Guttulatic calcite: A carbonate microtexture that reveals frigid formation conditions
Abstract
The paragenesis of carbonate pseudomorphic textures in the rock record that are inferred to represent replaced metastable ikaite (CaCO₃·6H₂O), which forms at frigid temperatures, is uncertain. Petrographic analysis of Mono Lake (California, USA) Pleistocene tufas allowed recognition of a distinctive calcite microtexture, termed guttulatic calcite, that forms during carbonate dehydration and is diagnostic for precursor ikaite. The texture is characterized by pseudo-hexagonal or spherical low-Mg cores, which likely formed initially as vaterite, with an ellipsoidal overgrowth, and a secondary high-Mg sparry or micritic cement. Observations of Mono Lake ikaite pseudomorphs, combined with a review of more ancient examples, indicate that guttulatic texture records carbonate dehydration of precursor ikaite and can be used to infer frigid paleotemperatures.
Additional Information
© 2021 The Authors. This paper is published under the terms of the CC-BY license. Manuscript received 11 November 2020. Revised manuscript received 29 July 2021. Manuscript accepted 3 August 2021. Published online 20 September 2021. This work was initiated under the Simons Collaboration for the Origin of Life (Simons Foundation, New York, USA) with support to J.P. Grotzinger. E.L. Scheller was supported by NASA Earth and Space Science Fellowship #80NSSC18K1255. Original authors are credited for figure panels in Figures 3E–3I and Figure 4A. We thank Nathan Stein for his contributions in the field. We humbly acknowledge the Kutzadika'a, the communities of Mono Basin, and other indigenous peoples whose identities may have been lost to colonialism, on whose land this work relies. Supplemental Material. Full SEM-EDS datasets, further descriptions of the methodology, and full references for the figure panels. Please visit https://doi.org/10.1130/GEOL.S.16589939 to access the supplemental material, and contact editing@geosociety.org with any questions.Attached Files
Published - g49312.1.pdf
Supplemental Material - G49312_SuppMat.pdf
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Additional details
- Eprint ID
- 113031
- Resolver ID
- CaltechAUTHORS:20220120-890623000
- NASA Earth and Space Science Fellowship
- 80NSSC18K1255
- Created
-
2022-01-20Created from EPrint's datestamp field
- Updated
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2022-01-20Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences (GPS)