Seminar: Drew Coleman – UNC-CH Geology

UNC-CH’s Department of Marine Sciences is proud to host a guest seminar by Drew Coleman. This event is scheduled for Wednesday, February 17th, at 12:30 pm. This seminar is remote only and will be broadcast live online via Zoom (Meeting ID: 934-0604-8353).

Presenter Affiliation: Professor, Department Chair, Department of Geological Sciences, University of North Carolina at Chapel Hill

Title: Finding the Silver (and Gold, and Molybdenum…) Lining in a Global Catastrophe: Linking Economic Mineralization and Super Eruptions

Abstract: Research in the Isotope Geochemistry Lab in the Department of Geological Sciences spans topics from anthropology to volcanology. I will introduce you to the breadth of projects moving through the lab, then focus on some recent work focused on the links between the record of volcanic super eruptions and magmas that fail to erupt and freeze in the crust. Finally, I will show how this research brought us to new understanding about the origins of some important metal commodities and the application of high-precision geochronology to resource exploration.

Most of us who took an introductory geology class learned that magmas rise through the crust as giant liquid blobs with some breaching the surface as volcanic eruptions and others stagnating and crystallizing into plutons. The analogy of magmatism to the physics of lava lamps, and the suggestion of huge liquid magma chambers lurking just beneath the surface in places like Yellowstone National Park are widely spread in information sources (e.g., textbooks displays in public parks, the web.) Recent advances in high-precision U-Pb zircon geochronology reveal that magmas accumulate in plutonic bodies over millions of years, in direct contradiction to these notions, and more in line with observations from geophysics and geochemistry. In fact, there are few demonstrable connections between super eruptions and the plutonic rock record. In addition, recognition that plutonic rocks are assembled over millions of years is inconsistent with essentially all models for the formation of economic mineral deposits such as Au, Ag, Mo, and Pb. Geochronologic data now link some of these deposits to growth of plutons during magmatism following super eruption events. With high-precision ages on plutons and economic mineralization, and new approaches to spatial analysis of large datasets, exploration for resources is entering a renaissance.