Geology topics

Kayla J Crosbie

Publications and source records attributed to Kayla J Crosbie.

3 recordsLinked to original sources

USGS2024

Geoelectric evidence for a wide spatial footprint of active extension in central Colorado

Three-dimensional magnetotelluric (MT) imaging in central Colorado reveals a set of north-striking high-conductivity tracks at lower-crustal (50–20 km) depths, with conductive finger-like structures rising off these tracks into the middle crust (20–5 km depth). We interpret these features to represent saline aqueous fluids and partial melt that are products of active extensional tectonomagmatism. These conductors are distributed over a wider region than the narrow corridor along which Rio Grande rift structures are traditionally mapped at the surface, and they consequently demarcate regions of the lower crust where accommodation of bulk extensional strain has concentrated conductive phases. Our observations reveal limitations in existing models of Rio Grande rift activity and may reflect unrecognized spatiotemporal variations in rift system evolution globally.

Colorado↗

USGS2023

Using airborne electromagnetics to improve depth to bedrock estimates in Wisconsin

Depth to bedrock is an important factor in hydrologic systems. The thickness of glacial sediments overlying bedrock in Wisconsin controls the routing of groundwater in surficial aquifers and its Depth to bedrock is often an important factor in hydrologic systems because hydraulic properties of bedrock and overlying sediments are typically appreciably different. For example, the thickness of glacial sediments overlying bedrock in Wisconsin controls the routing of groundwater in surficial aquifers and its connection with surface water bodies such as lakes and wetlands. In fractured bedrock environments, shallow bedrock can be vulnerable to degraded water quality when contaminants at the surface infiltrate quickly through permeable formations. Here, airborne electromagnetic surveys were acquired in three different parts of Wisconsin, totalling more than 5,700 flight line-kilometers, to improve understanding of depth to bedrock, the lithologic composition of overlying sediments, and as input structure for groundwater model development.

Wisconsin↗

USGS2022

Geophysical imaging of the Yellowstone hydrothermal plumbing system

The nature of Yellowstone National Park’s plumbing system linking deep thermal fluids to its legendary thermal features is virtually unknown. The prevailing concepts of Yellowstone hydrology and chemistry are that fluids reside in reservoirs with unknown geometries, flow laterally from distal sources and emerge at the edges of lava flows . Here we present a high-resolution synoptic view of pathways of the Yellowstone hydrothermal system derived from electrical resistivity and magnetic susceptibility models of airborne geophysical data . Groundwater and thermal fluids containing appreciable total dissolved solids significantly reduce resistivities of porous volcanic rocks and are differentiated by their resistivity signatures . Clay sequences mapped in thermal areas and boreholes typically form at depths of less than 1,000 metres over fault-controlled thermal fluid and/or gas conduits . We show that most thermal features are located above high-flux conduits along buried faults capped with clay that has low resistivity and low susceptibility. Shallow subhorizontal pathways feed groundwater into basins that mixes with thermal fluids from vertical conduits. These mixed fluids emerge at the surface, controlled by surficial permeability, and flow outwards along deeper brecciated layers. These outflows, continuing between the geyser basins, mix with local groundwater and thermal fluids to produce the observed geochemical signatures. Our high-fidelity images inform geochemical and groundwater models for hydrothermal systems worldwide.

Idaho, Wyoming↗