Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2536
Insights into Mountain Pass carbonatite formation from in-situ sulfur isotopes and geochemistry of sulfate and sulfide minerals Insights into Mountain Pass carbonatite formation from in-situ sulfur isotopes and geochemistry of sulfate and sulfide minerals
The Mountain Pass carbonatite stock hosts a world-class rare earth element deposit and may be classified as a carbonate-sulfate igneous rock, as it contains on average > 50 volume percent carbonate minerals and 20 to 30 volume percent sulfate minerals. The sulfates range in composition from barite to celestine and locally occur with sparse sulfide minerals. We investigate the origin of...
Authors
Erin Kay Benson, Kathryn E. Watts, Michael J. Pribil, Jay M. Thompson, Heather A. Lowers
Unprecedented burning in tropical peatlands during the 20th century compared to the previous two millennia Unprecedented burning in tropical peatlands during the 20th century compared to the previous two millennia
Tropical peatland wildfire incidence has risen in recent decades, driven by drainage for land use and intensified by severe droughts with global climate change. These disturbances have altered vegetation structure, disrupted ecosystem functioning, and increased carbon emissions, particularly in Southeast Asia. However, the long-term history and characteristics of wildfires in tropical...
Authors
Yuwan Wang, Ted R. Feldpausch, Graeme T. Swindles, Patrick Moss, Hamish A. McGowan, Thomas G. Sim, Paul J. Morris, Adam Benfield, Colin Courtney-Mustaphi, David Wahl, Encarni Montoya, Esther N. Githumbi, Euridice N. Honorio Coronado, Femke Augustijns, Gert Verstraeten, Jess O'Donnell, John Tibby, Juan C. Benavides, K. Anggi Hapsari, Karsten Schittek, Khairun Nisha Mohamed Ramdzan, Kunshan Bao, Lydia E. Cole, Lysanna Anderson, Mariusz Galka, Orijemie Emuobosa Akpo, Paul Strobel, Prabhakaran Ramya Bala, Rene Dommain, Rob Marchant, Raman Sukumar, Sakonvan Chawchai, Sarath Pullyottum Kavil, Scott Mooney, Thomas J. Kelly, Yang Gao, Apostolos Voulgarakis, Arnoud Boom, Chantelle Burton, Juan Carlos Berrio, Kelly Ribeiro, Liana O. Anderson, Mark Hardiman, Molly Spater, Susan E. Page, Angela Gallego-Sala
A diatom-based quantitative sea-ice proxy for the Bering and Chukchi seas A diatom-based quantitative sea-ice proxy for the Bering and Chukchi seas
Sea ice affects Earth's climate system on both regional and global scales. Its incorporation into climate can be used to achieve more accurate predictions of future climate. However, instrumental records of sea-ice concentration do not extend earlier than 1978. In an effort to extend this record, we constructed a proxy using the generalized additive model based on relative abundances of...
Authors
Anna Nesterovich, Beth E. Caissie
Conventional hydrothermal power-producing systems of the Great Basin, USA Conventional hydrothermal power-producing systems of the Great Basin, USA
As part of the update to the electric-grade conventional hydrothermal assessment of the Great Basin, USA, Monte Carlo analyses of identified resources within explored regions will be performed to make estimates of discovered resources and associated uncertainty. Analyses use conditional statistics where estimates are conditioned upon a hydrothermal favorability map, allowing for the...
Authors
Jacob DeAngelo, Erick R. Burns, Stanley Paul Mordensky
Open-source gravity reduction workflows for geothermal resource assessment Open-source gravity reduction workflows for geothermal resource assessment
Potential-field geophysical data such as gravity can enhance understanding of geothermal resources at all stages of the resource life cycle, including assessment, exploration, development, and monitoring, and at multiple scales, from the reservoir scale to regional scale. However, to make gravity data useful for geothermal resource characterization, several processing steps are required...
