Publications
Filter Total Items: 1147
Stratigraphy and paleogeographic significance of the Pennsylvanian-Permian Bird Spring Formation in the Ship Mountains, southeastern California
A thick sequence of limestone, dolomite, and minor sandstone assigned to the Pennsylvanian and lower Permian Bird Spring Formation is exposed in the Ship Mountains about 85 kilometers (km) southwest of Needles, California, in the eastern Mojave Desert. These strata provide a valuable reference section of the Bird Spring Formation in a region where rocks of this age are not extensively exposed. Thi
Authors
Paul Stone, Calvin H. Stevens, Keith A. Howard, Thomas D. Hoisch
Hysteresis of unsaturated hydromechanical properties of a silty soil
Laboratory tests to examine hysteresis in the hydrologic and mechanical properties of partially saturated soils were conducted on six intact specimens collected from a landslide-prone area of Alameda County, California. The results reveal that the pore-size distribution parameter remains statistically unchanged between the wetting and drying paths; however, the wetting or drying state has a pronou
Authors
Ning Lu, Murat Kaya, Brian D. Collins, Jonathan W. Godt
Paleogeographic insights based on new U-Pb dates for altered tuffs in the Miocene Barstow Formation, California
The type section of the Barstow Formation in the Mud Hills, north of Barstow, is a reference section for early to middle Miocene paleontology, magnetostratigraphy, and dated volcanic episodes. Thanks to this robust chronologic framework, much of the interpretation of the paleogeography of the region from about 18 Ma to 13 Ma is based on study of the rocks in the Mud Hills. Eastward from the type s
Authors
David M. Miller, Jose E. Rosario, Shannon R. Leslie, Jorge A. Vazquez
The Idaho cobalt belt
The Idaho cobalt belt (ICB) is a northwest-trending belt of cobalt (Co) +/- copper (Cu)-bearing deposits and prospects in the Salmon River Mountains of east-central Idaho, U.S.A. The ICB is about 55 km long and 10 km long in its central part, which contains multiple strata-bound ore zones in the Blackbird mine area. The Black Pine and Iron Creek Co-Cu prospects are southeast of Blackbird, and the
Authors
Arthur A. Bookstrom
Field guide to selected sites along the Idaho Cobalt Belt (ICB) and to the Beartrack Gold Deposit, in the eastern Salmon River Mountains
This field guide provides a road log to and geologic descriptions of selected sites in the Idaho cobalt belt, and at the Beartrack gold mine, in the eastern Salmon River Mountains.
Authors
Arthur A. Bookstrom, George King, Robert A. Perry, John Childs
Unique challenges facing Southwestern tribes: Chapter 17
Executive Summary
When considering climate change, risks to Native American lands, people, and cultures are noteworthy. Impacts on Native lands and communities are anticipated to be both early and severe due to their location in marginal environments. Because Native American societies are socially, culturally, and politically unique, conventional climate change adaptation planning and related poli
Authors
Margaret Hiza, Karletta Chief, Kirk Bemis, Mahesh Gautam, Beth Rose Middleton, Rebecca Tsosie
Monte Carlo simulations of product distributions and contained metal estimates
Estimation of product distributions of two factors was simulated by conventional Monte Carlo techniques using factor distributions that were independent (uncorrelated). Several simulations using uniform distributions of factors show that the product distribution has a central peak approximately centered at the product of the medians of the factor distributions. Factor distributions that are peaked
Authors
Mark E. Gettings
Overcoming the momentum of anachronism: American geologic mapping in a twenty-first-century world
The practice of geologic mapping is undergoing conceptual and methodological transformation. Profound changes in digital technology in the past 10 yr have potential to impact all aspects of geologic mapping. The future of geologic mapping as a relevant scientific enterprise depends on widespread adoption of new technology and ideas about the collection, meaning, and utility of geologic map data. I
Authors
Kyle House, Ryan Clark, Joe Kopera
Basin thickness variations at the Junction of the Eastern California Shear Zone and the San Bernardino Mountains, California: How thick could the Pliocene sections be?
We estimate the thickness of Neogene basin fill along the junction of the Eastern
California Shear Zone and the North Frontal thrust system of the San Bernardino Mountains
using gravity data with geologic and well log constraints. The geometry of the basin fill is of
interest for groundwater assessment and location of potential faults, as well as providing an upper
bound on the thickness of any po
Authors
Victoria E. Langenheim, Tammy L. Surko, Phillip A. Armstrong, Jonathan C. Matti
Dzhezkazgan and associated sandstone copper deposits of the Chu-Sarysu basin, Central Kazakhstan
Sandstone-hosted copper (sandstone Cu) deposits occur within a 200-km reach of the northern Chu-Sarysu basin of central Kazakhstan (Dzhezkazgan and Zhaman-Aibat deposits, and the Zhilandy group of deposits). The deposits consist of Cu sulfide minerals as intergranular cement and grain replacement in 10 ore-bearing members of sandstone and conglomerate within a 600- to 1,000-m thick Pennsylvanian f
Authors
Stephen E. Box, Reimar Seltmann, Michael L. Zientek, Boris Syusyura, Robert A. Creaser, Alla Dolgopolova
Vegetation, substrate, and eolian sediment transport at Teesto Wash, Navajo Nation, 2009-2012
On the Navajo Nation, southwestern United States, warming temperatures and recent drought have increased eolian (windblown) sediment mobility such that large, migrating sand dunes affect grazing lands, housing, and road access. We present an assessment of seasonal variations in sand transport, mobility, and ground cover (vegetation and substrate) within a 0.2-km2 study area near Teesto Wash, south
Authors
Amy E. Draut, Margaret Hiza Redsteer, Lee Amoroso
Regional geophysical expression of a carbonatite terrane in the eastern Mojave Desert, California
A world-class, rare earth element carbonatite deposit is located near Mountain Pass, in the eastern Mojave Desert of California and is hosted by Proterozoic rocks that extend along the eastern margins of the Clark Mountain Range, Mescal Range, and Ivanpah Mountains in a north-northwest trending fault-bounded block. This Proterozoic block is generally composed of a complex of 1.7 - 1.6 Ga gneisses
Authors
David A. Ponce, Kevin M. Denton, David M. Miller