State Key Laboratory of Palaeobiology and Stratigraphy

The International Commission on Stratigraphy (ICS) has a long tradition of producing international charts that communicate higher-order divisions of geological time and actual knowledge on the absolute numerical ages of their boundaries. The primary objective of ICS is to define precisely a global standard set of time-correlative units (Systems, Series, and Stages) for stratigraphic successions worldwide. These units are, in turn, the basis for the Periods, Epochs and Ages of the Geological Time Scale. Setting an international global standard is fundamental for expressing geological knowledge. It is also of considerable pragmatic importance as it provides the framework through which regional-scale higher-resolution divisions can be linked, equated and collated. This is a status update on the International Chronostratigraphic Chart and the ICS website www.stratigraphy.org.

Research Article| August 01, 2012 Evidence for end-Permian ocean acidification from calcium isotopes in biogenic apatite Jessica L. Hinojosa; Jessica L. Hinojosa * 1Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305, USA *E-mail: jess.l.hinojosa@gmail.com. Search for other works by this author on: GSW Google Scholar Shaun T. Brown; Shaun T. Brown 2Center for Isotope Geochemistry, Earth Science Division, E.O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA Search for other works by this author on: GSW Google Scholar Jun Chen; Jun Chen 3State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar Donald J. DePaolo; Donald J. DePaolo 2Center for Isotope Geochemistry, Earth Science Division, E.O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA4Department of Earth and Planetary Science, University of California, Berkeley, California 94720, USA Search for other works by this author on: GSW Google Scholar Adina Paytan; Adina Paytan 5Institute of Marine Sciences, University of California, Santa Cruz, California 95064, USA Search for other works by this author on: GSW Google Scholar Shu-zhong Shen; Shu-zhong Shen 6State Key Laboratory of Palaeontology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Nanjing 210008, China Search for other works by this author on: GSW Google Scholar Jonathan L. Payne Jonathan L. Payne 1Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Jessica L. Hinojosa * 1Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305, USA Shaun T. Brown 2Center for Isotope Geochemistry, Earth Science Division, E.O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA Jun Chen 3State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Guangzhou 510640, China Donald J. DePaolo 2Center for Isotope Geochemistry, Earth Science Division, E.O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA4Department of Earth and Planetary Science, University of California, Berkeley, California 94720, USA Adina Paytan 5Institute of Marine Sciences, University of California, Santa Cruz, California 95064, USA Shu-zhong Shen 6State Key Laboratory of Palaeontology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Nanjing 210008, China Jonathan L. Payne 1Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305, USA *E-mail: jess.l.hinojosa@gmail.com. Publisher: Geological Society of America Received: 22 Nov 2011 Revision Received: 11 Feb 2012 Accepted: 10 Mar 2012 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2012 Geological Society of America Geology (2012) 40 (8): 743–746. https://doi.org/10.1130/G33048.1 Article history Received: 22 Nov 2011 Revision Received: 11 Feb 2012 Accepted: 10 Mar 2012 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jessica L. Hinojosa, Shaun T. Brown, Jun Chen, Donald J. DePaolo, Adina Paytan, Shu-zhong Shen, Jonathan L. Payne; Evidence for end-Permian ocean acidification from calcium isotopes in biogenic apatite. Geology 2012;; 40 (8): 743–746. doi: https://doi.org/10.1130/G33048.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract End-Permian (ca. 252 Ma) carbon isotope, paleobiological, and sedimentary data suggest that changes in ocean carbonate chemistry were directly linked to the mass extinction of marine organisms. Calcium isotopes provide a geochemical means to constrain the nature of these changes. The δ44/40Ca of carbonate rocks from southern China exhibits a negative excursion across the end-Permian extinction horizon, consistent with either a negative shift in the δ44/40Ca of seawater or a change in the calcite/aragonite ratio of carbonate sediments at the time of deposition. To test between these possibilities, we measured the δ44/40Ca of hydroxyapatite conodont microfossils from the global stratotype section and point (GSSP) for the Permian-Triassic boundary at Meishan, China. The conodont δ44/40Ca record shows a negative excursion similar in stratigraphic position and magnitude to that previously observed in carbonate rocks. Parallel negative excursions in the δ44/40Ca of carbonate rocks and conodont microfossils cannot be accounted for by a change in carbonate mineralogy, but are consistent with a negative shift in the δ44/40Ca of seawater. Such a shift is best accounted for by an episode of ocean acidification, pointing toward strong similarities between the greatest catastrophe in the history of animal life and anticipated global change during the twenty-first century. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Well-preserved, abundant radiolarians provide high-precision biostratigraphic age constraints on the timing of the eruption of ophiolitic basalts exposed along the Yarlung–Tsangpo suture zone in southern Tibet. Dazhuqu terrane ophiolites were generated in an intra-oceanic supra-subduction zone setting within a relatively short (<10 Ma) interval from late Barremian to late Aptian. Accumulation of sediments upon the newly generated ophiolite initially occurred in a series of discrete rift-controlled sub-basins associated with various spreading centres. An increasing flux of arc-derived volcaniclastic sediment up-section indicates nearby volcanic arc activity. The Dazhuqu terrane developed in an intra-oceanic setting within Tethys where it was isolated from any continental influence.

