Geology topics

Mason A. Kass

Publications and source records attributed to Mason A. Kass.

5 recordsLinked to original sources

USGS2022

Rapid and gradual permafrost thaw: A tale of two sites

Warming temperatures and increasing disturbance by wildfire and extreme weather events is driving permafrost change across northern latitudes. The state of permafrost varies widely in space and time, depending on landscape, climate, hydrologic, and ecological factors. Despite its importance, few approaches commonly measure and monitor the changes in deep (>1 m) permafrost conditions with high spatial resolution. Here, we use electrical resistivity tomography surveys along two transects in interior Alaska previously disturbed by wildfire and more recently by warming temperatures and extreme precipitation. Long-term point observations of permafrost depth, temperature, and water content inform geophysical measurements which, in turn, are used to extrapolate interpretations over larger areas and with high spatial fidelity. We contrast gradual loss of recently formed permafrost driven by warmer temperatures and increased snowfall, with rapid permafrost loss driven by changes in air temperature, snow depth, and extreme summer precipitation in 2014.

Alaska↗

USGS2019

Heat and mass transport in a vapor-dominated hydrothermal area in Yellowstone National Park, USA: Inferences from magnetic, electrical, electromagnetic, subsurface temperature and diffuse CO2 flux measurements

Vapor‐dominated hydrothermal systems are characterized by localized and elevated heat and gas flux. In these systems, steam and gas ascend from a boiling water reservoir, steam condenses beneath a low‐permeability cap layer, and liquid water descends, driven by gravity (“heat pipe” model). We combine magnetic, electromagnetic, and geoelectrical methods and CO 2 flux and subsurface temperature measurements in the Solfatara Plateau Thermal Area in the Yellowstone Caldera to address several fundamental questions: (1) What are the structural and/or lithological controls on heat and mass transport in vapor‐dominated areas? (2) What is the geometry and size of convecting multiphase thermal plumes? (3) Are thermal plumes associated with subsurface rock alteration and demagnetization? Magnetic and electromagnetic data inversions suggest an asymmetric 50‐ to 100‐m thick basin of glacial deposits with the thickest part adjacent to the margin of a rhyolite flow. The 3‐D electrical conductivity model in the glacial basin reveals a narrow vertical conductor interpreted as a focused multiphase plume, which coincides at the ground surface with the heat and CO 2 flux maxima. The magnetic data suggest that destruction of magnetic minerals due to rock alteration associated with the hydrothermal plume occurs mainly near the ground surface. We propose a model where the buoyant multiphase plume forms in response to decompression, boiling, and phase separation of pressurized thermal groundwater that discharges from the brecciated base of a rhyolite flow into the basin of glacial deposits. Results from multiphase groundwater flow and heat transport numerical simulations corroborate the first‐order characteristics of this model.

Wyoming↗

USGS2017

In situ nuclear magnetic resonance response of permafrost and active layer soil in boreal and tundra ecosystems

Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience of permafrost requires an interdisciplinary approach, relying on (for example) geophysical investigations, ecological characterization, direct observations, remote sensing, and more. As part of a multi-year investigation into the impacts of wildfires to permafrost, we have collected in situ measurements of the nuclear magnetic resonance (NMR) response of active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes. Through statistical analyses and synthetic freezing simulations, we also demonstrate that borehole NMR can image the nucleation of ice within soil pore spaces.

Alaska↗

USGS2015

Regional tectonic setting for the Trinidad earthquake swarms (2000-2012) from gravity and magnetic data

Earthquakes in the Raton basin near Trinidad, Colorado, (Figure 1) are located (Rubenstein et. al., 2014) near a major gravity and magnetic boundary. These earthquakes also occur in an area of hydrocarbon production that includes several high-capacity produced water injection wells. This presentation gives a very basic outline of the relation between the earthquakes, the potential field data, and possible basement structure.

Colorado, New Mexico↗

USGS2014

Magnetic resonance sounding survey data collected in the North Platte, Twin Platte, and South Platte Natural Resource Districts, Western Nebraska, Fall 2012

This report is a release of digital data and associated survey descriptions from a series of magnetic resonance soundings (MRS, also known as surface nuclear magnetic resonance) that was conducted during October and November of 2012 in areas of western Nebraska as part of a cooperative hydrologic study by the North Platte Natural Resource District (NRD), South Platte NRD, Twin Platte NRD, the Nebraska Environmental Trust, and the U.S. Geological Survey (USGS). The objective of the study was to delineate the base-of-aquifer and refine the understanding of the hydrologic properties in the aquifer system. The MRS technique non-invasively measures water content in the subsurface, which makes it a useful tool for hydrologic investigations in the near surface (up to depths of approximately 150 meters). In total, 14 MRS production-level soundings were acquired by the USGS over an area of approximately 10,600 square kilometers. The data are presented here in digital format, along with acquisition information, survey and site descriptions, and metadata.

Nebraska↗