Collaborative Research: Episodic Construction of Magma Chambers: Multidisciplinary Investigations at a Field Laboratory (Tuolumne Intrusion, Sierra Nevada)

Berkeley Geochronology Center, Berkeley CA

Investigators

Abstract

Intellectual Merit: With mounting evidence that most plutons and batholiths are constructed episodically over timescales of up to millions of years, it is important to reexamine existing methodologies for studying their formation. To understand magma emplacement and cooling histories, multiple ages using several minerals with different closure temperatures and crystal sizes are needed. Likewise, more complex 3D thermal and geochemical scenarios for the magma chamber evolution must be considered. From this perspective, collaborative research is proposed, consisting of field-based integrated high-resolution geochronology, and3D thermal modeling, to investigate a set of related problems - examples include: (1) testing the validity of different episodic growth models, (2) understanding the significance of internal contacts within plutonic bodies, (3) quantifying the extent of chemical mixing or physical mingling, (4) understanding the geometry of intrusion and controls on this, (5) understanding the relations between plutons and related volcanoes, and (6) understanding the sources of hydrothermal fluids and their flow patterns around putons at depth. Understanding of these and similar issues will provide insights into magma formation and evolution, development of associate mineralization, and thermal and tectonic processes that drive and accompany magmatism. Broader Impacts: This project will support the involvement of graduate and undergraduate students from CSF and USC in the research. It involves close collaboration with Yosemite Park personnel in a variety of outreach programs in a Park with millions of visitors per year. In conjunction with the research, a variety of educational materials (particularly on the physics of heat flow and resulting thermal, rheological, and microstructural models of episodically constructed chambers) which will be made available to the public. A Tuolumne Intrusive Series (TIS) website regarding research and geology in the Park will be maintained. And the work will have broad scientific applicability.