Publications
Filter Total Items: 1493
Uranium-series ages of corals, sea level history, and palaeozoogeography, Canary Islands, Spain: an exploratory study for two Quaternary interglacial periods Uranium-series ages of corals, sea level history, and palaeozoogeography, Canary Islands, Spain: an exploratory study for two Quaternary interglacial periods
We present the first U-series ages of corals from emergent marine deposits on the Canary Islands. Deposits at + 20 m are 481 ± 39 ka, possibly correlative to marine isotope stage (or MIS) 11, while those at + 12 and + 8 m are 120.5 ± 0.8 ka and 130.2 ± 0.8 ka, respectively, correlative to MIS 5.5. The age, elevations, and uplift rates derived from MIS 5.5 deposits on the Canary Islands...
Authors
Daniel R. Muhs, Joaquin Meco, Kathleen R. Simmons
Glacial and Quaternary geology of the northern Yellowstone area, Montana and Wyoming Glacial and Quaternary geology of the northern Yellowstone area, Montana and Wyoming
This field guide focuses on the glacial geology and paleoecology beginning in the Paradise Valley and progressing southward into northern Yellowstone National Park. During the last (Pinedale) glaciation, the northern Yellowstone outlet glacier flowed out of Yellowstone Park and down the Yellowstone River Valley into the Paradise Valley. The field trip will traverse the following Pinedale...
Authors
Kenneth L. Pierce, Joseph M. Licciardi, Teresa R. Krause, Cathy Whitlock
SHRIMP-RG U-Pb ages of provenance and metamorphism from detrital zircon populations and Pb-Sr-Nd signatures of prebatholithic metasedimentary rocks at Searl Ridge, northern Peninsular Ranges batholith, southern California: Implications for their age, orig SHRIMP-RG U-Pb ages of provenance and metamorphism from detrital zircon populations and Pb-Sr-Nd signatures of prebatholithic metasedimentary rocks at Searl Ridge, northern Peninsular Ranges batholith, southern California: Implications for their age, orig
Twenty-four samples were collected from prebatholithic metasedimentary rocks along Searl Ridge, the north rim of the Diamond Valley Reservoir, Domenigoni Valley, centrally located in the northern Peninsular Ranges of southern California. These rocks exhibit progressive metamorphism from west to east across fundamental structural discontinuities now referred to as a “transition zone.”...
Authors
Wayne R. Premo, Douglas M. Morton
U-Pb zircon geochronology of plutonism in the northern Peninsular Ranges batholith, southern California: Implications for the Late Cretaceous tectonic evolution of southern California U-Pb zircon geochronology of plutonism in the northern Peninsular Ranges batholith, southern California: Implications for the Late Cretaceous tectonic evolution of southern California
Utilizing both sensitive high-resolution ion microprobe (SHRIMP) and conventional isotope dilution–thermal ionization mass spectrometry (ID-TIMS) methods, crystallization and/or emplacement ages have been obtained for a suite of Cretaceous intermediate-composition plutonic samples collected along a roughly E-W–trending traverse through the northern Peninsular Ranges batholith. Previously...
Authors
Wayne R. Premo, Douglas M. Morton, Joseph L. Wooden, C. Mark Fanning
Age and isotopic systematics of Cretaceous borehole and surface samples from the greater Los Angeles Basin region: Implications for the types of crust that might underlie Los Angeles and their distribution along late Cenozoic fault systems Age and isotopic systematics of Cretaceous borehole and surface samples from the greater Los Angeles Basin region: Implications for the types of crust that might underlie Los Angeles and their distribution along late Cenozoic fault systems
Nine U-Pb zircon ages were determined on plutonic rocks sampled from surface outcrops and rock chips of drill core from boreholes within the greater Los Angeles Basin region. In addition, lead-strontium-neodymium (Pb-Sr-Nd) whole-rock isotopic data were obtained for eight of these samples. These results help to characterize the crystalline basement rocks hidden in the subsurface and...
Authors
Wayne R. Premo, Douglas M. Morton, Ronald W. Kistler
Latest Quaternary paleoseismology and evidence of distributed dextral shear along the Mohawk Valley fault zone, northern Walker Lane, California Latest Quaternary paleoseismology and evidence of distributed dextral shear along the Mohawk Valley fault zone, northern Walker Lane, California
The dextral-slip Mohawk Valley fault zone (MVFZ) strikes northwestward along the eastern margin of the Sierra Nevada in the northern Walker Lane. Geodetic block modeling indicates that the MVFZ may accommodate ~3 mm/yr of regional dextral strain, implying that it is the highest slip-rate strike-slip fault in the region; however, only limited geologic data are available to constrain the...
