Nat. Science Foundation of China RFIS-II Project:

“The Stromatolite Geochemical Archive”

Photograph of living microbial mats on the left taken from Vasconcelos et al., 2006

building blocks of the NSFC project “ The stromatolite Geochemical Archive”

U-Pb dating in microbial carbonates

PhD candidate Yuxiang Jiang has successfully applied in-situ U-Pb dating in microbial carbonates spanning the Proterozoic to Phanerozoic, here is short excerpt of his research:

Some of the earliest bio-sedimentary life records on Earth are represented by microbial carbonates, which are also critical geochemical archives of ancient seawater chemistry and the environmental circumstances in which they precipitated. Reconstructing paleo-microbial environments on Earth and potentially other planets requires precise determination of the depositional ages of these materials. The (abiogenic) carbonate geochemistry communities can now use developments in in-situ laser ablation U-Pb dating using inductively coupled plasma mass spectrometry (LA-ICP-MS). Due to the effects of impurity mixing and diagenesis, microbial carbonates have received little geochronological study despite their broad relevance for understanding ancient seawater's environmental conditions and geochemical compositions. This study suggests using time-of-flight mass spectrometry (TOF-MS) to perform quick, quantitative elemental mapping before U-Pb spot dating to improve experiment success rates and data reliability. In addition, it offers four examples of the practical application of this approach.

 

Overview of recent and former projects

 

  • 2009-2011

Tectonic situation of the Cyclades blueshist belt, Sifnos Greece

  • 2008-2011

Geochemical signatures of the Rabaul Volcanis System, Papue New-Guinea

  • 2012-2015

Sr-Nd-O-C isotope compositions of deep and shallow water Ediacaran carbonates

  • 2012-2015

Diagenetic modification of ancient carbonates and implications on REE+Y

  • 2012-2017

Geochemistry of Post Marinoan Cap Dolomites from the Yangtze Platform

  • 2014-ongoing

Cd isotope Geochemistry as a new proxy for tracing bio-activity in Precambrian oceans

  • 2014-2019

Cd isotope fractionation between different mineral phases

  • 2016-2020

Redox controls determined on Cryogenian blackshales and Mn carbonates using novel stable isotopes

  • 2017-ongoing

    Paleo-geographic reconstruction of the Ediacaran/Cambrian W-Mongolian

    microcontinents using small shelly fossils and zircon provenance analyses

  • 2018-ongoing

    fractionation of stable metal isotopes in stromatolites

  • 2020-ongoing

    fractionation of Mg isotopes in carbonates

  • 2020-ongoing

    fractionation of Cd isotopes in marine drill cores from the South China Sea

  • 2021-ongoing

    Trace element mapping and in situ U-Pb dating of biogenic carbonates