Search

Pleuromeia Corda is an iconic lycopod genus in the Early Triassic floras of the world. Pleuromeia fossils are very significant in stratigraphy and palaeoenvironmental interpretation and have been regarded as an important Lower Triassic index fossil. Although some recent studies show that the genus occurred in the lower part of the Middle Triassic, no definite Pleuromeia has been reported from the late Middle Triassic and the younger strata so far. In this paper, some reproductive organ fossils of Pleuromeia from the upper Middle Triassic Tongchuan Formation in Shaanxi Province (belonging to the Ordos Basin), North China, are described for the first time, belonging to the new species Pleuromeia obovata Deng nov. sp. Highly accurate dating results of tuff layers indicate that the age of the new species is between 241.06 ± 0.12 Ma and 241.558 ± 0.093 Ma, equivalent to the early Ladinian. This is the youngest species of genus Pleuromeia so far. Spatiotemporal distribution of Pleuromeia indicates that the genus first appeared in the Induan (Early Triassic) in North China, occurred widespread and flourished in both Laurasia and Gondwana during the Olenekian (late Early Triassic), declined from the Anisian (early Middle Triassic), survived in the Ladinian in North China, and may have gone extinct as early as the end of the Middle Triassic. North China may well have included the place of origination and the last habitats of this genus. [ABSTRACT FROM AUTHOR]

Dicroidium Gothan is an extinct seed fern that was widely distributed in Gondwana during the Triassic but has not yet been unequivocally recorded in Laurasia. In this paper, a new species of the genus, Dicroidium sinensis Sun et Deng sp. nov., is described from the Middle Triassic sediments of the Ordos Basin, northwestern China, based on macromorphology and cuticular structures. This is the first record of Dicroidium in China, indicating that the genus was not unique to Gondwana and was also present in Laurasia. Dicroidium seems to have originated in the palaeotropics in the Permian (e.g., Jordan) and then widespread and flourished in Gondwana and extended to Laurasia during the Middle-Late Triassic period, and disappeared in the Early Jurassic. This genus may have migrated from Jordan to Laurasia along the western coast of the Tethys. Additionally, galls found in the leaf of Dicroidium sinensis proves the interactions between plants and insects. • A new species of Gondwanan genus Dicroidium is first definite record in Laurasia. • Dicroidium appeared in Permian, flourished in Triassic and disappeared in the Jurassic. • Galls indicate that the interactions between plants and insects were strong in Triassic. [ABSTRACT FROM AUTHOR]

The Yanchang Formation is extensively developed in the Ordos Basin and its surrounding regions. As one of the best terrestrial Triassic sequences in China and the major oil-gas bearing formations in the Ordos Basin, its age determination and stratigraphic assignment are important in geological survey and oil-gas exploration. It had been attributed to the Late Triassic and regarded as the typical representative of the Upper Triassic in northern China for a long time, although some scholars had already proposed that the lower part of this formation should be of the Middle Triassic age in the mid-late 20th century. In this paper, we suggest that the lower and middle parts of the Yanchang Formation should be of the Ladinian and the bottom possibly belongs to the late Anisian of the Middle Triassic, mainly based on new fossils found in it and high resolution radiometric dating results. The main source rocks, namely the oil shales and mudstones of the Chang-7, are of the Ladinian Age. The upper part of the Yanchang Formation, namely the Chang-6 and the above parts, belongs to the Late Triassic. The uppermost of the Triassic is missed in most parts of the Ordos Basin. The Middle-Upper Triassic Series boundary lies in the Yanchang Formation, equivalent to the boundary between Chang-7 and Chang-6. The Ladinian is an important palaeoenvironmental turning point in the Ordos Basin. Palaeoenvironmental changes in the basin are coincidence with that of the Sichuan Basin and the main tectonic movement of the Qinling Mountains. It indicates that tectonic activities of the Qinling Mountains are related to the big palaeoenvironmental changes in both the Ordos and Sichuan Basins, which are caused by the same structural dynamic system during the Ladinian. [ABSTRACT FROM AUTHOR]

Lepacyclotes Emmons is one of the most important Early-Middle Triassic lycopsids, a genus that became extinct during the Late Triassic-Jurassic. Due to its relatively short geological ranges, fairly wide geographic distributions, and strict palaeoecological requirements, this genus is important in stratigraphical correlation and palaeoenvironmental interpretation. Although this lycopsid has been studied for more than a century, there are less than 20 species of Lepacyclotes are known. In this paper, we report abundant new materials from the upper Middle Triassic of the Ordos Basin, North China for the first time. Two species are identified: Lepacyclotes zeilleri (Fliche) Retallack and L. ordosensis Deng sp. nov., with the former species yielding numerous in situ megaspores. Precise absolute dating of tuff layers intercalated in the strata bearing Lepacyclotes point to the early Ladinian (Middle Triassic). A comprehensive analysis of the previous data shows that the genus Lepacyclotes originated during the Early Triassic in multiple areas, flourished in late Early Triassic to early Middle, and strongly declined in the Middle Triassic. A few relicts survived in the Late Triassic and Early Jurassic. Lepacyclotes was adapted to salty, seawater-associated, or evaporative environments. Additionally, the generic diagnosis of Lepacyclotes is emended, and the relationships between the genus and its related genera have been discussed. • New materials of lycopsid Lepacyclotes zeilleri and a new species L. ordosensis are reported for the first time. • Lepacyclotes is of great stratigraphy significance due to its narrow geological range and wide geography distribution. • Lepacyclotes is adapted to salt-tolerant, seawater-associated or evaporative environments. [ABSTRACT FROM AUTHOR]

