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Understanding the complex patterns of latitudinal diversity gradients (LDGs) in deep time has been hampered by the absence of long-term records of LDGs through multiple climatic changes. We used records of marine invertebrate fossils to generate LDGs in each age bin from the Carboniferous icehouse to the Triassic greenhouse climates. We evaluated LDGs by subsampling, calculated evolutionary rates for different latitudinal zones, and assessed the modularity of the fossil data within latitudinal zones using the Louvain algorithm. Our results suggest that the LDG peaks may be shaped by multiple factors rather than alternating icehouse and greenhouse climates, although icehouse climates usually restrict diversity at high latitudes. In nearly all clades, peak diversity shifted northward during the late Carboniferous and early Permian, reflecting the northward drift of plates and increased habitat area. Changes in the steepness of the LDG was most pronounced at low latitudes and during biotic crises and recovery, while icehouse to greenhouse transitions created more deviation at high latitudes. Our results show a strong historical influence from previous LDG patterns in LDG dynamics, but one that was interrupted by upheavals in composition after dramatic environmental changes.

The surficial cycling of Mg is directly coupled with the global carbon cycle, a predominant control of Earth’s climate. However, how Earth’s surficial Mg cycle evolved with time had been elusive. Magnesium isotope signatures of seawater (δ26Mgsw) track the surficial Mg cycle, which could provide crucial information on the carbon cycle in Earth’s history. Here, we present a reconstruction of δ26Mgsw evolution over the last 2 billion years using marine halite fluid inclusions and sedimentary dolostones. The two independent archives yield consistent evolutionary trends of δ26Mgsw for the past 430 million years, and the dolostone records extend the δ26Mgsw curve to 2 billion years ago. Modeling results of the net CO2 sequestration efficiency (EMg−CO2) by the surficial Mg cycle based on the δ26Mgsw record reveal a secular decline EMg−CO2 during the past 2 billion years, with the periods of low EMg−CO2 coinciding with ice ages in the Phanerozoic. Our work underlines a previously under-appreciated, but indispensable role of dolostones in regulating Earth’s climate on geologic time scales.

The tectonic evolution of the Sibumasu Block during the Permian remains controversial, and Permian faunas and their paleobiogeographic affinities provide some insight into its paleogeographic and tectonic evolutionary histories. In this paper, a new brachiopod fauna dominated bySpinomartinia prolificaWaterhouse, 1981 is described from the uppermost part of the Taungnyo Group in the Zwekabin Range, eastern Myanmar. This brachiopod fauna includes 23 species and its age is well constrained as late Kungurian by the associated conodonts, i.e.,Vjalovognathus nicolliYuan et al., 2016 andMesogondolella idahoensis(Youngquist, Hawley, and Miller, 1951), contrary to the late Sakmarian age given to the same brachiopod faunas previously reported from southern Thailand and Malaysia. Based on comprehensive comparisons of the Cisuralian brachiopod faunas and other data in different parts of the Sibumasu Block, we consider that they are better subdivided into two independent stratigraphic assemblages, i.e., the lower (earlier)Bandoproductus monticulus-Spirelytha petaliformisAssemblage of a Sakmarian to probably early Artinskian age, and the upper (younger)Spinomartinia prolifica-Retimarginifera alataAssemblage of a late Kungurian age. The former assemblage is a typical cold-water fauna, mainly composed of Gondwanan-type genera, e.g.,BandoproductusJin and Sun, 1981,SpirelythaFredericks, 1924, andSulciplicaWaterhouse, 1968. The latter assemblage is strongly characterized by an admixture of both Cathaysian and Gondwanan elements, as well as some genera restricted to the Cimmerian continents. Notably, the spatial distribution pattern of these two separate brachiopod assemblages varies distinctly. The Sakmarian cold-water brachiopod faunas have been found in association with glacial-marine diamictites throughout the Sibumasu Block including both the Irrawaddy and Sibuma blocks. In contrast, the Kungurian biogeographically mixed brachiopod faunas are only recorded in the Irrawaddy Block, unlike the Sibuma Block that contains a contemporaneous paleotropical Tethyan fusuline fauna. Thus, it appears likely that by the end of Cisuralian (early Permian), the Sibumasu Block comprised the Irrawaddy Block in the south with cool climatic conditions, and the Sibuma Block in the north with a temperate to warm-water environment, separated by the incipient Thai-Myanmar Mesotethys.

