James Aronson Geochemistry and Sedimentary Petrology

Contact Information:

Overview of Research:

I use conventional K/Ar dating to determine the history of tectonically active areas such as Iceland, Taiwan and the East African rift. By dating the important potassium-bearing clay minerals illite and illite/smectite we explore the burial and subsurface fluid flow diagenetic processes that have affected sedimentary basins and volcanic terranes, including petroleum migration and ore emplacement. A current project utilizes the areal and stratigraphic distribution of K/Ar dates on detrital muscovite and illite in sandstones and shales in the Appalachian Basin to refine the history of the associated composite Appalachian orogenic belt on its east. I hope to build a single crystal laser fusion system for complementing the conventional dating approach to this problem.

With colleagues I continue studies at the early hominid fossil site of Hadar (Ethiopia). These are aimed at refining the chronology, at establishing the environment of deposition through sedimentological analysis, and at interpreting climate change from light isotope analysis of paleosol carbonates compared to soil carbonates from a variety of modern Ethiopian environments. These proojects are described in more detail below.

• Studies of early hominid fossil sites of Hadar (Ethiopia)
• Paleohydrological Studies Using Diagenetic/Hydrothermal Clay Minerals and Zeolites

Research Group Website: Potassium-Argon Dating Laboratory

Selected Recent Publications:

Altaner, S.P., Ylagan, R.F., Savin, S.M., Aronson, J.L., Belkin, H.E., and Pozzuoli, A., 2003, Geothermometry, geochronology, and mass transfer associated with hydrothermal alteration of a rhyolitic hyaloclastite from Ponza Island, Italy: Geochimica et Cosmochimica Acta, v. 67, p. 275-288.

Hailemichael, M., Aronson, J.L., Savin, S., Tevesz, M.J.S., and Carter, J.G., 2002, delta (super 18) O in mollusk shells from Pliocene Lake Hadar and modern Ethiopian lakes; implications for history of the Ethiopian monsoon: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 186, p. 81-99.

Aronson, J. (prefacer), and Bish, D.L.(prefacer), 2002, Reynolds commemorative volume [modified]: American Mineralogist, v. 87, p. 1517-1740.

Giday WoldeGabriel, Fraser Goff, and James Aronson, 2001, Mineralogy and K-Ar geochronology of mixed-layer illite/smectite from the Geysers coring project, Califonia, USA, 2001, Geothermics, 30 , p193-210.

G. WoldeGabriel, R.C.Walter, W.K.Hart, J.L.Aronson and S.A. Mertzman, Temporal relations and geochemical features of felsic volcanism in the central sector of the Main Ethiopian Rift, 1999, Acta Vulcanologica, 11 ,p.53-67.

Kimbel, W.H., Walter, R.C., Johanson, D.C., Reed, K.E., Aronson, J.L. et al., 1996, Late Pliocene Homo and Oldowan Tools from the Hadar Formation (Kada Hadar Member), Ethiopia, Journal of Human Evolution, 31, 549-561.