Revealing the climate of snowball Earth from Δ17O systematics of hydrothermal rocks
The snowball Earth hypothesis predicts that the entire Earth was covered with ice. Snowball Earth events were suggested to have occurred several times during the Precambrian. Classic paleo-thermometers (e.g., 18O/16O in marine carbonates) are not available from snowball Earth episodes, and only a fe...
Published in: | Proceedings of the National Academy of Sciences |
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Main Authors: | , , , , , , |
Format: | Text |
Language: | English |
Published: |
National Academy of Sciences
2015
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Subjects: | |
Online Access: | http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4418898/ http://www.ncbi.nlm.nih.gov/pubmed/25870269 https://doi.org/10.1073/pnas.1422887112 |
Summary: | The snowball Earth hypothesis predicts that the entire Earth was covered with ice. Snowball Earth events were suggested to have occurred several times during the Precambrian. Classic paleo-thermometers (e.g., 18O/16O in marine carbonates) are not available from snowball Earth episodes, and only a few reconstructions of 18O/16O in ancient meteoric water exist. Here we present a novel approach to reconstruct the 18O/16O composition of ancient meteoric waters using the triple oxygen isotopic composition (17O/16O and 18O/16O) of hydrothermally altered rocks. The inferred 18O/16O for waters that precipitated at (sub)tropical paleo-latitudes on a Paleoproterozoic (∼2.4 gigayears ago) snowball Earth are extremely low. Today, similar compositions are observed only in central Antarctica. |
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