Christa J Placzek

Lecturer B.A. The Colorado College M.S. University of Arizona Ph.D. University of Arizona

Office:	DB034-150
Phone:	(07) 4781 4756; International +61 7 4781 4756
Fax:	(07) 4781 4020
Email:	christa.placzek@jcu.edu.au

Teaching

• EA 5046 Earth and Environmental Geochemistry

• EA 3005 Minesite Rehabilitation

Research

My research focuses on climate, hydrology, and Earth surface geochemistry.I utilize a breadth of isotopic techniques, fieldwork, and numerical models to: 1) understand interactions between global climate and the terrestrial hydrologic cycle, and 2) quantify the rates and processes of rock weathering, regolith generation, surface erosion, and relating these rates and processes to environmental variables (e.g. time, uplift rate, and climate).

My colleagues and I have used these research foci in the Andes to highlight the connection between global climate and climate in the southern hemisphere tropics/subtropics. From this work it is now clear that changes in north Atlantic sea surface temperature gradients strongly, synchronously, and dramatically impact lakes in the distant central Andes. Continuing research includes coupling our paleolake record to new paleoclimate records from southern hemisphere tropics, including north Queensland

An important component of my work has been determining patterns of weathering and erosion and quantifying how climate and tectonics regulate the development of sediments, soils, and landscapes; the interpretation of both cosmogenic nuclide and U-series isotopic data gives us unprecedented insights into the rates and distribution of geomorphic processes across varied landscapes.Work in the Atacama Desert of northern Chile highlights the role of climate on rates of rock weathering and landscape modification. Ongoing research focuses on understanding the geographic distribution of and driving mechanisms for the “non-traditional” stable isotope fractionation of ²³⁸U over ²³⁵U. Recently, my colleagues have begun to apply Uranium isotopic ratios to environmental questions and ore formation processes associated with U ores that are subjected to in situ recovery.

These overlapping research focus in paleoclimate, surface processes, and Uranium mining is united by similar methodologies; the same geochemical methods that are used to date the effects of past climate change can also be used to quantify how and at what rates surface materials will weather.

Selected Publications

Placzek, C.J., Quade, J., Patchett, P.J., 2011, Isotopic tracers of paleohydrologic change in large lakes of the Bolivian Altiplano. Quaternary Research 75,231-244.

Placzek, C.J., Matmon, A., Granger, D.E., Quade, J., Niedermann, S., 2010, Active landscape evolution in the hyperarid Atacama measured by multiple terrestrial cosmogenic nuclides. Earth and Planetary Science Letters 295, 12-20.

Placzek, C., Quade, J., Rech, J., Patchett, P.J., Pérez de Arce, C., 2009, Geochemistry, chronology and stratigraphy of Neogene tuffs of the Central Andean region. Quaternary Geochronology 4, 22-36.

Placzek, C., Patchett, P.J., Quade, J., and Wagner, J.D.M., 2006.Strategies for successful U-Th dating of paleolake carbonates: an example from the Bolivian Altiplano. Geochemistry, Geophysics, Geosystems 7, Q05024.

Placzek, C., Quade, J., Patchett, P.J., 2006.Geochronology and stratigraphy of Late Pleistocene lake cycles on the Southern Bolivian Altiplano: Implications for causes of tropical climate change. Geological Society of America Bulletin 118, 515-532.

Adella Edwards of 6630staff last updated this page on 2 Aug 2012.