Dr Galen Halverson

Teaching Interests

My teaching efforts are concentrated on clastic and carbonate sedimentology, stratigraphy, and stable isotope geochemistry. In 2007, I will teach in Sedimentary & Structural Geology II, Petroleum Exploration III, and Environmental Geoscience III.

Research Interests

In general, I study Earth history through interrogation of the sedimentary record. My research involves a combination of field mapping, stratigraphy, and geochemistry, integrated to reconstruct how the earth's surface environment has evolved. Specific problems of interest include the timing and tempo of oxidation of the oceans, causes and consequences of Neoproterozoic (1000 - 541 million years ago) global glaciations, secular change in isotopic the chemistry of the oceans, as recorded by isotopic proxies (e.g. 87Sr/86Sr, d13C, d34S) preserved in chemical precipitates, and the influence of palaeogeography on palaeoclimate and geochemical evolution of the oceans. My past and present field areas include northwest Namibia, northeast Svalbard, East Greenland, northwest Canada, and central-South Australia. My analytical instruments of choice are gas source isotope ratio mass spectrometers, for measuring the ratios of light stable isotopes and multicollector inductively-coupled plasma mass spectrometers (MC ICP-MS) for measuring, among other systems, medium-heavy stable-isotopic ratios.

On-going projects include
1. Testing the hypothesis (Maloof et al., 2006) that the earth experienced multiple episodes of large-scale true polar wander c. 800 million years ago.

2. Reconstrucing the evolution of the concentration and sulfur isotopic composition of seawater sulfate in the Neoproterozoic and its link to oxygenation of the environment.

3. Establishing the iron isotope composition of Neoproterozoic glacial oceans and more generally applying iron isotope geochemistry to studying ancient sediments.

4. Investigating the record of ice-shelf collapse along the margin of the Larsen Ice Shelf, Antarctica

Publications

SUBMITTED

Halverson, G.P., Poitrasson, F., Hoffman, P.F., Nedelec, A., and Montel, J-M., submitted. Iron isotope composition of the Neoproterozoic Rapitan iron-formation, northwest Canada. Earth and Planetary Science Letters.

Halverson, G.P., submitted. Glacial sediments and associated strata, the Polarisbreen Group, northeastern Svalbard; in E. Arnaud, G. Shields, and G.P. Halverson (Eds.), The Geological Record of Neoproterozoic Glaciations. Geological Society of London.

IN PRESS

Hoffman, P.F., and Halverson, G.P., 2008. Otavi Group of the western Northern Platform, the Eastern Kaoko Zone and the western Northern Margin Zone. In: Miller, R. McG. (Ed.) The Geology of Namibia, Vol. 2, Geological Survey of Namibia (Windhoek), 69-136.

2007

Halverson, G.P., Dudas, F., Maloof, A.C., and Bowring, S.A., in press. Evolution of the 87Sr/86Sr Composition of Neoproterozoic Seawater. Palaeogeography, Palaeoclimatology, Palaeoecology 256, 103-129.

Halverson, G.P. and Hurtgen, M.T., 2007. Ediacaran growth the of the marine sulfate reservoir. Earth and Planetary Science Letters 263, 32-44.

Halverson, G.P., Maloof, A.C. Schrag, D.P., Dudas, F., and Hurtgen, M.T., 2007. Stratigraphy and geochemistry of a ca 800 Ma carbon isotope interval in northeastern Svalbard. Chemical Geology 237, 23-45.

Hoffman, P.F., Halverson, G.P., Domack, E.W., Husson, J.M., Higgins, J.A., and Schrag, D.P., 2007. Are basal Ediacaran (635 Ma) post-glacial "cap dolostones" diachronous? Earth and Planetary Science Letters 258, 114-131.

2006

Halverson, G.P., 2006. A Neoproterozoic Chronology; in S. Xiao and A.J. Kaufman (Eds.) Neoproterozoic Geobiology and Paleobiology, Topics in Geobiology 27. Springer, New York, pp. 231-271.

Hurtgen, M., Halverson, G.P., Arthur, M., and Hoffman, P.F., 2006. Sulfur cycling in the aftermath of a Neoproterozoic (Marinoan) snowball glaciation: evidence for a syn-glacial, sulfidic deep ocean. Earth and Planetary Science Letters 245, 255-571.

Maloof, A.C., Halverson, G.P., Kirschvink, J.L., Schrag, D.P., Weiss, Benjamin P., and Hoffman, P.F., 2006. Combined paleomagnetic, isotopic, and stratigraphic evidence for true polar wander from the Neoproterozoic Akademikerbreen Group, Svalbard. Geological Society of America Bulletin 118, 1099-1124.

2005

Halverson, G.P., Hoffman, P.F., Schrag, D.P., Maloof, A.C., and Rice, A.H., 2005. Towards a Neoproterozoic composite carbon-isotope record. Geological Society of America Bulletin 117, 1181-1207.

Hurtgen, M., Arthur, M.A., and Halverson, G.P., 2005. Neoproterozoic S isotopes, the evolution of microbial S species, and the burial efficiency of sulfide as sedimentary pyrite. Geology 33, 41-44.

<2005

Halverson, G.P., Maloof, A.C., and Hoffman, P.F. 2004, The Marinoan glaciation (Neoproterozoic) in northeast Svalbard. Basin Research 16, 297-324.

Halverson, G.P, Hoffman, P.F., Kaufman, A.J., and Schrag, D.P. 2002. A major perturbation of the carbon cycle before the Ghaub glaciation (Neoproterozoic) in Namibia: prelude to snowball Earth? Geochemistry, Geophysics, Geosystems 3, 10.1029/2001GC000244.

Hoffman, P.F., Halverson, G.P., and Grotzinger, J.P. 2002. Comment: Are Proterozoic cap carbonates and isotopic excursions a record of gas hydrate destabilization following Earth's coldest interval? (Kennedy, M.J. et al. 2001). Geology 30, 286-287.

Schrag, D.P., Berner, R.A., Hoffman, P.F., and Halverson, G.P., 2002. On the initiation of a snowball Earth; Geochemistry, Geophysics, and Geosystems 3, 10.1029/2001GC000219.

Hoffman, P.F., Kaufman, A.J., and Halverson, G.P. 1998. Comings and goings of global glaciation on a Neoproterozoic tropical platform. GSA Today 8, 1-8.

Hoffman, P.F., Kaufman, A.J., Halverson, G.P., and Schrag, D.P. 1998. A Neoproterozoic snowball Earth. Science 281, 1342-1346.

Expertise for Media Contact

Categories	Environment
Expertise	Geology, Sedimentology, Isotope Geochemistry, Palaeoclimatology

Entry last updated: Sunday, 4 May 2008