A5021054032- Geology and Paleoclimatology Research
- Archaeology and ancient environmental studies
- Isotope Analysis in Ecology
- Tree-ring climate responses
- Fire effects on ecosystems
- Heavy metals in environment
- Geological formations and processes
- Mercury impact and mitigation studies
- Geochemistry and Geologic Mapping
- Historical and Cultural Archaeology Studies
- Plant Water Relations and Carbon Dynamics
- Mining and Gasification Technologies
- Geological Studies and Exploration
- Groundwater and Isotope Geochemistry
- Marine and environmental studies
- Cryospheric studies and observations
- American Environmental and Regional History
- Radioactivity and Radon Measurements
- Lichen and fungal ecology
- Coastal wetland ecosystem dynamics
- Aeolian processes and effects
- Heavy Metal Exposure and Toxicity
- Environmental Changes in China
- Aquatic Invertebrate Ecology and Behavior
- Toxic Organic Pollutants Impact
University of Hawaiʻi at Mānoa
2025
Kansas State University
2018-2022
University of Pittsburgh
2012-2018
Planetary Science Institute
2013-2015
The mining and use of copper by prehistoric people on Michigan's Keweenaw Peninsula is one the oldest examples metalworking. We analyzed concentration lead, titanium, magnesium, iron, organic matter in sediment cores recovered from three lakes located near mine pits to investigate timing, location, magnitude ancient pollution. Lead concentrations were normalized lithogenic metals account for processes that can influence natural (or background) lead delivery. Nearly simultaneous enrichments...
Abstract Aim To assess the long‐term impacts of landscape fire on a mosaic pyrophobic and pyrogenic woody montane vegetation. Location South‐west T asmania, A ustralia. Methods We undertook high‐resolution multiproxy palaeoecological analysis sediments deposited in L ake O sborne ( H artz M ountains N ational P ark, southern asmania), employing analyses pollen, macroscopic microscopic charcoal, organic inorganic geochemistry magnetic susceptibility. Results Sequential fires within study...
Isle Royale, in Lake Superior, contains evidence of indigenous copper mining; however, the timing and geographical extent mining activity is poorly known. We analyzed metal, carbon, nitrogen, organic matter concentrations to document past pollution sediment cores recovered from McCargoe Cove; a long, narrow inlet Superior on Royale that receives drainage watershed numerous ancient mines. At Cove, lead, copper, potassium increase sediments after ad 1860 between 6500 5400 years before 1950 (yr...
<p>Quartz purity and cosmogenic nuclide analysis of Sioux Quartzite.</p>
<p>Quartz purity and cosmogenic nuclide analysis of Sioux Quartzite.</p>
The remnants of multiple ice sheet expansions beyond the southern limits Wisconsinan glaciation (ca. 75−12 ka, Marine Isotope Stage [MIS]-4 and MIS-2) Illinoian 191−125 MIS-6) are present in north-central USA. Sioux Quartzite-rich glacial erratics northeast Kansas, USA, have marked southernmost extent Laurentide Ice Sheet during Quaternary (38°−39°N). However, timing pre-Illinoian advances remains uncertain. To date deglaciation, we measured cosmogenic 10Be five quartzite boulders on...
Reconstructing centennial timescale hydroclimate variability during the late Holocene is critically important for understanding large-scale patterns of drought and their relationship with climate dynamics. We present sediment oxygen isotope records spanning last two millennia from 10 lakes, as well model simulations, indicating that Little Ice Age was dry relative to Medieval Climate Anomaly in much Pacific Northwest North America. This pattern consistent observed associations between El...
Sedimentological and geochemical results from Nir’pa Co, an alpine lake on the southeastern Tibetan Plateau, detail late-Holocene Indian summer monsoon (ISM) hydroclimate during last 3300 years. Constrained by modern calibration, elevated silt lithics low sand clay between 3.3 2.4 ka 1.3 present indicate two pluvial phases with levels near their current overflow elevation. Between ka, a sharp increase in corresponding decrease suggest drier conditions lower at Co. Hydroclimate expressions...
Abstract Drought has long been suspected as playing an important role in the abandonment of pre-Columbian Native American settlements across midcontinental United States between 1350 and 1450 CE. However, high-resolution paleoclimatic reconstructions reflecting local effective moisture (the ratio precipitation to evaporation) that are located proximity Mississippi period (1050–1450 CE) population centers lacking. Here, we present a 1600-year-long decadally resolved oxygen isotope (δ 18 O)...
The rise in mercury concentrations lake sediment deposited over the last ∼150 years is widely recognized to have resulted from human activity. However, few studies Great Lakes region used reconstruct atmospheric deposition on millennial time scales. Here we present a 9000-year record Copper Falls; small closed-basin Keweenaw Peninsula. Prior abrupt increases 19th and 20th centuries, remains at relatively low for 9000 years. Higher fluxes early Holocene (3.4 ± 1.1 μg m–2 yr–1) are attributed...
Abstract Cahokia is the largest documented urban settlement in pre-Columbian United States. Archaeological evidence suggests that city, located near what now East St. Louis, Illinois, began to rapidly expand starting around AD 1050. At its height, extended across 1000 ha and included large plazas, timber palisade walls, hundreds of monumental earthen mounds. Following several centuries occupation, city experienced a period gradual abandonment from about 1200 1400. Here, we present...
ABSTRACT The Old Copper Complex (OCC) refers to the production of heavy copper-tool technology by Archaic Native American societies in Lake Superior region. To better define timing OCC, we evaluated 53 (eight new and 45 published) radiocarbon ( 14 C) dates associated with copper artifacts mines. We compared these six lake sediment-based chronologies mining annealing Michigan District. C grouped archaeological context show that cremation remains, wood cordage embedded have ages overlap high...
Early industrial trace metal loadings are poorly characterized but potentially substantial sources of metals to the landscape. The magnitude legacy contamination in southwestern Pennsylvania, cradle North American fossil fuel industrialization, is reconstructed from concentrations a sediment core with proxies including major and chemistry, bulk density, magnetic susceptibility. Trace chemistry this record reflects 19th 20th century land use industry. In particular, early arsenic lake...
Visible derivative spectroscopy (VDS) analysis of sediment from Cleland Lake, Southeastern British Columbia provides a reconstruction paleolimnological productivity and hydrologic change during the past 14,000 calibrated 14 C years before present (cal yr BP). The first five principal components (PC) VDS data explain 97% variance in set. Four PCs correlate with standard reflectance spectra for diatom, dinoflagellate algae, cyanophyte pigments that record ecological change, while two are...
Abstract. The essential elements for the structure and function of forest ecosystems are found in relatively predictable proportions living tissues soils; however, both degree spatial variability elemental concentrations their relationship with wildfire history unclear. Quantifying association between nutrient plant tissue surface soils within fire-affected forests can help determine how these contribute to biogeochemical resilience. Here, we present concentration data (C, N, P, K, Ca, Mg,...