New chronological constraints for Cryogenian to Cambrian rocks in the Three Gorges, Weng'an and Chengjiang areas, South China

Yoshihiro Okada, Yusuke Sawaki, Tsuyoshi Komiya, Takafumi Hirata, Naoto Takahata, Yuji Sano, Jian Han, Shigenori Maruyama

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

The Neoproterozoic and Cambrian were two of the most dramatic periods in the history of the Earth, because large multi-cellular animals first appeared then in the so-called "Cambrian Explosion". To better understand this event, many paleontological and geochemical studies now focus on rocks in South China, because of the fossiliferous succession and good exposure. Since the recognition of the Yangtze Gorges and Chengjiang area as type localities of the Sinian (Ediacaran) and Meishucunian (Early Cambrian) Systems, both sections have been intensively investigated. In order to decipher the relationships between the evolution of life and surface environmental changes, it is necessary to understand their paleontological, geochemical and geo-chronological constraints. This study presents new chronological constraints for the Cryogenian to Cambrian rocks in the Three Gorges, Weng'an and Chengjiang areas, South China. We discovered two tuff layers, one at the base of the Shuijingtuo Fm at Three Gorges and the other at the bottom of the Dahai Member in Chengjiang. In addition, we collected sandstones from Neoproterozoic strata in the Three Gorges, Chengjiang and Weng'an areas for provenance analysis. Zircons, separated from the tuff layers, provide new Nano-SIMS U-Pb ages of 526.4 ± 5.4. Ma at the base of the Shuijingtuo Fm, and 523.9 ± 6.7. Ma at the bottom of the Dahai Member. The tuffaceous beds occur at an unconformity, and nodules are common in the Three Gorges, Meishucun and Taoying sections, indicating that major and relatively wide-scale volcanic and sedimentological events occurred at ca. 525. Ma. Moreover, carbonate carbon isotope chemostratigraphies at Morocco, Siberia, Three Gorges and Meishucun display different characteristics during the Tommotian. One possibility is that the South China Ocean was separated from an outer ocean at that time. Detrital zircons in sandstones have age populations at ca. 2.7, 1.8, 1.6, 1.0 and from 0.9 to 0.75. Ga. indicating that the paleo-hinterland of the Nanhua and Kangdian rift basins was geologically complex. Despite the lack of ca. 1.6. Ga rocks in the Yangtze and Cathaysia Blocks, these data are nevertheless interpreted to indicate derivation of the zircons from basement rocks in the Yangtze craton.

Original languageEnglish
Pages (from-to)1027-1044
Number of pages18
JournalGondwana Research
Volume25
Issue number3
DOIs
Publication statusPublished - Apr 2014
Externally publishedYes

Fingerprint

gorge
rock
zircon
tuff
sandstone
Sinian
Ediacaran
ocean
type locality
basement rock
unconformity
provenance
carbon isotope
craton
explosion
environmental change
carbonate
animal
history
basin

Keywords

  • LA-ICP-MS
  • Nano-SIMS
  • South China
  • U-Pb geochronology
  • Zircon

ASJC Scopus subject areas

  • Geology

Cite this

New chronological constraints for Cryogenian to Cambrian rocks in the Three Gorges, Weng'an and Chengjiang areas, South China. / Okada, Yoshihiro; Sawaki, Yusuke; Komiya, Tsuyoshi; Hirata, Takafumi; Takahata, Naoto; Sano, Yuji; Han, Jian; Maruyama, Shigenori.

In: Gondwana Research, Vol. 25, No. 3, 04.2014, p. 1027-1044.

Research output: Contribution to journalArticle

Okada, Y, Sawaki, Y, Komiya, T, Hirata, T, Takahata, N, Sano, Y, Han, J & Maruyama, S 2014, 'New chronological constraints for Cryogenian to Cambrian rocks in the Three Gorges, Weng'an and Chengjiang areas, South China', Gondwana Research, vol. 25, no. 3, pp. 1027-1044. https://doi.org/10.1016/j.gr.2013.05.001
Okada, Yoshihiro ; Sawaki, Yusuke ; Komiya, Tsuyoshi ; Hirata, Takafumi ; Takahata, Naoto ; Sano, Yuji ; Han, Jian ; Maruyama, Shigenori. / New chronological constraints for Cryogenian to Cambrian rocks in the Three Gorges, Weng'an and Chengjiang areas, South China. In: Gondwana Research. 2014 ; Vol. 25, No. 3. pp. 1027-1044.
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AU - Sawaki, Yusuke

AU - Komiya, Tsuyoshi

AU - Hirata, Takafumi

AU - Takahata, Naoto

AU - Sano, Yuji

AU - Han, Jian

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