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Research about Idaho, Montana, Nevada, Utah, Wyoming

Source-linked reports with geographic coverage including Idaho, Montana, Nevada, Utah, Wyoming.

5 recordsLinked to original sources

A portfolio framework for prioritizing conservation efforts for Yellowstone Cutthroat Trout populations

Managing and conserving native taxa are becoming increasingly challenging because of mounting threats and limited resources, predicating the need for frameworks to prioritize conservation actions. We integrated attributes of population persistence, genetic status, threats from nonnative species, and threats from climatic shifts to prioritize conservation actions for Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri . We used the individual attributes to rank populations and provide a framework for identifying the benefits of individual conservation actions. The majority of extant populations (57%) had a high probability (>0.75) of persistence, but nearly 70% of populations were either slightly hybridized or sympatric with nonnative species, and 44% of extant populations occupied habitat with low climatic resilience. Overall, we found that 36% of populations ranked as high (>0.75) conservation priority, and these populations primarily occupied large, relatively high‐elevation habitats. The prioritization framework provides a platform for identifying and ranking actions with the greatest conservation effectiveness.

Idaho, Montana, Nevada, Utah, Wyoming

Quantitative analysis versus semiquantitative optical emission spectrographic analysis of chromium, nickel, zinc, vanadium, and molybdenum in organic-rich Paleozoic marine strata, Western United States

Comparison of analytical results between the quantitative method and the semiquantitative six-step optical-emission spectrographic method commonly shows significantly lower values for the semiquantitative method. The lower values are most obvious for splits from the same samples of fine-grained organic-rich rocks where the concentrations of the metals chromium, nickel, zinc, vanadium, and molybdenum are greater than about 200 ppm (parts per million). Samples compared are Paleozoic marine rocks from the Western United States; they include the Permian Phosphoria Formation (Idaho, Montana, Utah, Wyoming), Mississippian Chainman Shale (Nevada and Utah), Mississippian Heath Formation (Montana), Mississippian Doughnut Formation (Utah), Devonian Woodruff Formation (Nevada), and Ordovician Vinini Formation (Nevada). The semiquantitative method consistently underestimates the concentration of the five metals studied by a factor of 1.7 to 2.7 and, thus, cannot be considered reliable for determining the concentration of metals in these rocks if the reported semiquantitative values exceed about 100 ppm. It is noteworthy that the most comprehensive analytical and statistical studies of metal concentrations in black shales of the United States have used the semiquantitative six-step optical-emission method of analysis.

Idaho, Montana, Nevada, Utah, Wyoming

Studies of the Permian Phosphoria Formation and related rocks, Great Basin-Rocky Mountain region

PART A: The transgression of the Permian Retort Phosphatic Shale Member of the Phosphoria Formation is dated by the occurrence of diagnostic brachiopods. The complex pattern of this transgression reflects the paleogeography and indicates two initial basins of deposition: one in southwestern Montana and one in southeastern Idaho. PART B: A new formation is proposed for middle Permian rocks of a transitional facies positioned laterally between the Rex Chert Member of the Phosphoria Formation in northeastern Utah and southeastern Idaho and the Plympton Formation in northeastern Nevada and northwestern Utah. PART C: The relationships of the Permian Park City Group to the Phosphoria and Park City Formations are clarified by the stratigraphy of four sections in northwestern Utah, northeastern Nevada, and southern Idaho. PART D: Five biostratigraphic zones based on the distribution of brachiopods and conodonts are proposed for the Park City Group. They are: the Peniculauris ivesi-Neostreptognathodus prayi Zone, the Peniculauris bassi-Neostreptognathodus sulcoplicatus Zone, the Peniculauris bassi-Neostreptognathodus sp. C Zone, the Thamnosia depressa Zone, and the Yakovlevia. multistriata-Neogondolella bitteri Zone. They range in age from Leonardian to Wordian.

Idaho, Montana, Nevada, Utah, Wyoming