Research Interests
My research interests cover a wide range of disciplines including igneous geochemistry, geochemistry of natural waters, hydrogeology, petrology, plate tectonics and petroleum geology. My academic research was rooted in igneous geochemistry involving radiogenic isotopes, major and trace elements for the purpose of modeling mantle melting processes and the evolution of magma. Results were incorporated into a regional geologic framework to better understand magma generation within the context of plate tectonics and overall crustal evolution, particularly the generation of forearc magmas (central Turkey and southern Alaska) associated with ridge subduction. I am presently involved with Professor Kevin Burke in the study of modern tectonics and associated igneous activity. Areas of interest include the African continent, Reunion hot spot and the Banda arc (Indonesia). We are also attempting to better understand ancient orogenic belts, basins and relict igneous provinces such as the Amazon Basin, Rokelide belt of West Africa and the Deccan hot spot tract. We base our analyses on igneous geochemistry, structural geology, stratigraphy, seismic interpretation, earthquake focal mechanisms, and the modeling of gravity data.I was also recently involved with the geochemical analyses and interpretation of natural brines recovered from deep wells along the Texas Gulf Coast. I hope to eventually expand this research into a study of the chemical reactions involving formation waters, associated oil and surrounding rock material. A better understanding of these chemical reactions may provide important clues as to hydrocarbon source regions, fluid migration pathways and also aid in predicting the presence or absence of nearby oil and gas reserves.
Research Background
My first research project (early 1980's) involved the collection, geochemical analysis and interpretation of Precambrian plutonic rocks from the South Snowy Block, Yellowstone National Park, Wyoming and Montana as my Master's Thesis. Age dating was performed using Rb-Sr isotopic analyses from which I became proficient in clean-lab procedures, preparation of reagents, acid digestion of rock powders, cation-exchange chromatography and the operation of a thermal ionization Mass Spectrometer. Major- and trace-element analysis provided me with experience in method development, high-temperature fusion and dissolution of rock powders, dilutions of sample solutions and operation of an Atomic Absorption Spectrophotometer. Results were ultimately published in the Journal of Geology (1984).
I was employed as an Exploration Geologist (Gulf of Mexico) at Getty Oil/Texaco from 1982-1985 and gained valuable skills in hydrocarbon exploration, well-log analysis, seismic interpretation, salt tectonics, growth faults, basin analysis, depositional models, reservoir calculations and seismic stratigraphy. I generated and evaluated prospects, worked closely with geologists from other companies and made frequent formal presentations to management. This experience made me aware of the business side of geology along with the importance of meeting deadlines, producing quality work, collaborating with other investigators, articulating information and viewing problems from different perspectives.
My Ph.D research (1987-1993) involved a geochemical study of Late Cretaceous-Early Tertiary volcanic rocks and sheeted dikes from ophiolites in central Turkey and southern Alaska. I also investigated near-trench siliceous dikes and metabasalts possibly related to the southern Alaskan ophiolites. Acquired skills included sample preparation and analysis using an Inductively Coupled Plasma Emission Spectrophotometer (ICP). I also wrote several computer programs for the geochemical data in order to model processes such as mantle melting, fractional crystallization and crustal assimilation. My overall research provided evidence that these various rock units were emplaced during subduction of active ridge systems. My data and conclusions were published in the journals Tectonophysics (1993), Geological Society of America Bulletin (1995) and Journal of Geophysical Research (1997 & 2000).
After receiving my Ph.D. in the summer of 1993, I began working for Professor Kevin Burke as a Postdoctoral Fellow. Our research on the Amazon Basin involved evaluating published isotopic ages from northeastern South America and northwest Africa, reconstructing the tectonic evolution of the West African Craton, and modeling of Amazon Basin evolution based on stratigraphy, gravity, structural and geochemical data. We concluded that the Amazon Basin formed as an impactogen during collision between South America and the West African Craton at ~500 Ma and our results were published in International Geology Review (1993).
Recent Research and Goals
My research goals broadly encompass two important fields of study: (1) regional tectonics/geochemistry, and (2) geochemistry of natural brines from hydrocarbon-bearing formations. I have recently collaborated with Professor Kevin Burke on several projects. Our study of the tectonic evolution of Sumba Island, Indonesia, addressed the current debate among various investigators regarding its origin. Our approach involved geochemical and petrographical analyses of volcanic and plutonic rocks collected from the island along with interpretation of the data within the context of regional seismic, structural, geochemical and stratigraphic information. We concluded that Sumba is a fragment of a volcanic arc located off southeastern Eurasia during the Late Cretaceous. The Sumba fragment was afterwards tectonically transported along an active arc system to its present position northwest of Australia. Our results are published in two papers that appeared in a recent issue of the Journal of Asian Earth Sciences.
We are presently working on a paper dealing with the origin of the Rokelide Orogenic Belt, northwest Africa, that is an extension of our previous work on the Amazon Basin. I performed geochemical analysis on volcanic and arc-related sedimentary rocks from the area and the data is interpreted within the context of other geological and geophysical information. Our conclusions relate Rokelide orogenesis to collision between the West African Craton and a volcanic-arc system at ~600 Ma, followed by collision of Africa with South America. These results are presently being compiled into a paper for possible publication.
Professor Burke and I, along with several other investigators, have recently submitted a proposal to investigate whether the African Plate has remained stationary with respect to the underlying mantle circulation over the past ~30 m.y. We presented a related study at the Fall '95 AGU meeting that challenged the popular belief that Reunion Island was an extension of the Deccan Trap's hot spot track. The proposal called for a three year study of the African Plate involving mantle tomography, geochemistry, 40Ar/39Ar dating, structural geology, seismic interpretation, modeling of gravity data, plate motion studies and satellite images. We hope to compile the results into a GIS format for access through the World Wide Web. Although our initial proposal as not funded, we may submit future proposals for this project to NSF and possibly major oil companies.
I also recently collaborated with Dr. Regina Capuano in the collection, geochemical analyses and interpretation of natural brines from hydrocarbon-bearing formations along the Texas Gulf Coast. We analyzed the water samples for hydrogen sulfide, cations, anions, alkalinity, pH, conductivity, total dissolved solids, stable isotopes and organic constituents using a combination of instruments and chemical techniques. We compared our water data with regional well information, hydrologic studies and other geochemical data. I coordinated and helped supervise the project that resulted in Masters Theses for several graduate students. I am interested in possibly analyzing the chemistry of brines and associated oil sometime in the future. I hope to model possible chemical partitioning and reactions involving formation waters, associated oil and surrounding rock material. I am particularly interested in learning about the different types of chemical signatures and reactions that characterize oil-bearing brines within geo-pressured formations. Hopefully the data can be used to further characterize hydrocarbon source regions, identify fluid migration pathways and possibly predict the location of hydrocarbon reserves.