An amended species, Glossophyllum shensiense (Sze) Sun et Deng emend. nov. is described here based on the leaf macromorphology and cuticular structures of new materials from the Middle Triassic Tongchuan Formation in Huating County, Gansu Province, China. The species is characterized by large and lanceolate-shaped leaves, as well as regularly orientated stomata. Based on morphology and epidermal structure, all records under the specific name Glossophyllum shensiense (Sze) are re-examined, and three species were proposed, including one newly amended species and two new species: Glossophyllum panii Sun et Deng sp. nov. and Glossophyllum lanceolatum Sun et Deng sp. nov. Following a systematic re-examination of all species of the genus Glossophyllum published in the literature, a total of 12 species were recognized. The spatio-temporal distribution of Glossophyllum indicated that the genus first appeared in the Induan of the Early Triassic in Siberia, and spread to the southern Fergana in Central Asia and China during the Middle-Late Triassic. Its diversification and geographical distribution flourished during the Late Triassic, and declined and disappeared within the Late Triassic. Paleoclimate reconstruction suggested that Glossophyllum inhabits areas with warm and humid climates and is restricted to the temperate and subtropical zones of the Northern Hemisphere. • Glossophyllum shensiense is amended based on macromorphology and cuticular structures of new fossils. • Two new species of Glossophyllum are described and 12 species are recognized. • Glossophyllum appeared in Induan, flourished in Late Triassic and disappeared before the Jurassic. [ABSTRACT FROM AUTHOR]

Male cones ofIxostrobus hailarensisfrom Lower Cretaceous strata of the Hailar region of north-east China were re-examined for features of their cuticle andin situpollen. The cones are loosely aggregated and possess helically arranged peltate microsporophylls containing resin bodies. Microsporophyll cuticle is thick, papillate and has elliptical stomata with 6–9 subsidiary and ∼10 encircling cells. Adaxial sporangia contain monosulcate pollen assignable to the dispersed taxonCycadopites minimus. Both the cuticle and pollen are distinct fromIxostrobusbut are consistent with the cycad generaAndrostrobus,Aegianthus,Loricanthusand the putative angiospermSolaranthus.Reanalysis of the type species ofAndrostrobus,A. zamioides, provides new information on its structure and allows an accurate delimitation of the genus and improved comparison with other genera. A new genus,Schimperstrobus, is erected for species now excluded fromAndrostrobus. Comparisons indicate thatSolaranthusrepresents a male cycad cone and thatAegianthus,LoricanthusandSolaranthusare synonyms;Aegianthushas nomenclatural priority. We emend the combined generic and specific diagnoses forAegianthus sibiricusto allow additional species to be placed in the genus, and erect the new combinationsAegianthus resiniferafor specimens previously assigned toLoricanthus, andAegianthus daohugouensisfor specimens previously placed withinSolaranthus. The Hailar cone conforms to the generic circumscription ofAegianthusand represents a new species that we nameA. hailarensiscomb. nov.Androstrobus phialophoraalso conforms withAegianthusand is transferred toAegianthus phialophoracomb. nov. Co-occurring withA. hailarensisare cuticles of the ginkgophyte leafSphenobaiera longifoliathat are similar to microsporophyll cuticles ofA. hailarensis. However, we discount that they belong to a single plant species and conclude that the cuticles of some Mesozoic ginkgoalean and cycadalean taxa may be virtually indistinguishable. We consider thatAegianthuswas widespread across China, Mongolia and southern Russia during the Upper Jurassic to Lower Cretaceous. [ABSTRACT FROM AUTHOR]

The existing δC data in the Cambrian from different regions of the world are analyzed here. There are four well-documented carbon isotope excursions with global significance. In ascending order, they are: (1) a large negative excursion, comparable to 'BACE' (BAsal Cambrian Carbon isotope Excursion) event, which occurs near the Precambrian-Cambrian boundary with a magnitude of 4‰-10‰ (PDB); (2) the 'ZHUCE' (ZHUjiaqing Carbon isotope Excursion) event, a distinct positive excursion (over 5‰) that can be recognized at the Fortunian Stage to Stage 2 transition; (3) another strong negative one, so-called 'ROECE' (Redlichiid-Olenellid Extinction Carbon isotope Excursion) event, shifting at the interval between Series 2 and Series 3, peaking at −3‰-−5‰ (PDB); (4) the famous Steptoean positive carbon isotope excursion (SPICE), which has been widely identified at the base of Furongian Series, Paibian Stage, with an amplitude about 4‰ (PDB). The four sharp δC shifts correlate well with coeval paleoceanographic changes and bioevents. Besides, there are some δC excursions from a few sections in previous studies, and more data are required to identify whether they are global or regional ones. [ABSTRACT FROM AUTHOR]

