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Deep‐water gravity depositional processes and evolution in arc systems have become topics of intense research focus in recent years. This study discusses the co‐evolution of volcanism and deep‐water gravity flow deposits at the southern margin of the Junggar Basin, based on petrology, geochronology and geochemical analyses. The results show that a massive collapse of unstable sediments from the slope was triggered by volcanism, resulting in the formation of slumping gravity flows. The occurrence of volcanic beds in the slump deposits confirm that synchronous volcanism likely affected sediment instability, triggering gravity flows. The Th/Yb, Ta/Yb and Th/Ta elemental ratios, U‐Pb ages of detrital zircons and paleocurrent directions indicate that the North Tianshan (NTS) island arc represents the provenance of the Qianxia Formation. Moreover, statistical data on the pyroclastic components in the gravity flow deposits reveal an intensity index of volcanism, indicating that volcanism is strongly related to gravity flow deposits, especially in terms of the type and distribution of the deposits. A model for volcanically‐triggered deep‐water gravity flow deposits is established, in order to provide a more in‐depth understanding of the co‐evolution of volcanism and gravity flow deposits within the depositional setting of the late Paleozoic NTS oceanic subduction margin in the Junggar Basin. [ABSTRACT FROM AUTHOR]

The end‐Triassic mass extinction is considered one of the "Big Five" extinction events in the Phanerozoic. However, whether the terrestrial ecosystem began to deteriorate or even collapse prior to the Triassic–Jurassic (Tr‐J) transition remains controversial. Compared with the documented data from the western Tethyan region, evidence from the eastern Tethyan realm is limited. We undertake a fitting analysis of the sedimentary system, floral community successions and major geological events of the Xujiahe Formation as reflected by the Qilixia Section, Xuanhan area, northeast Sichuan Basin, China. Our results reveal an oscillating fluvial‐lacustrine depositional system during the Late Triassic, with the dominant sedimentary processes mainly controlled by the Indosinian Movement. Beside the sedimentary influence on the Xujiahe Flora, climate changes played a more important role. Fluctuating conditions to cooler and dryer climates at this time promoted diversification of gymnosperms under an overall warm and humid climate setting in the Late Triassic in the Xuanhan area. Superimposed on this oscillating long‐term climate state, ecosystem destabilization occurred over 1 million years prior to the Tr–J interval in the Xuanhan study area, possibly in response to the intensified storm and wildfire activity and the following environmental changes. Although the Xujiahe Flora always recovered from the interruption of the tectonic movement, it ultimately collapsed under extreme climatic events and ecological pressures induced by the Late Triassic Central Atlantic Magmatic Province event. [ABSTRACT FROM AUTHOR]

Ptilozamites Nathorst 1878 is one of the most widespread genera of Mesozoic seed ferns, reaching its highest diversity during the Late Triassic. As a palaeogeographic and biostratigraphic marker restricted to the Late Triassic of the Southern Floristic Province in China, Ptilozamites chinensis Hsü 1950 had once been transferred to the genus Pseudoctenis Seward 1911. A detailed morphological and anatomical study of the well-preserved material collected from Upper Triassic sediments of South China, as well as the re-investigation of representative historical specimens demonstrate it belongs to the genus Ptilozamites. A neotype and an emended diagnosis for Ptilozamites chinensis are proposed. A comparison with the previously documented specimens of Ptilozamites chinensis suggests a different overall morphology during the developmental process of the plant. The paleogeographic distribution of Ptilozamites chinensis indicates a preference for hot and humid habitats during the Late Triassic of the Southern Floristic Province. • Systematic study supports the assignment of Ptilozamites chinensis. • Morphological and anatomical studies permitted the emendation of P. chinensis. • Intraspecific variations suggest different overall morphology of P. chinensis. • Tempo-spatial distribution pattern indicates climatic preferences of P. chinensis. [ABSTRACT FROM AUTHOR]

Anthrophyopsis Nathorst 1878 is a representative Late Triassic foliar genus with uncertain systematic affinities and poorly understood morphology and anatomy. Since its earliest report by Nathorst in 1878, 16 species have been documented worldwide. However, the taxonomic statuses of some taxa remain questionable. Out of 16 reported species, only three of them, including Anthrophyopsis crassinervis , A. tuberculata and A. venulosa can be retained as valid. Besides, four species, such as Anthrophyopsis brancai , A. miassica , A. narulensis and A. vachrameevii need further revision and investigation. Furthermore, nine species are invalid, including Anthrophyopsis decurrens , A. grandis , A. leeiana , A. multinervis , A. nilssoni , A. obovata , A. pilophorus , A. ripples and A. tenuinervis. The morphological diagnosis characters for genus Anthrophyopsis are detailed and updated, based on the new and well-preserved specimens from the Sichuan Basin, South China. A revision of historical collections and reported occurrences of this genus around the world was undertaken. Reviewing the valid species of Anthrophyopsis based on abundant Chinese material supports the emendation of the genus Anthrophyopsis and of its species. Stratigraphically, the occurrences of Anthrophyopsis are almost confined to the Upper Triassic, with only two questionable reports extending to the Lower Jurassic. The limited occurrences of valid Anthrophyopsis species in the Southern Floristic Province of China during the Late Triassic indicate that this genus represents a sensitive stratigraphic and palaeoclimatic marker. • Emended diagnoses at genus and species level of genus Anthrophyopsis are provided. • Global revisions of a series of Anthrophyopsis species are undertaken. • Reassessment of the morphology of Anthrophyopsis crassinervis is achieved. • Geological investigations of Anthrophyopsis demonstrate its short stratigraphic range. • Tempo-spatial analysis of Anthrophyopsis implies its possible migration route. [ABSTRACT FROM AUTHOR]

The end-Triassic mass extinction (ETME) is considered to be one of the five most severe extinction events in Earth history and caused the disappearance of ca. 80% of all species. The terrestrial ecosystems were also greatly affected by this extinction, but the severity of the land plant diversity loss is not well understood. Ferns are once a principal component of the terrestrial ecosystem from the late Paleozoic/early Mesozoic era and colonizers taxa commonly found in disturbed environments. In this study, we investigated the diversity and ecology of fern during the Triassic-Jurassic (Tr–J) transition in the Sichuan Basin of South China and focused for the first time on the impact of the end-Triassic mass extinction event on the fern communities. We assembled fern fossil records in 16 localities from the Rhaetian Xujiahe (XJH) Formation to the lowermost Jurassic Zhenzhuchong (ZZC) Formation. Our results indicate that no obvious mass extinctions of macro-microflora of ferns but a clear species turnover was recorded at ETME in the Sichuan Basin, reflected an appropriate response of plants in places far away from CAMP volcanism. The paleoecological analysis based on macroflora and microflora in the Sichuan Basin shows a warm and humid condition of tropical-subtropical climate during Rhaetian followed by an increase of specific dry-resistant taxa, indicating a dryer environment at the Earliest Jurassic. Additionally, multivariate statistical approaches (principal coordinates analysis, cluster analysis, network analysis) for fern macro-remains and spores data in the southeastern Sichuan Basin infer that the members of XJH and ZZC Formation cluster in three groups, corresponding to their environmental conditions, determined by humidity and temperature. • No obvious mass extinctions but a clear species turnover occurs at Tr–J transition. • Significantly increase of typical dry-resistant taxa agrees with global warming across the Tr-J boundary. • Both macro- and micro ferns reflect increased environmental stress across the Tr–J transition. [ABSTRACT FROM AUTHOR]