma, in which the CIA values (64–80, average = 75.5) have continued to decrease with increasing oxide ratios, thus reflecting mild chemical weathering conditions. The geochemical proxy records demonstrate that the intensity of chemical weathering has continually decreased and that the Qaidam Basin has experienced continuous aridification since ca. 12.6 Ma. We suggest that Middle-Miocene global cooling-related drying has exerted a significant influence on the trend of decreasing chemical weathering intensity since ca. 12.6 Ma. In addition, the Late Cenozoic rapid uplift and exhumation of the NE Tibetan Plateau could have limited the time that the silicate rocks were exposed in the weathering profile prior to the deposition, which may have led to their weakened intensity of chemical weathering.

Chinese loess deposits preserve abundant information on the aridification of the Asian interior and Asian monsoon evolution during the Quaternary. Although substantial progress has been made in deciphering the paleoclimatic record of the thick loess deposits in the western Chinese Loess Plateau (CLP), the environmental significance of variations in the magnetic susceptibility (χ) and the ultrafine ( 40 μm fractions) of the 416-m-long Xijin loess core from the Lanzhou Basin, northeastern Tibetan Plateau. Our results indicate that the 40 μm fraction and marine oxygen isotope record. Consequently, we conclude that the pedogenic component is a more accurate and sensitive indicator of weathering and soil formation than the χ record, and it is well suited to reconstructing high-resolution Quaternary climatic change in the western CLP. Furthermore, the proportion of the pedogenic component increased systematically over the past 2.2 million years, which may have been primarily caused by long-term global cooling since the Early Pleistocene together with the episodic uplift of the Tibetan Plateau.

The characteristics of the evolution of the South Asian monsoon during the late Miocene through the Pliocene are highly debated. To obtain a better understanding, we studied the clay mineral assemblages and the clay fraction content of a high-quality sedimentary sequence (borehole core ZK1) spanning the interval of 8.8–2.62 Ma in the Zhaotong Basin, southwestern Yunnan Province, on the southeastern margin of the Tibetan Plateau. Smectite, kaolinite, illite and vermiculite were the four main clay minerals identified, and changes in their relative abundance reveal a distinct pattern of climate change during the study interval. Until the very late Miocene kaolinite and smectite, with a small amount of illite, were dominant, suggesting a relatively warm and humid climate; from ~6.2 to ~2.8 Ma smectite was dominant, with a minor amount of kaolinite and illite, indicating a relatively cool and humid climate; and from ~2.8 to 2.62 Ma vermiculite (HIV) and illite were dominant, with a minor amount of kaolinite, indicating a relatively cold and humid climate. The variation in clay mineral assemblages indicate substantial changes in the South Asian monsoon in the Zhaotong Basin that promoted a change from a warm and humid climate in the late Micoene to cool and humid climate in the very late Miocene through Pliocene, followed by a gradual trend towards a cold and humid climate in the very late Pliocene. Comparison with records from elsewhere indicates that the observed variations in the South Asian monsoon were mainly controlled by global cooling rather than by Tibetan Plateau uplift.

The floristic and climatic changes at the onshore part of the Balingian Province of the Sarawak Basin in response to Neogene global cooling, aridification and grassland expansion were reconstructed in this study. We carried out palynological and petrographical studies on coal samples collected from the Early Pliocene Begrih Formation and the Late Pliocene Liang Formation. We compared these results with the available floristic and climatic data of the Early Miocene Balingian Formation to explore possible changes in vegetation and climate. The study results suggested that though there was increased seasonality or reduced rainfall as a result of Neogene global cooling and aridification, the onshore part of the Balingian Province had experienced everwet climates, and the flora in this region had changed from predominantly Kerangas forest during the Early Miocene to the species-rich peat swamp forest during the Early and Late Pliocene.

Two competing factors, the global cooling and the uplift of Tibetan Plateau, have been proposed to drive the central Asian aridification, but their relative role has seldom been discriminated in paleoclimate and paleoenvironment records. Here, we reconstruct a 14-million-year-long record of paleohydrology and paleoecology in the western Qaidam Basin by applying the compound-specific hydrogen (δ2H) and carbon (δ13C) isotope analyses to terrestrial leaf wax long-chain n-alkanes. The δ2H values are low during the interval of 14.6 to 13.0 Ma. Then the δ2H increases from 13.0 to 12.2 Ma and maintains high values from 12.2 to 3.2 Ma with a peak high value of −156.1‰ at 8.0 Ma. After 3.2 Ma, the δ2H values are low and vary larger than 30‰. The δ13C values decrease from 14.6 to 13.0 Ma and are low from 13.0 to 3.2 Ma except a high value at 3.8 Ma. Then they decrease slightly after 3.2 Ma. Low δ2H values indicate relatively wet climate between 14.6 and 13.0 Ma. The decreasing δ13C values during the same time period support the ecologic shift with the decline of warm component of conifers after the Mid-Miocene Climatic Optimum. High δ2H values since 13.0 Ma are synchronous with the uplift of northern Tibetan Plateau, implying tectonics-driven aridity. Large-amplitude variation in δ2H values since ca. 3.2 Ma seen in East and West Qaidam and lower δ13C values reveal the climatic cyclic responses to the Northern Hemisphere Glaciation.