The end-Permian mass extinction (EPME) has been recorded as the most severe biodiversity crisis in Earth's history, although the timing of the marine and terrestrial extinctions remains debatable. We present a new high-resolution magnetostratigraphic succession across the EPME and the Permian-Triassic boundary (PTB) from the Meishan sections in southeastern China, which contain the global boundary stratotype section and point (GSSP) for the base of the Triassic (also the Induan Stage) and the base of the Changhsingian Stage. We identified five normal and five reverse magnetozones, including MS1n to MS5n and MS1r to MS5r, from oldest to youngest, in the Changhsingian and Induan Stages. The Induan Stage was determined to consist of two polarity intervals, where the upper one is reverse (MS5r), and the lower one is normal (MS5n). The Changhsingian Stage is dominated by normal polarity, intercalated with four short-term reverse magnetozones (MS1r to MS4r). Consequently, the PTB and the Wuchiapingian-Changhsingian boundary are clearly located in MS5n and MS1n, respectively. These new magnetostratigraphic results provide a potential reference geomagnetic polarity pattern with which to refine the geomagnetic polarity time scale for the EPME and the Permian-Triassic transition.

We present an updated look at Carboniferous brachiopod biozonation from most of the world framed into a revised Carboniferous palaeogeography, based on a selection of the literature published on Carboniferous brachiopods since the nineteenth century. The biostratigraphic significance of the most important brachiopod taxa is synthesized in seven geographical correlations. The Mississippian is characterized by rich brachiopod faunas, with widespread taxa with a good potential for global correlation, such as Rugosochonetes , Delepinea , Buxtonia , Antiquatonia , Spinocarinifera , Marginatia , Fluctuaria , Ovatia , Rhipidomella , Lamellosathyris , Unispirifer , Tylothyris and Syringothyris . From the mid-Visean to the late Serpukhovian, taxa of gigantoproductidines are biostratigraphically significant, and occur everywhere except South America and Australia, which remain as distinct faunal successions for most of the period. A major turnover occurs at the beginning of the Pennsylvanian, characterized by a higher degree of provincialism. Pennsylvanian brachiopod faunas are diverse in China, Russia and North America, but otherwise they are less developed and are characterized mostly by endemic taxa, hampering long-distance correlation. An exception is the rapid diversification of taxa of the Choristitinae, which were widespread from the Bashkirian to the Moscovian, allowing long-distance correlation.

Since the beginning of the 21st century, the geoscience research has been entering a significant transitional period with the establishment of a new knowledge system as the core and with the drive of big data as the means. It is a revolutionary leap in the research of geoscience knowledge discovery from the traditional encyclopedic discipline knowledge system to the computer-understandable and operable knowledge graph. Based on adopting the graph pattern of general knowledge representation, the geoscience knowledge graph expands the unique spatiotemporal features to the Geoscience knowledge, and integrates geoscience knowledge elements, such as map, text, and number, to establish an all-domain geoscience knowledge representation model. A federated, crowd intelligence-based collaborative method of constructing the geoscience knowledge graph is developed here, which realizes the construction of high-quality professional knowledge graph in collaboration with global geo-scientists. We also develop a method for constructing a dynamic knowledge graph of multi-modal geoscience data based on in-depth text analysis, which extracts geoscience knowledge from massive geoscience literature to construct the latest and most complete dynamic geoscience knowledge graph. A comprehensive and systematic geoscience knowledge graph can not only deepen the existing geoscience big data analysis, but also advance the construction of the high-precision geological time scale driven by big data, the compilation of intelligent maps driven by rules and data, and the geoscience knowledge evolution and reasoning analysis, among others. It will further expand the new directions of geoscience research driven by both data and knowledge, break new ground where geoscience, information science, and data science converge, realize the original innovation of the geoscience research and achieve major theoretical breakthroughs in the spatiotemporal big data research.

