U-Pb sensitive high-resolution ion microprobe ages from the Doushantuo Formation in South China

constraints on late Neoproterozoic glaciations

Shihong Zhang, Ganqing Jiang*, Junming Zhang, Biao Song, Martin J. Kennedy, Nicholas Christie-Blick

*Corresponding author for this work

Research output: Contribution to journalArticle

183 Citations (Scopus)

Abstract

Two distinctive volcanic ash beds were found in the terminal Proterozoic Doushantuo Formation in south China. The lower ash bed, ∼2.5 m above the cap carbonate at the base of the Doushantuo, yields a U-Pb zircon age of 621 ± 7 Ma, providing the closest upper limit for a correlative of the Marinoan glaciation. The upper ash bed, near the Doushantuo-Dengying boundary, yields a U-Pb zircon age of 555.2 ± 6.1 Ma, providing for the first time a direct age determination for a prominent negative δ13C excursion (≤-5‰) above the Marinoan glacial level. This excursion, if interpreted to be of glacial origin, is much younger than the Gaskiers Formation (ca. 580 Ma) in Newfoundland, and perhaps the fifth or sixth such level in the Neoproterozoic. That interpretation, however, is not supported by the proliferation of organisms within strata encompassing the negative δ13C excursion in south China and globally, by the lack of a ca. 555 Ma glacial record, and by the absence of stratigraphic evidence for sea-level change. The data call for alternative paleoceanographic models for the origin of Neoproterozoic δ 13C excursions not clearly related to glaciation.

Original languageEnglish
Pages (from-to)473-476
Number of pages4
JournalGeology
Volume33
Issue number6
DOIs
Publication statusPublished - Jun 2005
Externally publishedYes

Keywords

  • Cap carbonates
  • Neoproterozoic glaciation
  • SHRIMP geochronology
  • South China
  • U-Pb

Fingerprint Dive into the research topics of 'U-Pb sensitive high-resolution ion microprobe ages from the Doushantuo Formation in South China: constraints on late Neoproterozoic glaciations'. Together they form a unique fingerprint.

Cite this