Research

Dr. Winton Cornell  is a Co-PI on an NSF proposal titled: “Atokan Sedimentary Record of the Rheic Ocean Closure Along the Southern Laurentian Margin".  He will be working on the X-ray (XRD) mineralogy and the whole-rock trace element geochemistry which will lead to an understanding of the lithogeochemistry. These results will complement the field sedimentology (lithology), the conodont stratigraphy, and the organic geochemistry, as we attempt to characterize mudstones in three reference sections to enable regional correlations in the Atokan of southern Oklahoma.

In Spring 2009, undergraduate student Ashley Johnson will work on: Pre-eruption compositional variation within the Campanian Ignimbrite: Glasses from distal ash layers and melt inclusions in phenocryst minerals. Ashley's work is in conjunction with a project Dr. Cornell has been working on with Lucia Pappalardo, Istituto Nazionale di Geofisica e Vulcanologia Osservatorio Vesuviano - sezione di Napoli, Napoli 80124 Italy (the Mt. Vesuvius Observatory).

Dr. James Derby's  principal area of current research is continuing studies on Silurian carbonate petroleum reservoirs of the Hunton Group in Central Oklahoma, and is serving as the principal Co-Editor of a multi-authored Memoir for the American Association of Petroleum Geologists (AAPG). Dr. Derby will also be principal advisor and committee chair of two Master’s theses on carbonate reservoirs in central & eastern Oklahoma to be initiated in Spring of 2009. Much current research and one Master’s study will be a continuation and outgrowth of research performed as the principal geologist in a study with Dr. Mohan Kelkar (Petroleum Engineering, Univ. of Tulsa) and others.

The AAPG Memoir is a volume initiated by, and is continued in honor of, the late Dr. James Lee Wilson, who mentored many of the carbonate geologists working today. The volume is titled “The Cambro- Ordovician Sauk Sequence of Laurentia – The Geology and Petroleum Potential of the Great American Carbonate Bank”. At present over 50 authors are contributing to the volume. The Co-editors are James Derby, Richard Fritz, William Morgan, and Charles Sternbach.

Dr. Derby continues to consult for petroleum exploration companies in various exploration ventures across the nation, mainly in advising and directing the work of younger geologists, or in detailed carbonate core description and reservoir analysis. With his background in Paleontology & Biostratigraphy he occasionally consults in this area to solve problems in correlation or formation identification.

While not formal research, Dr. Derby actively serves on the Board of Governors of the Oklahomans for Excellence in Science Education (OESE), advises other Board members on issues relating to geology, and regularly gives public lectures in areas of geologic science and its history.

Dr. Dennis Kerr  has research interests that include application of physical sedimentology and facies architecture to address questions regarding basin evolution and reservoir characterization. He has collaborated with faculty and students from other disciplines including geophysics, petroleum engineering and mathematics. Topics of current interest include: relationship between facies architectural elements and permeability anisotropy for eolian and meandering fluvial systems; Pennsylvanian sequence stratigraphy of northeastern Oklahoma platform and Arkoma basin and controls on distribution of oil, gas and coal resources; and tectonic evolution of the Ouachita trough (i.e., closure of Rheic Ocean) as expressed in the physical sedimentology, provenance and chemostratigraphy of the Atoka Formation.

Dr. Peter Michael  is studying submarine volcanism and hydrothermal venting along Eastern Lau Spreading Center (ELSC) and the Tofua arc, located in the Kingdom of Tonga, north of New Zealand. He is collaborating with scientists from Harvard University, Lamont-Doherty Earth Observatory Woods Hole Oceanographic Institution, Caltech and Oregon State University on a NSF-funded project to determine the chemistry of volcanic rocks from this fascinating volcanic feature, in order to understand how subduction of the Pacific plate has influenced the mantle composition and mantle melting. The rocks’ chemistry is also important in understanding how hot water that is venting from the seafloor nourishes bizarre communities of microscopic and macroscopic organisms whose life energy is derived from chemical reactions, not from sunlight.

