New record of fossil wood Xenoxylon from the Late Triassic in the Sichuan Basin, southern China and its paleoclimatic implications

The gecko species Gekko (Japonigekko) subpalmatus was previously recorded with a relatively wide distribution from eastern, southern, and southeastern China. However, the populations in southern China are currently recognized as another valid species G. (J.) melli. In this study, we conduct a detailed morphological examination and phylogenetic analysis of the populations currently treated as G. (J.) subpalmatus or G. (J.) melli, which are collectively designated as the G. (J.) subpalmatus complex. Our results reveal that the G. (J.) subpalmatus complex comprises three evolutionarily independent taxa. The populations from Zhejiang, eastern China are G. (J.) subpalmatus, those from southern China are G. (J.) melli, while those from the Sichuan Basin, southwestern China represent a cryptic species, Gekko (Japonigekko) cib sp. nov.. Gekko (Japonigekko) cib sp. nov. can be distinguished from all congeners, by its divergence from other complex members in the CYTB and 16S genes, and a combination of morphological characteristics, especially in hemipenial morphology. Historic records of G. (J.) subpalmatus complex are also reviewed.

Download Full-text

Biomarker distributions and depositional environments of continental source rocks in Sichuan Basin, SW China

Energy Exploration & Exploitation ◽

10.1177/0144598720915533 ◽

2020 ◽

Vol 38 (6) ◽

pp. 2296-2324

Author(s):

Siqin Huang ◽

Guosheng Xu ◽

Fanghao Xu ◽

Wei Wang ◽

Haifeng Yuan ◽

...

Keyword(s):

Sichuan Basin ◽

Lower Jurassic ◽

Upper Triassic ◽

Depositional Environments ◽

Source Rocks ◽

Late Triassic ◽

Ms Analysis ◽

Continental Source ◽

The Sichuan Basin ◽

Tricyclic Terpanes

In order to study the distributions of the biomarker of the continental source rocks in the Sichuan Basin, 71 source rock samples were collected from the Upper Triassic-Lower Jurassic strata in different regions. The n-alkanes, isoprenoids, terpane, sterane, sesquiterpenes, caranes and aromatics in the extracts were analyzed in detail. GC-MS analysis has been conducted to analyze the biomarker of the continental source rocks. The results of GC-MS analysis indicate that the Upper Triassic source rocks are high in the content of extended tricyclic terpanes, pristane, phytane, gammacerane, C28 regular sterane and carotene. However, they are low in content of rearranged compounds. The ratio of Pr/Ph is less than 1, with the characteristics of tricyclic terpane C21 > C23. The Lower Jurassic source rocks are extremely low in content (even zero) of extended tricyclic terpanes, pristane, phytane, gammacerane, C28 regular sterane and carotene, and high in content of rearranged compounds. The ratio of Pr/Ph is more than 1, with tricyclic terpane C21 > C23. These characteristics are still preserved after maturation. Moreover, during the sedimentation of the source rocks of T3x2–T3x3 members, the supply of continental plants was low (TAR < 1, with regular sterane C27 > C29, 1-MP/9-MP < 1). The source rocks of T3x5 member were low in salinity (slightly low content of gammacerane and carotene), being different significantly from the other Upper Triassic source rocks. In addition, during the sedimentation of the source rocks of J1dn Member, the supply of continental plants was also low (regular sterane C27 > C29, 1-MP/9-MP < 1), being quite different from that of J1l member. Through analysis of the difference in biomarkers, it is indicated that the sedimentary environment had changed from anoxic and brackish water during the Late Triassic to oxygen-rich and freshwater during the Early Jurassic in the Sichuan Basin. During this process, the types of organic matters had changed for several times.

Download Full-text

An unusual trackway of a possibly bipedal archosaur from the Late Triassic of the Sichuan Basin, China

Acta Palaeontologica Polonica ◽

10.4202/app.2012.0087 ◽

2013 ◽

Cited By ~ 1

Author(s):

Lida Xing

Keyword(s):

Sichuan Basin ◽

Late Triassic ◽

The Sichuan Basin

Download Full-text

Tectono-sedimentary Evolution of the Late Triassic Xujiahe Formation in the Sichuan Basin

Acta Geologica Sinica - English Edition ◽

10.1111/1755-6724.12159 ◽

2013 ◽

Vol 87 (6) ◽

pp. 1554-1568 ◽

Cited By ~ 9

Author(s):

Liang LUO ◽

Dong JIA ◽

Jiafu QI ◽

Guoqi WEI ◽

Fei DENG

Keyword(s):

Sichuan Basin ◽

Late Triassic ◽

Xujiahe Formation ◽

Sedimentary Evolution ◽

The Sichuan Basin

Download Full-text

Sedimentological and paleoecological aspects of the Norian–Rhaetian transition (Late Triassic) in the Xuanhan area of the Sichuan Basin, Southwest China

Palaeoworld ◽

10.1016/j.palwor.2019.04.006 ◽

2019 ◽

Vol 28 (3) ◽

pp. 334-345

Author(s):

Ning Lu ◽

Yong-Dong Wang ◽

Mihai Emilian Popa ◽

Xiao-Ping Xie ◽

Li-Qin Li ◽

...

