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Impact of Exhalative Hydrothermal Systems on Marine Chemistry: Applications for Mineral Assessment

Task Objectives

Results of the Metals in Basinal Brines and Petroleum project have brought to light exciting opportunities in ore genesis research. It has now been demonstrated that the immense discharges of fluids and metals from large sedex systems into the ocean were sufficient to affect global ocean chemistry. Recognition that these events manifest in the global secular marine chemical/isotopic records forms the foundation for a powerful new global assessment/exploration tool. The combination of our newly developed methods for measuring chemical variations in the paleo ocean and ore genesis research allows us, for the first time, to constrain the age, fluid flux, metal flux, depositional efficiency and duration of exhalative hydrothermal events. This also provides an exceptional global assessment tool that makes it possible to evaluate the size of hydrothermal systems and identify favorable stratigraphic ages and basins to explore. While these are important advances for ore genesis research and mineral assessment, these discoveries have broader implications for earth science. Specifically, that basin brine discharges during formation of sedex deposits are responsible for severe disruptions to global nutrient, biologic and carbon cycles. As such, we have a unique opportunity to utilize ore genesis research to understand the evolution of the Earth’s litho-, hydro-, atmo-, and bio-sphere.

The objective of this SubTask is to develop a multi-disciplinary investigation with ore genesis research/assessment at its core. During this year we will refine our research strategy and create an ore genesis core for this research activity. A scientific priority of this year is to further document secular marine chemical/isotopic changes caused by exhalative ore formation exploiting our new technologies/methodologies to measure secular chemical/isotopic change and reinterpret similar data being generated by other groups. These data will then be applied and evaluated as a new global assessment/exploration tool. This data will also allow us to constrain processes of ore formation (previously impossible through conventional ore genesis studies). At the same time, this data will be applied to broader issues related to these brine discharges (e.g. global anoxia and carbon sequestration, biologic productivity and aquatic mortality, marine chemical/isotopic cycles, climate change, etc). We will leverage our unique abilities in this new arena to establish cross-program research partnerships, supplying us with critical expertise and funding for these efforts. This will allow us to identify and establish research partnerships that can contribute to these investigations. Although ambitious, this is an unprecedented opportunity for Mineral Resources Program ore genesis research to significantly impact nearly every other earth science discipline.

Statement of Work

The scientific priority for this year is to apply new methods developed to document marine chemical/isotopic changes caused by exhalative ore formation and evaluate this methodology as a global assessment/exploration tool. Activities will include:

1. continue to establish research relationships to study broader issues related to these brine discharges (e.g. global anoxia and carbon sequestration, biologic productivity and aquatic mortality, marine chemical/isotopic cycles, climate change, etc)
2. finalize collection of data and analyses of trace/REE elements, Sr-Pb-Nd isotopes, C and S isotopes from a Lower Silurian section in Sweden
3. finalize a new method that has been development for d34S analysis of conodonts.

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