• Surface-modified carbon foam (SMCF) was obtained by carbothermal reaction of FeSO 4. • The carbothermal reaction greatly influences the microstructures of carbon foams. • Resulting Fe 2 O 3 particles were embedded into the honeycomb-like surface of SMCF. • High N, O and S contents are beneficial to the electrochemical performance. • The SMCF-1000 has relatively high specific capacitance and excellent cyclability. [Display omitted] This work developed novel surface-modified carbon foams (SMCFs) with high heteroatom contents and a certain amount of iron oxide particles via the carbothermal reduction reaction between iron oxide and the cyanate resin-based carbon foam. The effects of carbothermal reduction of iron oxide on microstructures and electrochemical properties of the carbon foams have been studied systematically using TG, XRD, FESEM, BET, and XPS. Results show that the carbothermal reduction greatly influences the microstructures of carbon foams when the temperature is higher than 600 °C. The generated iron oxide particles were embedded into the surface of carbon foams. With the increase of temperature, the surface became porous and rough with a certain graphitic structure. When the temperature arrives at 1000 °C, the as-prepared SMCF-1000 has a highest specific capacitance of 212.42 F g−1 at 1 A g−1, and the specific capacitance maintains 107% of the initial value after 10,000 charge-discharge cycles. In addition, the SMCF-1000 exhibits a maximum compressive strength of 2.52 MPa, which is expected to be a novel three-dimensional self-supporting electrode material. [ABSTRACT FROM AUTHOR]

In the Early Cretaceous floras of Northeast China ferns are represented by megafossils of Dicksoniaceae, Schizaeaceae, Osmundaceae, Cladophlebis (possible Osmundaceae), Hymenophyllaceae, Adiantaceae, Gleicheniaceae and ferns with monolete spores (the latter group includes fossils sharing some characteristics with members of the modern families Athyriaceae, Dryopteridaceae, Aspleniaceae and Pteridaceae). The habit, habitat, phytogeography and climatic setting are discussed for these ferns. Acanthopteris and Coniopteris (Dicksoniaceae) are interpreted as small to large creeping rhizomatous ferns. Ruffordia goeppertii (Dunker) Seward (Schizaeaceae) was a small fern with an upright rhizome. Some Cladophlebis also had an upright rhizome. Eogonocormus and Hymenophylloides (Hymenophyllaceae) were small and delicate creeping rhizomatous ferns. Athyrium asymmetricum (Meng) Deng had large but thin and flexible fronds and may have grown in thickets. Details of habit are not known for the other ferns but several are represented by large fronds. The co-occurrence (in fine-grained sediments in coal-bearing strata) of large and/or delicate, relatively complete fronds, fertile and sterile material and rhizomes with stipes (and possible frond attachments), shows that the majority of these ferns grew in moist habitats close to their depositional setting. Ferns such as Adiantaceae (represented only by foliage fragments) and others, represented only by dispersed spores, probably lived in different habitats. With the exceptions of Gleicheniaceae and Cladophlebis with small pinnules, these ferns occurred mainly or exclusively in the North Phytogeographic Province under a humid-temperate climate. [Copyright &y& Elsevier]

Reports on the discovery of an early Cretaceous Ginkgo biloba in Liaoning, Northeast China. Identification of Ginkgo biloba as a living fossil; Classification of Ginkgo as a very important gymnospermous genus that has only one surviving species; Evolutionary trends of the ovule-bearing organs of Ginkgo.

Pelliales is a basal lineage of the simple thalloid liverworts. Here, we describe a simple thalloid liverwort from the Middle Jurassic Xishanyao Formation of the Turpan–Hami Basin, Xinjiang Uygur Autonomous Region in northwestern China. The thalloid fossil liverwort is described as a new species: Pellites hamiensis (Pelliaceae, Pelliales). Pellites hamiensis nov. sp. resembles the extant species of Pelliaceae in having ribbon-like segments, conspicuous costae that appear as ridges on the ventral surface, rectangular cells with thickened walls adjacent to the margin, and elongated cells in the middle part of the thallus. The occurrence of P. hamiensis nov. sp. extends the fossil records of Pellites back to the Aalenian-Bajocian or Bajocian (ca. 170 Ma) and suggests that the divergence time of the Pelliaceae is no later than the Middle Jurassic. [ABSTRACT FROM AUTHOR]

