A5057254089- Geology and Paleoclimatology Research
- Paleontology and Stratigraphy of Fossils
- Geochemistry and Elemental Analysis
- Hydrocarbon exploration and reservoir analysis
- Isotope Analysis in Ecology
- Mercury impact and mitigation studies
- Methane Hydrates and Related Phenomena
- Geological and Geochemical Analysis
- Geological formations and processes
- Geological and Geophysical Studies
- Geological Studies and Exploration
- Radioactive element chemistry and processing
- Geochemistry and Geologic Mapping
- Marine and environmental studies
- Maritime and Coastal Archaeology
- Thallium and Germanium Studies
- Ocean Acidification Effects and Responses
- Paleontology and Evolutionary Biology
- Groundwater and Isotope Geochemistry
- Atmospheric and Environmental Gas Dynamics
- Astro and Planetary Science
- Advanced Data Processing Techniques
- Water-Energy-Food Nexus Studies
- Environmental Conservation and Management
- International Maritime Law Issues
College of Charleston
2018-2024
National High Magnetic Field Laboratory
2016-2022
Florida State University
2016-2022
Virginia Tech
2015-2018
Texas A&M University
2012-2015
For this study, we generated thallium (Tl) isotope records from two anoxic basins to track the earliest changes in global bottom water oxygen contents over Toarcian Oceanic Anoxic Event (T-OAE; ∼183 Ma) of Early Jurassic. The T-OAE, like other Mesozoic OAEs, has been interpreted as an expansion marine depletion based on indirect methods such organic-rich facies, carbon excursions, and biological turnover. Our Tl data, however, reveal explicit evidence for earlier deoxygenation ocean water,...
Chemical weathering consumes atmospheric carbon dioxide through the breakdown of silicate minerals and is thought to stabilize Earth's long-term climate. However, potential influence on pCO
Abstract. The element mercury (Hg) is a key pollutant, and much insight has been gained by studying the present-day Hg cycle. However, many important processes within this cycle operate on timescales responsive to centennial- millennial-scale environmental variability, highlighting importance of also investigating longer-term records in sedimentary archives. To end, we here explore timing, magnitude, expression signals retained sediments over past ∼ 90 kyr from two lakes, linked subterranean...
Both instrumental data analyses and coupled ocean-atmosphere models indicate that Atlantic meridional overturning circulation (AMOC) variability is tightly linked to abrupt tropical North (TNA) climate change through both atmospheric oceanic processes. Although a slowdown of AMOC results in an atmospheric-induced surface cooling the entire TNA, subsurface experiences even larger warming because rapid reorganizations ocean patterns at intermediate water depths. Here, we reconstruct...
Abstract The late Ludlow Lau Event was a severe biotic crisis in the Silurian, characterized by resurgent microbial facies and faunal turnover rates otherwise only documented during “big five” mass extinctions. This asynchronous Silurian marine extinction event preceded an associated positive carbon isotope excursion (CIE), CIE, although mechanism for this temporal offset remains poorly constrained. Here, we report thallium data from locally reducing strata within Baltic Basin to document...
The colonization and expansion of plants on land is considered one the most profound ecological revolutions, yet precise timing remains controversial. Because vegetation can enhance weathering intensity affect terrigenous input to ocean, changes in terrestrial plant biomass with distinct negative Δ199Hg Δ200Hg signatures may overwrite positive Hg isotope commonly found marine sediments. By investigating secular isotopic variations Paleozoic sediments from South China peripheral...
Abstract Lagerstätten—deposits of exceptionally preserved fossils—offer vital insights into evolutionary history. To date, only three Konservat-Lagerstätten are known from Early Jurassic marine rocks (Osteno, Posidonia Shale, and Strawberry Bank), all located in Europe. We report a new assemblage fossils Alberta, Canada, the first Konservat-Lagerstätte described North America. The Ya Ha Tinda includes articulated vertebrates (fish, ichthyosaurs), crinoids, crustaceans, brachiopods, abundant...
The timing and connections between global cooling, marine redox conditions, biotic turnover are underconstrained for the Late Ordovician. second most severe mass extinction occurred at end of Ordovician period, resulting in ~85% loss species two pulses. As only "Big 5" that during icehouse this interval is an important modern analog to constrain environmental feedbacks. We present a previously unexplored thallium isotope records from paleobasins record conditions document distinct rapid...
A widespread platinum (Pt) anomaly was recently documented in Greenland ice and 11 North American sedimentary sequences at the onset of Younger Dryas (YD) event (~12,800 cal yr BP), consistent with YD Impact Hypothesis. We report high-resolution analyses a 1-meter section lake core from White Pond, South Carolina, USA. After developing Bayesian age-depth model that brackets late Pleistocene through early Holocene, we analyzed quantified following: (1) Pt palladium (Pd) abundance, (2)...
Sedimentary mercury (Hg) concentrations are traditionally used to track atmospheric Hg deposition, which is thought be controlled by volcanic outgassing and potentially the emplacement of large igneous provinces (LIPs). enrichments subsequently inferred represent ancient intervals massive volcanism often link destabilization Earth’s environment extinction. The biogeochemical cycling controls on sequestration in sediments, however, both dynamic complex, with wide spatiotemporal variability....
Abstract Many metals present in trace concentrations the oceans are sensitive to reduction and oxidation reactions (termed redox‐sensitive or RSTMs) can therefore be affected during intervals of expanded oceanic anoxia euxinia (anoxic sulfidic waters). These RSTMs important micronutrients; their availability plays a significant role controlling metabolic pathways ecosystem structure. Understanding links restructuring potential collapse is since past deoxygenation events associated with...
The importance of dust as a source iron (Fe) for primary production in modern oceans is well studied but remains poorly explored deep time. Vast deposits are recognized from the late Paleozoic and provisionally implicated through Fe fertilization. Here, we document impacts on marine productivity Moscovian (Pennsylvanian, ca. 307 Ma) Asselian (Permian, 295 carbonate strata peri-Gondwanan terranes Iran. Autotrophic contents samples, detected by both point-count lipid-biomarker analyses, track...