A5023142778- Geology and Paleoclimatology Research
- Pleistocene-Era Hominins and Archaeology
- Evolution and Paleontology Studies
- Geological and Geochemical Analysis
- Isotope Analysis in Ecology
- Geological formations and processes
- Geochemistry and Geologic Mapping
- Archaeology and ancient environmental studies
- Geochemistry and Elemental Analysis
- Aeolian processes and effects
- Planetary Science and Exploration
- Forensic Anthropology and Bioarchaeology Studies
- NMR spectroscopy and applications
- Geophysical and Geoelectrical Methods
- Radioactive element chemistry and processing
- Landslides and related hazards
- Image Processing and 3D Reconstruction
- Methane Hydrates and Related Phenomena
- Mining Techniques and Economics
- earthquake and tectonic studies
- Radioactivity and Radon Measurements
- Geological and Geophysical Studies
- Mining and Resource Management
- Pacific and Southeast Asian Studies
- Paleontology and Evolutionary Biology
James Cook University
2012-2022
National Centre for Groundwater Research and Training
2022
Office of Science
2016
Los Alamos National Laboratory
2010
Purdue University West Lafayette
2008-2010
University of Arizona
2001-2008
New ages for flowstone, sediments and fossil bones from the Dinaledi Chamber are presented. We combined optically stimulated luminescence dating of with U-Th palaeomagnetic analyses flowstones to establish that all containing Homo naledi fossils can be allocated a single stratigraphic entity (sub-unit 3b), interpreted deposited between 236 ka 414 ka. This result has been confirmed independently by three H. teeth U-series electron spin resonance (US-ESR) dating. Two scenarios were tested...
Research Article| May 01, 2006 Geochronology and stratigraphy of late Pleistocene lake cycles on the southern Bolivian Altiplano: Implications for causes tropical climate change Christa Placzek; Placzek 1Department Geosciences, University Arizona, Tucson, Arizona 85721, USA Search other works by this author on: GSW Google Scholar Jay Quade; Quade P. Jonathan Patchett Author Article Information Publisher: Geological Society America Received: 01 Dec 2004 Revision 24 2005 Accepted: Oct First...
Over the last eight years, we have developed several paleoenvironmental records from a broad geographic region spanning Altiplano in Bolivia (18°S–22°S) and continuing south along western Andean flank to ca. 26°S. These include: cosmogenic nuclide concentrations surface deposits, dated nitrate paleosoils, lake levels, groundwater levels wetland plant macrofossils urine-encrusted rodent middens. Arid environments are often uniquely sensitive climate perturbations, there is evidence of...
Water is one of the main agent erosion in many environmental settings, but rates derived from beryllium-10 (10Be) suggests that a relationship between precipitation and rate statistically non-significant on global scale. This might be because strong influence other variables rate. In this 10Be compilation, we examine if mean annual has significant secondary control Our variable assessment first time 10Be-derived recognized fact, areas where slope <200m/km (~11°), influences as much basin...
Abstract We have developed an 87 Sr/ 86 Sr, 234 U/ 238 U, and δ 18 O data set from carbonates associated with late Quaternary paleolake cycles on the southern Bolivian Altiplano as a tool for tracking understanding causes of lake-level fluctuations. Distinctive groupings Sr ratios are observed. Ratios highest Ouki lake cycle (120–95 ka) at 0.70932, lowest Coipasa (12.8–11.4 0.70853, intermediate 0.70881 to 0.70884 Salinas (95–80 ka), Inca Huasi (~ 45 Sajsi (24–20.5 Tauca (18.1–14.1 cycles....
Water plays a critical role in erosion and sediment transport this relationship is most evident the hyperarid Atacama Desert of Northern Chile, region characterized by rates that fall to near zero cobbles boulders with cosmogenic nuclide concentrations indicative exposure for many millions years. Cosmogenic from are used both determine age hyperaridity onset place important constraints on geomorphic processes uniquely arid environment. Prior determinations focus primarily ages...
Abstract Lacustrine deposits exposed around Lake Aricota, Peru (17° 22′S), a 7.5-km 2 lake dammed by debris flows, provide middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline was obtained from radiocarbon dating vascular plant remains and other datable material with minimal 14 C reservoir effects (<350 yr). Diatomites associated highstands several meters above the modern level indicate wet episodes. Maximum attained before 6100 yr B.P. ended...
Research Article| September 01, 2012 Seismicity and the strange rubbing boulders of Atacama Desert, northern Chile Jay Quade; Quade 1Department Geosciences, University Arizona, Tucson, Arizona 85721, USA Search for other works by this author on: GSW Google Scholar Peter Reiners; Reiners Christa Placzek; Placzek 2School Earth Environmental Sciences, James Cook University, Townsville, QLD 4811, Australia Ari Matmon; Matmon 3Institute Hebrew Jerusalem 91904, Israel Martin Pepper; Pepper...
We report over 90 U‐Th dates from carbonates deposited around paleolakes on the Bolivian Altiplano. Petrographic and chemical data for tufas siliciclastic detritus contained within them allow (1) assessment of possible diagenetic effects, (2) a development strategy selection carbonate samples with low initial Th contents, (3) uncertainty due to Th. This allows us produce precise lacustrine carbonates. The principal consideration in dating such is composition quantity incorporated into...
Abstract A second K/Pg boundary interval in the northern sector of Antarctic Peninsula on Vega Island has been proposed, yet current temporal resolution these strata prohibits direct testing this hypothesis. To not only test for existence a but also provide increased age associated vertebrate fauna (e.g., marine reptiles, non-avian dinosaurs, and avian dinosaurs), succession was intensively re-sampled. Stratigraphic investigation Cape Lamb Member Snow Hill Formation, particular, overlying...
We report δ13C and δ18O results from carbonate-cemented cave sediments at Malapa in South Africa. The were deposited during a short-period magnetic reversal 1.977±0.003 Ma, immediately preceding deposition of Facies D that contain the type fossils Australopithecus sediba. Values range between -5.65 -2.09 with an average -4.58±0.54‰ (Vienna Pee Dee Belemnite, VPDB) values -6.14 -3.84 -4.93±0.44‰ (VPDB). Despite signs diagenetic alteration metastable aragonite to calcite, isotope are similar...
The Toomba flow is the youngest of Nulla volcanic province, located in north Queensland. This 120 km-long has yielded a published 40Ar/39Ar age 21,000 ± 3000 years. In contrast, seven conventional radiocarbon (14C) analyses carbon-bearing material beneath ages 16,000 to <2500 BP. These are younger than age, potentially due contamination charcoal by carbon that was not removed acid–base pre-treatment. We have re-examined using newly sampled buried combination with hydrogen pyrolysis...