The Ordos Basin, as the second largest petroliferous basin of China, contains abundant oil and gas resources, oil shale, and sandstone‐type uranium mineral resources. Chang 7 shale is not only the major source rock of the Mesozoic petroliferous system of the Basin, but is also crucial in determining the space‐time distribution relationship of the shale section for the effective exploration and development of the Basin's oil and gas resources. To obtain a highly precise age of the shale development section, we collected tuff samples from the top and bottom profile of the Chang 7 Member, Yishi Village, Yaoqu Town, Tongchuan District, on the southern margin of the Ordos Basin and performed high‐precision chemical abrasion (CA)–isotope dilution (ID)–thermal ionization mass spectrometry (TIMS) zircon U‐Pb dating on the basis of extensive laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) zircon U‐Pb dating data. Our results show the precise ages of the top and bottom zircon in the Chang 7 shale to be 241.06±0.12 Ma and 241.558±0.093 Ma, respectively. We first obtained Chang 7 age data with Grade 0.1‐Ma precision and then determined the age of the shale development in the Chang 7 Member to be the early‐Middle Triassic Ladinian. This result is supported by paleontological evidence. The deposition duration of the Chang 7 shale is 0.5Ma with an average deposition rate of the shale section being 5.3 cm/ka. Our research results provide time scale and basic data for further investigation of the basin–mountain coupling relation of the shale section, the sedimentary environment and volcanic ash and organic‐matter‐rich shale development relation, and the organism break‐out and organic‐matter enrichment mechanism. [ABSTRACT FROM AUTHOR]

The genus nameSchimperstrobuswas first used by Denget al. (2014) but is invalid as it was introduced without the designation of a type. We here selectAndrostrobus wonnacottiiHarris, 1941 as the type of the new genusSchimperstrobus. [ABSTRACT FROM AUTHOR]

Carbon-isotope stratigraphy launched since the early technological development of carbon-isotope measurement in 1950s, however, the emergence and advance of terrestrial carbon-isotope stratigraphy took quite a long way. At early stage the exploration of carbon-isotope stratigraphy based on the marine biological shell carbonates was verified by repeatable carbon-isotope stratigraphic data, laboratory chemical experiments and the later laboratory foraminiferal culture experiments. The breakthrough for testifying the fundamentals of terrestrial carbon-isotope stratigraphy lies on the synchronous fluctuations between the carbon-isotope stratigraphic curves derived from marine biological shell carbonates and those derived from terrestrial C3 plants. The character that carbon-isotope stratigraphic curves can be globally synchronously correlated over the marine and terrestrial/atmospheric reservoir mainly excludes the potential biasing factors, such as diagenetic bias, carbon-isotope variations in intra/inter individual plant in same species or between species, ecological changes, changes in aridity, changes in source input and representative sampling. Therefore, the fundamentals of terrestrial carbon-isotope stratigraphy based on C3 plant successfully established. The terrestrial carbon-isotope stratigraphy can be used for global stratigraphic correlation, reconstructing the evolution of atmospheric CO2 and can further verify the published global carbon-cycle models. The terrestrial carbon-isotope stratigraphy based on the compound specific biomarkers and single-grained pollen may be a promising perspective in future. [ABSTRACT FROM AUTHOR]

Carbon isotope stratigraphic records across the Triassic-Jurassic (Tr-J) boundary show carbon isotope excursions in both marine and terrestrial sections, indicating frequent perturbations of the global carbon cycles, which are linked to the ~600 kyr pulsed emplacement of the Central Atlantic Magmatic Province (CAMP). However, few detailed carbon isotope stratigraphic reports from high-latitude terrestrial deposition have been documented in contrast to the contemporaneous low- to mid-latitude records. It hampers the understanding of the climatic response in the high-latitude terrestrial areas and the modeling global carbon cycles triggered by CAMP volcanisms. Here, we present high-resolution organic carbon isotope data primarily originated from C3 plants in the Haojiagou section in the paleo-high-latitude Junggar Basin, NW China. Combined with previously published biostratigraphic and geochemical results, carbon isotope stratigraphy with distinct "initial negative carbon isotope excursions" (I-CIE) and "main negative carbon isotope excursions" (M-CIE) is built in the Junggar Basin and allows a global stratigraphic correlation. The end-Triassic mass extinction (ETE) and the Tr-J boundary is then well identified. The excursion magnitude is similar to that in Greenland and Poland where the sections are also terrestrial. Climatic pattern recorded in the Junggar Basin rapidly changed across the Tr-J transition and coincides with a bloom of fern spores, increased wildfire activities, enhanced hydrological cycles and soil loss. • δ13C records derived from C3 plants in paleo-high-latitude basin are reported. • ~3‰ δ13C fluctuation of atmospheric CO 2 between ETE horizon and TJB is witnessed. • Climatic pattern in the terrestrial basin rapidly changed at the T-J transition. • δ13C and climate changes coincide with a fern spike and increased wildfires. • Land section can correlate with coeval marine biostratigraphic ETE to TJB horizons. [ABSTRACT FROM AUTHOR]

