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The early Silurian Valgu Glaciation and its effects on ocean chemistry and conodont faunal turnover

Yan, Guanzhou ; Chi, Xiangri ; Calner, Mikael LU orcid ; Lehnert, Oliver ; Männik, Peep and Wu, Rongchang (2026) In Global and Planetary Change 264.
Abstract

The Telychian Age (Llandovery, Silurian) is marked by significant radiation among marine organisms, a faunal turnover, and palaeoenvironmental changes, collectively known as the Valgu Bioevent (Valgu BE), Valgu Carbon Isotope Excursion (Valgu CIE), and the Valgu Oxygen Isotope Excursion (Valgu OIE). However, the environmental drivers of these changes remain debated. Here we investigate the middle and upper Telychian strata of South China, as a case study to explore the mechanisms linking climate variability, ocean biogeochemistry, and ecosystem response, based on a robust bio- and chemostratigraphic framework. The Pterospathodus eopennatus Superzone is recognized and linked with the Valgu CIE in the studied area. Significant levels of... (More)

The Telychian Age (Llandovery, Silurian) is marked by significant radiation among marine organisms, a faunal turnover, and palaeoenvironmental changes, collectively known as the Valgu Bioevent (Valgu BE), Valgu Carbon Isotope Excursion (Valgu CIE), and the Valgu Oxygen Isotope Excursion (Valgu OIE). However, the environmental drivers of these changes remain debated. Here we investigate the middle and upper Telychian strata of South China, as a case study to explore the mechanisms linking climate variability, ocean biogeochemistry, and ecosystem response, based on a robust bio- and chemostratigraphic framework. The Pterospathodus eopennatus Superzone is recognized and linked with the Valgu CIE in the studied area. Significant levels of extinction (Datum points 1, 2, 4, and 6) of the Valgu BE are identified within the rising limb and peak interval of the Valgu CIE, corresponding to the rising limb of the Valgu OIE, the latter reflecting a concurrent sea-surface temperature decline of 4 °C due to global climate change and glaciation. The marine geochemistry data show that the Valgu BE and CIE occurred in a well‑oxygenated setting in the studied area, likely affected by the upwelling of deeper cool waters enforced by the Valgu Glaciation. This study suggests that both the rapid evolution of conodont faunas, and their faunal turnover, during the Valgu BE were accelerated by a strong global climate cooling.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Conodont biostratigraphy, Faunal turnover, Silurian climate change, Stable isotope chemostratigraphy, Valgu Glaciation
in
Global and Planetary Change
volume
264
article number
105582
publisher
Elsevier
external identifiers
  • scopus:105042997069
ISSN
0921-8181
DOI
10.1016/j.gloplacha.2026.105582
language
English
LU publication?
yes
id
a66d2f47-78c2-4d1d-b79e-b5f0f05fea12
date added to LUP
2026-08-31 14:35:45
date last changed
2026-08-31 14:54:15
@article{a66d2f47-78c2-4d1d-b79e-b5f0f05fea12,
  abstract     = {{<p>The Telychian Age (Llandovery, Silurian) is marked by significant radiation among marine organisms, a faunal turnover, and palaeoenvironmental changes, collectively known as the Valgu Bioevent (Valgu BE), Valgu Carbon Isotope Excursion (Valgu CIE), and the Valgu Oxygen Isotope Excursion (Valgu OIE). However, the environmental drivers of these changes remain debated. Here we investigate the middle and upper Telychian strata of South China, as a case study to explore the mechanisms linking climate variability, ocean biogeochemistry, and ecosystem response, based on a robust bio- and chemostratigraphic framework. The Pterospathodus eopennatus Superzone is recognized and linked with the Valgu CIE in the studied area. Significant levels of extinction (Datum points 1, 2, 4, and 6) of the Valgu BE are identified within the rising limb and peak interval of the Valgu CIE, corresponding to the rising limb of the Valgu OIE, the latter reflecting a concurrent sea-surface temperature decline of 4 °C due to global climate change and glaciation. The marine geochemistry data show that the Valgu BE and CIE occurred in a well‑oxygenated setting in the studied area, likely affected by the upwelling of deeper cool waters enforced by the Valgu Glaciation. This study suggests that both the rapid evolution of conodont faunas, and their faunal turnover, during the Valgu BE were accelerated by a strong global climate cooling.</p>}},
  author       = {{Yan, Guanzhou and Chi, Xiangri and Calner, Mikael and Lehnert, Oliver and Männik, Peep and Wu, Rongchang}},
  issn         = {{0921-8181}},
  keywords     = {{Conodont biostratigraphy; Faunal turnover; Silurian climate change; Stable isotope chemostratigraphy; Valgu Glaciation}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Global and Planetary Change}},
  title        = {{The early Silurian Valgu Glaciation and its effects on ocean chemistry and conodont faunal turnover}},
  url          = {{http://dx.doi.org/10.1016/j.gloplacha.2026.105582}},
  doi          = {{10.1016/j.gloplacha.2026.105582}},
  volume       = {{264}},
  year         = {{2026}},
}