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The end-Permian mass extinction (EPME) was known as the most severe biocrisis of the past 600 Ma. In order to explore the redox state of deep water environments, and the causal relationship between anoxia/euxinia and the EPME, this study selected the Penglaitan section in Guangxi, China, and measured the iron speciation and concentrations of trace elements and major elements. Several redox proxy approaches, including both iron speciation proxies and the excess fractions and enrichment factors of redox sensitive elements (RSEs), indicate that anoxia in the Penglaitan depositional environment was sporadic, with the majority of the section deposited under oxic conditions. This includes the interval immediately prior to and during the EPME; euxinia did not occur at the Penglaitan section around the EPME. Thus, anoxia was not the primary driver for the EPME at the Penglaitan section, and the accumulation of free H2S in the oceanic water-column could not have been the only proximal kill mechanism for the EPME at the Penglaitan section.

Permian–Triassic boundary microbialites (PTBMs) are organosedimentary carbonates formed immediately after the end-Permian mass extinction. All those reported PTBMs constrained by convincing conodont biozones are present stratigraphycally not higher than the Hindeodus parvus zone and most of them are dominated by thrombolites. This paper provides the first record of a brief, but spectacular development of stromatolite-dominated PTBMs within the basal Isarcicella isarcica conodont zone of the earliest Triassic from the Xikou section of South Qinling Block that was at the margin of the North China Block during the Permian–Triassic transition and was geographically separated from the major occurrence of post-extinction microbialites in the South China Block. This stromatolite cap overlies a 3.7-m-thick oolitic limestone and is composed of a lower 0.2-m-thick bed and an upper 0.5-m-thick bed, separated by a 0.2-m-thick greyish green siliciclastic mudstone. These two stromatolite beds mainly consist of columnar stromatolites with subordinate domal stromatolites. The intercolumn and interstitial spaces within the stromatolites are filled with oolitic grainstones. At the microscopic scale, laminoid structures in stromatolites comprise wavy, millimetric-domical and tangled laminae. The increased grain and fossil contents and/or bioturbation in the domical and tangled laminae indicate that the formation of these laminae is likely related to an increase in the populations and the disruptions by benthic metazoans, as well as an influx of sediment grains. The δ13Ccarb values fluctuate between 2‰ and 3‰ in the uppermost Permian strata; a distinct negative shift of 1.9‰ occurs at the topmost oolitic grainstone, just below the lower stromatolite bed, and the lowest value of −0.1‰ is located at the base of the upper stromatolite bed. The stratigraphic succession from stromatolites to thrombolites of the PTBMs may represent a transgressive succession and/or a transient ecosystem recovery immediately after the end-Permian mass extinction. The thrombolites-dominated PTBMs mainly developed in near-equator shallow marine geographic locations, and stromatolite-dominated PTBMs mainly developed at higher latitude settings, which probably indicates that a relatively lower diversity and abundance of marine benthic metazoans existed at higher latitudes after the end-Permian mass extinction.

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.

Although the precise age and magnitude of the end-Guadalupian biodiversity crisis is still debated, this “mass” extinction has been customarily linked with the onset of massive volcanism in the Emeishan Large Igneous Province (ELIP) in south China. The onset of ELIP eruptive activity at least partly coincides in time with episodes of regional subsidence interrupting the predominant regime of carbonate platforms during Capitanian times. Here, we present a strikingly similar but younger (early Wuchiapingian) subsidence episode from the Pingtang syncline in southern Guizhou, termed the Mapojiao Event. Shallow-marine, light-grey, thick-bedded bioclastic limestone of the Wuchiaping Formation (Unit A) are overlain by deep-marine radiolarian-sponge spicule, thin-bedded black limestone (Unit B). The latter is followed by volcaniclastic distal turbidites (Unit C). The base of the next overlying unit consists of cherty, nodular limestone (Unit D) rich in radiolarians and sponge spicules, whose respective abundances decline up-ward within a few meters. Concomitant replacement by a shallow marine benthic fauna documents the uplift that terminates the event. A total of five index species of Clarkina conodonts indicating an early Wuchiapingian age were obtained from Units A and B. Brachiopods of Wuchiapingian age were also documented in units A, B and D. Compilation of drowning events in the Guadalupian-Lopingian (G-L) interval suggests clustering into three episodes; 1: middle Capitanian, 2: possibly latest Capitanian, 3: early Wuchiapingian. The first drowning event is overlain by ELIP volcanics in sections near the center of the volcanic province. In peripheral areas, the first drowning is intercalated within carbonate platforms (e.g. Maoershan). A second drowning event cannot be excluded close to G-L boundary but it is obscured by the unconformity associated with an eustatic regression and by ambiguous conodont age control. Overlying this unconformity, the Wangpo Shale, which contains ELIP-derived volcanic materials, rests on the first (e.g. in Chaotian) drowning event. The striking similarities of the facies architecture shared by the first and third drowning events suggest a similar driving mechanism. Hence, we propose that the Mapojiao Event represents the youngest, early Wuchiapingian, burst of ELIP eruptive activity. There is no one-to-one correlation between these episodes related to ELIP eruptive activity and extinction phases of marine clades. Only the end-Guadalupian extinction has been correlated with the first eruptive episode. In marked contrast, the newly discovered Mapojiao drowning episode occurred within a diversification phase, which undermines any causal relations between the younger phases of ELIP volcanism and additional extinctions.

The Sakmarian Stage represents a critical time interval because the Late Paleozoic Ice Age reached its acme during this time. After extensive studies, we herein use the First Appearance Datum (FAD) of the conodont Mesogondolella monstra within the lineage from M. uralensis -> M. monstra -> M. manifesta at Bed 26/3 of the Usolka section in the southern Urals, Russia, as the primary signal for the base-Sakmarian GSSP. The first occurrence of the conodont Sweetognathus binodosus within the lineage from Sw. off. merrilli -> Sw. binodosus is used as an auxiliary marker for the base of the Sakmarian Stage. An extrapolated age for this GSSP is 293.52 +/- 0.17 Ma produced by a Monte Carlo simulation based on two ash beds dated by chemical abrasion isotope dilution thermal ionization mass spectrometry (CA-ID-TIMS). The Sr-87/Sr-86 isotopic value based on conodont apatite for the base of the Sakmarian Stage is approximately 0.70787. Two minor negative excursions in delta(13)C(carb )are present at the boundary levels and the upper one is consistent with the GSSP level. The documentation of fusulinaceans, ammonoids, brachiopods and palynology also aid intercontinental and marine-terrestrial correlation. The Usolka section meets the requirements for the GSSP and a monument has been established; correlation with sections in North America and South China is also well documented.

