The formation of dolomite at low temperature (< 80 °C) is uncommon in modern environments, however dolomite is abundant in the geologic record. The paradox between the scarcity of modern dolomite and abundance in ancient dolomite has been of long-term interest to geologists. …
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As the most robust accessory mineral, both physically and chemically, zircon can preserve valuable geochemical information of the melt that it crystallized from, which makes it an extremely powerful tool to investigate the nature of the first 500 Ma of Earth’s history. Zircon is…
Magma systems within the shallow crust drive volcanic processes at the surface. Studying active magma systems directly poses significant difficulty but details of ancient magma systems can provide insight to modern systems. The ancient intrusions now exposed in the Henry Mountai…
Interrogation of the chemical composition of rocky planets provides a deeper understanding of the history and evolution of the solar system. While laboratory studies of returned samples and remote sensing surveys of planetary surfaces can give insight into planetary history, one…
Groundwater has an important role in forging the composition of surface water, supplying nutrients crucial for the development of balanced ecosystems and potentially introducing contaminants into otherwise pristine surface water. Due to water-rock interactions, radium (Ra) in gr…
The goal of this project is to investigate potential environmental responses to the extensive volcanism associated with the Afro-Arabian Large Igneous Province, by analyzing major and trace element contents in the carbonate phase of Oligocene sediments from Ocean Drilling Progra…
The geochemistry of naturally occurring arsenic (As) has been investigated in the surface waters and ground waters of the shallow alluvial aquifers of the Humboldt River Basin (HRB) in northern Nevada using laboratory experiments, geochemical reaction path modeling, and statisti…
Speleothems are carbonate cave deposits that can preserve a geochemical record of local climate as they grow. Oxygen isotope ratios and trace element concentrations in speleothem calcite provide important continental proxies of past climate change. Conventionally, geochemical an…
This study presents the depositional facies, sequence stratigraphy, chemostratigraphy and diagenetic evolution of the Middle-Late Triassic Al Aziziyah Formation, Jifarah Basin northwest Libya. Eight measured sections were sampled and analyzed. High-resolution stable carbon isoto…
Prior studies of groundwater systems have associated increasing salinity and anoxic conditions with increasing radium (Ra) activities in water due to the decreasing effectiveness of Ra removal processes. However, the components of salinity (e.g. Ca vs. Na and SO42- vs. Cl-domina…
The issue of granite petrogenesis plays a key role in our overall understanding of the growth and differentiation of continents, as well as in our ability to unravel the tectonic histories of orogenic belts. Granites are ubiquitous magmatic products found in almost all tectonic …
A field survey was undertaken in Central Kalimantan, Indonesia (Borneo) to assess the extent and practices of Artisanal and Small-scale Gold Mining (ASGM), and to measure sediment and mercury flows in the provinces' rivers. More than forty mining operations were visited in six o…
The collision of India with Asia is an important geologic event preceded by the formation of now obducted ophiolites of Western Pakistan. Ophiolites along the suture zone between India and Asia can help elucidate the pre-terminal and terminal collisional history of the Himalaya …
Dynamics of δ34S and Δ 33S of oceanic sulfate and sedimentary pyrite over geologic time has been used to understand and extract information about the marine sulfur cycle. My Ph.D project uses this approach to study the evolution of the marine sulfur cycle and focuses on: •Provid…
Earth climate varies on long and short time scales and its patterns have been derived by a variety of geochemical proxies. The most commonly used paleoclimate proxy is the oxygen isotopic composition in carbonates (δ 18 O). δ18 O, however, is not a direct paleo-thermometer, and …
In many coastal communities, aquaculture is an important part of the local economy, though fish and shrimp farms may threaten habitats in these coastal systems. Aquaculture was introduced to the Setiu estuarine-lagoonal system (SEL) in Terengganu, Malaysia in the mid-1970s. As f…
Following extensive Late Triassic coral-constructed reefs and the aftermath of the end-Triassic mass extinction, Early Jurassic buildups are rare and constructed primarily by bivalves. The Pliensbachian exhibits a radiation of aberrant pterioid bivalves, the “Lithiotis” facies b…
The Halmahera arc is a north-south linear intraoceanic arc cutting across the islands of Halmahera and Bacan in NE Indonesia. The arc is the result of the eastward subduction of the Molucca Sea Plate, accommodating the westward movement of the Pacific and Philippine Sea Plates (…
Ocean models have been used to explain the reduction in atmospheric carbon dioxide concentration during the last glacial maximum; however, some models result in an intensification of bottom water reducing conditions. Redox-sensitive metals in sediments are potential constraints …