The research seeks to explain the use of Optically Stimulated Luminescence (OSL) and highlight the importance of this method for the evolutionary interpretation of tropical quaternary landscapes through systematic geochronological reconstitutions of a pedogeomorphological nature. To this end, studies that used OSL and corroborated the geochronological evolution of tropical landscapes were evidenced. Emphasis was given to Brazilian studies conducted in the state of Sao Paulo, in the Western Plateau and Peripheral Depression, that addressed the relationship between fluvial and planation surfaces (geomorphological systems) and their surface coverings, in addition to Holocene climatic pulsations, associating them with landforms and deposition processes of surface coverings. Such surveys showed recent erosive/depositional events, responsible for imposing new dynamics on pedogeomorphological systems. At the same time, they were able to establish regional morphoclimatic scenarios to review former geomorphological proposals based on relative dating and relatively subjective hypotheses. OSL was important and has undeniably contributed to the enhancement of evolutionary theories; the identification of Holocene climatic pulsations that lead to hot and wet periods (5.300–6.200, 4.200–4.600, 2.000–2.400, 800–1.200 and 0–400 years B·P.), interrupted by hot and dry periods (7.900–10.000, 6.200–6.600, 4.600–5.300, 2.400–4.200, 1.200–2.000, 400–800 years B·P.), resulting from global cooling events; the building of a geochronological database (ages); and the innovation of geomorphological knowledge regarding surface coverings of geomorphological surfaces in tropical climates.

In the Neoproterozoic Era, the Earth experienced two broad intervals of global glaciation, commonly known as Snowball Earth. There was also a rapid diversification of life, with the evolution of most of the eukaryotic lineages. Here, salient evidence for the Neoproterozoic global glaciations, including the carbon isotope record, is reinterpreted and an alternative explanation for the causes of glaciation is provided. The proliferation of life could have led to increases in atmospheric O2 levels and concomitant decreases in CO2 and CH4. Coupled biochemical and geochemical changes would have led to global cooling and glaciation. This so-called biotic hypothesis of the Snowball Earth is consistent with the most salient features of the reported evidence and explains the consecutive global glaciations.

Poor understanding of the differential evolution of interglacial climate over various regions in Eurasia greatly limits our ability to predict the specific local impacts of future climate change. Here we demonstrate starkly opposing trends in interglacial intensities in Asia and Europe over the early Middle Pleistocene and Mid-Brunhes Transitions based on the study of various climate proxies in the Paks loess record (Hungary), a key profile in the European Loess Belt. These contrasting climate trends imply major but unexplained differences in the regional response of Quaternary climate to shifts in forcing mechanisms during two major reorganizations of Earth's climate across Eurasia. Using new rock magnetic datasets from the Paks record we suggest that the changing dominance of Mediterranean, Atlantic (Westerlies) and continental air masses under the influence of the quasi permanent high pressure centres over the Fennoscandian ice sheet played a key role in the observed differences in the evolution of early Middle Pleistocene climate. We also propose that the intensification of the early Middle Pleistocene glaciation of Central Asian mountains may have strengthened and shifted the Siberian High westward on multi-millennial/orbital timescales, which in turn forced geographically contrasting expressions of the MIS 19 to 11 interglacials in Eurasia. This is the first coherent explanation for the geographically diverse response of regional climate to the early Middle Pleistocene climate transitions and points to the clear role of global cooling and expanded mid-latitude glaciers in driving these events.

West Georgia is part of the Caucasus biodiversity hotspot and hosts the Colchic vegetation, a ‘Tertiary’ refuge, with many endemic and relic species. Based on fossil pollen records from 21 localities in west Georgia quantitative climate reconstruction has been carried out covering the Miocene, Pliocene, and Pleistocene periods. Further, major shifts in vegetation have been unraveled using the biomization procedure. The obtained results were compared to global climate patterns and generally matched the late Neogene cooling trend as well as the subsequent cooling during the Pleistocene. However, the decrease in temperature in west Georgia was not accompanied by an increase in seasonality during the Mio- and Pliocene and no significant decrease in precipitation was observed. Climate stayed overall humid and mean annual temperatures never dropped significantly beneath modern values. These findings show that regional influences, like the buffering effect of the presence of the Paratethys and its remnants, modulated the climate in west Georgia. Even more importantly, since the Early Pleistocene the uplift of the Caucasus mountain range counteracts global climatic changes. This unique interplay of global climate and regional tectonic effects led to favorable climatic conditions for the development of the Colchic vegetation refuge.

Demand for cooling is increasing globally as a result of economic and population growth, as well as higher temperatures. Emerging economies like India contribute to half of this growth. Adaptation of cities to changing climatic conditions is needed, along with a reduction in cooling demand to limit the greenhouse emissions that are affecting climate change. This study proposes a methodology of analysis and adaptation of a traditional dwelling, the Pol House, in the Indian city of Ahmedabad. The use of various low carbon strategies to improve passive survivability, and increase indoor and outdoor comfort is studied through a simulation model. Results show that passive strategies like increased insulation in walls and roof, a seasonal shading schedule for the windows and courtyard, when coupled with increased air movement using simple fans have proven to be very effective. Indoor comfort time increased from 39% to 90–100% and Wet Bulb Globe Temperature in comfortable categories increased between 9% and 16% in all the rooms, during the periods analyzed. In conclusion, the adaptation of traditional dwellings to current climatic conditions can be achieved with low carbon emission strategies, using adaptive comfort method, and contributing to reducing global cooling demand.

Chemical weathering of continental silicates is a crucial geological process in regulating Earth’s long-term climate and participating in global carbon cycle. The increasing aridity and active tectonic settings in the northeastern Tibetan Plateau since the middle Miocene, combining the global cooling background, make this region ideal for studying how the weathering process interacts with climate and tectonics. We focus on a well-dated Cenozoic sedimentary profile in the northeastern Qaidam Basin and use sandstone petrography, heavy minerals, mudstone clay minerals and geochemical data to interpret sediment provenance and to reconstruct paleo-chemical weathering history (15.3–1.8 Ma) in the northeast Tibet. Our results demonstrate unchanged sediment sources (the South Qilian Shan and the North Qaidam belt) and moderate chemical weathering intensity (CIA values of 67–80) for the sediment source-to-sink system since the middle Miocene. The high chemical weathering intensity in 15.3–12 Ma corresponded to relatively warm and humid climate, indicating minor efforts of global cooling (14–12 Ma) to the local weathering processes. The weakening chemical weathering in 12–9 Ma was closely related to rapid exhumation of the South Qilian Shan and accelerated growth of the northeastern Tibetan Plateau. Uplift-induced enhancement of physical denudation and regional aridity had triggered the transition of chemical weathering regime from supply-limited to kinetic-limited. The inspiring enhanced chemical weathering in 9–6 Ma was attributed to orographic rainfall or intensified East Asian monsoon precipitation. The warm periods and onset of the Northern Hemisphere Glaciation during the Pliocene-Pleistocene controlled the evolution of chemical weathering in the Qaidam Basin. Collectively, we propose that the late Cenozoic chemical weathering intensity in the northeastern Tibet was both constrained by tectonic deformation and climate change. Our findings emphasize the discordance between chemical weathering intensity and climate in arid, tectonically-active regions and thus caution should be exercised while using paleo-weathering intensity to reconstruct paleoclimate history.