Tracking climate change and its relationships with chemical weathering and massive volcanic activity in deep-time greatly improves our understanding of the Earth's climate system. The Permo-Carboniferous period is a critical time interval with million year-scale glacial-deglacial cycles and massive basaltic volcanism, such as the Skagerrak-Centered (also named Skagerrak or Jutland) large igneous province. To explore the volcanism-climate interactions in this period, we obtained high precision CA-TIMS U-Pb zircon ages for three tuffaceous layers from a cored upper Pennsylvanian-lower Permian marginal marine succession in southern North China. These ages calibrate the Permo-Carboniferous biostratigraphy between ∼301–296 Ma in North China. From this dated core succession, mudrock samples and their calculated weathering index values were screened to constrain the weathering trends for the source landscapes and demonstrate a rapid increase with a subsequent decrease in source chemical weathering intensity during the period of ∼299 to 296.5 Ma. These trends coincide with the southern Gondwana glacial records, low latitude temperature changes, relative sea-level variations, and shifts in atmospheric pCO2 that together document an earliest Permian climate warming-cooling perturbation with a temperature maximum at ∼298 Ma. This climate warming in the Permo-Carboniferous icehouse correlates with the emplacement of the Skagerrak-Centered large igneous province, which likely released voluminous CO2 that led to climate warming during the Permo-Carboniferous transition. The immediately following cooling could possibly result from the rapid post-eruptional weathering of the massive basaltic rocks of this province in tropical latitudes, which would have sequestered atmospheric CO2 and promoted return to cooler icehouse conditions. This study supports the assertation that massive basaltic volcanism could first cause rapid climate warming and then may have an overall net cooling effect as previously suggested for the Deccan Traps and the Central Atlantic Magmatic Province.

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.

A major discrepancy for the age of the Selong Group from middle Cisuralian (Early Permian) to Changhsingian resulted from previous reports of Sakmarian, Kungurian and Guadalupian (Middle Permian) conodonts and Lopingian (Late Permian) brachiopods. Recently, Cisuralian and Guadalupian conodonts were reported again from the Selong Group and the basal part of the Kangshare Formation at the Selong section, but the age discrepancy remains. We present our conodont materials based on large samples collected from the Selong Group and our interpretation based on identifications using a sample population approach. Three conodont zones are recognized in our re-investigation of the upper part of the Selong Group. They include the Vjalovognathus sp., the Mesogondolella hendersoni, and the M. sheni zones, in ascending order. These zones are overlain by the basal Triassic Hindeodus parvus Zone and the Otoceras woodwardi Zone. Our reassessment of conodonts reported by previous studies from Selong and nearby sections suggest that all specimens consistently point to a Lopingian age; the upper part of the Selong Group is latest Changhsingian in age based on the presence of Clarkina orchardi and Mesogondolella sheni. Previously reported early Cisuralian and Guadalupian conodonts are misidentified using a form species concept. A hiatus may be present at the erosional surface between the Selong Group and the Waagenites Bed of the basal part of the Kangshare Formation. However, the hiatus is minimal because conodont and brachiopod assemblages above and below this surface are very similar, and it results from a latest Changhsingian transgression just before the extinction that follows a global latest Changhsingian regression. There is a distinct rapid end-Permian mass extinction at Selong within the Waagenites Bed, as indicated by the disappearances of all benthic brachiopods, rugose corals and Permian bryozoans. The burst of Clarkina species in the Waagenites Bed and throughout the entire Lower Triassic at Selong is interpreted as a southward migration of equatorial conodont animals associated with the rapid global warming beginning at the end of the Permian. The cool- or cold-water species of Mesogondolella, in the upper part of the Selong Group and the basal part of the Kangshare Formation, are representative of the uppermost Permian in the bipolar/bi-temperate cold-water province and are not reworked from the underlying Selong Group or any other unknown Cisuralian or Guadalupian deposits.

The paleogeographic evolution of the North Qiangtang Block during the Middle and Late Permian has been a contentious issue in recent decades. In this study, the Permian foraminiferal faunas were studied from the Raggyorcaka and Wangka areas in northern and eastern Tibet. The foraminifera from the Xueyuanhe Formation in the Raggyorcaka area suggest a Changhsingian rather than a Guadalupian (Middle Permian) age, as previously determined. A review of Permian strata in the North Qiangtang Block confirms the widespread onset of the Lopingian (Late Permian) paralic sedimentary facies containing gigantopterid plant fossils and the fusuline Palaeofusulina fauna, which lies unconformably over the different pre-Lopingian strata. The similar Lopingian facies and pronounced unconformity across the North Qiangtang and Simao blocks are interpreted as the initial collision between the Simao/Indochina and the South China blocks.

The Permian Period is punctuated by Earth system changes unlike any other in geological history. The start of the Permian witnessed the termination of the Late Paleozoic Ice Age, followed by the climatic transition from icehouse to greenhouse conditions. The Guadalupian-Lopingian (Middle-Late Permian) was characterized by two biocrises associated to volcanisms: (i) the end-Guadalupian crisis and (ii) the end-Permian mass extinction. Seawater Sr isotope (87Sr/86Sr) records can shed light on the evolution of the Permian Earth system. The Permian 87Sr/86Sr record suffers from a number of issues including low resolution and potential diagenetic alteration. In this paper, we summarize the existing Permian 87Sr/86Sr records and focus on the current challenges. We also present a new, high-resolution Permian 87Sr/86Sr curve derived from pristine brachiopod shells based on data resulting from careful diagenetic screening. Our new record shows that the 87Sr/86Sr of seawater decreased continuously from the earliest Permian to the middle Capitanian (late Guadalupian), with the lowest ratio of 0.706832 registered in the Colania douvillei-Kahlerina pachiytheca Zone. Subsequently, 87Sr/86Sr ratios increased from the late Capitanian to the latest Permian and reached a ratio of 0.707167 just 0.8 m below the first occurrence of the Hindeodus parvus. We employed a stochastic oceanic box model to explore the potential drivers of the Permian seawater Sr isotope record. Our results support that changes in the hydrothermal input, rather than changes in continental weathering intensity, are the most likely controlling factor for the observed variations in Permian seawater 87Sr/86Sr. Therefore, we suggest that the marine hydrothermal system (and hence ocean basin dynamics and deep-sea temperatures) may have been the driver of the pronounced decreasing 87Sr/86Sr trend across the Permian.

