Quantitative stratigraphy of the Wufeng and Lungmachi black shales and graptolite evolution during and after the Late Ordovician mass extinction

Fan, Junxuan; Chen, Qing; Melchin, Michael J.; Sheets, H. David; Chen, Zhongyang; Zhang, Linna; Hou, Xudong

doi:10.1016/j.palaeo.2013.08.005

Cited by 38 publications

(18 citation statements)

References 21 publications

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“…Sadler et al (2011) andFan et al (2013b) both found a gradual graptolite recovery and radiation during the early Rhuddanian. Sadler et al (2011) andCooper et al (2014) also noticed a long-term and significant graptolite mass extinction during the middle and late Telychian Age.…”

Section: Discussionmentioning

confidence: 93%

The Llandovery (Silurian) conodont species diversity on the Upper Yangtze Platform, South China; pp. 201–206

Chen¹,

Fan²,

Hou³

et al. 2014

Estonian Journal of Earth Sciences

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Conodonts are one of the stratigraphically most important fossil groups in the Silurian Period. We examine the regional diversity dynamics of the Llandovery condonts on the Upper Yangtze Platform. The data set of 41 species from seven sections is compiled from the Geobiodiversity Database. Four measures of taxonomic richness based on zonal counting are used to demonstrate the conodont diversity change. The CONOP (Constrained optimization) program is used to build up a more precise composite sequence, which provides the data for comparative analysis of diversity change. Conodont richness keeps growing from the Ozarkodina aff. hassi Zone through the Ozarkodina obesa Zone to the Ozarkodina guizhouensis Zone and reaches a peak at the fourth zone, the Pterospathodus eopennatus Zone. This significant growth was followed by a rapid decrease, which probably represents an extinction in the mid-Telychian. This extinction event can also be observed in other fossil groups such as graptolites and chitinozoans based on recent studies.

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Section: Discussionmentioning

confidence: 93%

The Llandovery (Silurian) conodont species diversity on the Upper Yangtze Platform, South China; pp. 201–206

Chen¹,

Fan²,

Hou³

et al. 2014

Estonian Journal of Earth Sciences

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“…Some outcrops of this unit in the Yichang District were described as yellow claystones since the carbonate rocks are intensively weathered (X. Chen et al, ; Mu & Rong, ; Zeng et al, ). The Kuanyinchiao Formation sections in Yichang area are generally rich in shelly Hirnantia Fauna fossils accumulated under a shallow but cool water environment (X. Chen et al, , ; Fan et al, ; Gorjan, Kaiho, Fike, & Chen, ; J. Liu, Rong, & Chen, ; Rong, ; Rong & Chen, ; Rong et al, ; L. Zhang, Fan, & Chen, ). The Kuanyinchiao Formation is 0.16 m thick (depth: 39.26–39.42 m) in the Well Yihuang 1 core dominantly composed of secondary recrystallized dolomites inserted by three calcareous marlstones with thin lamina but few in coarse bioclastics and not ideal for investigation of biotic structure (Figure ).…”

Section: Lithological Successions Of the Upper Ordovician In Well Yihmentioning

confidence: 99%

“…The Kuanyinchiao Formation sections in Yichang area are generally rich in shelly Hirnantia Fauna fossils accumulated under a shallow but cool water environment (X. Chen et al, 2004Chen et al, , 2006Fan et al, 2013;Gorjan, Kaiho, Fike, & Chen, 2012;J. Liu, Rong, & Chen, 2001;Rong, 1984;Rong & Chen, 1987;Rong et al, 2002;L.…”

Section: Kuanyinchiao Formationmentioning

confidence: 99%

Upper Ordovician continuous lithological succession in outer‐shelf facies, Yangtze Platform, South China: Facies changes and oceanographic reconstruction up to the Late Ordovician Hirnantian glaciation