Piecing together the history of carbon (C) perturbation events throughout Earth’s history has provided key insights into how the Earth system responds to abrupt warming. Previous studies, however, focused on short-term warming events that were superimposed on longer-term greenhouse climate states. Here, we present an integrated proxy (C and uranium [U] isotopes and paleo CO2) and multicomponent modeling approach to investigate an abrupt C perturbation and global warming event (∼304 Ma) that occurred during a paleo-glacial state. We report pronounced negative C and U isotopic excursions coincident with a doubling of atmospheric CO2 partial pressure and a biodiversity nadir. The isotopic excursions can be linked to an injection of ∼9,000 Gt of organic matter–derived C over ∼300 kyr and to near 20% of areal extent of seafloor anoxia. Earth system modeling indicates that widespread anoxic conditions can be linked to enhanced thermocline stratification and increased nutrient fluxes during this global warming within an icehouse.

As an important contributor to the habitability of our planet, the oxygen cycle is interconnected with the emergence and evolution of complex life and is also the basis to establish Earth system science. Investigating the global oxygen cycle provides valuable information on the evolution of the Earth system, the habitability of our planet in the geologic past, and the future of human life. Numerous investigations have expanded our knowledge of the oxygen cycle in the fields of geology, geochemistry, geobiology, and atmospheric science. However, these studies were conducted separately, which has led to one-sided understandings of this critical scientific issue and an incomplete synthesis of the interactions between the different spheres of the Earth system. This review presents a five-sphere coupled model of the Earth system and clarifies the core position of the oxygen cycle in Earth system science. Based on previous research, this review comprehensively summarizes the evolution of the oxygen cycle in geological time, with a special focus on the Great Oxidation Event (GOE) and the mass extinctions, as well as the possible connections between the oxygen content and biological evolution. The possible links between the oxygen cycle and biodiversity in geologic history have profound implications for exploring the habitability of Earth in history and guiding the future of humanity. Since the Anthropocene, anthropogenic activities have gradually steered the Earth system away from its established trajectory and had a powerful impact on the oxygen cycle. The human-induced disturbance of the global oxygen cycle, if not controlled, could greatly reduce the habitability of our planet.

The Permian marine-terrestrial system of the North China block provides an exceptional window into the evolution of northern temperate ecosystems during the critical transition from icehouse to greenhouse following the late Paleozoic ice age (LPIA). Despite many studies on its rich hydrocarbon reserves and climate-sensitive fossil flora, uncertain temporal constraints and correlations have hampered a thorough understanding of the records of geologic, biologic, and climatic change from the North China block. We present a new chronostratigraphy based on high-precision U-Pb chemical abrasion–isotope dilution–thermal ionization mass spectrometry (CA-ID-TIMS) geochronology of tuffs from a near-complete latest Carboniferous–Permian succession in North China. The results indicate that the predominance of continental red beds, climate aridification, and the disappearance of coals and characteristic tropical flora were well under way during the Cisuralian (Early Permian) in the North China block, significantly earlier than previously thought. A nearly 20 m.y. hiatus spanning the early Kungurian to the mid-Guadalupian (or later) is revealed in the northern North China block to have close temporal and spatial associations with the closure and/or subduction of the Paleo-Asian Ocean and its related tectonic convergence. This long hiatus was concomitant with the prominent loss of the highly diverse and abundant Cathaysian floras and the widespread invasion of the monotonous Angaran floras under arid climate conditions in the North China block. Similarities in the floral and climate shift histories between Euramerica and North China suggest that aside from the regional tectonic controls and continental movement, extensive volcanism during the Cisuralian may have played a major role in the global warming and aridification in the aftermath of the LPIA.

