T182 The Dynamics of Stratigraphy and Sedimentation (Posters)

Monday, 23 October 2017
9:00 AM - 6:30 PM
Halls 4EF

LACUSTRINE-FLUVIAL DYNAMICS OF THE WESTERN LAKE IDAHO

Paper number: T182-26
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

Lake Idaho occupied the western Snake River Plain (WSRP) in the Mio-Pliocene as evidence by sediments known as the Chalk Hills and Glenns Ferry Formations. This stratigraphic and mapping study in the Vines Hill region roughly 40 km west of Vale, Oregon on US-20 aims to understand the depositional environments of the transitional strata between the conventionally named formations (Chalk Hills and Glenns Ferry). The primary stratigraphic section represents several fluctuations of lake level, siliciclastic input from the paleo-Malheur river, and an ash fall tuff thought to be the Faust Tuff. Regional mapping illuminates the extent of a previously undescribed or mapped lacustrine oolitic gastropod limestone suggesting significant chemical changes in the western lake. This mapping also shows the limestone unconformably overlying a small rhyolite vent. Geochemical analysis and K-Ar dating to be completed will reveal absolute age of this section and allow us to correlate these strata more closely with better known sections to the east.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-308313

© Copyright 2017 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.