Keyword(s):

Sichuan Basin ◽

Southwest China ◽

Late Triassic ◽

The Sichuan Basin

Download Full-text

Late Triassic ecosystem variations inferred by palynological records from Hechuan, southern Sichuan Basin, China

Geological Magazine ◽

10.1017/s0016756817000735 ◽

2017 ◽

Vol 155 (8) ◽

pp. 1793-1810 ◽

Cited By ~ 10

Author(s):

LIQIN LI ◽

YONGDONG WANG ◽

VIVI VAJDA ◽

ZHAOSHENG LIU

Keyword(s):

Sichuan Basin ◽

Mixed Forest ◽

Terrestrial Ecosystem ◽

Late Triassic ◽

Simultaneous Increase ◽

Spores And Pollen ◽

Entire Interval ◽

Xujiahe Formation ◽

The Sichuan Basin ◽

Palynological Study

AbstractThe Late Triassic deposits of the Sichuan Basin, southwestern China are significant for hosting abundant and diverse fossil assemblages including plants (containing spores and pollen), bivalves and insects. However, the Late Triassic palaeoecological variations are still poorly documented in this region. Here we present results from a palynological study from the Upper Triassic Xujiahe Formation in Hechuan of Chongqing, southern Sichuan Basin. The palynological analysis revealed a well-preserved terrestrial palynoflora of high diversity, comprising 184 species in 75 genera of spores and pollen. Three palynological assemblages were recognized, reflecting terrestrial successions throughout the entire interval with significant changes in the vegetation. Cycads/bennettites/ginkgophytes and conifers show an increasing trend into younger deposits, while ferns and lycopsids decrease in relative abundance. The Late Triassic vegetation underwent changes from lowland fern forest to a mixed forest with more canopy trees. We applied the Spore-pollen Morphological Group (SMG) method and Sporomorph EcoGroup (SEG) model to interpret the palaeoclimate features. The results reveal that the lower part of the Xujiahe Formation was deposited under relatively warm and humid conditions with an overall cooling and drying trend from latest Norian to Rhaetian time, accompanied by a general decrease of ferns and simultaneous increase of gymnosperms, and a decline in diversity of miospores. This study presents data on variations within the terrestrial ecosystem prior to the end-Triassic extinction event in the Sichuan Basin, and therefore provides important information for understanding the changes in the vegetation preceding the end-Triassic event.

Download Full-text

Activity of Silica-Rich Hydrothermal Fluid and Its Impact on Deep Dolomite Reservoirs in the Sichuan Basin, Southern China

Acta Geologica Sinica - English Edition ◽

10.1111/1755-6724.13459 ◽

2017 ◽

Vol 91 (6) ◽

pp. 2214-2229 ◽

Cited By ~ 3

Author(s):

Dongya ZHU ◽

Dianwei ZHANG ◽

Quanyou LIU ◽

Zhijun JIN ◽

Zhiliang HE

Keyword(s):

Sichuan Basin ◽

Hydrothermal Fluid ◽

Southern China ◽

The Sichuan Basin

Download Full-text

First fossil foliage record in the red beds from the Upper Jurassic in the Sichuan Basin, southern China

Geological Journal ◽

10.1002/gj.4364 ◽

2021 ◽

Author(s):

Li Zhang ◽

Yongdong Wang ◽

Yiming Cui ◽

Ning Tian ◽

Xiaoping Xie ◽

...

Keyword(s):

Sichuan Basin ◽

Southern China ◽

Upper Jurassic ◽

Red Beds ◽

The Sichuan Basin

Download Full-text

Simulations of Stratus Clouds over Eastern China in CAM5: Sensitivity to Horizontal Resolution

Journal of Climate ◽

10.1175/jcli-d-13-00732.1 ◽

2014 ◽

Vol 27 (18) ◽

pp. 7033-7052 ◽

Cited By ~ 14

Author(s):

Yi Zhang ◽

Haoming Chen ◽

Rucong Yu

Keyword(s):

High Resolution ◽

Radiative Forcing ◽

Sichuan Basin ◽

Southern China ◽

Eastern China ◽

Dynamic Component ◽

Ambient Environment ◽

Stratus Clouds ◽

The Sichuan Basin ◽

The Impact

Abstract This paper evaluates the simulations of stratus clouds over eastern China (EC) in the Community Atmosphere Model, version 5 (CAM5), with an emphasis on the impact of changing horizontal resolutions on the performance. CAM5 in all experiments generally satisfactorily simulates the cloud radiative features over EC, including the spatial distributions of the continental shortwave cloud radiative forcing (SWCF) and stratus regimes, the responses of SWCF to the dynamic and thermodynamic ambient environment, and several relations in the environmental fields that are favorable to the stratus formation. Meanwhile, all experiments suffer from similar biases. Models tend to underestimate the stratus amount because of a corresponding underestimate of stratus occurrence frequency, while the stratus amount when present (AWP) is generally higher than that in the observation. Models also simulate similar errors in the environmental fields. The differences between low- and high-resolution experiments are distinct. An increase of resolution enhances the SWCF in southern China, but the skill deteriorates in the Sichuan basin. Correspondingly, the stratus amount increases in southern China from low- to high-resolution experiments, mainly because of more stratus occurrences, which are found to be related to the better represented environmental fields in the high-resolution experiments, especially the dynamic component. Several relations in the ambient environment are also slightly improved in the high-resolution experiments. Meanwhile, the reason for the decrease of stratus AWP within the Sichuan basin, which is mainly responsible for the decreased stratus amounts and weaker SWCF from low- to high-resolution experiments, is also discussed.

Download Full-text