The study of the rock chemistry is one component of the Ridge 2000 program that has designated ELSC as an “Integrated Study Site” where interdisciplinary research is underway to learn how these systems work “from mantle to microbes”.

In 2003 P. Michael participated in the Australian TELVE expedition to Valu Fa and the Tofua arc.

In 2004, Michael and TU undergrad Andrew Matzen traveled to Fiji and joined a voyage on RV Kilo Moana that studied a much longer section of ELSC. It was the second voyage in a multi-staged approach to explore ELSC, and to locate and map hydrothermal vents. Rocks, fluids and biota were sampled to develop the ISS completely.

The group at Harvard and LDEO is concentrating on the ELSC. At TU, we are concentrating on the seamounts that are located between the Tonga (Tofua) arc and ELSC because they provide an excellent opportunity to examine spatial relationships of mantle chemistry and melting in the back arc environment. The spatial constraints can be used to better understand the nature of the enrichment that is caused by subduction and the melting processes that take place in the arc and back-arc environments. Thirty-four seamounts were sampled (24 during cruise KM0417; 10 during cruise TELVE) at distances of 0 to 30 km from ELSC: i.e. considerably closer to ELSC than to Tofua arc.

At TU we are analyzing volatiles in glasses and melt inclusions from ELSC and nearby seamounts. We analyze Cl, F, S as well as K and Ti by electron microprobe (LINK). We analyze H2O and CO2 (really CO3) here using micro Fourier Transform Infrared Spectroscopy (micro-FTIR) LINK. We share these data with our collaborators at Harvard where major and trace elements are analyzed  (see facilities) and with those at LDEO and OSU where isotopes are analyzed. In this way, each group has a complete high-quality data set.

The Tonga subduction zone located north of New Zealand is a classic intraoceanic island arc with back-arc spreading. The subduction rate in the north is the fastest on earth. The Tofua volcanic arc is the currently active island arc. The Eastern Lau Spreading Center (ELSC) has propagated southwards in the last 3 million years, splitting the ancient arc into Lau Ridge + Tonga Ridge.

ELSC overlies progressively deeper portions of the subducting Pacific plate towards the north, and is at increasingly greater distances from the volcanic front of the Tonga arc. Therefore there is a continuous gradient in the subduction influence that is the hallmark of back-arc basin basalts. Over the same distance, from south to north (i) the spreading rate increases from 40-95mm/yr (full rate); (ii) crustal composition changes from andesitic, arc-influenced lavas to typical tholeitic basalts with normal MORB chemistry; (iii) the radiogenic isotopes change from values characteristic of the Pacific to those characteristic of the Indian Ocean; (iv) the ridge axis changes from an inflated cross section at depths of 1600-2000m to an axial valley with split volcanoes at depths of 2500-3000m; (v) the melt lens disappears; (vi) layer 2A thins.

Some initial results: The subduction influence (e.g., fluid mobile elements) along ELSC increases in several sharp gradients towards the south as ELSC gets closer to the arc. The six different tectonic segments of ELSC display mixing relationships in trace element ratio-ratio diagrams (e.g., Ba/La vs Th/La) in which one end member is a subduction component that is distinctive for each segment. Tofua arc volcanic rocks share the distinctive trace element characteristics of their corresponding ELSC segment, and extend the mixing trajectories to higher, more arc-like values. Seamounts that are located between Tofua arc and ELSC also share the distinctive trace element characteristics of the local arc + back-arc, and are intermediate in their trace element ratios. These observations are consistent with the model of Langmuir et al., (2006) in which magmas of back arc spreading centers form from two components: a dry side similar to mid-ocean ridges and a wet (trenchward) side that produces hydrous melts. We suggest that Tofua arc formed completely from the wet side. Seamounts have a small input from the dry side and a greater input from the wet side compared to ELSC, consistent with their location. Our data suggest that the contribution from the wet side varies in composition along the length of the axis, and that the distinctiveness at each latitude is maintained across the arc from Tofua arc to ELSC and beyond.