The largest mass extinction event in the Phanerozoic, known as the end-Permian mass extinction (or EPME, ca. 252 Ma) is coincident with the main eruption phase of Siberian Traps volcanism (ca. 252 to 250 Ma), a large igneous province (LIP). This LIP is estimated to have a volume larger than 2 × 106 km3 and to have released both mantle carbon dioxide (CO2) through extrusions and thermogenic methane (CH4) and carbon dioxide (CO2) through intrusions. The climatic consequences of these greenhouse gases is detrimental to both marine and terrestrial life and may have delayed the recovery of ecosystems after the extinction. Quantitatively, the amount of CO2 released can be estimated using global carbon (C) cycle model or plant and soil-based proxies with varying time resolution. In light of the recent advances in geochemical proxies of ocean anoxia and acidification, we review the latest uranium isotopes (δ238U) and calcium isotope (δ44/40Ca) records and Earth system modeling results to summarize the environmental response to the forcing of increased atmospheric CO2 concentrations. The extent of increase in oceanic anoxic area can be estimated by δ238U, and the δ44/40Ca records may be used to evaluate ocean acidification. This evidence suggests that excessive nutrient load in the ocean (decreased strength of meridional overturning circulation) and ocean acidification in poorly buffered seawater (potentially triggered by the Siberian Traps LIP) worked together to create the most severe biological crisis and delayed recovery of life in the Earth’s history.

The end-Permian mass extinction (EPME; ca. 251.94 Ma) is the most severe mass extinction in the geological record. Detailed paleobiological investigations show a very rapid EPME event, and recently published δ238U data show a large negative excursion and thus a massive shift to globally expanded anoxia at the main extinction phase in the latest Permian. The negative shift in δ238U is in correlation with a globally characterized negative δ13C excursion near the Permian-Triassic boundary (PTB). In some highly expanded PTB carbonate sections, however, there are two distinct negative δ13C excursions whereas uranium isotopes (δ238U) from such sections have not yet been examined, leaving a gap in the understanding of the global perturbations of marine redox conditions immediately following the EPME. Here, we present a new δ238U study of syn-depositional dolostones from a well-characterized and highly expanded drill core, which recorded two pronounced negative δ13C excursions across the PTB, from the Carnic Alps, Austria. This drill core extends 331-meters across the PTB and provides a unique opportunity to explore the detailed timing, duration, and extent of marine redox chemistry changes before, during, and immediately after the EPME. Our new δ238U record shows two negative shifts, which are correlated with the two negative δ13C excursions. The first negative δ238U excursion preceding the EPME confirms the recently published δ238U records from across the EPME and support that syndepositional marine dolostones can record δ238U trends of seawater similar to that of limestones. Modeling of uranium isotope cycling in the latest Permian and earliest Triassic oceans suggests two distinct stages of expanded marine anoxia separated by a brief interval (∼100 kyr) of reoxygenation across the PTB. The first anoxic episode lasted for ∼ 60 kyr while anoxic seafloor area expanded to cover >18% of the entire seafloor, coeval with the main EPME horizon, agreeing with marine anoxia as a proximate kill mechanism for the EPME. The second anoxic event was less intense compared to the first anoxic pulse but sustained for a longer duration. A global modeling of coupled C, P, and U cycles show that two pulses of volcanic carbon injection that drives global warming and increased phosphorus weathering rate can reasonably reproduce our data to match two phases of anoxia. The model also demonstrates that the loss of terrestrial vegetation in the EPME is crucial to generating an intervening interval of oxygenated ocean. Our new study adds to a growing body of evidence that the global marine redox conditions underwent rapid oscillations during the EPME event and continued afterward, which may have played a central role in delaying the marine ecosystem recovery in the Early Triassic.

Sedimentary deposits of the Permian–Triassic transition are well-exposed in numerous outcrops of South China. Depending on the palaeogeographic positions of the sections, their lithofacies vary from fully marine, shallow marine, lagoonal, lacustrine, and fluvial to alluvial. In the present study, conchostracans (Crustacea: Branchiopoda) were newly collected from the continental deposits of the Kayitou and Jialingjiang formations around the Kangdian Highland elevated by the Emeishan Basalt in the southern Sichuan, western Guizhou, and northeastern Yunnan provinces. The conchostracan fauna of the Kayitou Formation is composed of Pseudestheria chatangensis, Euestheria fuyuanensis, and Euestheria sp. aff. E. gutta. These species occur in varying lithofacies types of different sections. In particular, the late Permian Pseudestheria chatangensis occurs in grey siltstones interbedded with pebbly sandstones, which are interpreted as lacustrine deposits. Euestheria fuyuanensis and Euestheria sp. aff. E. gutta were obtained from yellowish to greenish–grey clay- and siltstones, interpreted as coastal plain deposits. In comparison to other regions, occurrences of Euestheria gutta are indicative of an early Induan to Olenekian (Early Triassic) age. The fossil record of Euestheria fuyuanensis is so far restricted to a few occurrences in the Kayitou Formation of Southwest China and, therefore, using this species for long-distance biostratigraphic correlation requires further investigation. The distribution of late Permian pseudestheriid and Early Triassic euestheriid species in the respective sections possibly depends on the local lithofacies and, therefore, a diachronous age of the Kayitou Formation within the study area can be assumed. Additionally, Magniestheria sp. aff. M. mangaliensis and Magniestheria sp. aff. M. subcircularis were recorded in the Jialingjiang Formation, which represents a lithostratigraphic unit considered as late Early Triassic (Olenekian). Further investigations of both taxonomy and the real stratigraphic ranges of the conchostracan species as well as cross-correlations with other age data are recommended, in order to better constrain the position of the Permian–Triassic boundary and the specific timing of the terrestrial end-Permian mass extinction in continental deposits of Southwest China.

