The College of Arts and Sciences

David Gombosi

PhD Candidate Earth Sciences

Advisor: Suzanne Baldwin

Research and Teaching Interests

The diffusion of argon and its relation to lunar impacts and the Earth-Moon system.

The Moon preserves an integrated record of surface impacts over the last ~4.5 billion years, whereas traces of most events on the Earth's surface have long since been destroyed through erosion. Thus observing the Moon and using it as a proxy for Earth, we can gain valuable information about the history of impact events on Earth. Dating these impact events is of particular interest as it has been suggested that increases or decreases in impact frequency have been the impetus for major changes in the evolution of life on Earth. Within the past decade advances in 40Ar/39Ar geochronology have permitted several studies to date lunar impact material, such as impact melts and glasses, allowing the determination of impact frequency with time. What is still poorly understood is if any of the daughter material (radiogenic 40Ar) diffuses out of lunar glasses over geologic time. If this is the case then any 40Ar/39Ar age from these impact glasses will yield a younger age than the age of the impact event. I’m attempting to understand how both molecular level physical damage and geochemistry can affect the diffusivity of Ar in these impact glasses, as part of the New York Astrobiology Institute. We hope to be able to quantify the amount of radiogenic 40Ar lost in a given material, which will allow us to correct for any loss of 40Ar when dating this material.

The uplift of the Cordillera Darwin complex, and the development of the fold thrust belt in Tierra del Fuego.

My M.S. thesis used low temperature thermochronology to examine the cooling rates of rocks within the Cordillera Darwin complex in southern Chile and Argentina. This is a group of high-grade basement material which represents the lowermost thrust sheet within the Tierra del Fuego fold and thrust belt. By understanding how the lower thrust sheets evolved this allows new insights into the formation of the foreland basin, and the Patagonian orocline. This project was is part of the project Testing the Polar Gateway Hypothesis: An Integrated Record of Drake Passage Opening & Antarctic Glaciation <>. The project’s overall goal is to understand how the development of the Antarctic Circumpolar Current evolved vis-à-vis the opening of the Drake Passage and what role this may have played in the initial glaciation of Antarctica. Although my thesis work on this project is now complete, I continue to have a collaborative relationship with this project.

New Technical Developments in geochemistry/geochronology.

I’m interested in advancing the techniques used to study the rock record. Most recently I’ve been working on a way to routinely correct for biases in (U-Th)/He ages due to zoning which can bias ages in zircon up to ~33% through using electron microprobe analysis.

General areas of interest:
Tectonics
Sedimentology
Geochemistry
Geochronology and thermochronology

Publications

Gombosi, D.J., Barbeau, D.L., Garver J.I., submitted. New thermochonometric constraints on the rapid Paleogene exhumation of the Cordillera Darwin complex related thrust sheets in the Fuegian Andes. Terra Nova.

Gombosi, D.J., Barbeau, D.L, Jr., Garver, J.I., and Reiners, P.W., 2008. Ceonozoic Thermal Evolution of the Darwin Complex and Related Terranes in Tierra del Fuego. Geological Society of America, abstracts with programs, 320-10.

Gombosi, D.J., and Barbeau D.L., Jr., 2008. Integration of hinterland low temperature thermochronology with flexural modeling: A new tool for foreland basin analysis. AAPG/SEG Student Expo Abstracts.

Gombosi, D.J., Barbeau, D.L., Jr., Hourigan, J.K., and Zhao, D., 2008. Microprobe Assisted Zoned Alpha Corrections in Zircon (U-Th)/He Chronology. 11th International Conference on Thermochronology, abstracts with programs, 110.

Barbeau, D.L., Swanson-Hysell, N., Olivero, E.B., Zahid, K.M., Gombosi, D.J., Murray, K.E., Gehrels, G.E., and Ducea, M.N., 2008. Kinematic history of the Fuegian Andes as indicated by U-Pb detrital zircon geochronology and rare earth element geochemistry of the Magallanes foreland basin. Geochimica et Cosmochimica Acta, 72, 12S, A53.

Gombosi, D.J., Barbeau, D.L., and Kendall, C.G., 2008. Foreland Basin Fills: What Controls Carbonate Versus Clastic Accumulation?. AAPG 2008 Annual Convention and Exhibition Abstracts Volume, 17, 68.