Authors
Ryan D. Gold, Richard W. Briggs, Stephen Personius, Anthony J. Crone, Shannon A. Mahan, Stephen Angster
A new map of global ecological land units — An ecophysiographic stratification approach A new map of global ecological land units — An ecophysiographic stratification approach
In response to the need and an intergovernmental commission for a high resolution and data-derived global ecosystem map, land surface elements of global ecological pattern were characterized in an ecophysiographic stratification of the planet. The stratification produced 3,923 terrestrial ecological land units (ELUs) at a base resolution of 250 meters. The ELUs were derived from data on...
Authors
Roger Sayre, Jack Dangermond, Charlie Frye, Randy Vaughan, Peter Aniello, Sean P. Breyer, Douglas Cribbs, Dabney Hopkins, Richard Nauman, William Derrenbacher, Dawn J. Wright, Clint Brown, Charles Convis, Jonathan H. Smith, Laurence Benson, D. Paco VanSistine, Harumi Warner, Jill Janene Cress, Jeffrey J. Danielson, Sharon L. Hamann, Thomas Cecere, Ashwan D. Reddy, Devon Burton, Andrea Grosse, Diane TRUE, Marc Metzger, Jens Hartmann, Nils Moosdorf, Hans Durr, Marc Paganini, Pierre Defourny, Olivier Arino, Simone Maynard, Mark Anderson, Patrick Comer
Changes in vegetation and biological soil crust communities on sand dunes stabilizing after a century of grazing on San Miguel Island, Channel Island National Park, California Changes in vegetation and biological soil crust communities on sand dunes stabilizing after a century of grazing on San Miguel Island, Channel Island National Park, California
San Miguel Island is the westernmost of the California Channel Islands and one of the windiest areas on the west coast of North America. The majority of the island is covered by coastal sand dunes, which were stripped of vegetation and subsequently mobilized due to droughts and sheep ranching during the late 19th century and early 20th century. Since the removal of grazing animals...
Authors
Kristine L. Zellman
Landscapes of Santa Rosa Island, Channel Islands National Park, California Landscapes of Santa Rosa Island, Channel Islands National Park, California
Santa Rosa Island (SRI) is the second-largest of the California Channel Islands. It is one of 4 east–west aligned islands forming the northern Channel Islands chain, and one of the 5 islands in Channel Islands National Park. The landforms, and collections of landforms called landscapes, of Santa Rosa Island have been created by tectonic uplift and faulting, rising and falling sea level...
Authors
R. Randall Schumann, Scott A. Minor, Daniel R. Muhs, Jeffery S. Pigati
Quantifying and valuing ecosystem services: An application of ARIES to the San Pedro River basin, USA Quantifying and valuing ecosystem services: An application of ARIES to the San Pedro River basin, USA
A large body of research exists that identifies and values ecosystem services - the benefits that ecosystems provide to humans (MA, 2005) - and their underlying ecological processes. However, the development of software decision support tools that integrate ecology, economics and geography that can be independently used within the public, private, academic and NGO sectors is a more...
Authors
Kenneth J. Bagstad, Darius J. Semmens, Ferdinando Villa, Gary Johnson
Pb-Sr-Nd-O isotopic characterization of Mesozoic rocks throughout the northern end of the Peninsular Ranges batholith: Isotopic evidence for the magmatic evolution of oceanic arc–continental margin accretion during the Late Cretaceous of southern Californ Pb-Sr-Nd-O isotopic characterization of Mesozoic rocks throughout the northern end of the Peninsular Ranges batholith: Isotopic evidence for the magmatic evolution of oceanic arc–continental margin accretion during the Late Cretaceous of southern Californ
Within the duration of the U.S. Geological Survey (USGS)–based Southern California Areal Mapping Project (SCAMP), many samples from the northern Peninsular Ranges batholith were studied for their whole-rock radioisotopic systematics (rubidium-strontium [Rb-Sr], uranium-thorium-lead [U-Th-Pb], and samarium-neodymium [Sm-Nd]), as well as oxygen (O), a stable isotope. The results of three...
Authors
Ronald W. Kistler, Joseph L. Wooden, Wayne R. Premo, Douglas M. Morton
Applying threshold concepts to conservation management of dryland ecosystems: Case studies on the Colorado Plateau Applying threshold concepts to conservation management of dryland ecosystems: Case studies on the Colorado Plateau
Ecosystems may occupy functionally distinct alternative states, some of which are more or less desirable from a management standpoint. Transitions from state to state are usually associated with a particular trigger or sequence of triggers, such as the addition or subtraction of a disturbance. Transitions are often not linear, rather it is common to see an abrupt transition come about...
Authors
Matthew A. Bowker, Mark E. Miller, Steven L. Garman, Travis Belote