South China has become the most important area to establish a global stratigraphic framework of the Wuchiapingian Stage because complete Wuchiapingian sequences include the GSSPs for the base and top of the stage. As the markers of the Wuchiapingian GSSP, conodonts are the most important fossil group to establish the Wuchiapingian biostratigraphic framework. However, few documents have investigated in detail the conodont biostratigraphic succession through the entire Wuchiapingian Stage. Furthermore, the conodont taxonomy of several WuchiapingianClarkinaspecies is still debated. Therefore, we here review all WuchiapingianClarkinaspecies from South China and figure ontogenetic growth series from juvenile to adult individuals for each valid and important species in order to revise both Wuchiapingian conodont taxonomy and the biostratigraphic succession. Based on the Penglaitan, Dukou, and Nanjiang sections, seven conodont zones (Clarkina postbitteri postbitteri,C.dukouensis,C.asymmetrica,C.leveni,C.guangyuanensis,C.transcaucasica, andC.orientalis) are recognized. The WuchiapingianClarkinaspecies lineage is also reviewed to confirm the conodont biostratigraphic framework. The Guadalupian-Lopingian boundary (GLB) interval represents a sequence boundary. The time framework of the pre-Lopingian extinction interval indicates that the beginning of the end-Guadalupian regression is in the upper part of theJinogondolella postserrataZone, and the beginning of the early Lopingian transgression is in the lower part of theClarkina dukouensisZone in South China.

Based on analyses of 565 conodonts from Meishan, Liangfengya, and Daijiagou (South China), and Abadeh (central Iran), we propose a revision of the seawater 87Sr/86Sr curve for the time period spanning 200 kyr prior to the Permian-Triassic boundary (PTB) to 330 kyr after the PTB. With carefully designed sample cleaning, conodonts faithfully record seawater 87Sr/86Sr. Seawater 87Sr/86Sr was 0.707030 ± 10,200 kyr prior to the PTB, rose to 0.707070 ± 10 approximately 39 kyr prior to the PTB (at the marine extinction horizon, the top of Bed 24e at Meishan), to 0.707080 ± 10 at the PTB, and to 0.707120 ± 20 at 330 kyr after the PTB. The rate of change of seawater 87Sr/86Sr was 0.0000185/Myr from the Capitanian minimum to ~ 100 kyr before the PTB, and was 0.00020 ± 7.5/Myr between ~ 100 kyr before and 330 kyr after the PTB. Over 6 Myr, this rate of change would result in a maximum 87Sr/86Sr of ~ 0.70825 at the end of the Early Triassic, compared with a model value of ~ 0.7080. The Sr data are consistent with the interpretation that the rise in marine 87Sr/86Sr was due primarily to an increase in the continental weathering and erosional flux, and that soil-binding vegetation was not re-established during most of the Early Triassic. The rapid rise in seawater 87Sr/86Sr began at least 30 kyr prior to the marine extinction at Meishan, indicating that the terrestrial extinction preceded that in the oceans.

The Guadalupian Epoch represents one of the most critical intervals during the Earth history which is characterized by a series of global geological and biological events. However, it is poorly constrained by radioisotopic ages in comparison with the high-precision dates from the Lopingian and lowest Triassic in South China and the Cisuralian in southern Urals, Russia. In this study, we report combined CA-ID-TIMS and SIMS U-Pb zircon geochronology for three ash beds from the base and lower part of the Kuhfeng Formation in the Chaohu area, southeastern China. Zircons from Ash Beds A, C and D were initially analyzed by SIMS and yielded weighted mean 206Pb/238U dates of 269.0 ± 1.4 Ma (MSWD = 1.03, n = 31), 266.3 ± 2.2 Ma (MSWD = 2.2, n = 29) and 262.2 ± 1.7 Ma (MSWD = 1.0, n = 20) in ascending order. However, high-precion U-Pb geochronology of the same ash beds by the CA-ID-TIMS method point to important inaccuracies in the SIMS results due to Pb-loss in zircons. Ash Beds A and C yielded two TIMS weighted mean 206Pb/238U dates of 272.95 ± 0.11 Ma (MSWD = 1.9, n = 7) and 271.038 ± 0.097 Ma (MSWD = 2.2, n = 8), respectively. The depositional age of 272.95 ± 0.11 Ma for Ash Bed A is postulated as the traditional Cisuralian-Guadalupian boundary (CGB) age in South China. Our new geochronology suggests that the Guadalupian Series in South China had a total duration of 13.85 ± 0.52 myr given a Guadalupian-Lopingian boundary (GLB) age of 259.1 ± 0.5 Ma. The new age calibration of the base of the Guadalupian Series is ca. 0.65 (± 0.51) myr older than – and improves upon – the previous estimates for the CGB age and the duration of the Guadalupian Epoch based on the 2016 International Chronostratigraphic Chart (ICC) and the 2012 Geologic Time Scale (GTS).

A brachiopod fauna including 15 species belonging to 14 genera is described from a thin carbonate succession of the Lugu Formation at the Anmu section in the northern part of the South Qiangtang Block, which is about 15 km south to the Longmu Co-Shuanghu Suture. The brachiopod fauna is late Kungurian or early Guadalupian in age in terms of the presence of the brachiopod species Vediproductus punctatiformis, “Cryptospirifer” omeishanensis, and Paraplicatifera regularis. This is also generally consistent with the age indicated by the fusulines (e.g., Cancellina, Chusenella, Monodiexodina, Nankinella, Neofusulinella, Pseudofusulina, and Sphaerulina) from this formation at the nearby Mari and Duoma A (DMA) sections. Palaeobiogeographically, the brachiopod fauna exhibits a typical Cathaysian affinity and all the species are reported commonly from the equivalents in South China and Cimmerian blocks, which strongly suggest that the South Qiangtang Block had drifted to a position in the warm-water or temperate regime close to South China.

We present a new, biostratigraphically calibrated organic and inorganic C-isotope record spanning the basal Late Permian to earliest Triassic from southern Guizhou (Nanpanjiang basin, South China). After fluctuations of a likely diagenetic overprint are removed, three negative carbon isotope excursions (CIEs) persist. These include a short-lived CIE during the early Wuchiapingian, a protracted CIE ending shortly after the Wuchiapingian–Changhsingian Boundary, and a third CIE straddling the Permian–Triassic boundary. Comparison of our new C-isotope record with others from the same basin suggests that influences of local bathymetry and of the amount of buried terrestrial organic matter are of importance. Comparison with other coeval time series outside of South China also highlights that only the negative CIE at the Permian–Triassic boundary is a global signal. These differences can be explained by the different volumes of erupted basalts between the Late Permian Emeishan and the younger Siberian large igneous provinces and their distinct eruptive modalities. Emeishan volcanism was largely submarine, implying that sea water was an efficient buffer against atmospheric propagation of volatiles. The equatorial position of Emeishan was also an additional obstacle for volatiles to reach the stratosphere and benefit from an efficient global distribution. Consequently, the local significance of these CIEs calls into question global correlations based on C-isotope chemostratigraphy during the Late Permian. The timing of the Late Permian Chinese CIEs is also not reflected in changes in species diversity or ecology, unlike the sudden and global Permian–Triassic boundary crisis and subsequent Early Triassic upheavals.