Abstract The phylogeographical evolution and the consequent changing distribution and diversity of rhynchonelliform brachiopods through the Ordovician are linked to the dynamic palaeogeography of the period. The Early Ordovician (Tremadocian and Floian) is characterized by globally low-diversity faunas with local biodiversity epicentres, notably on the South China Palaeoplate; low-latitude porambonitoid-dominated faunas with early plectambonitoid and clitambonitoid representatives, as well as high-latitude assemblages mostly dominated by orthoids, can be recognized, but many taxa are rooted in Late Cambrian stocks. The Early Ordovician displays a steady increase in rhynchonelliformean biodiversity, which was mostly driven by the increasing success of the Porambonitoidea and Orthoidea, but the billingsellids and early plectambonitoids also contributed to this expansion. During the Early to Mid Ordovician (Dapingian–Darriwilian), marine life experienced an unprecedented hike in diversity at the species, genus and family levels that firmly installed the suspension-feeding benthos as the main component of the Palaeozoic fauna. However, this may have occurred in response to an early Darriwilian annihilation of existing clades, some of which had been most successful during the Early Ordovician. New clades rapidly expanded. The continents were widely dispersed together with a large number of microcontinents and volcanic arcs related to intense magmatic and tectonic activity. Climates were warm and sea-levels were high. Pivotal to the entire diversification is the role of gamma (inter-provincial) diversity and by implication the spread of the continents and frequency of island arcs and microcontinents. The phylogeographical analysis demonstrates that this new palaeogeographical configuration was particularly well explored and utilized by the strophomenides, especially the Plectambonitoidea, which radiated rapidly during this interval. The porambonitoids, on the other hand, were still in recovery following the early Darriwilian extinctions. Orthides remained dominant, particularly at high latitudes. Biodiversity epicentres were located on most of the larger palaeoplates, as well as within the Iapetus Ocean. Provincial patterns were disrupted during the Sandbian and early Katian with the migration of many elements of the benthos into deeper-water regimes, enjoying a more cosmopolitan distribution. Later Katian faunas exhibit a partition between carbonate and clastic environments. During the latest Katian, biogeographical patterns were disrupted by polewards migrations of warm-water taxa in response to the changing climate; possibly as a consequence of low-latitude cradles being developed in, for instance, carbonate reef settings. Many clades were well established with especially the strophomenides beginning to outnumber the previously successful orthides, although this process had already begun, regionally, in the mid to late Darriwilian. At the same time, atrypoid and pentameroid clades also began to radiate in low-latitude faunas, anticipating their dominance in Silurian faunas. The Hirnantian was marked by severe extinctions particularly across orthide-strophomenide clades within the context of few, but well-defined, climatically controlled provincial belts. Supplementary material: The individual localities and a reference list for the data sources are provided at: http://www.geolsoc.org.uk/SUP18667