The Mesoproterozoic Jixian System (1.6–1.4 Ga) in the Luonan area, southern margin of the North China Craton (NCC), is characterized by complete development, continuous sedimentation and a low degree of structural deformation, resulting in well-preserved palaeontological and paleoenvironmental records. Carbon, oxygen and strontium isotopes of 382 dolostone samples from the Jixian System in Xiong'er Rift, southern margin of the NCC are analysed for the restoration of paleoenvironment and stratigraphic correlation. The results show that the δ13C values of these samples mainly concentrate between −1.8‰ and 2.0‰, and the values can be divided into three segments. The δ18O values are mainly between −6.5‰ and −3.5‰, with frequent fluctuations and weak regularity. The 87Sr/86Sr ratio ranges from 0.7051 to 0.7139, with an average value of 0.7085. Its fluctuations have certain regularity and are negatively correlated with the carbon isotopes, indicating that the sea-level changes during the Jixian period in the southern margin of the NCC. The carbon isotope curve of the samples from the study section is very similar to those of the Xiong'er Rift and the Yanliao Rift of the NCC. The −3.2‰ δ13C negative excursion in the middle and upper parts of the Xunjiansi Formation corresponds to the δ13C negative excursion from the top of the Wumishan Formation to the bottom of the Tieling Formation in the Yanliao Rift. Combined with previous research data, the Jixian System that deposited in the Xiong'er Rift and the Yanliao Rift can be approximately correlated with each other. In addition, the carbon isotope data obtained from this study is comparable to global carbon isotope values during the same period. The rise and oscillation of carbon and strontium isotope values during this period may be a response to the break-up of the Colombian supercontinent. [ABSTRACT FROM AUTHOR]

Studies the Upper Triassic coal-bearing strata in the Liupanshan Basin, Ningxia Hui Autonomous Region in China. Stratigraphy; Geological age; Significance to the oil-gas exploration of the basin and the interpretation of the sedimentary and tectonic history of the area during the early Mesozoic era.

An amended species, Nilssoniopteris neimenguensis ( Wang, 1984 ) Zhao et Deng, nom. nov., is described from the Lower Jurassic Hongqi Formation of the Xilinhot Basin, Inner Mongolia, northern China, based on leaf macromorphology and cuticular structures. Following a reexamination of the specimens published in the previous literature, a total of 86 species of Nilssoniopteris are recognized, and their stratigraphic and geographic distributions are analyzed. Nilssoniopteris first occurs in the Carnian of the Late Triassic of Central Europe and the southwest region of the United States. This genus spreads in the Euro-Sinian region in the Late Triassic and then gradually extends to the Siberian-Canadian region in the Early to Middle Jurassic, where it first experiences diversification and distribution expansion. After a decline in both diversity and geographic range in the Late Jurassic, Nilssoniopteri s species flourish and almost completely migrate to the Siberian-Canadian region during the Early Cretaceous, and the genus finally dies out in the Cenomanian of the Late Cretaceous. The paleoclimatic conditions of Nilssoniopteris also experience a change from the subtropical-tropical zone to the warm temperate zone, indicating that the species may have grown in the warm humid temperate and subtropical-tropical zones with a general preference for warm, humid climates. [ABSTRACT FROM AUTHOR]

• First documentation of the Pagoda Positive Carbon Excursion (PPCE) on Upper Yangtze Platform. • Astronomical tuning of 3 sections yielded similar PPCE durations of 4.0 ± 0.3 Myr. • PPCE is coeval with regional transgression-highstand and oscillating climate. The continuous and well exposed sections of the Upper Ordovician on the Upper Yangtze Platform were surveyed and sampled for δ13C and δ18O isotope and conodont fossils. The geochem-stratigraphic work in the Pagoda Formation has resulted in the recognition of a positive δ13C excursion, the Pagoda Positive δ13C Excursion (PPCE). The PPCE is a distinctive positive excursion occurring in the Middle-Late Katian, consists of three minor excursions ranging from 1.5 ‰ to 3 ‰, which has been identified in all the study sections on the Upper Yangtze Platform. The PPCE interval ranges through the conodont Hamarodus brevirameus and Protopandeordus inscrulptus conodont zones in ascending order, which indicates that the PPCE develops in the Middle-Late Katian of the Late Ordovician, while the Guttenberg δ13C Excursion (GICE) in the Baltoscandia and America extended from the Late Sandbian to the Early Katian. Spectral analysis of high-resolution magnetic susceptibility (MS) logs for the four study sections shows consistent wavelengths of ca. 2.0, 0.5, 0.18 and 0.15 m. The outcrop depth-series were tuned using 405-kyr long-eccentricity cycles and the astronomical tuning yields the duration of 3.7 to 4.4 myr for the PPCE event in different sections. This is the first documentation of the PPCE event on the Upper Yangtze Platform according to the geochemo-bio-cyclostratigraphy evidences, being identified within all portions of this platform in South China. It revised the previous description of the positive δ13C excursion of the Pagoda Formation on the Upper Yangtze Platform. The trigger of the PPCE was also briefly discussed in this paper. [ABSTRACT FROM AUTHOR]