We estimate global surface albedo from the areal proportion of land to sea in climatically-significant latitudinal belts at ten million-year intervals for the Late Cretaceous and Cenozoic (from 120 million years ago) using modern plate tectonic reconstructions and a composite apparent polar path designed to minimize known biases in the determination of paleolatitude. We find that global surface albedo stayed almost constant until it shifted 30% higher to the modern value of around 0.15 with the inception of the Late Cenozoic Ice Age 34 million years ago, reflecting polar ice-albedo amplification of global cooling resulting from the reduction of greenhouse gases below a critical threshold, most probably as the culmination of enhanced CO2 weathering consumption of continental mafic rocks in the equatorial humid belt. The contribution from cloud cover toward a planetary albedo is unclear in the absence of measurable proxies but might eventually be gauged from the role cloudiness evidently plays in maintaining radiative balance with the increasing land bias between northern and southern hemispheres over the Cenozoic.

Silicate weathering plays a key role in maintaining a habitable climate on Earth. Although the climate-weathering link has been verified by observations on river geochemistry and weathering profiles, it remains a big challenge to quantify this link in the geological past mainly because sedimentary records of weathering intensity are complicated by other factors such as tectonics, sediment provenance and sorting effects. To clarify the climate dependence of weathering on different spatial and temporal scales, 4 Myr weathering intensity records determined by Chemical Index of Alteration (CIA), are compiled from 12 sites along the East and Southeast Asian margins ranging from ca. 10°N to 40°N. All the CIA records show overall decreasing trends, corresponding to global cooling. The CIA stacks that indicate regional and continental-scale weathering intensity are produced by binning and averaging the CIA data from each site. To explore the weathering intensity-temperature relationship, literature data on sea surface temperature (SST) anomaly are presented for the paleo-temperature changes at comparable latitudes. The results show that the decrease in CIA stack since 4 Ma is larger in East Asia (71-82 in Pliocene down to ca. 62 in late Quaternary) than in Southeast Asia (73-75 in Pliocene to ca. 72 in late Quaternary), in part due to the amplified midlatitude cooling. The correlation analyses indicate the temperature sensitivity of stacked CIA record in Southeast Asia (ca. 0.8 CIA units/°C) is consistent with modern observations of surface soils and river sediments. In comparison, the response of weathering intensity to temperature change is more sensitive in East Asia, with a magnitude of ca. 2.4 CIA units/°C, which may relate to dynamic source-to-sink processes and weathering regime changes. This study provides the first observation on silicate weathering responses to temperature changes at various latitudes since the Pliocene, showing the similar responses, but with different magnitudes. Our findings provide new insights on continental weathering mechanism and late Cenozoic cooling.

The Quaternary loess–paleosol and underlying Neogene red clay sequences on the Chinese Loess Plateau (CLP) contain a remarkable continental record of past East Asian monsoon changes and aridification of the Asian interior. While monsoon variability during the Quaternary is reasonably well understood, the evolution and dynamics of the monsoon during the Neogene are still debated. The rock magnetism of aeolian sediments is a well-established tool for reconstructing the palaeoclimatic history of Asia. Here, we present a rock magnetic record from Late Neogene red clay sediments of the Chaona section in the central CLP. The results indicate that the main magnetic minerals in the red clay are magnetite, maghemite, hematite and goethite, similar to the overlying Quaternary loess-palaeosol sequences. The high-resolution rock magnetic record, combined with the results of other proxies, demonstrate a stepwise intensification of the summer monsoon and a progressive enhancement of the winter monsoon in East Asia during the Late Neogene. Based on the results, the climatic evolution of East Asia can be divided into three intervals: Interval III, from 8.1 to 6.8 Ma, is characterized by a cool, dry climate with a relatively weak East Asian Summer Monsoon (EASM) and East Asian Winter Monsoon (EAWM); Interval II, from 6.8 to 4.3 Ma, is characterized by cool/warm cycles; and Interval I, from 4.3 to 2.8/2.6 Ma, was warm and humid, and within which the EASM strengthened rapidly and the EAWM fluctuated considerably, with an increasing trend. We infer that before 4.3 Ma the variations of both the EASM and EAWM were closely related to global cooling and that the intensified EASM during the late Pliocene was primarily caused by tectonic events, including the gradual closure of the Panama Seaway and the uplift of the Tibetan Plateau, rather than by global cooling.

Geological evidence shows that the Asian inland environment experienced enhanced aridity from the Early to the Late Eocene. This enhanced Eocene aridity in the Asian inland was related to combined impacts from global cooling, topographic uplift and land–sea reorganization. However, the primary cause of the enhanced Eocene aridity in this region is still under debate and varies between global cooling and early Tibetan Plateau uplift. To distinguish between the importance of these factors, we evaluate the climatic impacts of these factors from a modeling point of view. Consistent with geological evidence, our simulations support the observed enhanced Eocene aridity in the Asian inland. Both global cooling (induced by atmospheric CO2 decrease) and topographic uplift contributed to intensified Asian inland aridity, while land–sea redistribution did not. The uplift of the central Tibetan Plateau during the early stage of the India–Asia collision is emphasized more to be responsible for the long-term Asian inland aridification during the Eocene, playing at least an equally important role as the global cooling induced by decrease in atmospheric CO2.