Nonmarine biostratigraphic/biochronologic schemes have been created for all or parts of the late Carboniferous–Middle Triassic using palynomorphs, megafossil plants, conchostracans, blattoid insects, tetrapod footprints and tetrapod body fossils, and these provide varied temporal resolution. Cross correlation of the nonmarine biochronologies to the Standard Global Chronostratigraphic Scale has been achieved in some parts of the late Carboniferous–Middle Triassic in locations where nonmarine and marine strata are intercalated, the nonmarine strata produce biochronologically significant fossils and the marine strata yield fusulinids, conodonts and/or ammonoids. Other cross correlations have been aided by magnetostratigraphy, chemostratigraphy and a growing database of radioisotopic ages. A synthetic nonmarine biochronology for the late Carboniferous–Middle Triassic based on all available nonmarine index fossils, integrated with the Standard Global Chronostratigraphic Scale, is presented here. The focus is on the nonmarine biostratigraphy/biochronology of blattoid insects, conchostracans, branchiosaurid amphibians, tetrapod footprints and tetrapod body fossils within the biochronological framework of land-vertebrate faunachrons. Correlation to the Standard Global Chronostratigraphic Scale presented here is divided into seven time intervals: Pennsylvanian, Carboniferous–Permian boundary, Cisuralian, Guadalupian, Lopingian, Permian–Triassic boundary and Early to Middle Triassic. The insects, conchostracans and branchiosaurs provide robust nonmarine correlations in the Pennsylvanian–Cisuralian, and the footprints and tetrapod body fossils provide robust correlations of varied precision within the entire Pennsylvanian–Middle Triassic. Radioisotopic ages are currently the strongest basis for cross correlation of the nonmarine biostratigraphy/biochronology to the Standard Global Chronostratigraphic Scale, particularly for the Pennsylvanian–Cisuralian. Chemostratigraphy and magnetostratigraphy thus far provide only limited links of nomarine and marine chronologies. Improvements in the nonmarine-marine correlations of late Paleozoic–Triassic Pangea require better alpha taxonomy and stratigraphic precision for the nonmarine fossil record integrated with more reliable radioisotopic ages and more extensive chemostratigraphic and magnetostratigraphic datasets.

Permian plant fossils have never been reported from the Shan Plateau in eastern Myanmar. Recently, a black to gray carbonaceous mudstone unit containing abundant plant fossils was discovered just below the lowest part of Thitspin Limestone Formation from the Linwe Area, eastern Myanmar. Although only five taxa were identified, the plant assemblage provides the first evidence of the occurrence of Cathaysian elements in eastern Myanmar and potentially indicates the presence of a highly diverse Permian flora. Among the five species, Cordaites principalis and Annularia mucronata were cosmopolitan species; while Callipteridum cf. koraiense, Taeniopteris crassinervis Mo and Rhipidopsis lobata were mostly recorded in the Cathaysia Flora. Therefore, the present assemblage generally indicates a palaeobiogeographical affinity to the Cathaysian Province. Stratigraphically, Callipteridum cf. koraiense was mainly reported from Cisuralian to Wordian; whereas Taeniopteris crasssnervis Mo and Rhipidopsis lobata were recorded from Capitanian to Changhsingian, which suggests a general Permian age based on the plant assemblage itself only. However, the carbonaceous mudstone at the outcrop is overlain by the Thitspin Limestone Formation containing middle Guadalupian fusulinids. Based on previous faunal analyses, the Sibumasu terrane contains typical Gondwanan cold-water faunas during the early Cisuralian, warm-water faunas occurred after Sakmarian. Thus, age of the fossil-plant-containing carbonaceous mudstone is very likely between late Cisuralian and early Guadalupian as constrained by its overlying fusulinids and its warm Cathaysian palaeobiogeographical affinity.