Climate warming, probably as a result of massive degassing of greenhouse gases from the Siberian Traps magmatism, has often been acclaimed as a major cause of the end-Permian mass extinction. Indeed, several studies have documented a sudden rise in seawater temperatures during the latest Permian-earliest Triassic, as evidenced by oxygen isotopic records measured on conodont apatite. However, whether such a rapid increase in seawater temperatures occurred before, during, or after the mass extinction remains controversial. Moreover, the pattern of this rise in seawater temperatures and its timing relative to the latest Permian-earliest Triassic carbon cycle disruption, mass extinction, as well as the Siberian Traps magmatism still need to be rigorously examined in various regions. In this study, we present high-resolution oxygen isotopic records of conodont apatite (δ18Oapatite) from the Upper Permian-lowermost Triassic interval at the Abadeh section, central Iran that are analyzed with in situ secondary ion mass spectrometry (SIMS) method. The δ18Oapatite results from Abadeh demonstrate a clear pattern consisting of three phases: (1) From the lower Wuchiapingian Clarkina dukouensis Zone to the end-Permian mass extinction horizon, δ18Oapatite values are relatively stable, fluctuating in the range of 18.28-20.15‰ with an average of 19.44‰. (2) δ18Oapatite value remains high as 19.26‰ at the mass extinction horizon. Above this horizon, a sudden decrease occurs in the Clarkina hauschkei Zone and reaches a low value of 17.05‰ close to the Permian-Triassic boundary. (3) In the lowermost Triassic, δ18Oapatite values maintain a low baseline in the range of 16.92-17.39‰ with an average of 17.11‰. Overall, the most dramatic change in δ18Oapatite values (i.e., a decrease of ~2‰), converting into an abrupt warming of ~10 °C, occurred above the mass extinction horizon and below the Permian-Triassic boundary at Abadeh. The Abadeh δ18Oapatite record is consistent with previous results documented in South China, Iran, and Armenia in terms of the timing and magnitude of a substantial warming, and therefore represents a global signature. If applying the high-precision temporal framework established in the well-dated Meishan GSSP section to Abadeh, the abrupt warming of ~10 °C took only a maximum duration of ~37 kyr (thousand years). By projecting the carbon cycle change, temperature rise, mass extinction at the Abadeh and Meishan sections, and the temporal evolution of the Siberian Traps magmatism onto a unified timescale, the temporal correlation strongly suggests that the switch from dominantly extrusive eruptions to widespread sill intrusions is probably the most annihilating phase of the Siberian Traps magmatism, and is temporally consistent with the end-Permian mass extinction.

The Guadalupian Epoch is marked by the formation of the Pangean supercontinent, global sea-level change, rifting and drifting of the Cimmerian continents, formation of large igneous provinces and dramatic biotic changes. A high-resolution biostratigraphic, chemostratigraphic and high-precision geochronologic framework of this critical transition is fundamental to understanding these events. Extensive studies of the latest Cisuralian and Guadalupian Series in both South China and North America reveal the same conodont lineages, but the conodont interval zones based on Jinogondolella within the Guadalupian Series are slightly diachronous. High-precision U-Pb geochronological studies (CA-ID-TIMS method) calibrate the base of the Guadalupian Series (base Roadian) at 273.01 ± 0.14 Ma. A previously reported age from an ash bed overlying the Emeishan flood basalts, 259.51 ± 0.21 Ma, is adopted for the Guadalupian/Lopingian boundary (GLB). Based on recently published geochronology and Bayesian age modeling from the Guadalupian Series, the base of the Capitanian is constrained at 264.28 ± 0.16 Ma and the base of the Wordian is interpolated to be 266.9 ± 0.4 Ma. The Illawarra Reversal is of early-middle Wordian age. Both North America and South China possess a distinct negative δ13Ccarb excursion of 3-5‰ at the latest Kungurian and early Roadian (LK-ER CIE), which coincides with the early stages of a significant 3rd order sea-level rise. The large end-Guadalupian δ13Ccarb negative excursion may have been affected by post-depositional diagenesis or a warming event associated with the Emeishan volcanism. The 87Sr/86Sr ratios in both regions declined from the latest Kungurian to the late Capitanian, but have different ratios and reveal several fluctuations in the middle Guadalupian. Measured δ18Oapatite values suggest that the Delaware Basin was 3-4°C cooler than the eastern Yangtze Block. Analysis of a new high-resolution database of marine taxa indicates only a minor pre-Lopingian diversity drop from 261.04 Ma to 259.98 Ma, which coincides with the peak Emeishan volcanism. The widely-perceived “end-Guadalupian mass extinction” in North America is evidently masked by, and possibly an artefact of, a stratigraphic truncation effect due to rapid lithofacies changes from limestone to laminated evaporites with the closure of the west Texas basins.

The end-Permian mass extinction (EPME) was the most severe extinction event of the Phanerozoic. To investigate oceanic redox conditions around the EPME, we conducted a series of geochemical analyses, including iron speciation, trace element geochemistry, total organic carbon (TOC), and nitrogen isotopes of kerogen (δ15Nkero), around the EPME at the Shangsi section, South China. Three intervals with different redox conditions can be distinguished based on iron speciation. During the first interval (early and middle Changhsingian), bottom waters were pervasively euxinic. In the second interval (late Changhsingian and the EPME), bottom water fluctuated between oxic and anoxic, but non-sulfidic conditions, with the oxic mode becoming increasingly predominant over time. During the third interval, following the EPME, bottom waters appeared to have been consistently anoxic, although again not pervasively euxinic. This redox history is supported by enrichments in the authigenic fraction of redox-sensitive elements. These relatively high δ15Nkero values (> 1.0‰) corresponding with Changhsingian euxinia suggest reducing bottom waters did not impinge on the photic zone. The shift to values near 0‰ within and above the EPME indicates an ecological expansion of diazotrophs. Stratigraphic trends of Nixs, Cdxs, Pxs, and TOC indicate that primary productivity was highest in the first interval, coinciding with euxinic bottom water, then decreased during the lower part of Interval 2 and remained at low level through the remainder of the studied section. The temporal relationship between redox condition and primary productivity suggests that euxinia was supported by high productivity and carbon export in the early Changhsingian. The expansion of N2 fixation coincides closely with the previously documented warming of the ocean surface at Shangsi and may be related to reduced oceanic circulation and suppressed vertical mixing. The temporal distribution of deepwater anoxia and euxinia suggests that they were not primary causes for the extinction of benthos at Shangsi.