In this article, we focus on transformations of a small peatland, located in the remote area of north-eastern Poland, which originated through partial terrestrialisation of Lake Czarne during the last 6000 years. We investigated the changes in vegetation patterns and linked them to climate changes and a concurrent succession of forest in the surroundings of the basin. We applied pollen, non-pollen palynomorph (NPP), and plant macrofossil analysis, supplemented with geochemistry and 14 C AMS dating. The transformation from poor fen to peat bog occurred within ca. 300 years (ca. 6000–5720 cal. BP). The hydrological changes on the peat bog, reconstructed qualitatively on the basis of selected NPPs (mostly HdV-10 and Archerella flavum ), occur simultaneously to the widely recognised climatic events. During the cool and wet ‘5.2’ and ‘4.2’ climatic events the potential increases in the water table on the peat bog were identified. The subsequent period of dynamic fluctuations of the water table (ca. 3400 and 2350 cal. BP) was related to the gradual expansion of Betula on the mire. This period also partially overlapped with the ‘2.8’ event that was responsible for water level fluctuations across Europe. The ‘1750–1350’ cal. BP global cooling event also might have led to a potential wet shift ca. 1700–1600 cal. BP. Since ca. 1600 cal. BP the water level has significantly dropped and poor fen conditions were reestablished. This article shows the potential of NPPs in the qualitative detection of palaeohydrological events on the peat land. However, there is still a need to combine NPP data with quantitative reconstructions of water table changes to understand the complexity of relationships between climate changes and water table–vegetation responses.

The transition from the extreme global warmth of the early Eocene ‘greenhouse’ climate to the present glaciated state is one of the most fundamental reorganizations of global climate known in the geologic record. The Middle to Late Eocene interval between 49 and 33 Ma was a globally important transition period from greenhouse to initial icehouse conditions. The Middle Eocene Climatic Optimum (MECO, ~ 40 Ma) was a transient period of global warming that interrupted the secular Cenozoic cooling trend. The Eocene-Oligocene transition (ca. 33.5 Ma) marks the first major decline in Cenozoic global temperatures and the initiation of Antarctic glaciation. However, a major challenge comes from recent investigations of plateau uplift processes and resulting environmental changes. The tectonic evolution of the Iranian plateau offers an explanation for global cooling during the Cenozoic, as a result of the gradual closure of the Neotethyan Sea, which led to the disappearance of the Indian Ocean-Mediterranean Sea connection, mountain building, extensional collapse, rifting, and flare-up type volcanism, erosion, and exhumation. Increasing topography by shortening as a result of subduction of the distal Arabian margin beneath the Iranian Plateau and contemporaneous exhumation of a metamorphic core complex between 49 and 33 Myr ago led to aridification of Iranian plateau and to the some elevation of the plateau. This rise in elevation is roughly contemporaneous with the emplacement of flare-up-type volcanics in the Urumiyeh-Dokhtar zone and over large portions of Central Iran. Peak volcanism occurred during the transient warming event MECO. New findings suggest that this global transition is linked to significant aridification and cooling in southwest Asia, and thus support the idea that global cooling is associated with the Eocene-Oligocene transition. The good match of tectonic deformation and uplift of the Iranian Plateau with climatic changes is significant.

The Eocene was an interval of climate evolution, when the extreme high temperatures of the earliest Cenozoic gave way to a global cooling trend. Fine-grained lacustrine sediments of Eocene age from northeastern China represent an excellent archive to study long-term environmental and climatic changes at high-resolution. The Huadian Basin is a Cenozoic, fault-bounded basin in Jilin Province, northeastern China. Though small in area, it contains numerous oil shale- and coal-bearing layers, which provide an abundant Middle to Late Eocene palynoflora. Eighty-five palynomorph genera and one hundred palynomorph species were identified in the Huadian Formation, allowing to distinguish 4 palynozones. The nearest living relatives of the recovered palynomorph taxa suggest the presence of subtropical evergreen and deciduous broad-leaved forests during deposition of the Huadian Formation. Using the coexistence approach (CA), we calculated seven paleoclimatic parameters, which indicate a subtropical warm and humid climate with a mean annual temperature above 13.6 °C and a mean annual precipitation of at least 887 mm. However, the climate became cooler and drier during the transition from the lower Oil Shale Member to the upper Carbonaceous Shale Member. Palaeoclimatic data from the various Middle and Late Eocene basins of northeastern China (i.e., the Huadian, Fushun, Yilan, Hunchun and Jishu basins) were compared with data from North American and European basins. Middle Eocene climate in the Northern Hemisphere was generally warm and humid, and the mean annual temperature and precipitation in northeastern China were similar to those in North America, though slightly lower than those of Europe. Similar trends in temperature and precipitation on different continents support the existence of a global Mid-Eocene cooling event. This paper is the first systematic study of Middle to Late Eocene seasonality in the Huadian Basin. Our results show an apparent differentiation in both temperature and precipitation between summer and winter, supporting the view that the East Asian Monsoon was established in northeastern China already during the Middle to Late Eocene. This Middle and Late Eocene monsoon was likely driven by the development of Pacific trade winds and an alternating, seasonal high- and low-pressure system over Siberia. The climatic changes observed in our dataset, especially the precipitation changes, appear to have played an important role in controlling oil shale formation in the Huadian Basin. A warmer and more humid climate, with abundant precipitation and high subsidence rates, formed a deeper Huadian depositional lake. High productivity and stable stratification provided the abundant organic matter and favorable preservation conditions necessary for oil shale accumulation.

