Search

Twenty taxa of fossil plants are described from the Sangonghe Formation (Lower Jurassic) of the Haojiagou section in the Junggar Basin, Xinjiang, NW China. The Sangonghe flora consists of Equisetales, ferns, bennettitaleans, ginkgoes, conifers and gnetales, but is dominated by ferns. It is a low species diversity but extraordinary flora for having a high proportion (45%) of thermophilous or arid-tolerant (xerophilous) elements, by comparing with 0% in the underlying Badaowan Formation and around 2% in the overlying Xishanyao Formation. These thermophilous or arid-tolerant (xerophilous) elements include Marattiopsis asiatica Kawasaki, Phlebopteris polypodioides Brongniart and Dictyophyllum sp. (ferns) , Otozamites leckenbyi Harris, Otozamites sp. , Zamites sp. and Dictyozamites sp. (bennettitaleans), Brachyphyllum ( Hirmeriella ?) sp. (conifers) and Cadmisega ephedroides Krassilov et Bugdaeva (gnetales). Based on the geological ranges of the known species and comparisons with the coeval floras in Eurasia, the age of the Sangonghe flora is Toarcian of the Early Jurassic. The flora reveals a climatic warming and aridification event, which occurred during the Toarcian in the Junggar Basin. Palaeontological (including palaeobotanical and palynological), sedimentological and geochemical data demonstrate that warming and aridification occurred widely across the north of China during the Toarcian, and this might be the response of the terrestrial ecosystem to the Toarcian Oceanic Anoxic Event (T-OAE).

Based on isotopic, lithologic and electrical data and logging cycle analysis technique, stratigraphic sequences in the Middle–Upper Cambrian Xixiangchi Group in the Sichuan Basin and its adjacent area are divided, and its sedimentary characteristics and evolution are analyzed. The Xixiangchi Group can be divided into 5 third-order sequences (Sq1–Sq5), of which sequences I to III (Sq1–Sq3) are relatively complete, sequences IV and V are denuded in the Late Cambrian because of the Dian-Chuan paleo-uplifts. Third-order sequences of the Xixiangchi Group in this area have the characteristics of thin in the west and thick in the east, showing that the Caledonian paleo-uplift is a synsedimentary paleo-uplift and the paleogeomorphology in the platform is a gentle slope. Sequence I develops high stand systems tract and transgressive systems tract. The other third-order sequences are dominated by highstand systems tracts, and the transgressive systems tracts last shortly in time and are limited in area. The basic features of evaporative–restricted platform of gentle slope type developed continuously in the sedimentary period of the Xixiangchi Group, its sedimentary environment of “high in west and low in east” and the change of micro paleogeomorphology in the platform control the continuous development of sedimentary facies. Open platform is developed only in sequence I and sequence II, and the inner beach of the platform and the edge beach of the platform are mostly developed in sequence II and sequence III. It indicates that there are two platform margin zones in the study area, a relatively stable, large-scale platform marginal zone in NE Guizhou–Western Hunan and Hubei, and a moving and small-scale platform marginal zone in North Chongqing–Western Hubei. Key Words: Sichuan Basin, Middle– Upper Cambrian, Xixiangchi Group, sequence stratigraphy, third-order sequence, carbon isotope composition, lithofacies paleogeography, sedimentary environment evolution

Normally, trees on the side directly exposed to sunlight will grow faster than the opposing side. This phenomenon is termed plant phototropism. Moreover, palaeomagnetists have revealed that the Junnar Block has never rotated since the Mesozoic. The petrified woods in the Jiangjunmiao area of Qitai County show the positive phototropism direction of SSW220. By compared with the modern normal growth stumps in plain area, which have positive phototropism direction of SSW 219 ± 5, this observation supports the conclusion of palaeomagnetic researchers: the Junggar basin has never rotated since the Late Jurassic.

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.

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, Nilssoniopteris 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.

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.

Two new species ofNilssoniopterisof the order Bennettitales,Nilssoniopteris hamiensisZhao and Deng, new species andNilssoniopteris crassiaxisZhao and Deng, new species, are established from the Xishanyao Formation (Middle Jurassic) of Sandaoling Coal Mine in Hami, Xinjiang, China, based on leaf macromorphology and cuticular features.Nilssoniopteris hamiensisn. sp. is characterized by its varied leaf shapes and trichome bases of 1–4 cells on the abaxial epidermis.Nilssoniopteris crassiaxisn. sp. is characterized by its broad midrib (especially near the leaf base) and trichome bases of 1–3 cells on the abaxial epidermis. Both species possess unique venation patterns that are not only simple and free, but also forked and merged to form closed loops. These anastomosing veins are even more complicated inN.crassiaxisn. sp. in that the veins can fork once, twice, or even three times, the forked veins can later merge with each other or with an adjacent vein to form a closed loop, which may later further disjoin. The generic diagnosis ofNilssoniopterisis thus accordingly emended, particularly in the venation pattern. In addition, the stratigraphic and geographical distributions of all 45 JurassicNilssoniopterisspecies worldwide have been summarized and analyzed to better understand their brief evolutionary history, indicating thatNilssoniopterismight be able to grow not only in subtropical regions as the living cycads are, but also in warm climatic regions.