The Bainang terrane, an intra-oceanic island arc subduction complex into which Tethyan oceanic rocks were accreted during the Cretaceous, is preserved within the Yarlung–Tsangpo suture zone of Tibet. The lithostratigraphic succession established from field mapping records a long history of sedimentation in different portions of the central Tethyan domain from Late Triassic to mid-Cretaceous time. These rocks are preserved within a south-verging imbricate thrust stack of thin (≪1 km thick) northward younging tectonic slices. Five lithotectonic units were mapped in the terrane and these units are assigned to two distinct tracts. The northern tract, which accumulated on the north side of Neotethys, was probably separated from its southern counterpart by a mid-ocean ridge. Detailed radiolarian biostratigraphy is used to constrain the timing of depositional events within each tract. Oceanic plate stratigraphy of the northern tract records its northward travel and mid-Cretaceous (late Aptian) approach towards a south-facing intra-oceanic subduction zone. Rocks in the southern tract developed closer to the Indian subcontinent and experienced thermotectonic subsidence and Mid-Jurassic basic alkaline intraplate magmatism. They were probably accreted late in the Cretaceous. Variations in structural style across the terrane indicate deformation at different depths and vertical growth of the wedge rather than lateral accretion. The overall tectonostratigraphy of the terrane reflects its development in a remote intra-oceanic setting.

The effective number of codons (N(c)) is a widely used index for characterizing codon usage bias because it does not require a set of reference genes as does codon adaptation index (CAI) and because of the freely available computational tools such as CodonW. However, N(c), as originally formulated has many problems. For example, it can have values far greater than the number of sense codons; it treats a 6-fold compound codon family as a single-codon family although it is made of a 2-fold and a 4-fold codon family that can be under dramatically different selection for codon usage bias; the existing implementations do not handle all different genetic codes; it is often biased by codon families with a small number of codons. We developed a new N(c) that has a number of advantages over the original N(c). Its maximum value equals the number of sense codons when all synonymous codons are used equally, and its minimum value equals the number of codon families when exactly one codon is used in each synonymous codon family. It handles all known genetic codes. It breaks the compound codon families (e.g., those involving amino acids coded by six synonymous codons) into 2-fold and 4-fold codon families. It reduces the effect of codon families with few codons by introducing pseudocount and weighted averages. The new N(c) has significantly improved correlation with CAI than the original N(c) from CodonW based on protein-coding genes from Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, Escherichia coli, Bacillus subtilis, Micrococcus luteus, and Mycoplasma genitalium. It also correlates better with protein abundance data from the yeast than the original N(c).

We report a simple and facile solid-state approach to large-scale synthesis of multiwalled carbon nanotubes (MCNTs), for the first time, by one-step direct thermolysis of a metal-organic framework [Ni(3)(btc)(2).12H(2)O] (btc = benzene-1,3,5-tricarboxylato) in a one-end closed conventional horizontal tube furnace under relatively low temperature without using any additional carrier gas or catalyst.

Abstract The trigger for biomineralization of metazoans in the terminal Ediacaran, ca. 550 Ma, has been suggested to be the rise of oxygenation or an increase in seawater Ca concentration, but geochemical and fossil data have not been fully integrated to demonstrate cause and effect. Here we combine the record of macrofossils with early marine carbonate cement distribution within a relative depth framework for terminal Ediacaran to Cambrian successions on the eastern Siberian Platform, Russia, to interrogate the evolution of seawater chemistry and biotic response. Prior to ca. 545 Ma, the presence of early marine ferroan dolomite cement suggests dominantly ferruginous anoxic “aragonite-dolomite seas”, with a very shallow oxic chemocline that supported mainly soft-bodied macrobiota. After ca. 545 Ma, marine cements changed to aragonite and/or high-Mg calcite, and this coincides with the appearance of widespread aragonite and high-Mg calcite skeletal metazoans, suggesting a profound change in seawater chemistry to “aragonite seas” with a deeper chemocline. By early Cambrian Stage 3, the first marine low-Mg calcite cements appear, coincident with the first low-Mg calcite metazoan skeletons, suggesting a further shift to “calcite seas”. We suggest that this evolution of seawater chemistry was caused by enhanced continental denudation that increased the input of Ca into oceans so progressively lowering Mg/Ca, which, combined with more widespread oxic conditions, facilitated the rise of skeletal animals and in turn influenced the evolution of skeletal mineralogy.