The world during the early Middle Triassic (Anisian) was characterized by a distinct recovery of the carbonate factory after the Permian–Triassic crisis. This recovery seems to have passed over the Anisian environment on the tropical northern margin of Gondwana (Israel, Levant Basin) and to have resulted in the low diversity of barren horizons of carbonate-secreting organisms. Four Anisian successions (the Ramon 1, Hameishar 1, Nafha 1, and David 1 boreholes) were studied to decode the factors preventing regional recovery. A multi-proxy analysis was performed on these boreholes, including the carbonate/siliciclastic ratio, total organic carbon (TOC), carbon/nitrogen (C/N) ratio and inorganic carbon (δ13Ccarb), oxygen (δ18Ocarb), and nitrogen (δ15N) isotopic compositions. The aim of assessing the combination of these proxies was to characterize the geochemical conditions in the regional basins. These successions record two C-cycle perturbation events, characterized by negative shifts in δ13Ccarb values and recognized in most successions, indicating the land-marine teleconnection effect on the C-cycle perturbation. The δ18Ocarb excursions revealed similar oscillation trends, with global warming evidenced by increasing circumtropical precipitation and terrestrial influxes, whereas global cooling was reflected by increased carbonate factory production. The low δ15N values in all of the studied successions indicated the presence and flourishing of N-fixers. The absence or scarcity of carbonate-secreting organisms suggests that these N-fixers were the source of the carbonate fraction in the sediments. Episodic events with high δ15N values suggest an accumulation of terrestrial organic matter (OM) or oxygenation events, allowing short-term colonization by benthic fauna at the marine sites.

Links between tectonics and regional climate have been extensively studied in Asia. However, despite decades of research, the relative roles of tectonics and global climate in pacing the long-term evolution of climate in Asia remain disputed. Today, climate in Asia is characterized by large-scale monsoonal circulation over India and southern China and exceptionally arid deserts across much of Central Asia that, to the north, yield to the wetter conditions of the steppe and taiga. How, why, and if these boundaries have changed during the Cenozoic has been limited by the lack of paleoclimate proxy data that can be broadly applied over space and time. We use a large compilation of pedogenic and lacustrine carbonate stable oxygen (δ18O) and carbon (δ13C) isotope data (>7,700 samples), which record large-scale atmospheric circulation and primary productivity, respectively, to reconstruct Cenozoic hydroclimate in Asia and delineate the boundaries through time of monsoonal and mid-latitude westerly moisture. The δ18O data indicate that atmospheric circulation has remained similar to today for at least 55 million years. Southern Tibet has always received southerly, likely monsoonal moisture, and this southerly moisture has likely rarely extended northward of the central Tibetan Plateau. In contrast, northern Tibet and Central Asia have received moisture dominantly via the mid-latitude westerlies, which have maintained a semi-arid to arid climate in Central Asia since the early Eocene. Thus, the spatial extent of large-scale atmospheric circulation appears largely unperturbed by contemporaneous changes in India-Asia collisional tectonics, extent of the Paratethys, and in global climate. The δ13C data support this interpretation, but yield additional details. Particularly low δ13C across a wide swath of eastern China during the Eocene suggests greater primary productivity due to a strengthened East Asia Monsoon, perhaps driven by high atmospheric pCO2 and globally warm temperatures. Consistently higher δ13C in Central Asia indicates that Central Asia has remained more arid than surrounding regions, such as northern India and southern China, which have received abundant precipitation due to the presence of monsoonal moisture. However, increases in δ13C across much of Central Asia throughout the Cenozoic—including particularly pronounced increases in Mongolia and Kazakhstan during the Neogene—imply that primary productivity has declined across much of Asia. This large-scale “de-greening” is attributable to the combined effects of Cenozoic global cooling and the late Cenozoic uplift of the Tian Shan and Altai mountains, which block westerly moisture. The uplift of these ranges in the late Miocene is supported by decreasing Neogene δ18O in eastern Kazakhstan and sharply increasing δ13C in the lee of the Altai. These regional data demonstrate that the Tian Shan and Altai reached sufficient elevations to interact with the westerly jet by the late Miocene, establishing a substantial rain shadow, and shifting the seasonality of precipitation in western Central Asia. We conclude that paleoclimatic changes during the Cenozoic in Central Asia are more tightly controlled by global climate and by the interaction of the mid-latitude westerlies with the Tian Shan and Altai rather than by changes in the height or extent of the Tibetan Plateau or Paratethys.

An unusually short glaciation interrupted the warm Pliocene around 3.3 Ma (Marine Isotope Stage (MIS) M2). Different hypotheses exist to explain why this glaciation event was so pronounced, and why the global climate system returned to warm Pliocene conditions relatively quickly afterwards. One of these proposed mechanisms is a reduced equator-to-pole heat transfer, in response to a tectonically reduced Indonesian Throughflow (ITF). The ITF is a critical part of the global thermohaline ocean circulation, transporting heat from the Indo-Pacific Warm Pool to the Indian Ocean. When ITF connectivity is reduced, the water and heat supply for the Leeuwin Current, flowing poleward along Australia's west coast, is also diminished. To assess the possible relationship between mid-Pliocene glaciations and latitudinal heat transport through the Indonesian Throughflow, we constructed a multi-proxy orbital-scale record for the 3.7–2.8 Ma interval from International Ocean Discovery Program (IODP) Site U1463, off northwest Australia. The comparison of the Site U1463 record with paleoclimate records from nearby Site 763 and West Pacific Warm Pool Site 806 allows for a detailed regional reconstruction of Pliocene paleoceanography and thus for testing the proposed hypothesis. An astronomically-paced decrease in potassium content characterizes the late Pliocene interval of U1463. This record documents the increasing aridity of northwest Australia, periodically alleviated by reinforced summer monsoon precipitation under summer insolation maxima. The δ 18 O record of the planktonic foraminifer Globigerinoides sacculifer correlates exceptionally well with the sea surface temperature (SST) record from Site 806 in the West Pacific Warm Pool, even during MIS M2. Hence, Site U1463 preserves an uninterrupted ITF signal even during Pliocene glaciations. However, the U1463 δ 18 O G.sacculifer record exhibits a 0.5‰ offset with the nearby Site 763A record around MIS M2. This implies that Site 763A, about 500 km west of U1463, more closely tracks Indian Ocean SST records across MIS M2. The U1463 data reveal that heat-transport through the Indonesian Throughflow did not shut down completely during MIS M2, but rather its intensity decreased prior to and during MIS M2, causing Site 763A to temporarily reflect an Indian Ocean, rather than an ITF signal. We conclude that ITF variability significantly influenced latitudinal heat transport by means of the Leeuwin Current and hence contributed to the relative intensity of MIS M2. We propose the ITF valve between the Pacific and Indian Ocean as a positive feedback mechanism, in which an initial sea level lowering reduces ITF heat transport, in turn amplifying global cooling by advancing the thermal isolation of Antarctica.

