31 Best Student Geologic Map Competition (Posters)

Students will present their research through geologic mapping projects (with a significant field mapping component) that address scientific or societal issues. The top three student-authored geologic maps will receive awards following this session.

Sunday, 19 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Geology of the Life 7.5-minute Quadrangle in Chester and Henderson Counties, Tennessee

Paper number: 31-13
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

The Life 7.5-minute quadrangle (latitudes 35°37ˊ30ˊˊ to 35°30ˊ00ˊˊ; longitudes 88°30ˊ00ˊˊ to 88°22ˊ30ˊˊ) is located in Henderson and Chester counties, Tennessee, within the Mississippi Embayment part of the eastern Gulf Coastal Plain. The quadrangle hosts the Upper Cretaceous Coon Creek Formation and McNairy Sand, as well as Quaternary terrace and alluvium deposits. Mapping of the Life quadrangle consisted of systematically surveying roads, creeks, and trails to locate and identify bedrock exposures during the spring and summer of 2025, resulting in 126 field observations and 30 sediment samples collected for X-Ray Fluorescence (XRF) major and trace elemental analysis. Our primary objectives focus on determining the spatial distribution of Upper Cretaceous lithofacies at a 1:24,000-scale and to integrate lithofacies observations with geochemical analyses.

On the Life quadrangle, the Coon Creek Formation consists of light gray to dark bluish gray, orange to reddish-brown to red, very-fine to coarse-grained, thinly-bedded to massive, micaceous, silty to sandy clay. These clays can grade into, or interbed with, white to red to purple to yellow, fine to medium-grained, laminated to thickly bedded, highly micaceous clayey to silty sand with the regular presence of ironstone concretions. The McNairy Sand consists of pink-to-purple, white-to-tan, reddish-brown to rust-red, and dark-gray, fine- to coarse-grained, sparsely conglomeratic, laminated to thickly-bedded, cross-bedded, frequently ferruginous and micaceous, argillaceous-sand, silty-sand, and sandstone. The stratigraphic contact between the McNairy Sand and the underlying Coon Creek Formation is gradational and can consist of similar lithofacies, making it difficult to determine in the field. The Coon Creek Formation records sediments deposited in a nearshore marine environment transitioning into a lower shoreface. The transition from the Coon Creek Formation to the McNairy Sand represents a progradation of the shoreline lithofacies and transition to deltaic deposits. No structural features were identified on the Life quadrangle; however, regional geophysical gamma ray logs show strata dipping 0.1˚ to 0.5˚ to the west. This work advances regional stratigraphic correlations of Upper Cretaceous units along the eastern Gulf Coastal Plain and the development of heavy mineral sand deposits in western Tennessee.

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

doi: 10.1130/abs/2025AM-413056

© Copyright 2025 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.