Geology topics
Research about Montana, Wyoming
Source-linked reports with geographic coverage including Montana, Wyoming.
Leasable mineral and waterpower land classification map of the Bozeman quadrangle, Montana, Wyoming: Lands withdrawn, classified, and prospectively valuable for leasable minerals; occurrences of other selected minerals ; and lands withdrawn or classified for waterpower and reservoir sites
No abstract available.
Coal bed correlations in the Tongue River Member of the Fort Union Formation, Monarch, Wyoming and Decker, Montana, areas
No abstract available.
Coal resource occurrence and coal development potential maps of the Bay Horse quadrangle, Powder River County, Montana, and Campbell County, Wyoming
No abstract available.
Coal resource occurrence and coal development potential maps of the Moorhead quadrangle, Powder River County, Montana, and Campbell County, Wyoming
No abstract available.
Climate appraisal maps of the rehabilitation potential of strippable coal lands in the Powder River basin, Wyoming and Montana
No abstract available.
Coal resource occurrence and coal development potential of the Black Draw quadrangle, Campbell County, Wyoming, and Powder River County, Montana
No abstract available.
Leasable mineral and waterpower land classification map of the Billings 1° x 2° quadrangle, Montana and Wyoming
No abstract available.
Exchangeable cations in Cretaceous bentonites from Wyoming and Montana
The research described herein was designed to determine the relationship between physical and chemical properties of bentonite and to evaluate the feasibility of using chemical properties of bentonites to predict their suitability for various industrial uses. Samples were chosen from both Wyoming and Montana from as broad an areal and stratigraphic distribution as possible. They may or may not be typical of mine-grade bentonite or of "average" bentonite. Samples described as containing volcanic ash or as being otherwise contaminated were omitted from this study.
Geochemistry of amphibolites from the central Beartooth Mountains, Montana-Wyoming
Trends of variation of major- and minor-element contents in amphibolites from the central Beartooth Mountains strongly suggest that these rocks of andesitic composition are derived from a tholeiitic, mafic igneous parent and not from a sedimentary parent. Discriminant functions based on minor-element content also indicate igneous parentage, whereas functions based on major-element content indicate a sedimentary parent, suggesting that the general assumption that the regional metamorphism is isochemical may not be entirely valid. Furthermore, chemical data on the amphibolites do not fit the fractionation curves of average Beartooth metadolerites, the most likely precursor. If, however, it is assumed that regional metamorphism and formation of amphibolites were accompanied by potassium metasomatism, then the higher concentrations of SiO 2 , Al 2 O 3 , K 2 O, and potassium-related minor elements in the amphibolites relative to metadolerite can be explained.
Map showing configuration and thickness, and potentiometric surface and water quality in the Madison Group, Powder River basin, Wyoming and Montana
With development of the coal resources of the Powder River Basin of Wyoming and Montana the demand for water will increase greatly. The study upon which this report is based was designed to make a preliminary evaluation of the available geo-hydrologic data for the Madison Group, which is an extensive aquifer underlying the Powder River Basin. Large yields from a few wells tapping the Madison indicate that the aquifer possibly could be utilized as one source of water for development of the coal resources of the area. Domestic and stock-water supplies have been developed for sandstone and coal aquifers at shallow depths in the basin, but these aquifers do not appear to be capable of supplying the large amounts of water require for coal development without endangering existing water supplies.
Trace-metal variation in soils and sagebrush in the Powder River Basin, Wyoming and Montana
A reconnaissance study of 28 trace metals in samples of surface soil (0-2.5 cm deep), subsurface soil (15-20 cm deep), and big sagebrush ( Artemisia tridentata ) that were collected from the Powder River Basin in Wyoming and Montana indicates that little variation occurs in nature at scales greater than about 35 km. This general lack of broadscale variation suggests that simple summary statistics for these materials could provide basinwide geochemical baselines for use in monitoring secular changes in the local geochemical environment. Samples of big sagebrush near the Dave Johnston Power Plant at the southern edge of the basin exhibit statistically significant reductions of strontium, vanadium, uranium, and selenium eastward from the plant.
High-level plateaus of the southeastern Beartooth Mountains, Montana and Wyoming: remnants of an exhumed sub-Cambrian marine plain
The Beartooth Mountains of south-central Montana and northwestern Wyoming are a northwesterly trending high rugged range made up mainly of Precambrian metamorphic rocks. The southeastern part of the range is characterized by extensive high-altitude flat or gently rolling plateaus separated by deep glaciated canyons. The plateaus along the crest of the range are at altitudes of more than 3,350 metres (11,000 ft), whereas those on the flanks of the range are much lower. They are almost entirely on Precambrian rocks, and only small patches of Cambrian sedimentary rocks still remain at a few places in the high mountains. Topographic profiles across the southeastern Beartooth Mountains show that: (1) plateaus bearing the sedimentary remnants lie very close to the position of the sub-Cambrian depositional surface as projected from known occurrences of that surface along the south side of the mountains; (2) other plateaus on the crest and southwest flank also lie near this projected position; and (3) high plateaus and other summits on the northeast slope in areas distant from known or projected positions of the sub-Cambrian surface are markedly accordant. We believe the plateaus along the crest and southwest flank of the range to be remnants of an exhumed marine plain of Early Cambrian or Precambrian age, and those on the northeast flank may possibly have a similar origin. The sub-Cambrian depositional surface was protected until early Tertiary time by a cover of Paleozoic sedimentary rocks, and parts of it probably were covered until Pliocene time by Eocene volcanic rocks. The surface subsequently has been profoundly modified by fluvial and glacial erosion and by mass wasting.