The last hyperthermal event in the Eocene, the Late Lutetian Thermal Maximum or Chron C19r event, took place at ~41.5 Ma, during a long-term global cooling phase which occurred between the warm Early Eocene Climatic Optimum and the icehouse Oligocene Epoch. This paleoclimatic event was first identified in the Equatorial Atlantic Ocean Drilling Program (ODP) Site 1260 as an abrupt peak in bulk Fe content and a short-lived decline in stable isotopes (δ13C, δ18O) and carbonate content. Additional studies have recently been carried from the Southern Atlantic ODP sites 702 and 1263. However, many issues were not addressed at these deep-sea sites and no land-based record of the event had been studied. Therefore, the beach cliff at Cape Oyambre (N Spain) was analyzed with the aim of identifying the C19r event and investigating its paleoenvironmental impact. Using magnetostratigraphic and biostratigraphic information, the astronomically tuned cyclo-stratigraphic record from Oyambre was accurately correlated with ODP Site 1260. This, combined with stable isotope data, allowed identification of the event in a conspicuous dark marl bed. Given that the associated negative carbon isotope excursion extends for 2/3 of a precession-driven hemicouplet, a 7–11 kyr duration was estimated, which agrees with recent estimates from the Atlantic deep-sea sites. Exceptional insolation conditions were found to have accelerated the hydrological cycle, increasing rainfall and runoff on land and terrestrial sediment input to the sea, which resulted in relatively low carbonate content in the deep-sea sediments. The terrestrial input also caused seawater eutrophication and freshening, leading to low δ13C and δ18O values, increased abundance of autochthonous and reworked calcareous nannofossil taxa, peaks in the abundance of opportunistic Reticulofenestra

The impact of climate change on biodiversity has been the focus of studies on the Phanerozoic biotic crises. However, it is still controversial whether climate change has caused the Frasnian–Famennian (F–F) biotic crisis since there is no unequivocal view on the global climate change during this critical period. In order to reconstruct palaeotemperatures during the F–F transition in South China (eastern Palaeotethys), a high-resolution oxygen isotope ( δ 18 O PO 4 ) record was obtained based on 104 measurements of conodont apatite from the Yangdi section. The oxygen isotope record based on mono-generic samples reveals an increase in δ 18 O PO 4 by 0.7‰ in the Lower Kellwasser horizon (LKH) and 1.4‰ in the Upper Kellwasser horizon (UKH), translating into low-latitude surface water cooling of ∼3 °C and ∼6 °C, respectively. These two δ 18 O PO 4 shifts agree well with the time-equivalent δ 18 O PO 4 records from the western Palaeotethys, suggesting that two climate cooling pulses in conjunction with the deposition of the Kellwasser horizons are a global signal during the F–F transition. The positive shift of δ 18 O PO 4 coincides with positive excursion in carbon isotope of carbonates ( δ 13 C carb ) in the UKH, indicating that enhanced burial of organic carbon resulted in a drop in atmospheric p CO 2 and thus global climate cooling. Cooling started immediately before the Upper Kellwasser biotic crisis, with the lowest temperature documented at the top of the UKH. Climate cooling during the deposition of the LKH is observed in conjunction with the sharp decline in metazoan reefs. The coincidence of cooling and the Kellwasser biotic crisis suggests that global cooling played a major role in the collapse of ecosystems.

Aridification of the Asian interior is one of the most significant paleoenvironmental events during the Cenozoic. However, continuous paleoclimatic records from desert interiors are scarce because of the lack of outcrops, erosion and discontinuous sediment accumulation. Here we report a multi-proxy climatic record for the last ∼3.55 Ma from paleomagnetically-dated drilling core WEDP01 from the central Tengger Desert, which is one of the most important sediment source areas for Northern Hemisphere atmospheric dust and the Chinese Loess Plateau. Analysis of grain-size components indicates the onset of continuous dust deposition at 2.6 Ma and desert formation at 0.9 Ma. In addition, analysis of major element content and sediment color reveals a stepwise process of increasing aridification and significant cooling in the Tengger Desert area. Simultaneous aridification events in northwest China during the Quaternary were probably induced by the uplift of the Tibetan Plateau. Northern Hemisphere glaciation may have been another important factor for Asian aridification; meanwhile, the increased dust emission from sources such as the Tengger Desert may provide a positive feedback mechanism for global cooling.