We report high-resolution, high-precision δ44/40Ca, δ88/86Sr, and 87Sr/86Sr records spanning the Permian-Triassic boundary (PTB) from the Meishan and Dajiang carbonate successions in south China. The goal of the study was to understand the behavior of Ca and Sr isotopes during a time period in Earth history characterized by severe biological and environmental perturbations, including a major mass extinction, flood basalt volcanism, ocean acidification, and sea level fluctuations. Dajiang displays negative δ44/40Ca and δ88/86Sr excursions and invariant 87Sr/86Sr ratios in the

A new Devonian oxygen isotope record based on 180 measurements of conodont apatite is reported from South China. The comparison with published Devonian δ18Oapatite data shows a considerable offset between records from different paleocontinents. This difference can be interpreted by regional variations in salinity, with the epicontinental seas having a distinctly lower salinity and δ18Oseawater than the open ocean due to the influence of fresh-water runoff. Our findings suggest that the oxygen isotope record from open ocean settings is the preferred archive for reconstructing the history of ocean temperature and/or ice volume over the Phanerozoic. Despite regional differences, the South China and European records show similar long-term trends characterized by a pronounced cooling during the Pragian to Eifelian followed by significant warming over the Eifelian/Givetian to Frasnian, and a further cooling starting in the Famennian, accelerating in the earliest Carboniferous. The Early Devonian cooling coincided with early vascular plant root − soil interactions and a significant diversity increase in both spores and megaplant fossils, suggesting that the rise of rooted vascular plants may have played a key role in triggering climate cooling. Subsequent climatic warming over the Middle to Late Devonian transition may have been linked to metamorphic CO2 input from the Acadian Orogeny, while Famennian cooling occurred in a context of exposure and weathering of basalts and ophiolites and coincided with the advent of seed plants. We conclude that climate changes during the Devonian were likely driven by a combination of plant evolutionary advances and changes in tectonics. We further test these interpretations by running the COPSE (Carbon, Oxygen, Phosphorus, Sulfur and Evolution) biogeochemical model. The model prediction is capable of reproducing the pCO2 record under these scenarios, although the model is not capable of reproducing the degree of temperature variation, likely due to its simplicity.

Description, Felsic volcanism in South China with Cu, Hg, and S released exacerbated environmental changes that drove the end-Permian extinction., The Siberian Traps large igneous province (STLIP) is commonly invoked as the primary driver of global environmental changes that triggered the end-Permian mass extinction (EPME). Here, we explore the contributions of coeval felsic volcanism to end-Permian environmental changes. We report evidence of extreme Cu enrichment in the EPME interval in South China. The enrichment is associated with an increase in the light Cu isotope, melt inclusions rich in copper and sulfides, and Hg concentration spikes. The Cu and Hg elemental and isotopic signatures can be linked to S-rich vapor produced by felsic volcanism. We use these previously unknown geochemical data to estimate volcanic SO2 injections and argue that this volcanism would have produced several degrees of rapid cooling before or coincident with the more protracted global warming. Large-scale eruptions near the South China block synchronous with the EPME strengthen the case that the STLIP may not have been the sole trigger.