Samples of Upper Ordovician marine carbonates from four sections on the Yangtze Platform (1, the Liangcun section northeast of Xishui County Town, Guizhou Province; 2, the Zhuazhuayan section southwest of Leibo County Town, Sichuan Province; 3, the Xiaogangwan section east of Wulong County Town, Chongqing Municipality; 4, the Shatan section north of Nanjiang County Town, Sichuan Province) have been analyzed for carbon isotope (δ 13 C) chemostratigraphy. A distinct positive δ 13 C excursion (δ 13 C max > 2) is observed in all sections, which ranges through the Hamarodus brevirameus conodont zone, and locally into slightly younger strata. The base of this zone is the First Appearance Datum (FAD) of H. brevirameus and its top coincides with the FAD of the conodont Protopanderodus insculptus . Based on its position in the H. brevirameus zone, this excursion is identified as the well-known Guttenberg Excursion (GICE) confirming the global significance of this paleoceanographic event. The fact that in the Black Knob Ridge section in the USA, the GSSP of the base of the global Katian Stage, the beginning of the GICE is just below the base of the Katian makes it possible to locate this key level in our study sections even in the absence of the diagnostic graptolite Diplacanthograptus caudatus . Our carbon curves through the GICE interval show three minor secondary peaks reflecting paleoceanographic changes or selective preservation of the isotope signal. However, because a global review of the GICE shows that such minor peaks, which are often based on a single elevated δ 13 C value, are of irregular occurrence, they are interpreted as local, rather than global, phenomena. The suggested global cooling in the early Katian might have favored the generation of methane hydrates and hence the reduction of the amount of 12 C in the marine carbonates. [ABSTRACT FROM AUTHOR]

Oil and gas discoveries within Proterozoic-Cambrian strata and the majority of shale gas production occurs in relatively stable tectonic regions and characterised by moderate thermal maturity (R o °<°2.5%). The Sinian–Silurian gas resource located in China's Sichuan Basin is a definitely different example of a concurrent conventional and unconventional gas system within a tectonically complicated basin and sourced from overly-mature organic shales (R o °>°2.5%). The system comprises two components, namely a conventional Sinian–Cambrian dolomite-hosted gas resource and an unconventional Cambrian-Silurian shale gas deposit, both represent trillion cubic meter accumulations. The migration-accumulation type Sinian–Cambrian gas system, is a result of numerous processes, including (1) paleo-high trapping within a relatively stable tectonic setting, (2) appropriate source materials located in a paleo-rift trough, (3) large-scale dolomite grainstone reservoirs located near the paleo-high, (4) adequate gas produced from in-situ crude oil cracking, and, (5) gypsum-salt and shale cap rock preservation. The self-contained source-reservoir Cambrian–Silurian shale gas system, is localized by deepwater organic-rich shelf facies, characterized by high silicon and calcium contents. The recent discovery of these two massive gas fields in old and over-matured sedimentary strata, has effectively extended the upper maturity limit of R o over 3.0%, which may indicate the efficacy of broadening current natural gas exploration areas, thus potentially increasing global natural gas resources significantly. Furthermore, the discovery may spark interest in natural gas exploration in widely distributed old strata, thus encouraging co-development of conventional and unconventional petroleum accumulations. [ABSTRACT FROM AUTHOR]

The end-Triassic mass extinction (ETE), one of the five largest mass extinctions, occurred at 201.6 Ma. It was characterized by dramatic declines in marine and terrestrial ecosystems and was approximately synchronous with the eruption of the Central Atlantic Magmatic Province (CAMP). Loss of marine biodiversity is linked to extreme global warming while the cause of floral destruction in terrestrial ecosystems remains open to debate. In this paper, biomarker records of higher plants are reported from terrestrial facies in the Haojiagou section of the high palaeolatitude Junggar Basin, northwest China. Strata around the ETE interval are marked by sharp increases in the abundances of cadalene, retene, pimanthrene and furans, which are synchronous with "fern spikes". These results are interpreted as indicating the demise of land vegetation and the enhanced burial of higher plants, consistent with palynological evidence for the loss of floral diversity. The fluctuations in the abundance of n -alkanes series and conversion of n -alkanes peak patterns coincide with wildfires indicated by polycyclic aromatic hydrocarbons. Based on integrated stratigraphic correlation, the increased burial of higher plants, wildfires and CAMP volcanism are synchronous both in the Haojiagou section and other classic Triassic-Jurassic boundary sections globally. We propose that widespread deforestation may be due to CAMP-derived acid rain and the rapid and large-scale demise of vegetation may have provided moisture-free fuels for wildfires. • Higher plant biomarkers are first reported in a high palaeolatitude terrestrial basin across the Triassic-Jurassic transition. • Similar biomarker features are witnessed at worldwide marine and terrestrial sections, suggesting a global deforestation. • Extensive deforestation and wildfires during the ETE period could be initially caused by the CAMP-originated acid rainfalls. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Proterozoic eukaryotic evolutionary was proposed to be divided into four stages. • Poor performance of oxygen in hindering or accelerating the evolution of eukaryote. • Oceanic temperature may have limited eukaryotic physiology during the Proterozoic. The emergence and diversity of eukaryotes that occurred in the Proterozoic Eon (2.5–0.541 Ga) are the most important parts of life's evolution on the Earth. However, the critical time and key environmental factor(s) are still controversial. Herein, we systematically compiled the reported fossils and convinced biomarkers of Proterozoic eukaryotes. The Proterozoic eukaryotic evolutionary timeline was proposed to be divided into four stages: (1) ambiguous origin (2.3–1.8 Ga), (2) slow evolution (1.8–0.8 Ga), (3) diversity fluctuation (0.8–0.635 Ga), and (4) first radiation (0.635–0.541 Ga). As aerobic organisms, the emergence and evolution of eukaryotes have been proposed to be hindered by low oxygen levels during the Proterozoic Eon. However, increasing evidence suggests that the Proterozoic oxygen content might have been higher than 1% PAL (present atmospheric level) since 2.3 Ga, allowing eukaryotes, including early animals, to survive. The Great Oxygenation Event (GOE) did not wake up eukaryotes. The Mesoproterozoic Oxygenation Event (MOE) did not accelerate the evolution of eukaryotes. The first and rapid radiation of eukaryotes after the Neoproterozoic Oxygenation Event (NOE) and global glaciations acted like the opening of Pandora's box. Hence atmospheric oxygen alone cannot be invoked as the only control on the evolution of eukaryotes. Instead, we suggest that oceanic temperature may have been an important environmental factor that limited eukaryotic physiology until the end-Proterozoic. [ABSTRACT FROM AUTHOR]

