T56 New Advances in Geobiology

Sunday, 22 September 2024
1:30 PM - 5:30 PM
208A

QUANTITATIVE DESCRIPTIONS OF THE SPATIAL ORGANIZATION OF ~1.9 BILLION-YEAR-OLD MICROBIAL BUILDUPS

Paper number: T56-9
Program: Technical Sessions
Time: 3:20 PM – 3:35 PM

Authors

Abstract

Stromatolites, laminated constructions built (at least in part) by microbes, serve as some of the earliest evidence of life in Earth's sedimentary rock record. These fossilized structures encode critical information about paleobiological and paleoenvironmental conditions. By better describing stromatolite morphogenesis—for example, constraining how biology (i.e., microbial activity) and physical parameters (i.e., seawater chemistry) contribute to form—scientists can generate new insights into the evolution of life and environment. Like for other fossils, morphological analyses hold the key to an improved understanding of these ancient constructions. At the centimeter- to meter-scale, such analyses involve: i) the shape of singular stromatolites and ii) the spatial relationships between individuals within a larger population.

Here, we describe exceptionally preserved bedding plane exposures of stromatolites in rocks of the Paleoproterozoic Pethei Group, Great Slave Lake, Northwest Territories, Canada. We use handheld photography and Structure from Motion (SfM) to build three-dimensional (3D) reconstructions of the bedding planes. Next, we trace individual stromatolites in our reconstructions and then quantify their organization (e.g., orientation, connectivity, and distribution); the resulting organizational metrics provide insights into growth dynamics. To deconvolve the relative contributions of biotic and environmental forcings to stromatolite morphology and organization, we merge our quantitative descriptions with micron- to decameter-scale sedimentological and geochemical observations. Finally, to improve inferences about morphogenesis, we compare our findings to other studies of microbially mediated constructions, both extant and fossilized in the sedimentary rock record.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5

doi: 10.1130/abs/2024AM-405373

© Copyright 2024 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.