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.

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.

Based on the drilling, logging, seismic and outcrop data, the formation and evolution of the late Sinian to early Cambrian intraplatform basin in Sichuan Basin was studied. Through the analysis of the total residual thickness of Member 3 + Member 4 of Dengying Formation, the total thickness of Maidiping Formation + Qiongzhusi Formation, and lithofacies characteristics of Maidiping Formation, the distribution of the intraplatform basin was defined and its controlling effect on natural gas distribution of Dengying Formation was revealed. The intraplatform basin was characterized by small total residual thickness of Member 3 and Member 4 of Dengying Formation, the large total thickness of Maidiping Formation and Qiongzhusi Formation, and the deep-water phosphorous-carbonaceous-siliceous mudstone in Maidiping Formation. Horizontally, the intraplatform basin was mainly distributed in Qingchuan-Ziyang-Yibin area, and experienced four evolution periods. During the period of Member 1 and Member 2 of Dengying Formation, the Sichuan Basin was a rimmed carbonate platform with the well developed mounds and shoals on the platform margin and its interior. The intraplatform basin in western Sichuan Basin was initially formed due to the first episode of Tongwan movement. During the period of Member 3 and Member 4 of Dengying Formation, the depositional center was formed in Moxi, Changning and Zhengxiong area due to extension and rifting of the Upper Yangtze Craton, thereafter, the Sichuan Basin evolved into a rimmed carbonate platform with an intraplatform basin. The second episode of Tongwan movement between Sinian and Cambrian led to the overall uplift and exposure of Sichuan Basin characterized by weathering denudation at high position and downward fluid erosion at low position. During the period of Maidiping Formation, three lithofacies zones were developed horizontally, and the third episode of the Tongwan movement between Maidiping Formation and Qiongzhusi Formation modified the sedimentary geomorphology locally. During the period of Qiongzhusi Formation and Canglangpu Formation, continuous deposition made the Sichuan Basin evolve into a gentle siliciclastic ramp. The evolution of the intraplatform basin not only promoted formation of high-quality platform-margin dolomite reservoirs of Member 4 of Dengying Formation, but also controlled distribution of the high-quality source rocks of Maidiping Formation and Qiongzhusi Formation. The dolomite of Dengying Formation in the surrounding area of the intraplatform basin was the most favorable hydrocarbon exploration area because of its good source-reservoir configuration. Keywords: Dengying Formation, Source rock, Dolomite, Intraplatform basin, Paleogeography, Sichuan Basin

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.

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.

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 ° 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.

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.

The Anyue Sinian–Cambrian giant gas field was discovered in central paleo-uplift in the Sichuan Basin in 2013, which is a structural-lithological gas reservoir, with 779.9 km2 proven gas-bearing area and 4 403.8×108 m3 proven geological reserves in the Cambrian Longwangmiao Formation in Moxi Block, and the discovery implies it possesses trillion-cubic-meter reserves in the Sinian. Cambrian Formations in Sichuan Basin. The main understandings achieved are as follows: (1) Sinian–Cambrian sedimentary filling sequences and division evidence are redetermined; (2) During Late Sinian and Early Cambrian, “Deyang–Anyue” paleo-taphrogenic trough was successively developed and controlled the distribution of source rocks in the Lower-Cambrian, characterized by 20–160 m source rock thickness, TOC 1.7%–3.6% and Ro 2.0%–3.5%; (3) Carbonate edge platform occurred in the Sinian Dengying Formation, and carbonate gentle slope platform occurred in the Longwangmiao Formation, with large-scale grain beach near the synsedimentary paleo- uplift; (4) Two types of gas-bearing reservoir, i.e. carbonate fracture-vug type in the Sinian Dengying Formation and dolomite pore type in the Cambrian Longwangmiao Formation, and superposition transformation of penecontemporaneous dolomitization and supergene karst formed high porosity-permeability reservoirs, with 3%–4% porosity and (1–6)×10−3 μm2 permeability in the Sinian Dengying Formation, and 4%–5% porosity and (1–5)×10−3 μm2 permeability in the Cambrian Longwangmiao Formation; (5) Large paleo-oil pool occurred in the core of the paleo-uplift during late Hercynian—Indosinian, with over 5 000 km2 and (48–63)×108 t oil resources, and then in the Yanshanian period, in-situ crude oil cracked to generate gas and dispersive liquid hydrocarbons in deep slope cracked to generate gas, both of which provide sufficient gas for the giant gas field; (6) The formation and retention of the giant gas field is mainly controlled by paleo-taphrogenic trough, paleo-platform, paleo-oil pool cracking gas and paleo-uplift jointly; (7) Total gas resources of the Sinian–Cambrian giant gas field are preliminarily predicted to be about 5×1012 m3, and the paleo-uplift and its slope, southern Sichuan Basin depression and deep formations of the high and steep structure belt in east Sichuan, are key exploration plays. The discovery of deep Anyue Sinian–Cambrian giant primay oil-cracking gas field in the Sichuan Basin, is the first in global ancient strata exploration, which is of great inspiration for extension of oil & gas discoveries for global middle-deep formations from Lower Paleozoic to Middle–Upper Proterozoic strata. Key words: Sichuan Basin, Anyue gas field, Fuling shale gas field, paleo-taphrogenic trough, paleo-oil pool, paleo-uplift, carbonate platform, unconventional oil and gas, shale gas, Weiyuan shale gas field