Additional studies: Volatile degassing from magmas - There is a remarkable gradient in the volatile contents of magmas along the ELSC that is related to the variable slab+wedge contribution to magmas, especially for H2O. Large differences in magmatic H2O result in significant variations in the abundance and species of volatiles Cl, H, C and S that are degassed from magmas and potentially supplied to hydrothermal systems. We are using volatile contents measured in melt inclusions and host glasses to determine the volatiles that have been degassed at the different hydrothermal sites we discovered on KM0417.

Dr. Kumar Ramachandran  is developing research projects focused on imaging subsurface structures using seismic refraction and reflection tomography (controlled source and earthquake data). This involves research and development in the areas of reflection seismic data processing and interpretation, and integration with other complementary geophysical methods.

Seismic Tomography and Reflection Seismology: Imaging Complex Structures.  Seismic reflection imaging of complex subsurface structures involves design and development of an acquisition and processing sequence that is planned for a specific target. This can be achieved by good seismic field acquisition design and data processing strategies for improving spatial and temporal resolution of complex structures. Such an approach can be successfully applied to map targets for hydrocarbon and mineral exploration, near surface environmental investigations, and deep seismic studies to map crust/mantle structure.

Quantitative interpretation of geophysical data through inverse methods.  Quantitative interpretation of gravity and magnetic data, together with seismic data by inversion/modeling is of direct application in oil exploration for target size and depth delineation. Dr. Ramachandran is interested in integrating gravity and magnetic modeling/inverse methods with seismic tomography to constrain the velocity models.

Mapping lithospheric structure.  Controlled source reflection and refraction seismic experiments enable imaging of the continental and oceanic lithosphere in two and three dimensions. Gravity, magnetic and heat flow studies offer additional constraints to synthesize an integrated structural interpretation. Results from laboratory measurements of physical properties of rocks at different temperature/pressure conditions offer additional constraints in interpreting their composition. Comparative study of regions with similar geology brings out the subtle differences in the lithospheric structure and helps differentiate the processes responsible for such differences. For example, warm and cold subducting slabs produce different Wadati-Benioff zone seismicity pattern. Continuous geodetic observations help to identify compression and extension stress regimes. Integrated modeling/interpretation enables mapping the structural elements and understanding of the tectonic forces in action. For example, at the Cascadia margin in British Columbia and Washington, the compressive regime is N-trending. Oblique subduction of the Juan de Fuca plate northeastward beneath North America has been shown to produce arc-parallel migration of the forearc creating an additional seismic hazard from the relative motions of the forearc blocks. Motions of the order of 7 to 9 mm/yr of the Cascadia forearc has been proposed, leading to large upper-plate earthquakes in the forearc over historically significant time.

Seismic tomography of reflection and refraction data of controlled source and earthquakes relocate the position of earthquakes within the 3-D velocity structure, simultaneously solving for P wave and possibly S wave velocity structure. Continued tomographic studies will improve the quality, resolution and coverage of the velocity model. Tomographic modeling can be targeted to specific zones in the subsurface to address a particular research aspect, like structure of a sedimentary basin, mapping a possible fault and computing Vp/Vs ratio for a target zone. Mapping the structural elements in subduction zones from reflection/refraction seismology, earthquake studies, and constraining the interpretation with gravity and magnetic data is one of my research interests. The results of such a study will delineate the structural elements and related earthquake hazards in subduction zones.

