Volcanoes to Vineyards: Geologic Field Trips through the Dynamic Landscape of the Pacific Northwest

This volume contains guides for 33 geological field trips offered in conjunction with the October 2009 GSA Annual Meeting in Portland, Oregon. Showcasing the region’s geological diversity, the peer-reviewed papers included here span topics ranging from accreted terrains and mantle plumes to volcanoes, floods, and vineyard terroir. Locations visited throughout Oregon, Washington, and Idaho encompass Astoria to Zillah. More than just a series of maps, the accompanying descriptions, observations, and conclusions offer new insights to the geologic processes and history of the Pacific Northwest insights that will inspire readers to put their boots on the evidence (or perhaps sip it from a glass of Pinot!) as they develop their own understanding of this remarkable and dynamic corner of the world.
A tale of two basins: Comparisons and contrasts in the high desert hydrogeology of Steens Mountain, southeastern Oregon
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Published:January 01, 2009
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CiteCitation
Michael L. Cummings, Sherry L. Cady, Robert B. Perkins, 2009. "A tale of two basins: Comparisons and contrasts in the high desert hydrogeology of Steens Mountain, southeastern Oregon", Volcanoes to Vineyards: Geologic Field Trips through the Dynamic Landscape of the Pacific Northwest, Jim E. O’Connor, Rebecca J. Dorsey, Ian P. Madin
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ABSTRACT
Steens Mountain, a fault-block in the northern Basin and Range Province, rises 1.7 km above flanking basins and drives hydrologic systems that include hot springs, fresh-water streams, and cold artesian wells in the Alvord Valley. It also feeds freshwater streams, desert wetlands, and shallow fresh-water and alkali lakes in the Harney Basin. Steens Mountain melt water from the winter snow pack partitions to surface-water and groundwater systems. How the composition of these fluids evolve along the various flow paths as a result of differences in the geology, interaction with geother-mal aquifers, surface storage time, degree of evaporation, and biology will be examined. Deep-seated flow paths feed Alvord Valley hot springs, which discharge to the east, in the rain shadow of Steens Mountain. The largest of these hot spring systems— Borax Lake—along with features at Mickey Hot Springs, offer ample opportunity to investigate how biosignatures form and become preserved in hydrothermally precipitated sinter deposits. Surface water moving off the westward-dipping slope of Steens Mountain passes through wetland environments to Malheur Lake in Harney Basin. This key point along the Pacific flyway provides wonderful wildlife viewing and the chance to ponder the impacts of biology on lake chemistry. Finally, we will visit the saline-alkaline Harney Lake, the terminal sump for the water moving through Malheur Lake and all of the nearly 40,000 km2 Harney Basin. At this locale, the focus will be on the influence of evaporative processes on water composition.
- aquifers
- arid environment
- artesian waters
- Basin and Range Province
- deserts
- discharge
- drainage basins
- eolian features
- evaporation
- faults
- field trips
- fresh water
- ground water
- guidebook
- Harney County Oregon
- hot springs
- hydrology
- North America
- Oregon
- rivers and streams
- road log
- springs
- Steens Mountain
- surface water
- terrestrial environment
- thermal waters
- United States
- wetlands
- southeastern Oregon
- Harney Lake
- Malheur Lake
- Alvord Basin