190 Global Stratigraphy (Posters)

Tuesday, 21 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Geologic Mapping Advances Supporting Research and Conservation at John Day Fossil Beds National Monument

Paper number: 190-0
Program: Technical Sessions
Time: 8:00 AM – 8:15 AM

Authors

Abstract

John Day Fossil Beds National Monument (JODA) in Oregon preserves ~105 million years of geologic history, and contains one of the most continuous well exposed Cenozoic stratigraphic records in North America. Established in 1975, JODA spans ~14,000 acres across the Clarno, Painted Hills, and Sheep Rock Units, holding clues to past paleoclimates along with 2,200 extinct fossilized species.

Prior mapping at JODA (1990s-2014) established the foundational geologic framework. However, the analog maps created present challenges in digital translation, in addition to inconsistencies in the delineation of the Big Basin Member, structural complexities like the Hancock Dacite Dome, and various stratigraphic boundaries.

We present geologic maps of the three JODA units using GIS and GPS based techniques, including ESRI products, StraboSpot, and Trimble GPS. Our maps resolve inconsistencies throughout previous efforts including formalizing sub-members (lower, middle, and upper) of the Big Basin Member, and provide increased geospatial accuracy including 3-dimensional projections of JODA's geology. Leveraging tuff bed age revisions incorporated with high resolution imagery, we developed an overlay that enhances visualization of stratigraphic relationships, improving correlations of paleontological finds.

Our maps illustrate modernization in geologic mapping, enhancing our ability to precisely locate fossiliferous units and interpret complex structural geology, highlighting the evolving precision of geologic techniques and their critical role in supporting the preservation and contextualization of significant sites. These high-resolution maps provide indispensable resources for federal land management, supporting the park’s mission to preserve geological resources of the John Day region and provide further scientific and public understanding.

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

doi: 10.1130/abs/2025AM-412823

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