Dr. Robert W. Scott  presented two papers at the 8th International Congress on Rudists in Izmir, Turkey in June 2008. During October 2007 he taught at China Geosciences University, Beijing and conducted research on Cretaceous stratigraphy and rudist evolution. He is involved in the new IGCP 555 “Rapid Environmental/Climate Change in the Cretaceous Greenhouse World: Ocean-Land Interactions,” which is an international collaboration with Chinese geologists. The Chinese have cored the complete Cretaceous lacustrine section in the Songliao Basin. The five-year project will compare Cretaceous environmental data in China with locales in other countries.

In addition to serving as an adjunct faculty member of the Department of Geosciences, he is president of Precision Stratigraphy Associates, which provides quantitative solutions to stratigraphic problems and training in sequence stratigraphy. Dr. Scott was a research geologist at Amoco Production Company for twenty years conducting stratigraphic and paleontologic studies of Mesozoic and Cenozoic rocks worldwide. Prior to joining Amoco, he taught geology for eight years, first at the Waynesburg College, Pennsylvania and then at the University of Texas at Arlington. His Ph.D. research at the University of Kansas was on Early Cretaceous paleocommunities and stratigraphy in the U.S. Western Interior and he earned Masters and Bachelors degrees at the University of Wyoming. He has more than 130 published papers and abstracts, and has served on several SEPM committees and research groups, served as secretary-treasurer of the Society for Sedimentary Geology (SEPM), and as an officer of the SEPM Foundation and of the Tulsa Geological Society. His current research is compiling a Cretaceous chronstratigraphic database and applying it to interdisciplinary international team research on Cretaceous oceanic red beds. He directs student research on carbonate reservoirs and paleontology.

Dr. Bryan Tapp  is the Co-PI on several grant proposals involving educational outreach through the Oklahoma State Regents - No Child Left Behind, and through NSF - Math Science Partnership. The Regents proposal is an extension of successful grant based workshops involving cooperative efforts between the University and the major Non-Profits in Tulsa: Gilcrease Museum, Oklahoma Aquarium, Tulsa Zoo, Tulsa Air and Space Museum & Planetarium, and Mary K. Oxley Nature Center working with middle and high school science teachers. The NSF proposal is to develop an interdisciplinary Masters program in Environmental Sciences that will serve secondary school teachers in the region as well as traditional students seeking expertise in Environmental Sciences. Dr. Tapp is also co-PI on an NSF proposal in Biogeosciences to extend ground-breaking work on the biogeochemical characterization of acid rock drainage systems in a high alpine setting. This is a team effort involving faculty and researchers from several institutions.

Dr. Tapp is working on research projects involving the characterization of the structural evolution and tectonic style of the ShoVelTum area, in between the Arbuckle Uplift and the Wichita Uplift. This region has not been well characterized. These studies will attempt to develop balanced cross sections of significant oil and gas fields, and may lead to the development of a regional balance for the system. In addition, Dr. Tapp is working to try to understand the detailed structural evolution of the Arbuckle Uplift, and the role that the structural system plays in the hydrodynamics of the Arbuckle-Simpson Aquifer through field geophysical characterization.

Undergraduate students are encouraged to participate in these research efforts along with the graduate students involved in the studies.

Catherine Webster  is researching the Biogeochemistry of high alpine acid drainage systems. The current target area is Grizzly Peak Caldera, Colorado. This is a collaborative research effort between Catherine, Dr. Bryan Tapp of the University of Tulsa, and Dr. Susan Pfiffner, a research microbiologist at the University of Tennessee. Within the scope of this project are DNA, PFLA and proteomic microbial analyses, geochemical and nano-scale analyses utilized to characterize the ferricrete, biocolloidal materials, biofilms and non-organic films. This research team seeks to discover what role microbes play in the sedimentation and geochemical processes in these high alpine systems. Field work is accomplished in a short window of opportunity during the months of July and August after the snow pack has melted, allowing access to all sampling sites. Whenever possible, undergraduate students are given the opportunity to experience field work in this environment.

Catherine has been awarded a faculty research grant and has a NSF proposal submitted to extend this ground-breaking research.