Chen

Kershaw

et al. 2018

Island Arc

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Ordovician sequences at Huanghuachang, northern Yichang City of Hubei Province, Central China, are representative of an outer‐shelf setting of the Yangtze epicontinental sea, South China Block. Continuous drill cores of the Well Yihuang 1 penetrated the Upper Ordovician units of the Miaopo, Pagoda, Linhsiang, Wufeng, and Kuanyinchiao Formations in ascending order. Such a continuous succession gives valuable insights into environmental changes and an extinction event through Late Ordovician time. Results suggest that sluggish circulation and oligotrophic conditions were characteristic of the region from Sandbian to early Hirnantian Epochs of the Late Ordovician. Thin‐bedded limestones within the Miaopo Formation shales and nodular limestones of the Pagoda and Linhsiang Formations are mainly wackestones and mudstones with sparse and fine‐grained trilobite, cephalopod, gastropod, ostracod, and crinoid bioclasts with rare brachiopod and bivalve bioclasts, further showing gradual decreasing in abundance and grain size upwards through the succession. Such biological and lithological changes are interpreted as a trend towards a deeper and calmer seafloor below storm wave‐base. The Kwangsian Orogeny of the late Katian Epoch altered the geography of the region, creating a large embayment in the area of the Well Yihuang 1 core. Thus the sequence developed upwards to the Wufeng Formation graptolitic black shales consistent with formation in a dysoxic and stagnant embayment that excluded carbonate production and benthic biota, but ideal for preservation of planktic graptolite fossils. Bioclastic packstone and quartz grain lenses interlayered with the black shales are occasionally sourced from southeastward shallow submarine highs closed to the Cathaysian Land. Change from this interpreted sluggish ocean circulation affecting the ocean floor was delayed to the early Hirnantian Epoch, when active circulation is related to the onset of the latest Ordovician glaciation which resulted in an oxygenated ocean floor during regression, favorable for the thriving shelly Hirnantia Fauna.

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“…; Kleffner & Barrick ; Fan et al . ), very few have used these methods as part of the process of assessing or selecting the best GSSP candidate section or horizon (e.g. Benoist ; Bettley et al .…”

mentioning

confidence: 99%

“…They noted that once a GSSP is precisely placed within a composite succession, its relationship to all other levels in the composite are also defined, within the limits of resolution of the composite. Although many studies employing methods of quantitative stratigraphical correlation, such as graphic correlation or CONOP, have included GSSPs within their data sets (for the Ordovician-Silurian, e.g., see Kleffner 1989Kleffner , 1995Armstrong 1995;Sadler et al 2009;Kleffner & Barrick 2011;Fan et al 2013), very few have used these methods as part of the process of assessing or selecting the best GSSP candidate section or horizon (e.g. Benoist 2000;Bettley et al 2001;Paul & Lamolda 2009).…”

mentioning

confidence: 99%

A new approach to quantifying stratigraphical resolution: application to global stratotypes

Melchin

Sheets

Mitchell

et al. 2017

LET

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Horizon annealing (HA) provides a method to order all horizons in a chronostratigraphic data set, including marker beds and isotopic excursions, as well as horizons that lack exact local markers (such as taxon first appearances) and are, thus, constrained only by local stratigraphical order. Global stratotype section and point (GSSP) levels placed within an HA composite succession can be precisely correlated with levels in all other sections in the composite that span the same interval. We present two approaches to the quantitative assessment of the uncertainty or error in the placement of horizons within the composite section: a permutation method (jackknife analysis) and a sensitivity analysis (the relaxed fit curve). From jackknife analysis, we calculate a standard deviation (σ) of the variation in horizon placements and estimate the 95% confidence interval of the variation in horizon placement within the composite. We also directly assess the relative stability of event positions using the results of the jackknife. These approaches provide an objective method for assessing the relative strengths of GSSP candidates, in which we prefer those sections and horizons that are the most precisely controlled in the HA composite. Integration of biostratigraphical, chemostratigraphical and lithostratigraphical marker horizons into the HA process markedly improves levels of constraint within the composite compared to biostratigraphical data alone. In a temporally scaled composite, the 95% confidence intervals on horizon placements could be used to estimate temporal resolution. In our study, we estimate that the average temporal resolution is approximately 319 kyr, which approaches the range of that needed to test hypotheses of orbitally driven cyclicity.

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Quantitative stratigraphy of the Wufeng and Lungmachi black shales and graptolite evolution during and after the Late Ordovician mass extinction

Cited by 38 publications

References 21 publications

The Llandovery (Silurian) conodont species diversity on the Upper Yangtze Platform, South China; pp. 201–206

The Llandovery (Silurian) conodont species diversity on the Upper Yangtze Platform, South China; pp. 201–206

Upper Ordovician continuous lithological succession in outer‐shelf facies, Yangtze Platform, South China: Facies changes and oceanographic reconstruction up to the Late Ordovician Hirnantian glaciation

A new approach to quantifying stratigraphical resolution: application to global stratotypes

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