Insects have evolved diverse methods of predator avoidance, many of which implicate complex adaptations of their wings (e.g., Phylliidae, Nymphalidae, Notodontidae). Among these, angiosperm leaf mimicry is one of the most dramatic, although the historical origins of such modifications are unclear owing to a dearth of paleontological records. Here, we report evidence of pinnate leaf mimesis in two lacewings (Neuroptera): Bellinympha filicifolia Y. Wang, Ren, Liu & Engel gen. et sp. nov. and Bellinympha dancei Y. Wang, Ren, Shih & Engel, sp. nov., from the Middle Jurassic, representing a 165-million-year-old specialization between insects and contemporaneous gymnosperms of the Cycadales or Bennettitales. Furthermore, such lacewings demonstrate a preangiosperm origin for leaf mimesis, revealing a lost evolutionary scenario of interactions between insects and gymnosperms. The current fossil record suggests that this enigmatic lineage became extinct during the Early Cretaceous, apparently closely correlated with the decline of Cycadales and Bennettitales at that time, and perhaps owing to the changing floral environment resulted from the rise of flowering plants.

Titanosaurs were a globally distributed clade of Cretaceous sauropods. Historically regarded as a primarily Gondwanan radiation, there is a growing number of Eurasian taxa, with several putative titanosaurs contemporaneous with, or even pre-dating, the oldest known Southern Hemisphere remains. The early Late Cretaceous Jinhua Formation, in Zhejiang Province, China, has yielded two putative titanosaurs, Jiangshanosaurus lixianensis and Dongyangosaurus sinensis . Here, we provide a detailed re-description and diagnosis of Jiangshanosaurus , as well as new anatomical information on Dongyangosaurus . Previously, a ‘derived’ titanosaurian placement for Jiangshanosaurus was primarily based on the presence of procoelous anterior caudal centra. We show that this taxon had amphicoelous anterior-middle caudal centra. Its only titanosaurian synapomorphy is that the dorsal margins of the scapula and coracoid are approximately level with one another. Dongyangosaurus can clearly be differentiated from Jiangshanosaurus , and displays features that indicate a closer relationship to the titanosaur radiation. Revised scores for both taxa are incorporated into an expanded phylogenetic data matrix, comprising 124 taxa scored for 548 characters. Under equal weights parsimony, Jiangshanosaurus is recovered as a member of the non-titanosaurian East Asian somphospondylan clade Euhelopodidae, and Dongyangosaurus lies just outside of Titanosauria. However, when extended implied weighting is applied, both taxa are placed within Titanosauria. Most other ‘middle’ Cretaceous East Asian sauropods are probably non-titanosaurian somphospondylans, but at least Xianshanosaurus appears to belong to the titanosaur radiation. Our analyses also recover the Early Cretaceous European sauropod Normanniasaurus genceyi as a ‘derived’ titanosaur, clustering with Gondwanan taxa. These results provide further support for a widespread diversification of titanosaurs by at least the Early Cretaceous.

A fossil arthropod similar to Fuxianhuia and displaying an exceptionally well-preserved alimentary canal with in situ gut contents is reported from the lower Middle Cambrian (ca. 510 Myr ago) of South China. Three-dimensionally preserved, paired phosphatic nodules, arranged in series along both sides of the gut and containing spherical bacteria, probably represent serial digestive glands. The gut is filled with fragments of the eodiscoid trilobite, Pagetia. The well-developed digestive glands and the fragmentary trilobite remains suggest (i) that the arthropod was a durophagous, possibly selective predator, and (ii) that small trilobites such as eodiscoids were a major food source in Cambrian marine ecosystems. This fossil association augments the small number of previously described associations providing more or less direct evidence of predator-prey relationships in Cambrian epibenthic communities.