The Eocene/Oligocene (E/O) transition, corresponds to an abrupt global cooling, thought to have been one of the greatest temperature changes in the mid-Cenozoic Earth’s history. Sparse studies have successfully reconstructed the terrestrial ecological response to this temperature change. Here, we report results from the study of organic carbon isotopes (δ13CTOC), together with n-alkanes biomarker analysis, in the Yongdeng Section, Lanzhou Basin, Northwest China, and discuss changes in δ13CTOC and their mechanisms. The results show that between 35.3 Ma and 31.0 Ma, δ13CTOC ranged from −26.72‰ to −21.27‰. The main change occurred at 33.4 Ma, when δ13CTOC became heavier by 3‰. At this time the long-chain n-alkane members (C27, C29 and C31) were dominant, suggesting the most likely sources of organic matter were terrestrial plants. Combining these results with existing measurements of plant δ13CTOC and sporopollen data in adjacent areas, we infer that this change at 33.4 Ma might have been caused by an increase in gymnosperm content especially coniferous trees adapted to cold climates, which have a heavier δ13CTOC than that of the angiosperms, this would have been a response to the global cooling characteristic of this period.

The last glaciation during the late Paleozoic ice age commenced at around the Guadalupian–Lopingian (G–L) boundary and is synchronous with the emplacement of the Emeishan large igneous province. Using CA-TIMS zircon U–Pb dating, we obtained an age of 259.51 ± 0.21 Ma for the uppermost tuff from the Puan volcanic sequence in the eastern Emeishan large igneous province, constraining the timing of Emeishan volcanism and providing another candidate age for the G–L boundary. In addition, we determined an age of 259.69 ± 0.72 Ma for a basal claystone in the immediately overlying Longtan Formation from a drill core section in southwest South China. These ages, along with source weathering trends of mudstones from the lower Longtan Formation, and compiled paleotemperature records, indicate an earliest Wuchiapingian cooling coinciding with the onset of the last Permian glaciation. This global cooling is associated with positive shifts in both organic and carbonate carbon isotopic records and likely a decrease in atmospheric pCO2. A hypothesised causal linkage is proposed in which the rapid post-eruptive basaltic weathering of the Emeishan province in an equatorial humid belt may accelerate the atmospheric CO2 consumption and lead to climate cooling. Our work supports the long-term climate cooling effects of large igneous provinces.

The mid-Holocene environmental transition was characterised by global cooling and the abrupt weakening of the Northern Hemisphere monsoon systems. It is generally considered the key driver of the collapse of several mid-Holocene agricultural societies, on a global scale. However, only a few previous studies have tried to verify the climatic origin of the collapse of these societies, using the compilation of spatiotemporal data at a large scale. Especially, the nature of mid-Holocene human-environment interactions in the climatically-sensitive margin of the East Asian summer monsoon front remains to be thoroughly understood. However, a systematic compilation of archaeological data at a regional scale can be used to verify the role the mid-Holocene environmental transition played in the collapse of late Neolithic cultures in China. Here, we present a regional compilation of Holocene records from sub-aerial sedimentary deposits, lake sediments, and archaeological sites in the deserts of NE China and the adjacent regions to explore human-environment interactions during the mid-Holocene. Comparison of the records of Holocene climate change with the evolution of archaeological sites reveals that the mid-Holocene environmental transition resulted in ecosystem degradation in the deserts of NE China, rendering these areas much less habitable. Faced with substantially increased environmental pressures, the late Neolithic inhabitants used several subsistence strategies to adapt to the environmental transition, including change in agricultural practices and ultimately migration. Overall, our results support the view that a widespread mid-Holocene drought destroyed the rain-fed agricultural and/or plant-based subsistence economies, ultimately contributing to the collapse of late Neolithic cultures in NE China.

To investigate the change of climate during the Pliocene-Pleistocene transition in the Asian interior, sporopollen records from the 567.3 m-247.9 m depths (ca. 2.87–1.52 Ma) of the core PL02 in the Yinchuan Basin were studied, which could be regarded as an excellent archive of vegetation and climate changes. The results indicated that the climate of the Yinchuan Basin was relatively warm and humid with a desert steppe environment before 2.6 Ma. At the beginning of the early Pleistocene, the pollen content of xerophytic plants (Nitraria and Chenopodiaceae) increased sharply, the climate became drier than that of the late Pliocene, and the environment obviously worsened. However, from 1.99 Ma to 1.73 Ma, xerophytic plants in the pollen content decreased for a short time, and the climate became more humid. After 1.73 Ma, the pollen content of herbaceous plants continually increased, and the vegetation type shifted from desert steppe to desert, which reflects a cold and dry climate. In the study region, the vegetation change suggested an aridification trend in Central Asia inland since the late Pliocene, which might be related to global cooling and the uplift of the Tibetan Plateau.

A high-resolution potassium content record of sediments from Integrated Ocean Drilling Program (IODP) Site U1422 drilled in the northern Sea of Japan was employed to yield an astronomical timescale for this ∼205 m thick sedimentary archive. The K content was quantified using the natural gamma radiation (NGR) data routinely measured on DV JOIDES Resolution. The U1422 K (wt.%) series shows an increasing trend with time, which parallels the growth of North Hemisphere ice sheets since ∼4 Ma, as revealed by the global benthic foraminifer's oxygen isotope stack (LR04). We propose that K content variations reflect changes in the relative contributions of Asian eolian dust and volcanic weathering products, in response to changes in global ice volume. Using the shipboard age model, constrained by palaeomagnetism and nanofossils datums, we tuned the U1422 K content variations to the LR04 stack. Our tuned age model for site U1422 goes back to 3.9 Ma. The studied record indicates that Asian dust generation is enhanced during periods of global cooling. The synchronous variations between the U1422 K record and the LR04 stack also suggest that global cooling played a dominant role in promoting the central Asian aridification since ∼3.9 Ma, while the uplift of Tibetan Plateau plays a secondary role, considering many disagreements still exists between the timing and amplitude of the Qinghai-Tibetan uplift and the evolution of central Asian aridity since the early Pliocene.

