A5055374792- Geological and Geochemical Analysis
- earthquake and tectonic studies
- Geochemistry and Geologic Mapping
- High-pressure geophysics and materials
- Geology and Paleoclimatology Research
- Geological and Geophysical Studies
- Geological and Tectonic Studies in Latin America
- Hydrocarbon exploration and reservoir analysis
- Astro and Planetary Science
- Geological formations and processes
- Paleontology and Stratigraphy of Fossils
- Geological Studies and Exploration
- Methane Hydrates and Related Phenomena
- Evolution and Paleontology Studies
- Planetary Science and Exploration
- Nuclear Physics and Applications
- Geomagnetism and Paleomagnetism Studies
- Geochemistry and Elemental Analysis
- Marine and environmental studies
- Geological Modeling and Analysis
- Pleistocene-Era Hominins and Archaeology
- Atmospheric and Environmental Gas Dynamics
- Archaeology and Natural History
- Cultural, Social, and Media Studies
- Mineralogy and Gemology Studies
University of Houston
2014-2024
British Geological Survey
2011
New Mexico Institute of Mining and Technology
1986-2010
New Mexico Bureau of Geology and Mineral Resources
2010
University of Georgia
2003
University at Albany, State University of New York
1987-1994
Beijing Seismological Bureau
1994
Planetary Science Institute
1994
University of California, Los Angeles
1990-1994
Czech Academy of Sciences, Institute of Geology
1994
Thermochronologic, sedimentologic, oceanographic, and paleoclimatic studies suggest that rapid uplift unroofing of southern Tibet began about 20 million years ago the present elevation much Tibetan plateau was attained by 8 ago. Hypotheses advanced to explain tectonic evolution India-Asia collision, which 40 50 ago, predict timing rates crustal thickening margin Asia. However, these models do not prominently enhanced early Miocene denudation are manifested in a variety geological records. A...
Regional mapping, stratigraphic study, and 40 Ar/ 39 Ar geochronology provide the basis for an incremental restoration of Himalayan fold‐thrust belt in western Nepal. Tectonostratigraphic zonation developed other regions Himalaya is applicable, with minor modifications, From south to north major structural features are (1) Main Frontal thrust system, comprising two three sheets Neogene foreland basin deposits; (2) Boundary sheet, which consists Proterozoic early Miocene, Lesser...
Structural and thermochronological investigations of southern Tibet (Xizang) suggest that intracontinental thrusting has been the dominant cause for formation thickened crust in southernmost Tibetan plateau since late Oligocene. Two thrust systems are documented this study: north dipping Gangdese system (GTS) younger south Renbu‐Zedong (RZT). West Lhasa, juxtaposes Late Cretaceous forearc basin deposits Lhasa Block (the Xigaze Group) over Tethyan sedimentary rocks Indian plate, whereas east...
Two end‐member kinematic models of crustal shortening across the Himalaya are currently debated: one assumes localized thrusting along a single major thrust fault, Main Himalayan Thrust (MHT) with nonuniform underplating due to duplexing, and other advocates for out‐of‐sequence (OOS) in addition MHT underplating. We assess these two based on modeling thermochronological, thermometric, thermobarometric data from central Nepal Himalaya. complement set compiled literature 114 40 Ar/ 39 Ar, 10...
Neogene extension of the Tibetan plateau is manifested as a series north–south trending graben, most prominent which Yadong‐Gulu rift. The Nyainqentanghla Shan, NE–SW mountain range ∼100 km NW Lhasa, bounds western margin Yangbajian central segment eastern edge massif marked by low angle (∼25°) detachment fault shear zone amphibolite grade mylonites. 40 Ar/ 39 Ar thermal history results from samples collected along two deeply incised valleys within reveal that rapid cooling event propagated...
The southern Andes between 33° and 45°S latitude are characterized by a series of complex basins that spanned the contemporaneous active continental margin, which itself was volcanic activity. filled with thick (up to 3000 m) accumulations interbedded sedimentary strata late Oligocene‐early Miocene age. We interpret these developed during phase moderate extension within plate margin system, triggered an increased rate convergence Farallon (Nazca) South American plates 28 26 Ma. This history...
Research Article| July 01, 2006 Tectonic evolution of the Himalayan thrust belt in western Nepal: Implications for channel flow models Delores M. Robinson; Robinson 1Department Geological Sciences, University Alabama, Tuscaloosa, Alabama 35487 USA Search other works by this author on: GSW Google Scholar Peter G. DeCelles; DeCelles 2Department Geosciences, Arizona, Tucson, Arizona 85721, Copeland 3Department Houston, Texas 77204, Author and Article Information Publisher: Society America...
