A NEW FUTURE FOR METAMORPHIC GEOLOGY

Metamorphic geology as an academic pursuit has been in decline in the United States for decades for multiple reasons. However, recent technological developments afford new opportunities for major advancement in the field. In the spirit of Mike Brown’s accomplishments, we discuss one of those key developments; the unprecedented ability to unravel complex structure using new technologies. We show how high resolution terrain models developed from Structure from Motion/Multiview Stereo models, LiDAR, or both, provide the ability to resolve structure at cm levels over distances of km. We discuss using combinations of data acquisition techniques including imagery from manned aircraft, unmanned aerial systems, and ground-based observations and conclude the choice of technique depends on scale, access, and cost limitations. These high resolution models are most important at sites that are often most important, but lost in conventional field studies-- inaccessible cliff faces. We show examples of how high resolution mapping in an area of well-established stratigraphy, the Death Valley region, can be used to unravel polyphase folding and remote finite strain estimates. Similarly we show how the techniques can be used to provide new insights into some of the most complex metamorphic rocks on earth; accretionary complex rocks in southern Alaska. Using these methods integrated with petrologic studies and geochronology we now have the opportunity to understand the inner workings of orogenic belts in ways that could only be dreamed of as little as a decade ago. In the past, sedimentary geologists held all the cards in the understanding of orogenesis with high resolution stratigraphic records. Now, however, with modern technology, metamorphic geology holds the key with the potential to unlock detailed records of the inner workings of continental deformation. If these new data are integrated with observations from nearby sedimentary basins there is a potential for new understandings of orogenesis, but that integration will require a major collaborative effort within communities that today remain largely disconnected.