Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2354
The Holbrook Lineaments: The geophysical boundary zone between the Proterozoic Mazatzal and Yavapai Provinces, southwest USA
A horizontal gradient analysis of the isostatic gravity and aeromagnetic anomaly grids of the NewMexico-Arizona-southernCalifornia area was carried out, focused on eastern Arizona and western New Mexico, to define the transitional boundary between the Proterozoic Yavapai province to the west and the Mazatzal province to the east. The two provinces differ substantially in their favorability to host
Authors
Mark E. Gettings
Geoelectric hazard maps for the Pacific Northwest
Maps of extreme value, horizontal component geoelectric field amplitude are constructed for the Pacific Northwest United States (and parts of neighboring Canada). Multidecade long geoelectric field time series are calculated by convolving Earth surface impedance tensors from 71 discrete magnetotelluric survey sites across the region with historical 1‐min (2‐min Nyquist) geomagnetic variation time
Authors
Jeffrey J. Love, Greg M. Lucas, Anna Kelbert, Paul A. Bedrosian
Exploring viable geologic interpretations of gravity models using distance-based global sensitivity analysis and kernel methods
We have explored ways to integrate alternative geologic interpretations into the modeling of gravity data. These methods are applied to the Vaca Fault east of Fairfield, California, USA, where the structure across the fault is in question, and the Vaca Fault is used as a case study to demonstrate the method. The Vaca Fault is modeled using gravity data collected along a 10 km line perpendicular to
Authors
Geoffrey Phelps, Celine Scheidt, Jef Caers
Outburst floods provide erodability estimates consistent with long-term landscape evolution
Most current models for the landscape evolution over geological timescales are based on semi-empirical laws that consider riverbed incision proportional to rock erodability (dependent on lithology) and to the work performed by water flow (stream power). However, the erodability values obtained from these models are entangled with poorly known conditions of past climate and streamflow. Here we use
Authors
Daniel Garcia-Castellanos, Jim E. O'Connor
Breaching of strike-slip faults and successive flooding of pull-apart basins to form the Gulf of California seaway from ca. 8–6 Ma
The geologic record of the formation of marine basins during continental rifting is uncommonly preserved. Using GIS-based paleotectonic maps, we show that marine basin formation in the Gulf of California–Salton trough oblique rift (Mexico and the United States) occurred in a stepwise manner as crustal thinning lowered elevations within the Gulf of California Shear Zone, and subsidence along strike
Authors
Paul J. Umhoefer, Michael H. Darin, Scott E. K. Bennett, Lisa A. Skinner, Rebecca J. Dorsey, Michael E. Oskin
Geochemical characterization and modeling of regional groundwater contributing to the Verde River, Arizona between Mormon Pocket and the USGS Clarkdale gage
We use synoptic surveys of stream discharge, stable isotopes, and dissolved noble gases to identify the source of groundwater discharge to the Verde River in central Arizona. The Verde River more than doubles in discharge in Mormon Pocket over a 1.4 km distance that includes three discrete locations of visible spring input to the river and other diffuse groundwater inputs. A detailed study of th
Authors
Kimberly R. Beisner, W. Payton Gardner, Andrew G. Hunt
Sulfur isotopes of host strata for Howards Pass (Yukon–Northwest Territories) Zn-Pb deposits implicate anaerobic oxidation of methane, not basin stagnation
A new sulfur isotope stratigraphic profile has been developed for Ordovician-Silurian mudstones that host the Howards Pass Zn-Pb deposits (Canada) in an attempt to reconcile the traditional model of a stagnant euxinic basin setting with new contradictory findings. Our analyses of pyrite confirm the up-section 34S enrichment reported previously, but additional observations show parallel depletion o
Authors
Craig A. Johnson, John F. Slack, Julie A. Dumoulin, Karen Duttweiler Kelley, Hendrik Falck
Geologic and hydrologic concerns about pupfish divergence during the last glacial maximum
Martin et al.'s [1] double-digest, restriction-site-associated DNA sequencing of Death Valley pupfish species (Cyprinodon) and new time-calibrated phylogenetic analysis provide estimated divergence ages for North American pupfish at two scales. On the larger temporal and spatial scale, Martin et al. conclude that the Death Valley pupfish shared common ancestry with: Cyprinodon albivelis Rio Yaqui,
Authors
Jeffrey R. Knott, Fred Phillips, Marith C. Reheis, Donald Sada, Angela S. Jayko, Gary Axen
Rapid 3-D analysis of rockfalls
Recent fatal and damaging rockfalls in Yosemite National Park indicate the need for rapid response data collection methods to inform public safety and assist with management response. Here we show the use of multiple-platform remote sensing methods to rapidly capture pertinent data needed to inform management and the public following a several large rockfalls from El Capitan cliff in Yosemite Val
Authors
Greg M. Stock, A. Guerin, Nikita N. Avdievitch, Brian D. Collins, Michel Jaboyedoff
Against the current— The Mojave River from sink to source: The 2018 Desert Symposium field trip road log
The Mojave River evolved over the past few million years by “fill and spill” from upper basins near its source in the Transverse Ranges to lower basins. Each newly “spilled into” basin in the series? sustained a long-lived lake but gradually filled with Mojave River sediment, leading to spill to a yet lower elevation? basin. The Mojave River currently terminates at Silver Lake, near Baker, CA, but
Authors
David M. Miller, R.E. Reynolds, Krishangi D. Groover, David C. Buesch, H. J. Brown, Geoffrey Cromwell, Jill N. Densmore, A.L. Garcia, D. Hughson, J.R. Knott, Jeffrey E. Lovich
World distribution of uranium deposits
Deposit data derived from IAEA UDEPO (http://infcis.iaea.org/UDEPO/About.cshtml) database with assistance from P. Bruneton (France) and M. Mihalasky (U.S.A.). The map is an updated companion to "World Distribution of Uranium Deposits (UDEPO) with Uranium Deposit Classification, IAEA Tech-Doc-1629".
Geology was derived from L.B. Chorlton, Generalized Geology of the World, Geological Survey of Cana
Authors
M. C. Fairclough, J. A. Irvine, L. F. Katona, W. L. Simmon, P. Bruneton, Mark J. Mihalasky, M. Cuney, M. Aranha, O. Pylypenko, K. Poliakovska
In situ distributions of magnetic susceptibility in some igneous rocks
Measurements of in-situ magnetic susceptibility were compiled from mainly Precambrian crystalline basement rocks beneath the Colorado Plateau and ranges in Arizona, Colorado, and New Mexico. The susceptibility meter used samples about 33 cubic centimeters of rock and measures variations in the modal distribution of magnetic minerals that form a minor component volumetrically in these coarsely crys
Authors
Mark E. Gettings