—Records of Early Triassic marine reptiles, when they first emerged after the end Permian mass extinction, are rare. During an excavation at Majiashan, Chaohu, Anhui Province, a new sauropterygian specimen was found co-occurring with the ichthyopterygian Chaohusaurus from the Upper Member of the Nanlinghu Formation, of Olenekian (Spathian, Early Triassic) age, for which a new taxon, Majiashanosaurus discocoracoidis, gen. et sp. nov., is erected. This skeleton is exposed in ventral view, with the last three cervical vertebrae together with 19 dorsal, three sacral, and more than 18 caudal vertebrae preserved. The cervical centra are keeled ventrally, and cervical ribs are double-headed, carrying a free anterior process. The transverse processes of the dorsal vertebrae are not distinctively elongated. The dorsal ribs are single-headed, and the clavicles articulate on the anteromedial aspect of the scapula. The humerus is curved. These features allow assignment to a new sauropterygian taxon. The interclavicle has no posterior process, and the scapula is of typical eosauropterygian shape, with a broad and ventrally expanded glenoidal portion that is separated from a narrow posterodorsal blade by a distinct constriction. The coracoid is round and plate-like without a waist. This feature is different from that of all other known eosauropterygians, but resembles that of placodonts.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

Previous reports of Cambrian bryozoans have proved not to be bryozoans. No pre-Ordovician bryozoans have been recognized. The oldest unequivocal bryozoans known from North America, Britain, and Russia are evidently of early Arenigian age. New bryozoans recently collected from the Fenxiang Formation in the Daping and Guanzhuangping sections, situated in the area east of the Yangtze Gorges, are described here, including one new genus, Orbiramus , and six new species, Nekhorosheviella nodulifera, N. semisphaerica, Orbiramus normalis, O. ovalis, O. minus , and Prophyllodictya prisca. These are assigned to the Trepostomida, apart from the last species which belongs to the Cryptostomida. The new bryozoans are from the conodont Paltodus deltifer deltifer Zone of the late Tremadocian age, the first three species possibly being present in the P. deltifer pristinus Subzone at the base. Therefore, they are the oldest bryozoans known from anywhere in the world. Extensive reefs resulting from a major regression in the late Tremadocian were dominated by bryozoans in the upper Fenxiang Formation. The bryozoans lived in a shoal environment and accumulated essentially in situ, showing no signs of significant transportation.

Abstract Ophiolitic rocks distributed along the Yarlung Tsangpo suture zone in southern Tibet are the few remaining fragmentary remnants of many thousands of kilometres of the ocean space that formerly existed between India and Eurasia. Portions of mid-Jurassic and mid-Cretaceous intra-oceanic island arcs can be recognized amongst those rocks that have been studied in detail. Complete suprasubduction zone ophiolite successions are preserved in the Dazhuqu terrane, which crops out both east and west of Xigaze. Radiolarians in inter-pillow cherts and immediately overlying sedimentary rocks indicate a Barremian ophiolite generation event. Palaeomagnetic data show that this ophiolite formed at equatorial latitudes south of the Lhasa terrane before its south-directed emplacement onto the northern margin of India. Highly refractory ultramafic rocks in the Luobusa ophiolite appear to be of Mid-Jurassic age and are potentially related to intra-oceanic island arc remnants in the nearby Zedong terrane. Ophiolitic massifs along the suture in western Tibet are thrust southwards onto northern India and record Late Jurassic ocean-floor development. Miocene north-directed back-thrusting associated with India-Asia collision has further complicated interpretation of regional geology. The ophiolitic rocks of the Yarlung Tsangpo suture zone provide evidence for the former existence of multiple oceanic island arc segments within Neotethys and suggest that consumption of the oceanic space between India and Asia was more complicated than has been predicted by existing models.