Male cones of Ixostrobus hailarensis from Lower Cretaceous strata of the Hailar region of north-east China were re-examined for features of their cuticle and in situ pollen. 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 taxon Cycadopites minimus. Both the cuticle and pollen are distinct from Ixostrobus but are consistent with the cycad genera Androstrobus, Aegianthus, Loricanthus and the putative angiosperm Solaranthus. Reanalysis of the type species of Androstrobus, 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 from Androstrobus. Comparisons indicate that Solaranthus represents a male c...

The existing δ 13C 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 δ 13C shifts correlate well with coeval paleoceanographic changes and bioevents. Besides, there are some δ 13C excursions from a few sections in previous studies, and more data are required to identify whether they are global or regional ones.

The Triassic-Jurassic (Tr-J) boundary marks a major extinction event, which (similar to 200 Ma) resulted in global extinctions of fauna and flora both in the marine and terrestrial realms. There prevail great challenges in determining the exact location of the terrestrial Tr-J boundary, because of endemism of. : and the scarcity of fossils in terrestrial settings leading to difficulties in linking marine and terrestrial sedimentary successions. Investigation based on palynology and bivalves has been carried out over a 1113 m thick section, which is subdivided into 132 beds, along the Haojiagou valley on the southern margin of the Junggar Basin of the northern Xinjiang, northwestern China. The terrestrial Lower Jurassic is conformably resting on the Upper Triassic strata. The Upper Triassic covers the Huangshanjie Formation overlaid by the Haojiagou Formation, while the Lower Jurassic comprises the Badaowan Formation followed by the Sangonghe Formation. Fifty six pollen and spore and one algal on were identified from the sediments. Based on the key-species and abundance of spores and pollen, three zones were erected: the Late Triassic (Rhaetian) Aratrisporites-Alisporites Assemblage, the Early Jurassic (Hettangian) Perinopollenites-Pinuspollenites Assemblage, and the Sinemurian Perinopollenites-Cycadopites Assemblage. The Tr-J boundary is placed between bed 44 and 45 coincident with the boundary between the Haojiagou and Badaowan formations. Beds with Ferganoconcha (?), Unio-Ferganoconcha id Waagenoperna-Yananoconcha bivalve assemblages are recognized. The Ferganoconcha (?) bed is limited to the upper Haojiagou Formation, Unio-Ferganoconcha and Waagenoperna-Yananoconcha assemblages are present in the middle and upper members of the Badaowan Formation. The sedimentary succession is interpreted as terrestrial with two mainly lake deposit intervals within Haojiagou and Badaowan formations, yielding fresh water algae and bivalves. However, the presence of brackish water algae Tasmanites and the marine-littoral facies bivalve Waagenoperna from the Badaowan Formation indicate that the Junggar Basin was influenced by sea water caused by transgressions from the northern Tethys, during the Sinemurian.