Understanding the interplay of climatic and biological events in deep time requires resolving the precise timing and pattern of paleotemperature changes and their temporal relationship with carbon cycle variations and biodiversity fluctuations. In situ oxygen isotope analyses of conodont apatite from South China enables us to reconstruct high-resolution seawater temperature records across the Permian–Triassic boundary (PTB) intervals in the upper slope (Meishan), lower slope (Shangsi), and carbonate platform (Daijiagou and Liangfengya) settings. Constrained by the latest high-precision geochronological dates and high-resolution conodont biozones, we can establish the temporal and spatial patterns of seawater temperature changes and assess their potential connections with the carbon cycle disruption and biodiversity decline. We find a rapid warming of ~ 10 °C during the latest Permian–earliest Triassic that postdated the onset of the negative shift in δ13Ccarb by ~ 81 kyr (thousand years), the abrupt decline in δ13Ccarb by ~ 32 kyr and the onset of mass extinction by ~ 23 kyr, which contradicts previous claims that the extreme temperature rise started immediately before or coincided with the onset of mass extinction. Our new evidence indicates that climate warming was most likely not a direct cause for the main pulse of the end-Permian mass extinction (EPME), but rather a later participant or a catalyst that increased the pace of the biodiversity decline. In addition, a prominent cooling is recorded in the earliest Changhsingian, with the main phase (a drop of ~ 8 °C in ~ 0.2 Ma) confined to the lower part of the Clarkina wangi zone and synchronous with the positive limb of the carbon isotope excursion (CIE) around the Wuchiapingian–Changhsingian boundary (WCB) in Meishan and Shangsi. Further long-term and high-resolution studies from other sections are needed to confirm the full contexts and underlying dynamics of the WCB “cooling event”.

The Qiangtang Metamorphic Belt (QMB) was considered to have either formedin situby amalgmation of the North and South Qiangtang blocks or been underthrust from the Jinsha suture and exhumed in the interior of a single ‘Qiangtang Block’. A newSphaeroschwagerinafusuline fauna discovered in the Raggyorcaka Lake area supports the interpretation that the North and South Qiangtang blocks were separated by a wide ocean during Asselian (Early Permian) time, indicating that the QMB was formed by the suturing of the Palaeotethys Ocean along the Longmu Co-Shuanghu suture.

An Early Permian (Cisuralian) conodont fauna is reported for the first time from the Sibumasu Terrane in eastern Myanmar. The conodont fauna includes Vjalovognathus nicolli and typical Mesogondolella idahoensis; some M. idahoensis possess transitional characters with M. lamberti and M. siciliensis. This fauna indicates a late Kungurian age. The longest range of the Taungnyo Group was from late Tournaisian to late Kungurian, and the range of the overlying Moulmein Limestone might be from late Kungurian through Guadalupian (Middle Permian). The nearly synchronous occurrence of identical conodont faunas from eastern Myanmar, the Lhasa Block and northwestern Australia provides important evidence that these tectonic units had a close paleogeographic, paleobiogeographic and paleoclimatic evolution during the late Cisuralian. The occurrence of this conodont fauna across the continuous boundary interval between the Taungnyo Group and Moulmein Limestone might indicate a paleoclimatic transition from Early Permian cool-water conditions to a Middle to Late Permian warm-water setting due to tectonic drifting of the relevant blocks and/or paleoclimatic amelioration after the Late Paleozoic Ice Age (LPIA) from Carboniferous to Cisuralian. This discovery also suggests that the terranes in eastern Myanmar are complicated by subsequent tectonic mergence and possibly of multiple origins based on the conodont and fusuline faunal affinities in different areas of eastern Myanmar.

Climatic warming has been widely cited as a driver for many mass extinction events in Earth history, including the middle-late Permian Guadalupian-Lopingian boundary (GLB) mass extinction and end-Permian mass extinction (EPME) investigated in this study. However, the role of warming in driving the EPME event is under debate because current paleotemperature studies indicate the rapid increase in sea-surface temperature postdate the onset of the EPME event, and a reliable paleotemperature record across the GLB event is lacking. Here, we present a high-resolution and successive δ 18 O record using low-Mg calcite shells of brachiopods (bLMCs) from a single stratigraphic section in central China to reconstruct paleotemperature changes from the middle to the latest Permian. After a rigorous screening for diagenesis, our data show a ∼1.0‰ decrease in δ 18 Ocalcite (and thus climatic warming) during the middle Capitanian, followed by a gradual ∼2.0‰ increase (climatic cooling) during the late Wuchiapingian. From the latest Wuchiapingian to the early Changhsingian, δ 18 O decreased gradually and reached the lowest values of -4.0‰ (and thus rapid climatic warming) immediately before the Permian-Triassic boundary. The two warming events are coeval with the onset of the Emeishan Large Igneous Province and the Siberian Traps Large Igneous Province, respectively, suggesting the two volcanic events are the plausible drivers of these climatic warming events. A close comparison of paleontological and geochemical records indicates that the warming events occurred predate the GLB and EPME events, this is in contrast with conodont δ 18 Oapatite data which document the rapid climatic warming lagged the onset of the extinction event. The comparison between δ 18 O of bLMCs and δ 18 O of conodonts from the same section shows that the long-term trends are similar, but, at higher temporal resolution, discrepancies are present, entailing further investigation in the near future. Our study confirms that δ 18 O of the brachiopod shells underwent important changes during the end of Paleozoic, highlighting that sea surface temperature is a key factor to understand the biosphere history, since it changes simultaneously with the biological crises, and that bLMCs are invaluable archive for tracking physical and chemical conditions of past oceans.

