Neoproterozoic syn‐glacial carbonate precipitation and implications for a snowball Earth

Geobiology ◽  
2021 ◽  
Author(s):  
Ashleigh v. S. Hood ◽  
Donald E. Penman ◽  
Maxwell A. Lechte ◽  
Malcolm W. Wallace ◽  
Jonathan A. Giddings ◽  
...  
Keyword(s):  
Snowball Earth ◽  
Carbonate Precipitation

scholarly journals Episode of intense chemical weathering during the termination of the 635 Ma Marinoan glaciation

2016 ◽  
Vol 113 (52) ◽  
pp. 14904-14909 ◽  
Author(s):  
Kang-Jun Huang ◽  
Fang-Zhen Teng ◽  
Bing Shen ◽  
Shuhai Xiao ◽  
Xianguo Lang ◽  
...  
Keyword(s):  
South China ◽  
Chemical Weathering ◽  
Snowball Earth ◽  
Carbonate Precipitation ◽  
Isotopic Data ◽  
Low Intensity ◽  
Cap Carbonates ◽  
Cap Carbonate ◽  
Carbonate Deposition ◽  
Global Precipitation

Cryogenian (∼720–635 Ma) global glaciations (the snowball Earth) represent the most extreme ice ages in Earth’s history. The termination of these snowball Earth glaciations is marked by the global precipitation of cap carbonates, which are interpreted to have been driven by intense chemical weathering on continents. However, direct geochemical evidence for the intense chemical weathering in the aftermath of snowball glaciations is lacking. Here, we report Mg isotopic data from the terminal Cryogenian or Marinoan-age Nantuo Formation and the overlying cap carbonate of the basal Doushantuo Formation in South China. A positive excursion of extremely high δ26Mg values (+0.56 to +0.95)—indicative of an episode of intense chemical weathering—occurs in the top Nantuo Formation, whereas the siliciclastic component of the overlying Doushantuo cap carbonate has significantly lower δ26Mg values (<+0.40), suggesting moderate to low intensity of chemical weathering during cap carbonate deposition. These observations suggest that cap carbonate deposition postdates the climax of chemical weathering, probably because of the suppression of carbonate precipitation in an acidified ocean when atmospheric CO2 concentration was high. Cap carbonate deposition did not occur until chemical weathering had consumed substantial amounts of atmospheric CO2 and accumulated high levels of oceanic alkalinity. Our finding confirms intense chemical weathering at the onset of deglaciation but indicates that the maximum weathering predated cap carbonate deposition.

How Should Snowball Earth Deglaciation Start

2020 ◽  
Author(s):  
Jiacheng Wu ◽  
Yonggang Liu ◽  
Zhouqiao Zhao
Keyword(s):  
Snowball Earth

Improvement of Concrete Durability by Bacterial Carbonate Precipitation

2015 ◽  
Vol 1 (2) ◽  
pp. 90 ◽  
Author(s):  
Hariharan Harikrishnan ◽  
Shine Kadaikunnan ◽  
Innasimuthu Ganesh Moorthy ◽  
Alexander Ronaldo Anuf ◽  
Karuppiah Ponmurugan ◽  
...  
Keyword(s):  
Carbonate Precipitation ◽  
Concrete Durability

SOURCES OF CARBONATE PRECIPITATION IN MONO LAKE SEDIMENTS: δ18O AND CARBONATE CLUMPED ISOTOPES AS LAKE LEVEL PROXIES

2017 ◽  
Author(s):  
Miquela Ingalls ◽  
◽  
Sophie Westacott ◽  
Makayla Betts ◽  
Jana Meixnerova ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Lake Level ◽  
Mono Lake ◽  
Carbonate Precipitation ◽  
Clumped Isotopes
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