A comprehensive, high resolution stratigraphic database of fusulinoidean foraminifers reveals that this group of protists suffered extreme losses during the Guadalupian extinction. Most species (88%) were eliminated gradually over the course of 9 myr during the Wordian and Capitanian ages. A pulse of greatly elevated per capita extinction frequency occurred during the last million years of the Capitanian (260–259 Ma). Contrary to prevailing opinion, the end-Capitanian event did not preferentially eliminate large, morphologically complex species in the families Schwagerinidae and Neoschwagerinidae, because most species in those families were already extinct. Rather, 69 percent of the species eliminated at the end of the Capitanian were small, morphologically conservative representatives of the Ozawainellidae, Schubertellidae and Staffellidae. Survivors from these families comprised the low-diversity association of Wuchiapingian fusulinoideans. Schubertellids, and to a lesser extent ozawainellids, diversified in the late Wuchiapingian and Changhsingian ages before the final demise of fusulinoideans during the end-Permian mass extinction. The Wordian–Capitanian fusulinoidean attrition might have been caused by photosymbiont loss and habitat reduction stemming from an interval of global cooling termed the Kamura event (∼265–259.5 Ma), although the onset of fusulinoidean diversity decline predates geochemical evidence for the beginning of the Kamura event by ∼3 myr. The end-Capitanian extinction pulse might reflect environmental deterioration from the combined effects of global cooling, Emeishan effusive volcanism and sea-level lowstand.

The fossil record of a major clade often starts after a mass extinction even though evolutionary rates, molecular or morphological, suggest its pre-extinction emergence (e.g. squamates, placentals and teleosts). The discrepancy is larger for older clades, and the presence of a time-scale-dependent methodological bias has been suggested, yet it has been difficult to avoid the bias using Bayesian phylogenetic methods. This paradox raises the question of whether ecological vacancies, such as those after mass extinctions, prompt the radiations. We addressed this problem by using a unique temporal characteristic of the morphological data and a high-resolution stratigraphic record, for the oldest clade of Mesozoic marine reptiles, Ichthyosauromorpha. The evolutionary rate was fastest during the first few million years of ichthyosauromorph evolution and became progressively slower over time, eventually becoming six times slower. Using the later slower rates, estimates of divergence time become excessively older. The fast, initial rate suggests the emergence of ichthyosauromorphs after the end-Permian mass extinction, matching an independent result from high-resolution stratigraphic confidence intervals. These reptiles probably invaded the sea as a new ecosystem was formed after the end-Permian mass extinction. Lack of information on early evolution biased Bayesian clock rates.

Abstract Geochemical evidence suggests that terminal Ediacaran (ca. 551–539 Ma) oceans experienced expansive anoxia and dynamic redox conditions, which are expected to have impacted animal distribution and behaviors. However, fossil evidence for oxygen-related behaviors of terminal Ediacaran animals is poorly documented. Here, we report a terminal Ediacaran trace fossil that records redox-regulated behaviors. This trace fossil, Yichnus levis new ichnogenus and new ichnospecies, consists of short and uniserially aligned segments of horizontal burrows that are closely associated with microbial mats. Thin-section analysis shows that the trace-making animal moved repeatedly in and out of microbial mats, with mat-burrowing intervals interspersed by epibenthic intermissions. This animal is hypothesized to have been a bilaterian exploring an oxygen oasis in microbial mats. Such intermittent burrowing behavior reflects challenging and dynamic redox conditions in both the water column and microbial mats, highlighting the close relationship between terminal Ediacaran animals and redox dynamics.

