scholarly journals High-resolution variation in ostracod assemblages from microbialites near the Permian-Triassic boundary at Zuodeng, Guangxi region, South China

2019 ◽  
Vol 535 ◽  
pp. 109349 ◽  
Author(s):  
Junyu Wan ◽  
Aihua Yuan ◽  
Sylvie Crasquin ◽  
Haishui Jiang ◽  
Hao Yang ◽  
...  
2016 ◽  
Author(s):  
Björn Baresel ◽  
Hugo Bucher ◽  
Morgane Brosse ◽  
Fabrice Cordey ◽  
Kuang Guodun ◽  
...  

Abstract. This study is based on zircon U-Pb ages of 12 volcanic ash layers and volcanogenic sandstones from two marine sections with conformable formational Permian-Triassic boundaries (PTB) in the Nanpanjiang Basin (South China). Our dates of single, thermally annealed and chemically abraded zircons bracket the PTB in Dongpan and Penglaitan and provide the basis for a first proof-of-concept study utilizing a Bayesian chronology model comparing the three sections of Dongpan, Penglaitan and the Global Stratotype Section and Point (GSSP) Meishan. Our Bayesian modeling demonstrates that the formational boundaries in Dongpan (251.938 ± 0.029 Ma), Penglaitan (251.982 ± 0.031 Ma) and Meishan (251.956 ± 0.033 Ma) are synchronous within analytical uncertainty of ca. 30 ka. It also provides quantitative evidence that the ages of the paleontologically defined boundaries, based on conodont Unitary Associations zones in Meishan and on macrofaunas in Dongpan, are identical and coincide with the age of the formational boundaries. The age model also confirms the extreme condensation around the PTB in Meishan, which distorts the projection of any stratigraphic points or intervals onto other more expanded sections by means of Bayesian age-depth models. Dongpan and Penglaitan possess significantly higher sedimentation rates and thus offer a greater potential for high resolution studies of environmental proxies and correlations around the PTB than Meishan. This study highlights the power of high-resolution radio-isotopic ages that allow a robust intercalibration of patterns of biotic changes and fluctuating environmental proxies and will help recognizing their global, regional or local significance.


Solid Earth ◽  
2017 ◽  
Vol 8 (2) ◽  
pp. 361-378 ◽  
Author(s):  
Björn Baresel ◽  
Hugo Bucher ◽  
Morgane Brosse ◽  
Fabrice Cordey ◽  
Kuang Guodun ◽  
...  

Abstract. This study is based on zircon U-Pb ages of 12 volcanic ash layers and volcanogenic sandstones from two deep water sections with conformable and continuous formational Permian–Triassic boundaries (PTBs) in the Nanpanjiang Basin (South China). Our dates of single, thermally annealed and chemically abraded zircons bracket the PTB in Dongpan and Penglaitan and provide the basis for a first proof-of-concept study utilizing a Bayesian chronology model comparing the three sections of Dongpan, Penglaitan and the Global Stratotype Section and Point (GSSP) at Meishan. Our Bayesian modeling demonstrates that the formational boundaries in Dongpan (251.939 ± 0.030 Ma), Penglaitan (251.984 ± 0.031 Ma) and Meishan (251.956 ± 0.035 Ma) are synchronous within analytical uncertainty of  ∼  40 ka. It also provides quantitative evidence that the ages of the paleontologically defined boundaries, based on conodont unitary association zones in Meishan and on macrofaunas in Dongpan, are identical and coincide with the age of the formational boundaries. The age model also confirms the extreme condensation around the PTB in Meishan, which distorts the projection of any stratigraphic points or intervals onto other more expanded sections by means of Bayesian age–depth models. Dongpan and Penglaitan possess significantly higher sediment accumulation rates and thus offer a greater potential for high-resolution studies of environmental proxies and correlations around the PTB than Meishan. This study highlights the power of high-resolution radio-isotopic ages that allow a robust intercalibration of patterns of biotic changes and fluctuating environmental proxies and will help recognizing their global, regional or local significance.


2019 ◽  
Vol 157 (4) ◽  
pp. 677-689 ◽  
Author(s):  
Binsong Zheng ◽  
Chuanlong Mou ◽  
Renjie Zhou ◽  
Xiuping Wang ◽  
Zhaohui Xiao ◽  
...  