We report extensive major and trace element data for the Permian-Triassic boundary (PTB) at Meishan, China. Analyses of 64 samples from a 2.5 m section span the last 75 kyr of the Permian and the first 335 kyr of the Triassic, from beds 24 to 34. We also report data for 20 acetic acid extracts that characterize the carbonate fraction. Whole rock major element data reflect the change of lithology from carbonate in the Permian to mudstone and marl in the Triassic, indicate an increase of siliciclastic input and MgO in and above the extinction interval (beds 24f–28), and silica diagenesis in carbonates below the extinction horizon. Above bed 27, enrichment factors calculated with respect to Al and Post-Archean Australian Shale (PAAS) are ∼1 for most trace elements, confirming that siliciclastic input dominates trace element distributions in the Triassic. Within the extinction interval, beds 24f and 26 show increases in As, Mo, U and some transition metals. V, Cr, Co, Ni, Cu, Zn, Pb, and Ba are variably enriched, particularly in bed 26. Below the extinction interval, the top of bed 24d shows enrichment of V, Cr, Co, Ni, Cu, Zn, Pb, and Ba in a zone of diagenetic silicification. Trace elements thus reflect siliciclastic input, diagenetic redistribution, and responses to redox conditions. Trace element patterns suggest either a change in provenance of the detrital component, or a change in the proportion of mechanical to chemical weathering that is coincident with the beginning of the extinction in bed 24f. Ba, Zr, and Zn behave anomalously. Ba shows little variation, despite changes in biological activity and redox conditions. The enrichment factor for Zr is variable in the carbonates below bed 24f, suggesting diagenetic Zr mobility. Zn shows a sharp drop in the extinction horizon, suggesting that its distribution was related to phytoplankton productivity. Rare earth element content is controlled by the siliciclastic fraction, and carbonate extracts show middle rare earth enrichment due to diagenesis. Ce and Eu anomalies are not reliable indicators of the redox environment at Meishan.

Geological samples must be archived for all if we are to solve the riddles of Earth’s complex history. Geological samples must be archived for all if we are to solve the riddles of Earth’s complex history.

The modern loss of species diversity has been labelled the ‘sixth extinction’ subsequent to the five major mass extinctions widely recognised in the Phanerozoic geologic record – the end-Or...

Permian faunal affinity in the Lhasa Block plays a critical role in reconstructing its paleogeographic evolution. Cisuralian and Guadalupian faunas have been described from the Lhasa Block, but very few Lopingian (late Permian) brachiopods have been reported so far. In this paper, a new diverse brachiopod fauna consisting of 17 species of 17 genera and an unidentifiable Orthotetoidea is described from the uppermost part of the Xiala Formation at the Aduogabu section in the central part of the Lhasa Block. The age of this fauna can be assigned to the Changhsingian (late Lopingian) as indicated by the associated foraminifersColaniella parva(Colani, 1924) andReichelina pulchraMiklukho-Maklay, 1954. Characteristic brachiopods includeSpinomarginifera chengyaoyenensisHuang, 1932,Haydenella wenganensis(Huang, 1932), andAraxathyriscf.dilatatusShen, He, and Zhu, 1992. They also generally suggest a Changhsingian age. Paleobiogeographically, this fauna is uniformly composed of typical Tethyan elements represented bySpinomarginiferaHuang, 1932 andHaydenellaReed, 1944, and some cosmopolitan elements, but no typical cold-water taxa of Gondwanan affinity. This is in contrast to the contemporaneous brachiopod faunas from the Tethys Himalayan region that are characterized by typical cold-water taxa of Gondwanan affinity, e.g.,Costiferina indica(Waagen, 1884),Retimarginifera xizangensisShen et al., 2000,Neospirifer(Quadrospina)tibetensisDing, 1962. Thus, it is strongly indicative that the Lhasa Block had drifted into a relatively warm-water regime during the Changhsingian. An analysis of the paleobiogeographic change of brachiopods in the Lhasa Block throughout the entire Permian further suggests that the Lhasa Block probably had rifted away from the northern peri-Gondwanan margin between the latest Cisuralian and middle Guadalupian, that is, the Neotethys Ocean had opened before middle Guadalupian.