Trees on the side directly exposed to sunlight generally grow faster than on the opposite side, a phenomenon termed plant phototropism. There are in situ vertical trunks of silicified wood in the Xiadelongwan area of Yanqing County, north Beijing, where the first National Geologic Park of Petrified Wood of China has been built since 2002. A few trunks have well-preserved growth rings. One petrified stump from the formation shows a positive phototropism direction of SW230°. As compared with the modern normal growth stumps in Beijing plain area, which have a positive phototropism direction of SW210 ° ± 5°, the evidence of wood phototropism supports the conclusion of previous palaeomagnetic studies that the North China Plate has rotated clockwise since the Late Jurassic. The known petrified wood stumps in the Yanshan-Liaoning area are mainly found from the strata of 165-136 Ma, which corresponds to the main stage of the Yanshanian Movement. [ABSTRACT FROM AUTHOR]

• First precise zircon U-Pb age from the Cuizhuang Formation in the Xiong'er Basin. • Abundant organic wall microfossils found from the Paleoproterozoic red mudstones. • Oxygenated water is a possible key factor for the eukaryote preservation as fossil. North China Craton is one of the old cratons preserved continues recording of the early evolution of eukaryotes. Organic wall microfossils (OWMs) of eukaryotic affinity have been found in the late Paleoproterozoic sediments from the Yanliao and Xiong'er basins that located in the northern and southern margins of the North China Craton. However, accurate Paleoproterozoic stratigraphic correlation of these two basins still lacks precise chronological and convincing paleontological evidence. Here, we report a SIMS zircon U-Pb age (1647.8 ± 4.3 Ma) from a tuffite layer at the bottom of the Cuizhuang Formation of the Xiong'er Basin, which provides direct chronological evidence for its isochronous deposition with the Chuanlinggou Formation in the Yanliao Basin. Besides, abundant OWMs were recovered from red shales of the Chuanlinggou Formation from the present Taihang Mountains, which is located in the southern branch of the Yanliao Basin and close to the Xiong'er Basin. They are primarily spheroidal microfossils and contain at least one unambiguous unicellular eukaryotic taxa (Valeria lophostriata) and three probable eukaryotic taxa (Schizofusa sinica , Dongyesphaera tenuispina ?, large Leiosphaeridia spp.). Our finding further confirms the appearance of unicellular eukaryotes in the Paleoproterozoic ocean and the expanding of their living scopes from the cratonic marginal basin to the intracratonic basin. However, the absence of eukaryotic OWMs in black shales and green shales with more hypoxic depositional waters than those of red shales, indicates that the oxygenated water is probably a key factor to the survival of eukaryotes and even their preservation as OWMs. [ABSTRACT FROM AUTHOR]

Abstract: The Gleicheniaceae is an ancient leptosporangiate fern family with fossil records dating back to the Palaeozoic. Fossil gleicheniaceous plants in China have received much attention and it has been suggested they play an important role for understanding the origin and evolution of the Gleicheniaceae. In this paper, the fossil diversity of gleicheniaceous plants is analyzed based upon systematic review of 27 species ascribed to six genera of fossils recorded from the Permo-Carboniferous to Cretaceous/Tertiary of China. The reproductive structures, including sori, sporangia, annuli and in situ spores (including their ultrastructure) are especially emphasized and discussed in a systematic and evolutionary context. The palaeogeographical distribution and stratigraphical ranges of these fossils are investigated based on detailed fossil records at the species level. Our study indicates that fossil gleicheniaceous plants in China have undergone evolutionary processes that include origin, decline, recovery and radiation, during different episodes from the Carboniferous to Cretaceous/Tertiary. [Copyright &y& Elsevier]

