Genesis of banded iron formations.  We used a multi-isotope approach to determine the genesis of banded iron formations (BIFs) from Transvaal, South Africa. This research is part of a large NASA-funded Astrobiology project directed by Dr. Clark Johnson.  It was carried out along with Dr. Brian Beard.
Methods: petrography, mineral chemistry, Fe, C, and O isotope determinations. Techniques: ion exchange chromatography, MC-ICP-MS, EMPA, SEM.

Distribution and fractionation of Fe during mineral/fluid interaction.  This is a collaborative project between Dr. Adam Simon (University of Nevada, Las Vegas), who is/will be responsible for performing the experiments, and Adriana Heimann, as well Clark Johnson and Brian Beard.  Adriana Heimann is responsible for the Fe isotope part of the study.  Knowing experimentally-determined Fe isotope fractionation factors between magnetite and chloride solutions is fundamental for understanding measured Fe isotope compositions in evolved igneous rocks that are prone to experiencing fluid/rock interaction with evolved magmatic liquids (Heimann et al., 2008).  The experiments consist of reacting magnetite and chloride solutions at different pressures and temperatures and determining the partitioning of Fe between magnetite and the chloride solution and the resulting Fe isotope fractionation.  The results of this research have a bearing on the transport of Fe and other metals in hydrothermal fluids and the formation of metal ores.

Origin of gahnite-bearing rocks and associated sulfides at the Cambrian Angas Pb-Zn (Ag, Au) deposit, Kanmantoo, South Australia.  This is a collaboration project that I have just started with Dr. Paul G. Spry (Iowa State University) and Dr. Ross Both (Australia) that aims at understanding the genesis of the Angas deposit by a study of the petrography and mineral chemistry of gahnite (zincian spinel, ZnAl2O4)-bearing rocks and spatially associated sulfides.

Previous research
1- Previous research focused on the geochemistry of Mn garnet and garnet-rich rocks spatially associated with the giant Broken Hill Pb-Z-Ag deposit, minor Broken Hil-type ocurrences, and horizons unrelated to mineralization in the Curnamona Province, Australia. The main objective was to determine the origin of the garnet-rich rocks (protoliths and formation processes) utilizing major and trace element analysis, especially Rare Earth Elements and Yttrium (REEY) and other traces, of individual garnets and whole rocks. The effects of metamorphism and mobilization on the geochemistry of garnet were also determined. Finally, statistical analysis was used to determine interelement correlations and to develop a geochemical exploration tool for the search of this kind of ore.

2- A second component of the research focused on the geochemistry and style of mineralization of Proterozoic Pb-Zn-Ag mineralized, low metamorphic grade sequences. The emphasis was towards the understanding of the origin of the different types of mineralization in the Olary Domain, and the relationship to garnet-rich rocks and the giant Pb-Zn-Ag Broken Hill deposit.

3- Previous research focused on the chemistry of zincian spinels spatially associated with Proterozoic metamorphosed massive sulfide deposits in Colorado and its use as an exploration guide in the search for this kind of ore.  An additional investigation deals with reaction textures and metamorphic reactions in zincian hercynite-bearing cordierite-gedrite gneisses from the Front Range (Evergreen, Colorado) that contain spectacular coronas and symplectic textures (Heimann et al., 2006).

         heimanna -at- ecu -dot-edu