AbstractPermian–Triassic boundary (PTB) volcanic ash beds are widely distributed in South China and were proposed to have a connection with the PTB mass extinction and the assemblage of Pangea. However, their source and tectonic affinity have been highly debated. We present zircon U–Pb ages, trace-element and Hf isotopic data on three new-found PTB volcanic ash beds in the western Hubei area, South China. Laser ablation inductively coupled plasma mass spectrometry U–Pb dating of zircons yields ages of 252.2 ± 3.6 Ma, 251.6 ± 4.9 Ma and 250.4 ± 2.4 Ma for these three volcanic ash beds. Zircons of age c. 240–270 Ma zircons have negative εHf(t) values (–18.17 to –3.91) and Mesoproterozoic–Palaeoproterozoic two-stage Hf model ages (THf2) (1.33–2.23 Ga). Integrated with other PTB ash beds in South China, zircon trace-element signatures and Hf isotopes indicate that they were likely sourced from intermediate to felsic volcanic centres along the Simao–Indochina convergent continental margin. The Qinling convergent continental margin might be another possible source but needs further investigation. Our data support the model that strong convergent margin volcanism took place around South China during late Permian – Early Triassic time, especially in the Simao–Indochina active continental margin and possibly the Qinling active continental margin. These volcanisms overlap temporally with the PTB biocrisis triggered by the Siberian Large Igneous Province. In addition, our data argue that the South China Craton and the Simao–Indochina block had not been amalgamated with the main body of Pangea by late Permian – Early Triassic time.


2021 ◽  
Author(s):  
Zhenyang Zhao ◽  
Shuangjian Li ◽  
Genhou Wang ◽  
Jian Gao ◽  
Tianbo Yang ◽  
...  

Fossil Record ◽  
2020 ◽  
Vol 23 (1) ◽  
pp. 33-69 ◽  
Author(s):  
Jana Gliwa ◽  
Abbas Ghaderi ◽  
Lucyna Leda ◽  
Martin Schobben ◽  
Sara Tomás ◽  
...  

Abstract. The Permian–Triassic boundary section in the Aras Valley in NW Iran is investigated with respect to carbonate microfacies, biostratigraphy (particularly conodonts, nautiloids, and ammonoids), chemostratigraphy (carbon isotopes), and environmental setting. Correlation of the data allows the establishment of a high-resolution stratigraphy based on conodonts (with four Wuchiapingian, 10 Changhsingian, and three Griesbachian zones), ammonoids (with nine Changhsingian zones), and carbon isotopes; it forms the base for the reconstruction of the environmental changes before and after the end-Permian extinction event at the studied locality. In the Aras Valley section, there is no evidence for the development of anoxic conditions, associated with the end-Permian mass extinction.


2019 ◽  
Vol 132 (3-4) ◽  
pp. 521-544 ◽  
Author(s):  
Borhan Bagherpour ◽  
Hugo Bucher ◽  
Torsten Vennemann ◽  
Elke Schneebeli-Hermann ◽  
Dong-xun Yuan ◽  
...  

Abstract We present a new, biostratigraphically calibrated organic and inorganic C-isotope record spanning the basal Late Permian to earliest Triassic from southern Guizhou (Nanpanjiang basin, South China). After fluctuations of a likely diagenetic overprint are removed, three negative carbon isotope excursions (CIEs) persist. These include a short-lived CIE during the early Wuchiapingian, a protracted CIE ending shortly after the Wuchiapingian–Changhsingian Boundary, and a third CIE straddling the Permian–Triassic boundary. Comparison of our new C-isotope record with others from the same basin suggests that influences of local bathymetry and of the amount of buried terrestrial organic matter are of importance. Comparison with other coeval time series outside of South China also highlights that only the negative CIE at the Permian–Triassic boundary is a global signal. These differences can be explained by the different volumes of erupted basalts between the Late Permian Emeishan and the younger Siberian large igneous provinces and their distinct eruptive modalities. Emeishan volcanism was largely submarine, implying that sea water was an efficient buffer against atmospheric propagation of volatiles. The equatorial position of Emeishan was also an additional obstacle for volatiles to reach the stratosphere and benefit from an efficient global distribution. Consequently, the local significance of these CIEs calls into question global correlations based on C-isotope chemostratigraphy during the Late Permian. The timing of the Late Permian Chinese CIEs is also not reflected in changes in species diversity or ecology, unlike the sudden and global Permian–Triassic boundary crisis and subsequent Early Triassic upheavals.


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