The Guadalupian Epoch was characterized by major changes in paleogeography, paleoclimate, and biodiversity. Yet, the paucity of precise and accurate radioisotopic dates from the Guadalupian stages in their type area, Guadalupe Mountains National Park in West Texas has rendered their calibration inadequate. In this study, we report high-precision U-Pb zircon geochronology by the CA-ID-TIMS method from three ash beds (2σ internal errors only) in the Rader Member of the Bell Canyon Formation at the Back Ridge Section (262.127 ± 0.097 Ma, MSWD = 0.89, n = 3), the lower Pinery Member of the Bell Canyon Formation at the Frijole Section (264.23 ± 0.13 Ma, MSWD = 0.89, n = 8) and the basal South Wells Member of the Cherry Canyon Formation at the Monolith Canyon Section (266.525 ± 0.078 Ma, MSWD = 0.62, n = 5). The Bayesian interpolation statistics method is used to establish an age-stratigraphy model that estimates the base of the Capitanian to be 264.28 ± 0.16 Ma, serving as the best age estimate for the Capitanian Stage at present. In addition, we review the existing geochronology from the Guadalupian Series in West Texas and seek to propose more precise temporal estimates of Guadalupian geological and biological events. These data constrain the high-frequency sequences of the Cherry Canyon and Bell Canyon formations in the Guadalupe Mountains National Park area. Accordingly, the base of the Wordian is estimated at 266.9 ± 0.4 Ma and the Illawarra geomagnetic polarity reversal in West Texas at 267.4 ± 0.4 Ma to 266.5 ± 0.3 Ma. The global end-Guadalupian extinction began in the conodont zone of Jinogondolella altudaensis above the base of the Reef Trail Member of the Bell Canyon Formation and might continue to the Clarkina postbitteri postbitteri Zone in the earliest Wuchiapingian. The conodonts display a rapid evolutionary rate during this interval. This constrains the biotic crisis from ca. 260 Ma to 259 Ma based on our conodont age estimation. The emplacement of the Emeishan Large Igneous Province (ELIP) in South China has been constrained to ca. 260 Ma to 257.4 Ma based on zircon U-Pb geochronology by the CA-ID-TIMS method, overlapping with the end-Guadalupian extinction, which provides support for the temporal relationship between them. Additionally, the ELIP persisted into the early Wuchiapingian and may have hampered ecosystem restoration during the post-extinction interval.

As an important tool in natural resource exploration, palaeogeography provides a portrayal of deep time Earth. The South China Block located in the eastern Palaeotethys includes multiple natural resources (e.g., coal, shale gas, bauxite, etc.) in the Permian, which are well known for their important economic significance. In this paper, data gathered from literature amount to 431 stratigraphic sections of Wuchiapingian age from South China. These data were quantitatively analyzed and dynamically reconstructed in the global context under the revised plate motion model by GPlates software for the first time. A schematic 3-D model was constructed based on the high-resolution reconstructions in this paper, showing two relatively large highlands developed in the South China Block during the Wuchiapingian, including the Kangdian Highland in the west and the Cathaysia Highland in the east and a small Yunkai Highland in the south. A broad platform-dominated depositional system with small uplifts and depressions was developed between these two highlands. These reconstructions show great potential to explore enriched coal seams and shale gas in the peripheral areas of the two ancient highlands in the west and east of the South China Block. Based on the dynamic evolution of this depositional system, South China experienced an overall sea-level rise with frequent secondary transgressions and regressions during the Wuchiapingian. This is in contrast to the widespread continental and evaporite deposits on much of Pangea and its surrounding margins after the end-Guadalupian global regression. Compilation of conodont biostratigraphic data suggest that the temporal and spatial constraints on the unconformity across the Guadalupian-Lopingian boundary (GLB) resulted from Dongwu Uplift movement. The regression began during the Jinogondolella shannoni Zone and ended in the Clarkina leveni Zone, but the response time varies in different localities of South China. These results provide detailed information about sea-level eustacy, tectonic uplift, sedimentary hiatus, resource accumulation and palaeoclimate change from the South China Block during the Wuchiapingian.

The end-Permian marine extinction (EPME) eliminated >80% of species globally, making it the most severe extinction of the Phanerozoic. Anoxia and euxinia are potential kill mechanisms that may have contributed to this biotic crisis. However, redox changes in the atmosphere-ocean system are likely to have been complex, with both the vertical location of the oxic-anoxic boundary (in the water column or sediments), and the total area or volume of anoxic and euxinic water in the global ocean changing over time. In this study, we generated iron speciation and major and trace element data from 141 samples of the Meishan-1 core, which was drilled at a site 550 m to the west of the Meishan D section. Iron speciation results, in combination with authigenic concentrations and enrichment factors of redox-sensitive metals (Mo, V, and U), and previously published macrofossil, trace fossil, and bioturbation evidence, suggest that: 1) Beds 21-24d were deposited beneath a predominantly oxic water column, 2) Beds 24e-28 were deposited under a persistently anoxic watermass with intermittently euxinic bottom water, and 3) Beds 29–34 were deposited under primarily ferruginous conditions. Excess fractions and enrichment factors of U, V and Mo in the anoxic and euxinic intervals of the Meishan-1 core suggest that authigenic precipitation of redox-sensitive trace metals mainly occurred before and during the EPME, with nearly no detectable authigenic U, V, or Mo accumulating after the EPME. Our results, along with published U, V and Mo concentrations from across the Neotethys, Paleotethys, and Panthalassic Ocean basins, indicate that oceanic trace metal reservoirs were depleted before and during the main extinction interval. This depletion of oceanic trace elements suggests a spatial expansion of both anoxic and euxinic watermasses prior to and during the EPME. The apparent coincidence in timing between the mass extinction and the areal expansion of anoxic and euxinic watermasses suggests that these factors played important roles in the loss of marine biota around the Permian-Triassic boundary (PTB), through oxygen deprivation and H2S toxicity.

Previous studies suggested rapid evolution of conodonts across the Permian–Triassic boundary (PTB), and the end-Permian mass extinction pattern varies in different sections in South China. Here we document a high-resolution conodont succession from a carbonate facies of the Changhsingian Stage and across the PTB at the Daijiagou section, about 35 km north to Chongqing City, Southwest China. Two genera and twelve species are identified. Seven conodont zones are recognized from the uppermost part of the Lungtan Formation to the lowest Feixianguan Formation. They are the Clarkina liangshanensis , C. wangi , C. subcarinata , C. changxingensis , C. yini , C. meishanensis , and Hindeodus parvus zones in ascending order. Based on the high-resolution biostratigraphical framework at Daijiagou, the end-Permian mass extinction was rapid and it began in the base of the Clarkina meishanensis Zone. Associated with the extinction, a negative excursion of δ 13 C carb started in the middle part of Clarkina yini Zone with a progressive shift of 1.6‰ to the middle part of the Clarkina meishanensis , followed by a sharp shift of 3.51‰ from the Clarkina meishanensis Zone to the Hindeodus parvus Zone. Our study also suggests that the Triassic index species Hindeodus parvus co-occurred with Hindeodus changxingensis and Clarkina zhejiangensis and directly overlies the Clarkina meishanensis Zone at the Daijiagou section. All these data from the Daijiagou section and some previous studies of other sections in Sichuan, Guizhou provinces and Chongqing City suggest that the first occurrences of Hindeodus parvus are slightly earlier than the sharp negative excursion of δ 13 C carb and the FAD at the Meishan GSSP section. We consider that the slight difference of the end-Permian mass extinction, chemostratigraphy and conodont biostratigraphy at Daijiagou and its adjacent areas is most likely subject to different lithofacies, fossil preservation, and the constraint on the stratigraphic resolution rather than a different tempo of the end-Permian mass extinction in a global sense. The whole Changhsingian conodont succession at Daijiagou provides a high-resolution correlation with other equivalent sections in the Palaeotethys. The controversial results of biostratigraphy and chemostratigraphy between the sections investigated in this paper and the Meishan GSSP section also provide some important implications that accurate chronocorrelation requires the evaluation of multiple, varied stratigraphcal signals rather than relying solely on the FAD of the Triassic index species Hindeodus parvus for recognizing the Permian–Triassic boundary (PTB). Growth series of abundant specimens for each species are figured. The taxonomy of some Hindeodus species in the PTB interval is updated.

