DETERMINATION OF THE PERMIAN-TRIASSIC BOUNDARY IN AUSTRALIA FROM CARBON ISOTOPE STRATIGRAPHY

1994 ◽  
Vol 34 (1) ◽  
pp. 330 ◽  
Author(s):  
R. Morante ◽  
J.J. Veevers ◽  
A.S. Andrew ◽  
P.J. Hamilton
Keyword(s):  
Carbon Isotope ◽  
Isotope Composition ◽  
Time Correlation ◽  
Depositional Environments ◽  
Sedimentary Record ◽  
Triassic Boundary ◽  
Global Comparison ◽  
Wide Range ◽  
Isotope Stratigraphy ◽  
Permian Triassic Boundary

Significant excursions in the carbon isotope composition of organic matter from sedimentary sections across the Permian/Triassic boundary are documented from the Bonaparte, Canning, Carnarvon, Perth, and Bowen Basins. The analysed sections represent a wide range of depositional environments from marine to non-marine, among which precise time correlation is uncertain. The sense and magnitude of the isotopic excursions are comparable to those found elsewhere around the world from marine carbonates at this time. Early Triassic sediments consistently bear carbon more depleted in the carbon-13 isotope than do latest Permian sediments. The isotope excursion provides an isochronous global datum in the sedimentary record at the palaeontologically determined Permian/Triassic boundary. This carbon isotope chemostratigraphic scheme has application for:correlation between different depositional environments, at scales ranging from intrabasinal to global;comparison of sedimentation rates; andrecognition of lacunas in the sedimentary record.

Are Late Permian carbon isotope excursions of local or of global significance?

2019 ◽  
Vol 132 (3-4) ◽  
pp. 521-544 ◽  
Author(s):  
Borhan Bagherpour ◽  
Hugo Bucher ◽  
Torsten Vennemann ◽  
Elke Schneebeli-Hermann ◽  
Dong-xun Yuan ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
South China ◽  
Sea Water ◽  
Equatorial Position ◽  
Late Permian ◽  
Terrestrial Organic Matter ◽  
Triassic Boundary ◽  
Atmospheric Propagation ◽  
Isotope Record ◽  
Permian Triassic Boundary

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.

scholarly journals The Permian-Triassic boundary in Wyoming: the case of the disappearing paraconformity

1992 ◽  
Vol 6 ◽  
pp. 242-242
Author(s):  
James M. Renner ◽  
Donald W. Boyd
Keyword(s):  
Depositional Environment ◽  
Depositional Environments ◽  
Compelling Evidence ◽  
Carbonate Facies ◽  
Triassic Boundary ◽  
Physical Evidence ◽  
Depositional Processes ◽  
Marine Facies ◽  
Permian Triassic Boundary ◽  
Continuous Deposition

Long-standing interpretations of paleontologic, sedimentologic, and stratigraphic evidence from Permian-Triassic marine sequences in western Wyoming have suggested an interruption in deposition of several million years' duration between the two systems, even though physical evidence of unconformity is subtle and somewhat equivocal. We postulated that an unconformity of this duration should be more pronounced in paralic and non-marine facies in central and southeast Wyoming than in adjacent inner-shelf marine facies in westcentral Wyoming. Therefore, we correlated an erathem boundary-bearing sequence from westcentral Wyoming (where it is faunally controlled) to southeast Wyoming (where it is non-fossiliferous) and studied this sequence for evidence of hiatus. The correlations were made using surface sections, surface gamma-radiation logs, and subsurface log suites.In southeast Wyoming, the lithostratigraphic equivalent to the systemic boundary in westcentral Wyoming is located within a redbed-evaporite sequence traditionally interpreted as having accumulated in paralic and/or terrestrial depositional environments. Physical evidence of disconformity at this surface in southeast Wyoming is no greater, and is in places less, than at several other horizons within the boundary-bearing sequence. Also, petrologic examination of the terrigenous clastic units below, through, and above the boundary-bearing sequence in central and southeast Wyoming suggests notable stability of the depositional environment. Southeastward stratigraphic thinning of various units within this boundary-bearing sequence is demonstrable; however, compelling evidence of regional truncation is not evident, and the stratigraphic thinning appears to be due to primary depositional processes rather than post-depositional erosion during hiatus.We interpret slow, episodic, yet generally continuous deposition of evaporite and siliciclastic units in southeast Wyoming across the Permian-Triassic boundary. If true, then conventional biostratigraphic estimates of the duration of a hiatus separating Permian inner and middle-shelf carbonate facies from overlying Triassic siliciclastics in western Wyoming appear to be overly long, and may need re-evaluation.

scholarly journals A quantitative taxonomic review of Fusichonetes and Tethyochonetes (Chonetidina, Brachiopoda)

2017 ◽  
Vol 91 (6) ◽  
pp. 1296-1305 ◽  
Author(s):  
Hui-ting Wu ◽  
G. R. Shi ◽  
Wei-hong He
Keyword(s):  
Cladistic Analysis ◽  
Species Classification ◽  
Triassic Boundary ◽  
Morphological Variations ◽  
Key Characteristics ◽  
Wide Range ◽  
Kolmogorov Smirnov ◽  
Morphological Variables ◽  
End Members ◽  
Permian Triassic Boundary

AbstractTwo middle Permian (Capitanian) to Early Triassic (Griesbachian) rugosochonetidae brachiopod genera, Fusichonetes Liao in Zhao et al., 1981 and Tethyochonetes Chen et al., 2000, have been regarded as two distinct taxa and used as such for a wide range of discussions including biostratigraphy, paleoecology, paleobiogeography, and the Permian-Triassic boundary mass extinction. However, the supposed morphological distinctions between the two taxa are subtle at best and appear to represent two end members of a continuum of morphological variations. In this study, we applied a range of quantitative and analytical procedures (bivariate plots, Kolmogorov-Smirnov test, categorical principle component analysis, and cladistic analysis) to a dataset of 15 quantified morphological variables, integrating both key external and internal characters, measured from 141 specimens of all well-known Fusichonetes and Tethyochonetes in order to test whether or not these two genera could be distinguished in view of the chosen characters. The results indicate that these two genera are morphologically indistinguishable and that the species classification previously applied to these two genera appears to represent polyphyletic groupings within the genus Fusichonetes. Consequently, Tethyochonetes is concluded to be a junior synonym of Fusichonetes. The diagnosis and key characteristics of Fusichonetes are clarified and refined based on a new suite of well-preserved specimens from the Permian−Triassic Xinmin section in South China.

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