Research Interests - Paul A. Schroeder

Biomineralization in hot spring environments

Interdisciplinary collaboration with microbiologists have led to my studies in Geomicrobiological Interactions in thermal hot springs. Studies include the effects of clay minerals on sinter formation in Yellowstone National Park.   Studies have also been conducted on biomineralizaton  in Kamchatka, Russia along with an international team of scientists. This work has been supported by the National Science Foundation’s programs: Biocomplexity and the Environment: Coupled Biogeochemical Cycles and  Microbial Observatories. In this unique collaborative and interdisciplinary effort along with many other scientists we address questions related to understanding the role of micro-organisms in hot springs.  The broader impact of this work is related to discovering novel enzymes for manufacturing processes and gaining a better understanding of how life worked during early earth history. This work is documented by San Francisco's Exploritorium Museum of Science, Art, and Human Perception.

Geologic record of climate change

This work started with a National Science Foundation supported study of A modern test of the assumptions used for determining paleo-atmospheric carbon dioxide from goethite-bound carbon. The concept of using goethite-bound carbon isotopes as a proxy for estimating paleo-atmospheric PCO2 throughout the Phanerozoic has been a kingpin for paleoclimatic modeling efforts such as Bob Berner's GEOCARB model. In this study we tested the underlying assumptions used by Crayton Yapp, developer of the goethite inferred paleo-atmospheric PCO2 barometer. The work is being performed on soil/saprolites found overlying granite terrains in the Piedmont of Georgia, including Panola Mt. Georgia. We have found that carbon is bound in gibbsite. Sanples collected from a residual weathering profile developed on a Paleozoic granite in the Georgia Piedmont, were examined for 14C content and found to be geologically young. Combining the results of 14C, 26Al, and 10Be analyses offers the potential to assess differential rates of chemical weathering and continental denudation in order to understand better the links between rates of silicate rock weathering, climate, and soil residence times.

Kaolin Research

These investigations involve the study of impurities associated with kaolin deposits. The quality and nature of kaolin ore are important factors in the manufacturing of high-end paper coating products. One of the problems with processing the mined kaolin is the difficulty in stripping the kaolin of all the impurities without drastically reducing or losing the usable product.

I have developed a novel spectroscopic method for quantifying trace contaminants in clay ores.  My published works on kaolin crystal-chemistry in the clay deposits have given new insights to their geologic origins and industrial utilization. In association with his work in the Georgia kaolin district, I have also co-discovered the first in-place evidence for a 35 million year old major meteorite impact deposit in the southeastern United States. 

Other research projects include studies of Discriminating short- and long-range iron ordering in kaolinite using vibrational spectroscopy. It is a two year project funded by English China Clay International Inc (now IMYERYS). Research projects have also included (a) Studies of impurity phases associated with East Georgia Kaolin Deposits, a two year project supported by the J.M. Huber Corporation and (b) Investigation of ordering schemes for Fe substitution in kaolinite using 27Al and 29Si MAS NMR spectroscopy supported by English China Clay International Inc.

Tectonic evolution of North Anatolian Fault zone and Neo-Tethys suture belts from Aegean Sea to Western Anatolia and the recent discovery of kaolin deposits within these tectonic belts have become a new focus of earth scientists from both the standpoints of the assessing its importance in the global clay industry and assessing the magnitude of silicate alteration effects on global climate change. The purpose of this research is to determine (1) the alteration mechanism of volcanic rocks to kaolin group minerals, and estimate its role in the mass-balance of global element cycles, (2) the distribution of parent, secondary and tertiary minerals in order to estimate the extent of hydrothermal alteration zones, and (3) to verify alteration stages and physico-chemical conditions of volcanic tuffs by geochemical analysis of the waters. The occurrence of phyllosilicates and their degree of alternation in both active and inactive geothermal systems will be studied, thus making available the unique opportunity to study the modes of mineral conversions and temperature controlled reaction kinetics.

Kaolinite occurrences are located in NW and SW of the town of Gönen, Turkey. Halloysite mineralization occurs in the S and SE of the town of Yenice. Both modes of mineralization have formed along the main NNE-SSW trending Gönen-Yenice fracture system by hydrothermal alteration of mainly andesitic to dacitic volcanics and welded tuffs of Early to Larly Miocene age. Some occurrences in the Gönen area are associated with small fractures and cracks, and forming "silica gossan" overlying the kaolin bodies and are characteristic features of hydrothermal deposits. The four halloysite deposits ( all of them are in the Biga Peninsula in the south of Yenice) have indications that they formed in a similar geological environments. For this reason, this area is selected as a proposed research area due to its unique occurrences and hydrothermal alterations associated with branches of major active North Anatolian Fault system.

Shale Research

Studies of nitrogen fixation in illitic clays during diagenesis. This work was supported by a two year Petroleum Research Fund project. The role and nature of ammonium in clay structures bears information about mechanisms of clay mineral transformations that accompany oil generation, migration and trapping. This work intends to develop a clay/nitrogen index that will aid in the evaluation of hydrocarbon potential of rocks within sedimentary basins.

X-ray Diffraction and Vibrational Spectroscopy

X-ray diffraction and FTIR facilities for mineralogical research (supported by NSF EAR-9911501). This grant from the National Science Foundation Earth Sciences Instrument and Facilities Program provides partial support for the costs of upgrading the X-ray diffraction (XRD) and Fourier transform infrared spectrometer (FTIR) facilities for mineralogical research in the Geology Department at the University of Georgia (UGA).

These facilities allow analytical support to a robust geological research and teaching program. Approximately 40 students per year receive practical training and/or theoretical familiarization with these analytical methods. XRD and FTIR labs are generally considered cost-effective analytical facilities and are commonly used by geological industries. For this reason, students who receive training are placed at a competitive advantage in the job market.