CURRENT RESEARCH INTERESTS

I use a multidisciplinary approach to solving research problems including petrology, facies analysis, sequence stratigraphy, biostratigraphy, taphonomy, geochemistry, diagenesis, computer modeling, and basin analysis. The research problems I choose tend to involve extensive field data collection combined with specific laboratory techniques needed to solve the problem. For example, my research involving Paleozoic strata typically requires detailed biostratigraphic databases for which I have set up a conodont-processing lab at NMSU. Because of the multidisciplinary nature of my research projects I often work collaboratively with other scientists, whose skills and expertise augment mine. My graduate students typically work on MS thesis projects related to my research interests (see profiles of my students). However, this not always the case and I have had students working on a wide variety of topics from calcrete development to speleogenesis. My current research projects fall into three main areas of interest:

1. Salt-Sediment Interaction and Halokinesis

This research effort focuses on the structural and sedimentologic response of strata deposited adjacent to passively rising salt bodies. I primarily use detailed analysis of outcrops as analogs to geometries and stratal patterns previously only recognized in subsurface datasets (i.e seismic lines and well logs). I have assembled a research team comprising graduate students and geoscientists from several different universities (NMSU, UNLV, ASP-Adelaide and UNAM-Mexico City) and from industry to collect sedimentologic, sequence stratigraphic, biostratigraphic, geochemical, and structural data in order to test and calibrate salt-tectonic models and to decipher the complex evolution of salt systems. With my research team, I have developed a model for passive diapirism, identified and defined halokinetic sequences and determined the primary controls on their formation, and provided a blue print for the outcrop recognition of salt welds. Funding for this research has come primarily from several ACS-PRF grants and a 13-company industry consortium that pays an annual fee with a five-year minimum commitment. We are currently in Phase III (third consecutive term) of the consortium.

I am currently working in 3 different field areas collecting data to further develop the concepts outlined above.

Cretaceous -Tertiary strata of La Popa basin, NE Mexico

La Popa basin in northeastern Mexico contains superbly exposed salt diapirs and evacuation structures (secondary welds) that deform Lower Cretaceous to Lower Tertiary strata around their margins and controlled depositional patterns in adjacent sedimentary rocks. My personal research in this area has focused on the sedimentologic and biological aspects of hermatypic reefal platforms associated with bathymetric relief generated by the near-surface rise of salt diapirs in the basin. The reefal facies serve as incredibly sensitive water depth and chemistry indicators from which we can back track out salt body geometry and migration pathways. The reefs also contain a fascinating evolutionary and biologic community history crossing the K-T boundary. We have recently completed a sedimentologic analysis of a tsunami back-flow horizon that was associated with KT boundary Chicxulub meteorite impact.

Neoproterozoic to Cambrian strata of the Flinders Range, South Australia

I have just started studying salt diapirs in this area and am working with researchers and students at the Australian School of Petroleum at the University of Adelaide, SA. Exposures of salt diapirs here are present at many structural and stratigraphic levels (i.e. authochonous salt layers, remnant pinnacles, vertical stocks and walls, allochthonous salt sheets and canopies, primary, secondary vertical and inclined, and tertiary salt welds. Contained within the minibasins of these salt structures are the famous Ediacaran fauna. I am looking at how this earliest metazoan fauna responded to near-diapir conditions and potential associated methane seeps.

Late Paleozoic-Mesozoic strata of the Paradox basin, Utah

I have also just started working in this area with Tim Lawton (NMSU) and Brenda Buck (UNLV). Preliminary data suggests that strata adjacent to large salt-cored anticlines indicate diapiric salt wall movement from the Permian Cutler Formation through the Jurassic Chinle Formation. These are dominantly non-marine facies arranged into halokinetic sequences. Locally the salt walls have undergone extensive sediment loading by the Cutler Fm. and have been partially welded out.

2. Carbonate cyclicity and buildups within Ancestral Rocky Mountains basins

I have been interested in the nature and controls on the pronounced worldwide stratigraphic cyclicity present in the Carboniferous-Permian section since my master's studies on the mid-continent Pennsylvanian cyclothems. I have been working with Lynn Soreghan at the Univ. of Oklahoma and several graduate students on exposures in southern New Mexico that contain exceptionally well-exposed Pennsylvanian phylloid algal mound complexes along the margins of Ancestral Rocky Mountains basins. The cyclicity and algal facies character is primarily glacioeustatically controlled with a strong tectonic component.

3. Mid to Late Paleozoic tectono-stratigraphic evolution of the western margin of North America

This is a long term project collecting stratigraphic and biostratigraphic data from the Devonian through the Permian section in Nevada and Utah. Currently I am focusing on the Late Devonian strata (Frasnian-Famennian mass extinction boundary) with emphasis on integrating stratigraphic, paleoecologic, and geochemical datasets in order to discern paleooceanographic conditions prior to, during, and directly after the extinction event and at the onset of the Antler orogeny. I have been working with Nancy McMillan, a geochemist at NMSU on this project and we have sought funding from the Dreyfus Scholar program and NSF. Another part of this project will be to understand the enigmatic Late Devonian Stansbury uplift in western Utah and how it may have influenced sedimentation patterns on the shelf and within the Pilot basin.