RuGGEd

Introduction

RuGGEd (Ruby Mountains Geochronology and Geoscience Education) is an NSF-funded collaborative research and education project focused on the geologic evolution of the Ruby Mountains – East Humboldt Range – Wood Hills metamorphic core complex in northeastern Nevada. Along with Co-PI’s Al McGrew (University of Dayton) and Carrie Bruno Meisner (Great Basin College) I am working to understand the Cretaceous to present thermal and exhumational history of the range, and to take advantage of the tremendous local geology to create new outreach and educational opportunities for students and the general public.

 

Carrie Meisner is in charge of many of the outreach activities, and has put together an interactive map and field guide to the area and a RuGGEd YouTube channel to showcase some of our efforts. Keep checking back, we are updating both regularly!

Project Description

One of the most dramatic shifts in the tectonic architecture of North American in the Phanerozoic is the Late Cretaceous to Cenozoic transition of the Cordillera from large-scale shortening and crustal thickening to widespread regional extensional collapse. While certain aspects of this geologic history are well understood, a number of critical questions remain unresolved regarding the distribution, rates, style, and timing of the early extensional evolution. Key to addressing these crucial questions are the metamorphic core complexes (MCCs) – regions where extreme crustal extension has exposed thick crustal sections with protracted tectonic histories. However, each of the classic MCCs of the northeastern Great Basin yield fundamentally disparate interpretations of the timing and tectonic significance of exhumation depending on whether the data derive from deeper or shallower structural levels. In each case, lines of evidence drawn primarily from higher temperature thermochronometry, integrated P­–T–t paths, and structural analyses of mid- to deep-crustal rocks suggest older, more protracted and often more complex exhumational histories; in contrast, low-temperature thermochronometry and syntectonic sedimentation commonly record a simpler and more youthful record of widespread Miocene extensional unroofing. This study will directly address these problems and bridge the current gap in understanding by using low- and medium-temperature (U-Th)/He and ⁴⁰Ar/³⁹Ar thermochronology within a detailed and well-understood structural framework to constrain a complete cooling and exhumational history for northeastern Nevada’s Ruby Mountains – East Humboldt Range – Wood Hills MCC (REHW). By integrating a range of thermochronometers and field relationships this study will reconcile disparate exhumational histories derived from disconnected investigations of deep-crustal and upper-crustal processes. In doing so, it will directly test competing hypotheses for the onset, duration, and driving forces of Basin and Range extension and exhumation. Specifically, this proposal will address three key questions: (1) when did extension initiate in the REHW, (2) how did the crustal geotherm evolve during the Cretaceous to present, and (3) if early phases of extension occurred, why did they fail to produce a syntectonic stratigraphic record?

This project also contains substantial outreach and educational components. By forging an innovative collaboration between two R1 Research institutions and Great Basin College —  the institution primarily responsible for training science educators across most of rural Nevada — we will assure the rapid translation of our research results into extensive, high-quality educational outreach materials and virtual and traditional field experiences developed for a broad range of learners. Outreach materials will highlight the central role that northeastern Nevada’s tectonic history plays in its citizens’ physical and economic well-being.