Through the Generations

The tradition of Rocky Mountain geology remains strong at all scales, spatially and temporally. This volume fosters that tradition with its collection of peer-reviewed papers associated with the 2010 GSA Annual Meeting in Denver, Colorado. Spatially, this volume discusses theories of continental mountain building events in tandem with microscopic observations and parts per billion trace element concentrations. Temporally, the volume covers geologic history from the Precambrian to modern issues of climate change and energy, groundwater contamination, geologic hazards, and landscape evolution. Many of the trips propose new interpretations of famous geologic ideas and environs such as Laramide deformation, the Colorado Mineral Belt, the Lewis and Clark Line, the Chalk Cliffs, and Garden of the Gods.
A geologic and anthropogenic journey from the Precambrian to the new energy economy through the San Juan volcanic field
-
Published:January 01, 2010
Abstract
The San Juan volcanic field comprises 25,000 km2 of intermediate composition mid-Tertiary volcanic rocks and dacitic to rhyolitic calderas including the San Juan-Uncompahgre and La Garita caldera-forming super-volcanoes. The region is famous for the geological, ecological, hydrological, archeological, and climatological diversity. These characteristics supported ancestral Puebloan populations. The area is also important for its mineral wealth that once fueled local economic vitality. Today, mitigating and/or investigating the impacts of mining and establishing the region as a climate base station are the focuses of ongoing research. Studies include advanced water treatment, the acid neutralizing capacity (ANC) of propylitic bedrock for use in mine-lands cleanup, and the use of soil amendments including biochar from beetle-kill pines. Biochar aids soil productivity and revegetation by incorporation into soils to improve moisture retention, reduce erosion, and support the natural terrestrial carbon sequestration (NTS) potential of volcanic soils to help offset atmospheric CO2 emissions. This field trip will examine the volcano-tectonic and cultural history of the San Juan volcanic field as well as its geologic structures, economic mineral deposits and impacts, recent mitigation measures, and associated climate research. Field trip stops will include a visit to (1) the Summitville Superfund site to explore quartz alunite-Au mineralization, and associated alteration and new water-quality mitigation strategies; (2) the historic Creede epithermal-polymetallic-vein district with remarkably preserved resurgent calderas, keystone-graben, and moat sediments; (3) the historic mining town of Silverton located in the nested San Juan-Silverton caldera complex that exhibits base-metal Au-Ag mineralization; and (4) the site of ANC and NTS studies. En route back to Denver, we will traverse Grand Mesa, a high NTS area with Neogene basalt-derived soils and will enjoy a soak in the geothermal waters of the Aspen anomaly at Glenwood Springs.
- archaeology
- areal geology
- base metals
- Cenozoic
- Colorado
- faults
- field trips
- grabens
- guidebook
- human activity
- igneous rocks
- metal ores
- mineral resources
- mining
- North America
- outcrops
- Phanerozoic
- Precambrian
- reclamation
- road log
- Rocky Mountains
- San Juan volcanic field
- soils
- systems
- tectonic elements
- Tertiary
- thermal waters
- U. S. Rocky Mountains
- United States
- volcanic rocks