Dissolved-solids-load contributions of the Pennsylvanian Eagle Valley Evaporite to the Colorado River, west-central Colorado

Abstract

Surface-water dissolved-solids loads for the upper Colorado River basin in westcentral Colorado were used to estimate dissolved-solids-load contributions from the Eagle Valley Evaporite of Pennsylvanian age to the Colorado River. Results indicate that the Eagle Valley Evaporite contributed a total of ϳ800 000 metric tons of salt per year to the Colorado River. Minerals that dissolved from the Eagle Valley Evaporite were contributed to the Colorado River in the following order (by mass): Halite (60%) Ͼ gypsum and/or anhydrite (29%, excluding mass of chemically bound water) Ͼ dolomite (10%) Ͼ magnesite (0.7%). Salts from the Eagle ValleyEvaporite contributed ϳ60% of the total annual dissolved-solids load for the U.S. Geological Survey station Colorado River near Cameo, although the evaporite is exposed or underlies unconsolidated surficial deposits over only ϳ5% of the Colorado River basin upstream from that station.

Can flexural-slip faults related to evaporite dissolution generate hazardous earthquakes? The case of the Grand Hogback monocline of west-central Colorado

“…(2) Hydrochemical evidence: Groundwater discharge from the Eagle Valley Evaporite in springs and alluvial aquifers causes a dramatic increase in the dissolved load of the rivers that traverse the area (Warner et al, 1984;Chafi n and Butler, 2002). Barrett and Pearl (1976) estimated that Yampah Hot Spring in Glenwood Springs discharges around 240 metric tons of dissolved halite and gypsum per day.…”

Methods for evaluating potential sources of chloride in surface waters and groundwaters of the conterminous United States

“…Chloride loads in excess of precipitation inputs can be attributed to evaporite dissolution but also may have other minor geologic sources (for example, geothermal waters) or anthropogenic sources. In the absence of anthropogenic sources, weathering rates can be calculated by comparing concentrations in rivers from upstream and downstream locations (Chafin and Butler, 2002). Natural rates of chloride release to groundwaters and surface waters from rock weathering of evaporites can be increased by irrigation in arid basins, through enhanced dissolution of evaporite minerals in the unsaturated zone by excess irrigation water (Ghassemi and others, 1995).…”

Modeled Sources, Transport, and Accumulation of Dissolved Solids in Water Resources of the Southwestern United States1

“…These include Glenwood Springs and Dotsero Springs, which discharge solutes from the Eagle Valley Evaporite to the Colorado River (Iorns et al. , 1965; Chafin and Butler, 2002); Paradox Springs, which discharge solutes from the Hermosa Formation to the Dolores River (Iorns et al. , 1965; Chafin, 2002); and Blue Springs, which discharges solutes from the Redwall Limestone to the Little Colorado River (Metzger, 1961; Bills et al.…”

“…Four of the largest point sources of dissolved solids to the Colorado River ( U.S. Department of the Interior, 2005 ) are springs associated with medium-yield Paleozoic sedimentary rocks in the SPARROW model. These include Glenwood Springs and Dotsero Springs, which discharge solutes from the Eagle Valley Evaporite to the Colorado River ( Iorns et al , 1965 ; Chafin and Butler, 2002 ); Paradox Springs, which discharge solutes from the Hermosa Formation to the Dolores River ( Iorns et al , 1965 ; Chafin, 2002 ); and Blue Springs, which discharges solutes from the Redwall Limestone to the Little Colorado River ( Metzger, 1961 ; Bills et al , 2007 ). Gypsum and halite beds in the Southwest generally occur in geologic formations within the medium-yield and high-yield sedimentary rocks, and in other studies that focus on those specifically, they have the highest relative yields (40 and 80 in Table 2 , respectively, from Meybeck, 1987 ).…”