Research Article| April 01, 1990 Episodic rapid uplift in the Himalaya revealed by 40Ar/39Ar analysis of detrital K-feldspar and muscovite, Bengal fan Peter Copeland; Copeland 1Department Geological Sciences, State University New York at Albany, 1400 Washington Avenue, 12222 Search for other works this author on: GSW Google Scholar T. Mark Harrison Author Article Information Publisher: Society America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print 0091-7613 Geology (1990) 18 (4):...
Two distinctive molasse deposits within the Indo-Asian collision zone have been investigated to help understand post-Oligocene evolution of Himalaya and southern Tibetan plateau. The Siwalik Group (predominantly fluvial sandstones siltstones), is widespread throughout foothills from Pakistan eastern India. Paleomagnetic analysis a measured section in Bakiya Khola, southeastern Nepal, constrains depositional ages ($$t_{dep}$$) between 10.8 4.9 Ma. average accumulation rate during this...
Dean Hamer and his team of researchers at the National Cancer Institute made a remarkable discovery: in families with two gay brothers, 33 out 40 pairs shared distinctive pattern one region X chromosone, far higher number than chance alone would predict. DNA family studies confirmed much average rate homosexuality among male relatives on mother's side family. The discovery gene marker - popularly, though inaccurately called launched furious international debate about profound scientific,...
Research Article| March 01, 2017 Location, location, location: The variable lifespan of the Laramide orogeny Peter Copeland; Copeland 1Department Earth and Atmospheric Sciences, University Houston, Texas 77204, USA Search for other works by this author on: GSW Google Scholar Claire A. Currie; Currie 2Department Physics, Alberta, Edmonton, Alberta T6G 2E1, Canada, Timothy F. Lawton; Lawton 3Centro de Geociencias, Universidad Nacional Autónoma México, Querétaro 76230, México Michael Murphy...
The Gangdese batholith, southern Tibet, was part of an Andean‐type arc at the margin Asia prior to collision India and approximately 50 40 Ma. Fission‐track Ar/ 39 Ar analyses 28 rocks from 10 granitoid plutons along ∼250 km length batholith in Lhasa region provide a detailed understanding age postcrystallization erosional tectonic history these rocks. These data suggest range ages for 94 42 Ma, with majority being Tertiary age. cooling histories all are characterized by marked...
Field mapping, structural analysis, and geochronologic data from northwestern Nepal reveal major normal right‐slip motion along a previously unrecognized west‐northwest striking system of shear zones that we term the Gurla Mandhata–Humla fault (GMH). The GMH obliquely cuts across Greater Himalayan Crystalline sequence into Lesser imbricate thrust belt via two right‐step‐over structures. average slip direction on parallels strike orogen. Motion this has resulted in an apparent left separation...
U-Pb dating on zircon and monazite from different varieties of leucogranites in the Karakoram Batholith reveals two distinct pulses plutonism at 25.5 +0.3/-0.8 21.4 +0.3/-0.6 Ma. In both granites, these minerals contain inherited components, documenting presence Precambrian material magma source. A crustal origin long residence times source rocks are confirmed by highly negative $$\epsilon _{i}^{Nd}$$, strongly positive _{i}^{Sr}$$, $$T_{DM}^{ND}$$ excess to 1 Ga. biotite gneiss a granitic...
Research Article| November 01, 2007 The structure and rate of late Miocene expansion C4 plants: Evidence from lateral variation in stable isotopes paleosols the Siwalik Group, northern Pakistan Anna K. Behrensmeyer; Behrensmeyer 1Department Paleobiology, MRC 121, National Museum Natural History, Smithsonian Institution, P.O. Box 37012, Washington, DC 20013–7012, USA Search for other works by this author on: GSW Google Scholar Jay Quade; Quade 2Dept. Geosciences Desert Laboratory, University...
Since the beginning of collision between India and Asia at about 50 Ma, convergence in Himalaya has largely been taken up along major thrust zones. In this study, samples Lesser Formations, to 10 km below Main Central Thrust (MCT), Greater Sequence, 12 above MCT, have analyzed by 40 Ar/ 39 Ar U‐Pb methods investigate thermal history MCT. The ages can be summarized as follows: (1) youngest from muscovites (3.1 Ma), biotites (3.4 hornblendes (4.1 Ma) all come within 1 (2) there is a marked...
Abstract Placing geologic events in a temporal framework is essential to telling the story of Earth history. However, clastic sedimentary rocks can be difficult date an absolute reference because they are made up grains that older than rock which now found, and some do not contain fossils allow precise Geologic Timescale. For such rocks, isotopic dating detrital minerals used estimate time deposition; must younger youngest grain analysed. many researchers eschew this simple straightforward...