The Visean–Serpukhovian boundary is not yet defined by a Global Stratotype Section and Point (GSSP) but it is recognizable operationally by the appearance of the conodont Lochriea ziegleri in the L. nodosa–L. ziegleri chronocline. Foraminiferal successions across this boundary in the type area of the Serpukhovian Stage (Moscow Basin, Russia), elsewhere in Russia and in the central United States suggest that the appearances of Asteroarchaediscus postrugosus , Janischewskina delicata , Eolasiodiscus donbassicus , and specimens controversially referred to “ Millerella tortula ” are reliable, auxiliary indices to the base of the Serpukhovian. In southern Guizhou Province, China, Visean–Serpukhovian rock sequences from slope and platform settings have yielded rich associations of conodonts and foraminifers, respectively. The Nashui section is a leading candidate for the Serpukhovian GSSP because its slope deposits contain an uninterrupted record of conodont occurrences including the L. nodosa–L. ziegleri transition. Foraminifers recovered from the Nashui section are comparatively rare and include none of the basal Serpukhovian indices. In contrast, the nearby Yashui section represents a platform interior setting in which foraminifers flourished and conodonts were nearly absent. The base of the Serpukhovian at Yashui is marked approximately by the appearance of “ tortula -like” specimens. Although it is not possible to correlate biostratigraphically between the Nashui and Yashui sections, the occurrence of “ tortula -like” specimens at the Yashui section allows correlation with the mid-Venevian Substage of the Moscow Basin at a level coinciding with the appearance of L. ziegleri . Together, the slope and platform sections comprise an informative biostratigraphic reference area for micropaleontologic characterization of the Visean–Serpukhovian boundary in southern Guizhou.

The temporal change of redox conditions of the Yangtze ocean has been revealed by investigating the Ediacaran–Cambrian transition section at Zhalagou, South China. During the earliest Cambrian, cherts and shales were deposited under an anoxic and ferruginous bottom water with significantly increasing total organic carbon and P contents, and negative shift in kerogen δ 13 C values in the lowest part of the section. Euxinic bottom water conditions occurred during the earliest Cambrian Stage 2, with the surface water dominated by N 2 utilization by cyanobacteria or sulphur bacteria leading to negative kerogen δ 15 N values. During Stage 3, dissolved oxygen and sulphate concentrations were significantly increased, and thus the oxidized surface water and the redox transition zone overlying a euxinic bottom water may have been expanded, resulting in an increase in kerogen δ 15 N increasing to 2–4‰, a decrease in pyrite δ 34 S decreasing to as low as –24.6‰ and differences in δ 34 S values between kerogen and pyrite as high as 37‰. This period coincided with the abrupt appearance of large-body metazoans. Thus, the expanding oxic surface water may have reinforced the evolution of animals or vice versa. Interestingly, kerogen δ 34 S values show negative relationships to FePy/FeHR ratios and pyrite sulphur contents, indicating that they can be used to reflect redox conditions, with the lightest values being obtained from euxinic environments.

Based on leaf physiognomy of the Late Pliocene Tuantian megaflora from the Mangbang Formation of Tengchong County in western Yunnan, a quantitative reconstruction of palaeoclimate was performed with Leaf Margin Analysis (LMA) methodology and the Climate-Leaf Analysis Multivariate Program (CLAMP). The latter produced the following parameters: mean annual temperature (MAT) from 17.2 to 17.7°C; warmest month mean temperature (WMMT) from 25 to 25.5°C; coldest month mean temperature (CMMT) from 9.5 to 10.8°C; length of growing season (GRS) from 9.5 to 9.7 months; growing season precipitation (GSP) from 1834.3 to 1901.2 mm; mean monthly growing season precipitation (MMGSP) from 222.4 to 230.5 mm; precipitation during the three consecutive wettest months (3-WET) from 892.1 to 917.8 mm; precipitation during the three consecutive driest months (3-DRY) from 474.5 to 512.8 mm; relative humidity (RH) from 76.7 to 77.8%; specific humidity (SH) from 10.7 to 10.8 g/kg; and enthalpy (ENTHAL) from 31.8 to 32 kj/kg. However, the MAT obtained from the Chinese LMA regression at 18.7°C, is slightly higher than that from CLAMP. The integrated analysis of these data and three adjacent pollen floras in western Yunnan suggests that the Gaoligong Mountains (a southern portion of the Hengduan Mountains) were only raised to modest altitudes in the Late Pliocene.