A fundamental aspect of taxonomy at the generic level, critical to understand Early Triassic conodont evolution, is the composition of the multielement apparatus. In this paper, we document a platform-bearing new conodont genus, Parafurnishius n. gen., as well as its multielement apparatus from the Griesbachian Feixianguan Formation (Lower Triassic) in Xuanhan County, northeastern Sichuan Province, southwest China. The new conodont genus is characterized by numerous robust and irregularly distributed conical denticles with variable platform morphology that has a possible affinity with the P1 elements of Furnishius. These genera have apparatuses similar to those of Ellisonia and are classified with the family Ellisoniidae. The strong intraspecific variation of P1 elements and the growth series within the entire sample population suggest that Parafurnishius may have evolved from the Griesbachian Isarcicella by developing random denticle positioning away from the platform centre, and then possibly evolved into younger Triassic Furnishius by developing a stable blade configuration. This preferred interpretation implies an ellisonid apparatus for Isarcicella. Alternatively, Parafurnishius may have evolved from Ellisonia and developed a homeomorphic P1 element with Isarcicella. This new taxon has strong intraspecific variation of denticle growth orientation during the Early Triassic.

Meishan Section D with the Wuchiapingian/Changhsingian and Permian/Triassic GSSPs has become the most intensively studied section because it records the whole process of the largest biological extinction during the Phanerozoic. Numerous data including high-precision geochronology, multiple isotope chemostratigraphy, magnetostratigraphy, and high-resolution multiple fossil biostratigraphy have been determined during the last decade. Conodonts are very abundant in the Changhsingian Stage at the Meishan sections and their biostratigraphy together with geochronologic and multiple geochemical data provide a basic temporal framework to calibrate the end-Permian mass extinction and realize global correlation between sections at Meishan and those in other regions of the world. However, major discrepancies exist in various previous studies of conodonts from the Meishan sections. Many different authors have documented very different species ranges based on different concepts and approaches of taxonomy. We here employ a sample population approach to revise and refine the high-resolution conodont biostratigraphic framework for the Changhsingian Stage and end-Permian mass extinction interval across the Permian–Triassic boundary (PTB) at the Meishan sections. Eight zones are recognized from the latest Wuchiapingian to the basal Triassic. They are, in ascending order, the Clarkina longicuspidata Zone in the uppermost Wuchiapingian; the Clarkina wangi Zone, Clarkina subcarinata Zone, Clarkina changxingensis Zone, Clarkina yini Zone, Clarkina meishanensis Zone, Clarkina zhejiangensis–Hindeodus changxingensis Zone in the Changhsingian Stage, and the Hindeodus parvus Zone in the basal Triassic. Conodont evolutionary lineages for the whole Changhsingian are also tentatively established. All species are described in detail and growth series of different specimens for valid species are figured as completely as possible. The temporal relationship of each conodont zone with geochemical excursions, geochronologic calibration and magnetostratigraphical polarity zones are provided, which is critical to understand the tempo of the end-Permian mass extinction.

Yuan, D.X., Zhang, Y.C., Zhang, Y.J., Zhu, T.X. & Shen, S.Z., 2014. First records of Wuchiapingian (Late Permian) conodonts in the Xainza area, Lhasa Block, Tibet, and their palaeobiogeographic implications. Alcheringa 38, 546–556. ISSN 0311-5518.Conodonts are among the best fossil groups to provide high-resolution biostratigraphic correlation and resolve the palaeobiogeographic evolution of the Permian. However, they have been rarely reported from the Lhasa Block in Tibet. Here we report the first discovery of Wuchiapingian (early Lopingian) conodonts from the Xiala Formation in the Lhasa Block, Tibet. This conodont fauna includes two genera and three species (Clarkina liangshanensis, C. orientalis, Iranognathus sp.). The conodont fauna indicates that the Xiala Formation previously assigned to the Guadalupian actually ranges from late Kungurian to late Wuchiapingian. The existence of the late Wuchiapingian conodont species Clarkina orientalis and C. liangshanensis in the Lhasa Block provides additional d...

A Kubergandian (Kungurian) fusuline fauna from the lower part of the Lugu Formation in the Cuozheqiangma area, central Qiangtang Block is described. This fusuline fauna belongs to the Southern Transitional Zone in palaeobiogeography, and is characterised by the presence of the distinctive bi-temperate genus Monodiexodina and many genera common in lower latitude Tethyan areas such as Parafusulina and Pseudodoliolina. The occurrence of Monodiexodina in the fauna confirms that the seamount-type carbonates of the Lugu Formation did not originate from the Palaeotethys Ocean, but rather from a branch of the Neotethys Ocean after the rifting of the Qiangtang Block from the Tethys Himalaya area in the Artinskian. © 2014 Geological Society of China.

New conodont samples have been systematically collected at high stratigraphic resolution from the upper part of the Longtan Formation through to the lower part of the Yelang Formation at the Zhongzhai section, southwestern Guizhou Province, South China, in an effort to verify the first local occurrence of Hindeodus parvus in relation to the Permian–Triassic boundary at this section. The resampled conodont fauna from the Permian–Triassic boundary interval comprises five identified species and two undetermined species in Hindeodus and Clarkina . Most importantly, the first local occurrence of Hindeodus parvus is found for the first time from the bottom of Bed 28a, 18 cm lower than the previously reported first local occurrence of this species at this section. Considering the previously accepted PTB at the Zhongzhai section, well calibrated by conodont biostratigraphy, geochronology and carbon isotope chemostratigraphy, this lower (earlier) occurrence of H . parvus suggests that this critical species could occur below the Permian–Triassic boundary. As such, this paper provides evidence that (1) the first local occurrences of H . parvus are diachronous in different sections with respect to the PTB defined by the First Appearance Datum (FAD) of this species at its GSSP section in Meishan, China and that (2) the lower stratigraphic range of H . parvus should now be extended to latest Permian.

