Geological Society of America

141 New Advances in Geobiology

This session will focus on new research at the intersection between geologic and biologic processes with special emphasis on novel materials and methods, new field sites, and advances at the intersections of scientific fields.

Monday, 20 October 2025
1:30 PM - 5:30 PM
HBGCC, 305

Spatially Resolved Deconvolution of Texture Formation and Initial Diagenetic Mechanisms in Carbonate Dendrolitic Microbialites

Paper number: 141-6
Program: Technical Sessions
Time: 2:55 PM – 3:10 PM

Authors

Victoria Cassady Presenting Author
University of Southern California, Los Angeles, CA
Victoria Petryshyn
University of Southern California, Los Angeles, CA
Joan Bernhard
Woods Hole Oceanographic Institution, Woods Hole, MA
Aaron Celestian
Natural History Musuem Of Los Angeles, Los Angeles, CA
Mengshi Liu
University of Southern California, Los Angeles, CALIFORNIA
Ariel McCormack
University of Southern California, Los Angeles, CALIFORNIA
Kelsey Perez
University of Southern California, Los Angeles, California
Will Berelson
USC, Earth Sciences, Los Angeles, CA
David Bottjer
Univ Southern California Dept Earth Sci, Los Angeles, CA
Frank Corsetti
University of Southern California, Los Angeles, CA

Abstract

Microbialites–macroscopic organosedimentary structures (rocks) formed by interactions between microbial communities and detrital/chemical sediments —represent some of the oldest evidence of life on Earth and remain a target for extraterrestrial investigation. Microbialites are recognizable as macroscopic manifestations of microbial activity because of their textures, consisting of visible remnants of primary mineralogy and cemented channel architecture. Despite the importance of texture, the origin, evolution, and dependence of texture on in situ localization of microbial consortia is unknown. Recently, we characterized texture in incipient CaCO₃ microbialites from Little Hot Creek (LHC), a geothermal system in eastern California, where rapidly-lithifying microbial mats have a dendrolitic (shrub-like) texture strikingly similar to certain ancient microbialites. We used fluorescently labelled embedded coring (FLEC) to preserve internal textures of minerals, microbial biofabrics, and channel architecture in thin section. This allowed for direct comparison to thin sections of ancient microbialite counterparts, addressing a methodological gap between modern and ancient structures. In a new series of experiments, we combined FLEC with incubation in an H¹³CO₃ spike solution and used Raman spectroscopy to map incorporation of ¹³C into newly formed calcium carbonate to show where calcite precipitated in relation to microbial biofabrics. We show how specific microbial consortia-mineral surface relationships create micro-environments favoring authigenic CaCO₃ precipitation, and how meso-scale microbialite form may emerge from these spatial relationships. Lastly, we examine the role of endolithic microboring as a micritizing force and initial diagenetic step in carbonate microbialites immediately following mineral precipitation, and its potential involvement in producing micrite in ancient microbialites.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-413771

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