281-8 Constructing a Calibrated Roughness Model for Dating Lava Flows of the Arid Southwest US

Session: Petrology, Volcanology, and Mantle Plumes across the Solar System, Part II

Presenting Author:

Authors:

Abstract:

Surface roughness of lava flows presents a unique topographic signature useful for relative dating or calibrated absolute dating of lava flows. Previous work in the Mount Adams Volcanic Field (WA) demonstrated that the surface roughness of a flow decreases over time as its surface is weathered and smoothed. This has potential to improve hazard analysis by facilitating rapid identification and approximate dating of lava flows across a volcanic system using topographic data. This is particularly useful for low-K basalt flows that are challenging for traditional Ar-Ar dating. However, weathering rates, and therefore smoothing, are likely strongly linked to climate, and no study has yet analyzed the impact of smoothing in regions outside the temperate Northwest US. This study aims to analyze lava fields across the arid western US to develop a calibrated surface roughness model. From southern Idaho to New Mexico, the arid western US is replete with cinder cones and associated lava fields, including Sunset Crater (AZ), Lava Beds (CA), Craters of the Moon (ID), El Malpais (NM), Lunar Crater (NV), and Markagunt Plateau (UT), among others. These lava fields are generally cinder cone-derived basaltic lava flows weathering under comparable arid conditions. These similarities are important to minimize the variability introduced by the appearance of a flow (such as pahoehoe versus a’a) and other variables that can impact the smoothing of the flow over time based on a lava’s chemistry, viscosity, and other variables. This study will investigate how disparate but similar lava fields under comparable weathering conditions can be dated using a calibrated surface roughness model. The results will be contrasted to a previously developed calibration model for flows in the Mount Adams Volcanic Field to provide insight into the effect of climate over time. This is an important step towards developing calibration curves that transcend a single volcanic system or climate zone for application on a global scale or on other planets such as Mars.

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

doi: 10.1130/abs/2025AM-9834

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.