Zhang, Y.C., Wang, Y., Zhang, Y.J. & Yuan, D.X., 2013. Artinskian (Early Permian) fusuline fauna from the Rongma area in northern Tibet: palaeoclimatic and palaeobiogeographic implications. Alcheringa 37, 529–546. ISSN 0311–5518.A fusuline fauna consisting of ten species in five genera from the Qudi Formation of the Jiaomuri and Gangtangcuo sections in the Rongma area, northern Tibet, is described. This fauna contains a few typical Peri-Gondwanan fusuline species such as Pseudofusulina pamirensis, Neodutkevitchia insignis and N. sp. cf. N. tumidiscula. The fauna is dated as Artinskian based on the presence of both genera Chalaroschwagerina and Praeskinnerella. The Peri-Gondwanan fusuline fauna in the Qiangtang Block is grouped palaeobiogeographically into the Southern Transitional Zone, which is located in the southern part of the Peri-Gondwanan blocks during the late Sakmarian and Artinskian. Moreover, the occurrence of the Peri-Gondwanan fusuline fauna, the lithological transition from glacimarine depos...

Large carbon cycle perturbations are associated with the end-Permian mass extinction and subsequent recovery, but Late Permian (Lopingian) carbon cycle dynamics prior to the mass extinction event remain poorly documented. Here we present a high-resolution δ13Ccarb chemostratigraphic framework from latest Guadalupian to earliest Triassic time, calibrated with high-resolution conodont biostratigraphy and high-precision geochronology. We observe two large negative excursions in δ13Ccarb, the first in uppermost Guadalupian strata and the second at the end of the Changhsingian stage, and between these events distinctive excursions from the middle Wuchiapingian to the early Changhsingian. The end-Changhsingian excursion represents a major reorganization of the global carbon cycle associated with the end-Permian mass extinction. However, the extent to which the end-Guadalupian and Wuchiapingian/Changhsingian boundary excursions result from local versus global controls remains unresolved. Regardless of their underlying causes, these three excursions provide chemostratigraphic markers for global correlation of Lopingian strata.

A high-resolution oxygen isotope record based on 356 measurements of conodont apatite from several low latitudinal sections in South China, USA and Iran was composed in order to unravel Permian palaeotemperature and ice volume history. The conodont apatite δ 18 O record is compared to published brachiopod calcite δ 18 O records. Brachiopods and conodonts from different palaeocontinents show significantly different δ 18 O values, suggesting differences in local climatic conditions (e.g., evaporation/precipitation ratio). As a consequence, secular changes in palaeotemperature and oxygen isotope composition of Permian sea water cannot be reconstructed from records combined from different areas, but have to be based on records from a specific area. Oxygen isotope analyses of different conodont taxa suggest that Streptognathodus and Hindeodus lived in near-surface seawater and recorded surface water temperature, whereas the habitat of gondolellid genera was variable depending on sea level, with both near-surface and deeper waters as potential life habitat. The oxygen isotope record measured on conodonts from South China exhibits relative high values between 22 and 23‰ VSMOW during the glaciated Early Permian, translating into warm seawater temperature between 26 and 30 °C, assuming that the Late Palaeozoic ice volumes were comparable to the Pleistocene glacial maxima. In contrast to the earlier view that the Late Palaeozoic Ice Age (LPIA) terminated in the late Sakmarian, the South China conodont apatite oxygen isotope record suggests waning of the ice sheets in the Kungurian. Ice melting is indicated by a pronounced decrease in δ 18 O of 2‰ VSMOW, which is interpreted as reflecting the combined effect of climatic warming and glacial ice melting. Significant temperature fluctuations (4 °C warming succeeded by 6 to 8 °C cooling) are observed during the Guadalupian–Lopingian transition, interpreted as combined climate changes induced by Emeishan volcanism and changes in habitat depth of gondolellid conodonts. Oxygen isotope values increase to 22‰ VSMOW in the Changhsingian, which suggests climate cooling and Clarkina moving to deeper waters because of the Changhsingian sea level rise. Across the Permian–Triassic boundary, δ 18 O values decrease from 22 to 19‰ VSMOW, parallel to the significant negative carbon isotope excursion and the eruption of the Siberian Traps. The latter is pointing to a cause–effect relationship as a consequence of the massive release of volcanic greenhouse gases derived from the Siberian volcanism and related processes.

A fusuline fauna of seven species belonging to six genera from the lower part of the Lugu Formation in the Qiangtang Block, Tibet, is described for the first time. This fauna is assigned to the middle Kungurian based on the dominance of Cancellina primigena (Hayden). Biogeographically, the fauna is characterised by influx of many palaeoequatorial Tethyan taxa by comparison with the underlying Artinskian fauna. The palaeobiogeography of fusuline fauna in the Qiangtang Block from the Artinskian to the middle Kungurian is characterised by a pronounced transition from peri-Gondwanan affinity to a transitional affinity (Tethyan Cimmerian subregion). This transition is considered to have resulted from the combined effects among a northward drift of the Qiangtang Block, contemporaneous global climatic amelioration during the Permian, and the oceanic currents along the new-formed Neotethys Ocean.

The tectonic evolution of the Qiangtang Block in the Qinghai–Tibetan Plateau has been a controversial subject for a long time. In this paper, the discovery of new stratigraphic and fusuline fossil evidence from the Permian sequences (Qudi and Lugu formations) of the Qiangtang Block is reported and the palaeogeographical position and tectonic history of this block during the Late Cisuralian (Late Early Permian) are discussed. The Qudi Formation is typified by thick turbidite deposits and contains Artinskian fusulines such as Pseudofusulina and Chalaroschwagerina . The fusulines were deposited as grains involved in debris flow deposits, suggesting a synchronicity with the depositional time of the turbidites. The subsequent Lugu Formation is dominated by seamount-type carbonates with an irregular basalt base. Fusulines Cancellina , Pseudodoliolina and Parafusulina in the base of the carbonates confirm its age as middle Kungurian. The transition from the turbidite Qudi Formation to the seamount Lugu Formation is here interpreted to be a continuous depositional process recording the Qiangtang Block's separation from the Indian Plate. This separation signaled the opening of the Neotethys Ocean between the Qiangtang Block and the Indian Plate. Palaeogeographically, the Qiangtang Block's separation is comparable with the Baoshan Block's separation in the east and Central Pamir's separation in the west. By contrast, the ultimate opening of the Neotethys Ocean by the separation of India–Pakistan and northern Oman is apparently much later than this event recorded in the Qiangtang Block. Consequently, it is interpreted that the opening of the Neotethys Ocean in the whole northern Gondwanan margin is a diachronous series of events.