Fossil life in the Precambrian is commonly preserved as carbonaceous compressions, where Pre-Cryogenian carbonaceous compressions mainly occur in organic-poor rocks. Black-shale-preserved carbonaceous compressions have become more common since the Ediacaran Period. To explore the depositional context of carbonaceous compressions, micro X-ray fluorescence spectroscopy (μ-XRF) was used to image elemental distributions in carbonaceous compressions and surrounding rocks in Mesoproterozoic and Ediacaran-aged rocks. The carbonaceous compressions preserved in the Xiamaling green silty mudstones (1.40 Ga) and Lantian black shales (0.63 Ga) were selected and scanned, respectively. The behavior of redox-sensitive elements (Mo, U, V, Zn, Cu) in the Xiamaling and Lantian rocks and carbonaceous compressions suggest that the overlying water conditions during their sedimentation were not sulfidic. However, the co-enrichments of Fe and S in Xiamaling and Lantian carbonaceous compressions indicate pyrite permineralization. The Lantian carbonaceous compressions have a higher pyrite permineralization degree and a lower organism decomposition degree than those of the Xiamaling carbonaceous compressions. We speculate that these differences are related to a higher sulfate reduction rate and a lower dissimilatory iron reduction rate in the sediments hosting the Lantian carbonaceous compressions. Such conditions might be achieved through rapid burial and encircling by clay minerals. Overall, our results shed new light on understanding the preservation processes of the Precambrian life and the influence of environmental factors. [Display omitted] • Multi-element imaging of the Precambrian carbonaceous compressions using μ-XRF • The Xiamaling and Lantian carbonaceous compressions formed in non-sulfidic water. • Rapid burial by clay minerals and pyritization help the preservation of organisms. [ABSTRACT FROM AUTHOR]

The "hothouse" Triassic climate provides a key window to study megamonsoon systems. However, high-quality paleoclimate proxy records are rarely reported from the Tethys realm, where the seasonal meridional migration of the intertropical convergence zone (ITCZ) should be the most remarkable. Here, continuous and well-dated proxy records are used to study monsoon activity in the northeastern Tethys from the Middle Triassic lacustrine sediments (Ch7 black shale, Yanchang Formation) in the Ordos Basin (China). The proxies, including natural gamma-ray intensity, magnetic susceptibility, and element concentrations and ratios (U, K, Zr/Al, Zr/Rb and Sr/Rb), document a strong precession signal in the sediments. We propose that the periodic deposition of the Ch7 black shale occurred in response to intensifications in a monsoon-driven climate enhanced by the early Ladinian warming event. Climate variability in the Ordos Basin (~25°N) reflects the harmonics of ~100 kyr, ~20 kyr and ~10 kyr cycles and is highly coherent with solar insolation at 9° latitude, suggesting that this monsoon system might have been modulated by tropical solar insolation. The dominance of tropical climate processes in this mid-latitude monsoon region can be attributed to the dramatic dynamics of the ITCZ and intense monsoon circulation in the Tethys realm. • Deposition of Ch7 black shale was paced by the precession-controlled monsoon activity. • Warming event in the early Ladinian triggered Ch7 black shale deposition. • Semi-precession signal in the Ordos Basin responded to tropical insolation forcing. • Tropical insolation was the dominant driver of the Tethyan monsoon. [ABSTRACT FROM AUTHOR]

The article looks at a study which compares the phototropism direction of the trunk of the fossil wood with the living normal growth stumps, thus verifying the paleomagnetic evidence whether the plates rotated. It mentions wood phototropism phenomenon with different tectonic movements which recovered from the palaeomagnetic record. It also mentions eccentricity of tree growth rings should be related to the direction of sunshine.

Trees grow towards the sunlight via a process of phototropism. The trunk phototropism processes are frequently observed in Northern Hemisphere from high latitude to at least the Tropic of Cancer region, and also occur in some in situ preserved vertical petrified woods in various geological ages. However, such evidence is still very limited and poorly known in fossil record; and the relationship between tree ring phototropism and rotation of tectonic blocks is unclear. Here we report the eccentricities of living and fossil trees as a proxy to determine geological block rotation at the same latitudes within the North China Block. The dominant eccentricity of living trees is southwest 219° ± 5°. By contrast, standing in situ fossil trunks in the Mid-Late Jurassic Tiaojishan Formation and the Late Jurassic Tuchengzi Formation had average eccentricities of 237° and 233.5°, respectively. These differences shed light on the palaeogeographical changes, indicating that the North China Block rotated clockwise from the Late Jurassic to the present day. This result is largely coincident with the palaeomagnetic results, indicating that the North China Block rotated clockwise by 26.5° ± 5.5° since the Middle to Late Jurassic transition. [ABSTRACT FROM AUTHOR]