107-23 Testing a Database Approach to Describing Microbialite Features

Session: Sedimentary Geology Division/SEPM Student Research Poster Competition: Dynamics of Stratigraphy and Sedimentation

Presenting Author:

Authors:

Abstract:

Microbialite morphology, texture, and geochemistry (“properties”) record important information about the physical and chemical environment in which they formed. A lack of widespread agreement around microbialite descriptive terminology makes it challenging to generate consistent descriptions of microbialites that allow robust interpretation of form-environment relationships and trends over time and space. Since a complete description of microbialite properties spans multiple spatial scales, a hierarchical database approach might be useful in creating a universal framework for microbialite description. 

We used a new database based on Grey and Awramik (2020) to characterize microbialite morphologies and textures. We use descriptors at four distinct scales: megascopic (observable at outcrop), macroscopic, mesoscopic (observable from outcrop to hand-sample scale), and microscopic (visible petrographically). The database prompts users via a set of pull-down menus supported by help images to aid in consistent data entry. Descriptions can be supplemented by attaching photos, maps, stratigraphic sections, or other data.   

The beta version of this database has a locally-hosted, Microsoft Access-based frontend, while the backend—coded in open-source PostgreSQL—is hosted on NSF’s Jetstream server. We tested this version on stromatolites from a variety of localities and ages, assessing the user experience and determining whether property coding in a hierarchical structure improves comparisons across time and space. We found that the hierarchical structure ensures consistency in applying terms at the appropriate scale, but also introduces challenges for coding stromatolites that were collected without such a hierarchical framework in mind.  Most users would likely find gaps in their observational framework, particularly if stromatolite morphology was not the main goal of the original project. On the other hand, the database permits empty cells, perhaps making observational gaps more apparent. Our preliminary work also underscores the importance of community input in choosing the variables that are coded and the controlled vocabulary used to describe microbialite properties. If database parameters do not adequately represent the important characteristics of microbialites, the database will have limited utility. Our small-scale experiment thus far suggests promise as a useful, coherent repository for microbialites described by different workers. Further, the hierarchical, non-genetic descriptive framework allows for morphological comparisons across space and time. 

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10436

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