Authors
Collin Cronkite-Ratcliff
Geologic map of the Sierra Nevada, California and western Nevada Geologic map of the Sierra Nevada, California and western Nevada
THE GEOLOGIC MAP OF THE SIERRA NEVADA is a core component of the Sierra Nevada Earth Science Atlas, which also includes geophysical, neotectonic, economic, and geochronologic data. The map illustrates the distribution of geologic units across the Sierra Nevada and related adjacent areas. Geologic units are grouped by type and age into three categories: Principally Paleozoic and Mesozoic
Authors
Russell Graymer, M. D. O'Neal
Stepovers and beyond: Structural control of The Geysers geothermal system and the broader Clear Lake region Stepovers and beyond: Structural control of The Geysers geothermal system and the broader Clear Lake region
Fault geometry exerts a first-order control on geothermal systems by governing stress localization, fracture development, and permeability, yet in complex fault networks or broader shear zones, the relative influence of individual geometric features is often difficult to resolve. In the northern California Coast Ranges, The Geysers geothermal field is commonly interpreted to occur within...
Authors
Benjamin L. Melosh
Origin of the Pd/Pt ratio of the J-M Reef, Stillwater Complex, Montana, USA Origin of the Pd/Pt ratio of the J-M Reef, Stillwater Complex, Montana, USA
The J-M reef of the Stillwater Complex is characterized by a high Pd/Pt ratio (mean ~3.8 with a standard error of 0.03) with a homogeneous geospatial distribution at the deposit scale. In this contribution, we demonstrate that the Pd/Pt ratio of the reef is the product of equilibration of an immiscible sulfide liquid with a silicate melt rich in Pd relative to Pt. Despite the high tenors...
Authors
Michael Jenkins, William D. Smith
Miocene evolution of the Humboldt Current Miocene evolution of the Humboldt Current
Diatom records from the East Pisco Basin (EPB) of southern Peru and offshore Ocean Drilling Program (ODP) Hole 682 A reveal stepwise increases in the primary productivity of the Humboldt Current during the middle and late Miocene. Although diatoms are present back through the late middle Eocene, successively enhanced diatom production occurs during the Miocene in four steps. The first...
Authors
John A. Barron, Thomas J. DeVries, Jason J. Coenen
Is satellite-derived bathymetry vertical accuracy dependent on satellite mission and processing method? Is satellite-derived bathymetry vertical accuracy dependent on satellite mission and processing method?
This research focusses on three satellite-derived bathymetry methods and optical satellite instruments: (1) a stereo photogrammetry bathymetry module (SaTSeaD) developed for the NASA Ames stereo pipeline open-source software (version 3.6.0) using stereo WorldView data; (2) physics-based radiative transfer equations (PBSDB) using Landsat data; and (3) a modified composite band-ratio...
Authors
Monica Palaseanu-Lovejoy, Jeffrey J. Danielson, Minsu Kim, Bryan Eder, Gretchen Imahori, Curt D. Storlazzi
Advancing current understanding of Martian impact-generated hydrothermal systems through novel coupled modeling: Insights from Gale, Jezero, and other craters Advancing current understanding of Martian impact-generated hydrothermal systems through novel coupled modeling: Insights from Gale, Jezero, and other craters
Impact-generated hydrothermal systems are considered potentially habitable environments on Mars, Earth, and other planetary bodies for microbial life. However, there is an ongoing debate regarding what geological features on Mars provide definitive evidence for such systems. Although earlier studies have modeled hydrothermal processes in Martian craters, they often lacked integration...
Authors
Alexander J. Trowbridge, Simone Marchi, Joshua M. Taron, Gordon R. Osinski
The geology of Canadian potash: A critical mineral for feeding the world The geology of Canadian potash: A critical mineral for feeding the world
Potash, potassium-bearing water-soluble salt, is the primary global economic source of potassium. Potash is recognized as a critical mineral in Canada as it is the largest source of potassium used in fertilizers. It is essential for global agricultural productivity and food security. Canada is the world’s largest potash exporter with vast deposits in the widely mined Prairie Evaporite of
Authors
E.J. Matheson, Mark D. Cocker, M. E. Snyder, Craig Funk, R. Boehner, Chaowei Yang, M.P.B. Nicolas, N. W. Kruger