This work documents a new flora from the Upper Permian Hongshan Formation of Acheng County, Heilongjiang Province, Northwest China. The flora consists of 20 species: Paracalamites sp., Pecopteris tangwangheensis Huang, Callipteris obese Huang, Callipteris shenshuensis Huang, C. tangwangheensis Huang, C. heilongjiangensis Huang, C. zeilleri Zalessky, C. sp., Comia yichunensis Huang, C. tenueaxis Huang, Iniopteris sibirica Zalessky, Supaia teiliensis Huang, Compsopteris tchirkovae Zalessky, C. cf. adzvensis Zalessky, Nilssonia sp. 1, Nil. sp. 2, Taeniopteris cf. densissima Halle, T. cf. nystraemii Halle, T. sp. and Noeggerathiopsis derzavinii Neub. It is dominated by Angara species but mixed with some typical Cathaysian elements. The age of the flora is assigned to late of the Late Permian according to the stratigraphic ranges of the known species and the comparisons of it with the similar floras. The new discovery indicates that the final collision between the North China Plate and Siberian Plate occurred in Late Permian along the Xar Moron River-Changchun-Yanji sutured zone, and the Paleoasian Ocean was finally closed at the end of the Permian.

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.

The mass extinction at the end-Triassic is one of the five biggest in the Phanerozoic However it is the least well understood among these five events, and only till last decade it became a great academic interesting subject to geologists. The evidences for this event come obviously from bivalves, brachiopods, ammonites, corals, radiolaria, ostracods and foraminifera of marine habitats, and plants and tetrapods of terrestrial realm. By contrast, for some of other groups, such as marine gastropods and marine vertebrates, no mass extinction has been recognized yet. The extinction event is strongly marked at specific level but shown a complicated situation at generic and family levels. Dramatic changing of the environment, such as the temperature raise due to the greenhouse effect, the marine anoxic habitats caused by a sudden transgression after the regression at the end of Triassic, has been claimed to be the main cause of the extinction. Many hypotheses have been suggested to demonstrate the mechanisms of the environment changing, among which two popular ones are the bolide impact and volcanic eruption.

Fossil conifer twigs and foliage referred to Brachyphyllum liaoningense sp. nov. were collected from the Tuchengzi Formation of Beipiao Basin, Liaoning Province, Northeast China. The leaves are arranged spirally on twigs, with a basal cushion tapering into a small free part. The length of the free part is little less than the width. Stomata exist on both adaxial and abaxial cuticles, but more on the abaxial side. The stomata are rounded or elliptic in form and arranged in longitudinal files in the abaxial cuticle, the epidermal cells between the stomatal files are elongated rectangular or in strip-form. The guard cells are sunken. The subsidiary cells are monocyclic, 5-7 in number, lack encircling cells. A few stomata are scattered on the adaxial cuticle, which are similar to those of the abaxial cuticle except that they have encircling cells. It is presumed that the subsidiary cells of Brachyphyllum show a tendency of increasing in number from Jurassic to the Early Cretaceous.

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.

A new Jurassic schizaeaceous fernKlukiopsis jurassica gen. et sp. nov. from Yima, Henan Province, China is described. The new fern is characterized by the abaxial sori arranged in two rows, apical and complete annulus and more than 800 smooth trilete spores in each sorus.

Based upon the new data of spore-pollen, plant and bivalve fossils, the coal-bearing strata in the Liupanshan Basin, Ningxia Hui Autonomous Region, Northwest China, which were formerly assigned to the Middle Jurassic Yan’an Formation, are divided into two parts in the present study. The major part is assigned to the Upper Triassic and the overlying part remains in the Jurassic. The new division is of significance to the oil-gas exploration of the basin and the interpretation of the sedimentary and tectonic history and the geographic environment of Liupanshan area during the early Mesozoic.

Four species of the Early Cretaceous genus Athyrium viz., A. cretaceum Chen et Meng, A. fuxinense Chen et Meng, A. hulunianum Chen, Ren et Deng and A. hailaerianum Deng et Chen from Northeastern China have been systematically studied by scanning electron microscope. The palaeoecology of the Early Cretaceous Athyrium has also been discussed in detail in this paper.

The genus name Schimperstrobus was first used by Deng et al. (2014) but is invalid as it was introduced without the designation of a type. We here select Androstrobus wonnacottii Harris, 1941 as the type of the new genus Schimperstrobus.

Eogonocormus gen. nov., a new Early Cretaceous fern of Hymenophyllaceae from north-eastern China, is described based upon the type species Eogonocormus cretaceum sp. nov. The frond is small, thalloid, dichotomous and with a creeping rhizome. The sori are rounded, borne marginally on the fan-like ends of pinnule lobes, with 8–12 sori in each lobe. The spores are rounded or subrounded, trilete, with baculate, granulate, spinate and reticulate sculptures. Hymenophyllites linearifolius Deng is re-examined and transferred to the new genus as E. linearifolium based upon the characteristics of its sori.