Scholarly Works, Department of Geosciences
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Research articles, presentations, and other scholarship
Recent Submissions
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Triassic stem caecilian supports dissorophoid origin of living amphibians
(Nature Research, 2023-01-25)Living amphibians (Lissamphibia) include frogs and salamanders (Batrachia) and the limbless worm-like caecilians (Gymnophiona). The estimated Palaeozoic era gymnophionan–batrachian molecular divergence suggests a major gap ... -
Pulse of atmospheric oxygen during the late Cambrian
(National Academy of Sciences, 2011)A rise in atmospheric O2 has been linked to the Cambrian explosion of life. For the plankton and animal radiation that began some 40 million yr later and continued through much of the Ordovician (Great Ordovician ... -
The worm turned, and the ocean followed
(National Academy of Sciences, 2009-05-19) -
Sulfur isotopes track the global extent and dynamics of euxinia during Cretaceous Oceanic Anoxic Event 2
(National Academy of Sciences, 2013)The Mesozoic Era is characterized by numerous oceanic anoxic events (OAEs) that are diagnostically expressed by widespread marine organic-carbon burial and coeval carbon-isotope excursions. Here we present coupled ... -
Devonian rise in atmospheric oxygen correlated to the radiations of terrestrial plants and large predatory fish
(National Academy of Sciences, 2010)The evolution of Earth's biota is intimately linked to the oxygenation of the oceans and atmosphere. We use the isotopic composition and concentration of molybdenum (Mo) in sedimentary rocks to explore this relationship. ... -
Proterozoic ocean redox and biogeochemical stasis
(National Academy of Sciences, 2013)The partial pressure of oxygen in Earth's atmosphere has increased dramatically through time, and this increase is thought to have occurred in two rapid steps at both ends of the Proterozoic Eon (~2.5-0.543 Ga). However, ... -
Thallium isotopes reveal protracted anoxia during the Toarcian (Early Jurassic) associated with volcanism, carbon burial, and mass extinction
(National Academy of Sciences, 2018-06-26)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 the Toarcian Oceanic Anoxic Event (T-OAE; ∼183 Ma) of the Early ... -
Stratigraphic evidence of two historical tsunamis on the semi-arid coast of north-central Chile
(Pergamon-Elsevier, 2021-07-21)On September 16, 2015, a Mw 8.3 earthquake struck the north-central Chile coast, triggering a tsunami observed along 500 km of coastline, between Huasco (28.5°S) and San Antonio (33.5°S). This tsunami provided a unique ... -
Effects of acetate, propionate, and pH on volatile fatty acid thermodynamics in continuous cultures of ruminal contents
(American Dairy Science Association, 2022-11-01)To investigate the effects of acetate, propionate, and pH on thermodynamics of volatile fatty acids (VFA) in the rumen, a dual-flow continuous culture study was conducted to quantify production of major VFA, interconversions ... -
The Sedimentary Geochemistry and Paleoenvironments Project
(Wiley, 2021-07-05) -
Seismic detection of a deep mantle discontinuity within Mars by InSight
(Proceedings of the National Academy of Sciences, 2022-10-18)Constraining the thermal and compositional state of the mantle is crucial for deciphering the formation and evolution of Mars. Mineral physics predicts that Mars’ deep mantle is demarcated by a seismic discontinuity arising ... -
Reduced Marine Molybdenum Inventory Related to Enhanced Organic Carbon Burial and an Expansion of Reducing Environments in the Toarcian (Early Jurassic) Oceans
(American Geophysical Union, 2022-12)Many metals present in trace concentrations in the oceans are sensitive to reduction and oxidation reactions (termed redox-sensitive trace metals or RSTMs) and can therefore be affected during intervals of expanded oceanic ... -
Environmental drivers of the first major animal extinction across the Ediacaran White Sea-Nama transition
(National Academy of Sciences, 2022-11)The Ediacara Biota—the oldest communities of complex, macroscopic fossils—consists of three temporally distinct assemblages: the Avalon (ca. 575–560 Ma), White Sea (ca. 560–550 Ma), and Nama (ca. 550–539 Ma). Generic ... -
Subsurface permeability contrasts control shallow groundwater flow dynamics in the critical zone of a glaciated, headwater catchment
(Wiley, 2022-09-01)Groundwater flow direction within the critical zone of headwater catchments is often assumed to mimic land surface topographic gradients. However, groundwater hydraulic gradients are also influenced by subsurface permeability ... -
Using Macro- and Microscale Preservation in Vertebrate Fossils as Predictors for Molecular Preservation in Fluvial Environments
(MDPI, 2022-09)Exceptionally preserved fossils retain soft tissues and often the biomolecules that were present in an animal during its life. The majority of terrestrial vertebrate fossils are not traditionally considered exceptionally ... -
Formation of miarolitic-class, segregation-type pegmatites in the Taishanmiao batholith, China: The role of pressure fluctuations and volatile exsolution during pegmatite formation in a closed, isochoric system
(Mineralogical Society of America, 2021-10)The Taishanmiao granitic batholith, located in the Eastern Qinling Orogen in Henan Province, China, contains numer-ous small (mostly tens of centimeters in maximum dimension) bodies exhibiting textures and mineralogy ... -
Shallow Faulting and Folding in the Epicentral Area of the 1886 Charleston, South Carolina, Earthquake
(Seismological Society of America, 2022-08)The moment magnitude (M-w) similar to 7 earthquake that struck Charleston, South Carolina, on 31 August 1886 is the largest historical earthquake in the United States east of the Appalachian Mountains. The fault(s) that ... -
Femoral specializations to locomotor habits in early archosauriforms
(Wiley, 2022-05)The evolutionary history of archosaurs and their closest relatives is characterized by a wide diversity of locomotor modes, which has even been suggested as a pivotal aspect underlying the evolutionary success of dinosaurs ... -
Putative fossil blood cells reinterpreted as diagenetic structures
(PeerJ, 2021-12-16)Red to red-orange spheres in the vascular canals of fossil bone thin sections have been repeatedly reported using light microscopy. Some of these have been interpreted as the fossilized remains of blood cells or, alternatively, ... -
Terrestrial records of the early Albian Ocean Anoxic Event: Evidence from the Fuxin lacustrine basin, NE China
(China University Geosciences, 2022-01)The early Albian Oceanic Anoxic Event 1b (OAE 1b) is well documented in the Tethys, Pacific and North Atlantic, but few studies have evaluated whether or not terrestrial records of OAE 1b exist. In order to identify ...