The early Pleistocene is represented by a succession of glacial-interglacial cycles character-ized by a general tendency towards global cooling, with increasing aridity and seasonality.The large deer Eucladoceros is found in abundance in Europe during this period of faunaldispersions. The dietary plasticity of Eucladoceros and how it can mirror early Pleistoceneclimatic variations will be explored here using Dental Microwear Texture Analysis. Thewide range of dental microwear textures for Eucladoceros reflects a low selectivity and highplasticity in its diet. It is an appropriate proxy to track vegetal resource availability. Oscil-lations were identified between a browsing and a grazing signal. This study proposes thata browsing signal is associated with a fossil assemblage deposited during an interglacialevent characterized by warmer temperatures and deciduous vegetation. A grazing signalmore likely indicates a glacial event with cooler temperatures and a developed herbaceous,bushy layer. Le Pléistocène inférieur correspond à une succession de cycles glaciaires-interglaciairescaractérisée par une tendance générale au refroidissement global, avec une aridité et unesaisonnalité croissantes. Le cervidé de grande taille Eucladoceros est abondant en Europedurant cette période de dispersions fauniques. Grâce à l'analyse de texture de la micro-usuredentaire, nous explorons la plasticité alimentaire d'Eucladoceros et la manière dont celle-ci reflète les variations climatiques du Pléistocène inférieur. La large gamme de texturesde micro-usure dentaire d'Eucladoceros reflète sa faible sélectivité et sa forte plasticité ali-mentaire. De fait, il constitue un outil approprié pour aborder la disponibilité en ressources végétales dans le milieu. Nous identifions des oscillations entre un signal brouteur et unsignal paisseur. Nous proposons qu'un signal brouteur soit associé à un assemblage fossiledéposé lors d'un évènement interglaciaire caractérisé par des températures plus chaudeset une végétation décidue, tandis qu'un signal paisseur correspondrait plutôt à un évène-ment glaciaire, avec des températures plus froides et la présence d?une strate herbacée etarbustive développée. This project was supported by the “Agence nationale dela recherche” (ANR TRIDENT: grant number: ANR-13-JSV7-0008-01; PI.: Gildas Merceron).

Climate and vegetation history from the Yucatan Peninsula, southeastern Mexico, are inferred from a mangrove sediment core deposited between the middle and late Holocene (~5600–1700 cal yr B.P.) in the Rio Hondo Delta. Fossil pollen and concentrations of Ca and Fe and Ca/Fe ratio in sediments are used to record changes in vegetation and climate. Palaeoecological and palaeoclimatic interpretations obtained from pollen abundances and associations and Fe/Ca ratio coincide with dynamics of major global forcings of climate change like ITCZ, ENSO and global cooling. Mesic conditions enabled tropical forest expansion during the middle Holocene (~5600–3650 cal yr B.P.), although there were periodic dry episodes at ~5200 cal yr B.P. and at ~4300 cal yr B.P. that caused disturbance and enabled herbaceous vegetation to expand. Changes in sedimentation and a gradual change from semi-evergreen to dry tropical forest occurred at ~3650 cal yr B.P., with increasing ENSO activity and southward migration of the ITCZ during transition of the middle to late Holocene. The driest period and lowest forest cover occurred between ~2600 and 2000 cal yr B.P. Data show that over the last two millennia, influence of the ENSO on southeastern Mexico is stronger compared to other proxy-records of climate variability from the Caribbean region.

Rising sea level in the coming century is of significant concern, yet predicting relative sea level change in response to eustatic sea level variability is complex. Potential analogues are provided by the recent geological past but, until recently, many sea level reconstructions have been limited to millennial scale interpretations due to age uncertainties and paucity in proxy derived records. Here we present a sea level history for the tectonically stable “far-field” Great Barrier Reef, Australia, derived from 94 high precision uranium–thorium dates of sub-fossil coral microatolls. Our results provide evidence for at least two periods of relative sea level instability during the Holocene. These sea level oscillations are broadly synchronous with Indo-Pacific negative sea surface temperature anomalies, rapid global cooling events and glacial advances. We propose that the pace and magnitude of these oscillations are suggestive of eustatic/thermosteric processes operating in conjunction with regional climatic controls.

This study is a preliminary quantitative analysis of Paleocene calcareous nannofossil assemblages of the Tenida area (Egypt) in order to establish a detailed biostratigraphic framework as well as to reconstruct the paleoclimatic trends. A total of 48 samples with an average sample spacing of 1.5 m allowed the identification of 63 calcareous nannofossil species belonging to 19 different genera. The preservation of the studied samples varies from poor to moderate and is characterized by the frequent presence of small frangible placoliths, and nannoliths. This study recognizes three calcareous nannofossil biozones in the Danian-Thanetian time interval; Chiasmolithus danicus (NP3) Zone, Ellipsolithus macellus (NP4) Zone, and Heliolithus kleinpellii (NP6) Zone. Moreover, the multivariate statistical analysis of the calcareous nannofossil communities reveals a relationship between the distribution of these nannofossil assemblages and variations in paleoclimatic trends. Accordingly, the relative abundances of Coccolithus pelagicus in addition to nine calcareous nannofossil genera along with the diversity and preservation indices of calcareous nannofossil elements have been used to elucidate changes in paleoclimatic trends. Based on the cyclic change from cold to warm climates, it was possible to subdivide the Paleocene Period recorded in the Tenida section into four paleoclimatic intervals. The oldest is a global cooling trend spanning 2.01 Myr long, starting in the early Paleocene (Danian) during the deposition of the lower part of the Kharga Shale Member. This cooling trend is followed by a ∼ 0.56 Myr warming trend during deposition of the middle part of the Kharga Shale Member that was followed by a return to a cooling mode, with an estimated duration of roughly 1.67 Myr. The last interval includes a 0.39 Myr long period at the Selandian/Thanetian boundary interval, which is dominated by a global warming trend during deposition of the upper part of the Upper Kharga Shale Member.