Earth's transition from an icehouse to hothouse during the Late Paleozoic was characterized by a series of high paleolatitude glacial-interglacial events. However, the exact timing of these events remains unresolved. Here, we report on fifty-five calcitic shells of brachiopods and bivalves screened to obtain reliable 87Sr/86Sr ratios for Cisuralian (298.9-272.95 Ma) and Guadalupian (272.95-259.1 Ma) seawater. Specifically, we used well-preserved shells to build a 87Sr/86Sr seawater curve for the Sydney Basin, and then with the marine Look-up Table of the Permian calculated numerical ages of the stratigraphic succession. This allowed us to match seawater changes to the coeval P1 – P3 glacial-interglacial cycles recorded in the sedimentary successions of the Sydney Basin. Evaluation of the 87Sr/86Sr results revealed that onsets of the P2 and P3 glaciations in the Sydney Basin should be assigned to the early Artinskian and late Wordian, respectively. The range of 87Sr/86Sr values recorded by brachiopods from the Wandrawandian Siltstone coupled with recent geochronological dating of the Broughton Formation suggest that glacial phase P3 lasted about 2 Myr and was confined to the late Wordian – early Capitanian. Dating obtained using the Sr-isotope proxy from brachiopods agrees with the geochronologic ages, and they suggest that the glacial phases P1 to P3 became progressively shorter in duration and less intense. Conversely, the corresponding interglacials became progressively longer, and thus, documenting the gradual transition of the Permian icehouse to an ice-free greenhouse world. Our study confirms that strontium isotopes measured in screened brachiopod shell archives are sufficiently robust to date Paleozoic marine sedimentary successions, and are most valuable in sedimentary successions that otherwise lack geo-chronological dating.

Two new Middle Permian foraminifer faunas are described from the Xiala Formation in the Zhabuye and Xiadong sections in the central Lhasa Block. The presence of some significant taxa in paleobiogeography such as Shanita, Lysites biconcavus, Hemigordiopsis subglobosa, indicates that the Lhasa Block was in the Cimmerian Province in paleobiogeography during the Middle Permian. Furthermore, the Nankinella-Chusenella fusuline assemblage that occurs in the upper part of the Xiala Formation in the Xiadong section resembles contemporaneous fusuline faunas from the Xainza and Bashor areas in the Lhasa Block and the northern part of the Tengchong Block. The endemism of the Nankinella-Chusenella assemblage in the Lhasa and Tengchong blocks indicates that these two blocks were isolated from both the South Qiangtang Block and the northern Gondwanan margin during the Middle Permian. It further suggests that both the Bangong-Nujiang Ocean and the Neotethys Ocean would have opened before the Middle Permian. A new species Chusenella tsochenensis sp.nov. was described.

The Lopingian is the uppermost series of the Paleozoic and it is bracketed by two major biological events, including the pre-Lopingian crisis and the end-Permian mass extinction (EPME). A high resolution temporal framework is essential to understand the patterns and causes of the extinction. Lopingian strata of South China have been intensively studied because three GSSPs have been defined in the region. Based on the review and updates to data from the Shangsi section as well as correlation with the Meishan section, the time framework for the Lopingian is revised, including biostratigraphy, chemostratigraphy, magnetostratigraphy, cyclostratigraphy and geochronology. The temporal framework is constrained by both precise geochronologic data and a high resolution conodont succession, and provides the possibility that the current high resolution marine international standard can also be applied to nonmarine strata by means of geochronology, magnetostratigraphy and cyclostratigraphy. The entire Lopingian high resolution conodont succession is for the first time, since the Lopingian Series was adopted as the international standard, recognized at a single section in South China and the succession correlates very well with the Lopingian GSSP sections at Penglaitan and Meishan. The Permian-Triassic boundary (PTB) of the Shangsi section is constrained to the basal 6 cm interval of Bed 28b in view of ammonoids, bivalves, conodonts, U-Pb ages and the EPME. The mass extinction interval is between Bed 27 and lower Bed 28a according to the EPME pattern at the Shangsi section, and the alternative interval between extinct Permian species and new Triassic species is from upper Bed 28a to lower Bed 28b. Unitary Association (UA) analysis of Lopingian conodonts reveals 15 unitary association zones (UAZs) based on seven important Lopingian sections of South China. Most of the UAZs correlate well with the standard biozonation, except for UAZ 3 to UAZ 5 and UAZ 12. The correspondence between UAZs and standard conodont biozones at the Shangsi section provides a practical example to understand controls on conodont UAZ determination. The Lopingian conodont succession is temporally calibrated by geochronologic ages, identified 405-kyr eccentricity cycles, and a Monte Carlo analysis at the Shangsi and Meishan sections. Updated ages for the base of the Lopingian and base of the Changhsingian are provided.