Research

Evolution of Oxygen

Gerald working in the lab

I am currently conducting research on the evolution of oxygen as a major constituent in the Earth's atmosphere. Other studies have focused around evaluating Fe and S isotopes as well as Fe(II)/Fe(III) ratios and Mo concentration in sedimentary rocks and old soil horizons (paleosols) throughout the Archean and Proterozoic Eons in the attempt to quantify an observed shift in the oxidation state of the atmosphere. These studies have suggested a significant increase in the oxygen content of the atmosphere during the Paleoproterozoic Era (2500 Ma - 1600 Ma). In this effort, I am examining the geochemistry of Paleoproterozoic sedimentary rocks deposited in marine environments. My research furthers our understanding of the oxidation state of the atmosphere during the Paleoproterozoic Era through the evaluation of the U-Th-Pb system through Pb-isotopes. As differences in Pb-isotope signatures maybe source related, lanthanide element (REE) concentrations and anomalies are assess sedimentary provenance. REE anomalies may also serve to provide constraints of the evolution of oxygen during the Great Oxidation Event.

Geoinformatics

Geoscientists study natural and simulated geological processes at different scales, from microscopic to global. The data, collected through these studies, originate from a diverse and growing set of instruments that measure, for example, geochemistry of surface water, groundwater, and soil, potential slip along a seismic fault, or isotopic composition of rocks. Rapid access to the data from these instruments is both desired and necessary for deriving information, and assessing the Earth’s natural resources and hazards.

With the proliferation of the data collection equipment, the volume of these complex data, which are produced by scientists with a broad range of perspectives, is reaching a critical limit which makes access to the data more difficult. We are at a stage where integration and interoperability issues, related to these diverse, cross-scale, and cross-discipline data, commonly lead to significant problems that hamper effective scientific research and rapid access to important natural hazard/resources data. This is where geoinformatics can help

The transition from data to information is achieved through computation, visualization, and other digital processes that make the data more meaningful to the scientists. Other issues, in addition to the ones related to management and integration of data, include those involved in information transfer and processing, and production and consumption of information and knowledge. These topics fall under the realm of the informatics science. Conducting efficient, cross-disciplinary, scholarly communication among the scientists, who are working from different perspectives on the same phenomenon, increasingly depends on the existence of standards - provided by informatics science - for the storage, management, integration, and representation of data, information, and knowledge.

Geoinformatics, as a specialized branch of the informatics science, deals with the creation and processing of information about the geosphere component of the Earth system. This newly established and emerging discipline provides mechanisms for the conceptualization, design, modeling, and implementation methodologies for the management, processing, and representation of the geological information and knowledge. More specifically, geoinformatics applies informatics science to study the structure, composition, function, production, environment, and interactions of different components of information systems that involve storage, processing, management, and conveying information and knowledge in geoscience. The fact that major professional societies such as the Geological Society of America (GSA) and American Geophysical Union (AGU) have recently introduced a new division and section in geoinformatics, respectively, strongly indicates the improved perception of the geoscience community of the value of geoinformatics in their research and education.

A wide range of laboratory and field instruments, continuously acquire a variety of complex data about natural processes and features of the Earth system. Traditionally, Earth scientists deal with these data on an individual basis, without any data or procedural standard. The collected data remain in Excel sheets, or rarely in personal databases, with ad hoc data formats and schemas. The unstructured formats/schemas create real problems for rapid access, integration, and interoperability of the data, and, later, for visualization and representation of the information that can be extracted from these data. These problems are compounded by the exponential growth in the availability of data-collecting and data-generating equipment, which make efficient handling of the voluminous data impractical. These emerging problems have indeed been identified by funding agencies, such as the National Science Foundation. The NSF, through a series of continuing workshops, which started in March of 2007, has recently proposed to develop the “National Geoinformatics System of the United States”. This new initiative by the NSF indicates that the funding agency values geoinformatics as one of the promising areas in NSF’s so-called “cyberinfrastructure” initiative (www.adec.edu/nsf/nsfcyberinfrastructure.html).

Geomorphology and Surface Hydrology

Dr. Jordan Clayton conducts an active research program in fluvial geomorphology and sediment transport. His work focuses on the dynamic balance between the morphology of river channels, their surface sediments, the basin's flow regime and sediment flux, and changes over time. His field studies have included the Colorado River and Fall River basins in Rocky Mountain National Park, the Whitewater River basin in Kansas, the Wisconsin River in Wisconsin (see Quaternary Paleoenvironments), and numerous other watersheds in California, Colorado, Mississippi, New Mexico and Virginia. Current graduate students are working on problems related to Atlanta's urban hydrology and the development of fluvial features on Saturn's moon of Titan.

Dr. Daniel Deocampo conducts research on the geochemical and geomorphic evolution of landscapes in evaporitic and volcaniclastic terrains. He has studied landforms, weathering processes, and controls on water quality in several lake basins of East Africa, and is currently studying paleosols developed on volcanic ash near Rome, Italy (see Archaeological Geology).

Hydrogeology

For the past two decades, hydrology and hydrogeology research at Georgia State University has focused upon the evolution of natural water systems within Georgia and the southeastern Piedmont. Dr. Seth Rose and his students have completed numerous studies involving the utilization of isotope hydrology, particularly environmental tritium, to better estimate the residence-time of shallow ground water in Piedmont Provinces. Shallow flow systems are the source of stream base flow which is an important water resource throughout the region. The hydrology and hydrogeology program at GSU has taken a leading role in studying the effects of urbanization upon the hydrology and geochemistry of stream flow within the Atlanta metropolitan region. Recent studies have focused upon better understanding major ion variation through the Upper Chattahoochee basin. We also have a strong interest in studying the chemical interactions of aqueous contaminants (particularly metals) on sediments. Currently we are involved in studying temporal variation patterns in rainfall and runoff to discern possible effects of climate change on water resources in the southeastern United States.

Quarternary Paleoenvironments

Dr. Jordan Clayton, Dr. Daniel Deocampo, and Dr. Lawrence Kiage conduct active research programs studying various aspects of continental sediments. The overall purpose of this research is to understand the sedimentary record of environmental change on the continents.

Dr. Clayton studies both Pleistocene and modern river environments (see Geomorphology and Surface Hydrology). His field studies have included the reconstruction of catastrophic flooding associated with the drainage of Glacial Lake Wisconsin in the late Pleistocene.

Dr. Deocampo uses geochemical and mineralogical methods to study the sedimentary records of paleolakes, wetlands, and volcaniclastic sediment to reconstruct paleohydrology and paleoclimate. Much of this work relates to paleoenvironments associated with ancient humans and hominids (see Archaeological Geology). He has studied modern and ancient lake basins in East Africa, the Great Basin of the western U.S.A., and volcanic paleosols in central Italy.

Dr. Kiage uses remote sensing, geographic information systems (GIS), and palynology (fossil pollen) to understand Quaternary and Recent biogeography and environmental change. He has studied environments and paleoenvironments in East Africa and coastal Louisiana, and he is actively involved in the new field of Paleotempestology, involving the reconstruction of ancient tropical cyclone (hurricane) activity by means of geological proxies.

Other areas of research:

* Environmental Geosciences
* Geochemistry
* Geosciences Education
* Interdisciplinary Research
* Climatology & Biogeography
* Geographic Information Systems (GIS)
* Mineralogy/Petrology
* Paleontology
* Remote Sensing
* Sedimentology & Stratigraphy
* Structural Geology & Computational Systems Earth Science
* Urban & Economic Geography