... alkalic dikes. The 3-km-thick upper Libby Creek Group is bounded by a thrust fault below and by the Cheyenne Belt above and contains carbonates and marine slates. The early Proterozoic Deep Lake, lower Libby Creek, and upper Libby Creek Groups collectively are named the Snowy Pass Supergroup. Lithologies...

...BRADLEY S VAN GOSEN Abstract Recently, naturally occurring asbestos (NOA) has drawn the attention of numerous health and regulatory agencies and citizen groups. NOA can be released airborne by (1) the disturbance of asbestos-bearing bedrocks through human activities or natural weathering, and (2...

... National Park, Montana ( Fenton and Fenton, 1937 ). Clark Fork district, Idaho ( Anderson, 1930 ). Clark Fork quad., Idaho ( Harrison and Jobin, 1963 ). Libby quad., Montana ( Gibson, 1948 ). Thompson Lakes quad., Montana ( Johns, 1960 ). Pleasant Valley quad., Montana ( Johns, 1962...

... differing opinions on how best to weight the evidence provided by Rb–Sr, K–Ar, and paleomagnetic data. Depending on the rate of sedimentation for Aldridge strata below the sills dated by Anderson and Davis ( 1995 ) and Missoula Group strata above our Bonner–Libby transition sample, we suggest...

... Deep Lake Group, which primarily consists of polymictic metaconglomerate and quartzite; (2) the ∼4.4-km-thick lower part of the Libby Creek Group, which primarily consists of quartzite; and (3) the ∼3-km-thick upper part of the Libby Creek Group, which primarily contains metamorphosed dolostone...

... has been found to those depths. From rock chemical trends among major cations and sulfur, the metals-transporting brine was interpreted as a group-b (Na 2 SO 4 -NaCl) type (Salt Lake type) of Hardie and Eugster (1970) . It differed from brines that deposited Mississippi Valley-type deposits...

... highly attenuated North American basement. The Proterozoic Belt Supergroup is an important element in the regional geology of northwestern Montana. Harrison (1972) divided the Belt into four groups. From base to top they are (1) the lower Belt or Prichard Formation, (2) the Ravalli Group, (3...

.... The poles are grouped by letter and numbered from oldest to youngest. The A poles (squares) are from pre–Belt-Purcell intrusions and strata (A1—Croker Island pluton, A2—St. Francois Volcanics, A3—Michikamau Anorthosite, A4—Harp Lake Anorthosite, A5—Laramie Anorthosite Complex and Sherman Granite, and A6...

... to be described from the Blue Lizard mine. Like several of the other new uranyl sulfates from here, libbyite contains a uranyl–sulfate structural unit that has not previously been found in Nature. Libbyite is named in honour of American nuclear chemist Willard F. Libby (1908–1980) for his work on nuclear...

..., and metasedimentary rocks are unconformably overlain by the Deep Lake, Lower Libby Creek, and Upper Libby Creek Groups of the Paleoproterozoic Snowy Pass Supergroup (Fig. 1 ) ( Houston et al., 1968 ; Karlstrom et al., 1983 ; Houston and Karlstrom, 1992 ). The Snowy Pass Supergroup is intruded by 2,100–2,000-Ma...

.... , and Last , W.M. , eds., Sedimentology and Geochemistry of Modern and Ancient Saline Lakes: SEPM, Special Publication 50, p. 267 – 290 . Gao , G. , and Land , L.S. , 1991 , Early Ordovician Cool Creek Dolomite, middle Arbuckle Group, Slickhills, SW Oklahoma, USA: origin and modification...

... M. , Jr. , 1956 , “ A Correlation and Regional Stratigraphic Analysis of the Formations of the Trinity Group and the Genesis and Petrography of the Ferry Lake Anhydrite ” (summary), Trans. Gulf Coast Assoc. Geol. Soc. , Vol. VI , pp. 91 – 108 . Forgotson , James M. , 1958...

... beyond the edge of the clay. The landowners around Tulare Lake have drilled groups of wells on the Kings River fan near Hanford, which tap aquifers beneath the clay. The Hanford people claim that these wells deplete the local shallow-water supply and they are attempting to prohibit the export...

... and asbestosis due to intermixed crystalline silica and asbestos. Daroowalla (2001) Natural mineral dusts Dusts generated from desert areas, dry lake beds, agricultural areas during dry periods. Inhalation. 
 Possible silicosis, asbestosis.
 Possible uptake of metals or metalloids such as arsenic...

... al., 1998 ). The Purcell Lava is dated at 1443 ± 7 Ma, and several tuff beds within the Belt basin have also been dated and provide good internal chronology, including the Libby tuff in the middle part of the Missoula Group (1401 ± 3 Ma; Evans et al., 2000 ; Fig. 3 ). A suite of younger mafic rocks...

... at 2656 ± 3 Ma ( Qiu et al., 1999 ). Mylonites in orthogneiss northwest of the Lake Seabrook granite contain recrystallized K feldspar, green chloritic (?) biotite, brown biotite, and muscovite ( Libby et al., 1991 ). The assemblage chlorite + K feldspar + biotite + muscovite indicates temperatures of 300...

... and Moyie Lake areas is the lithostratigraphic correlative of the Creston Formation in areas to the north and west, the Ravalli Group to the south in the United States, the Appekunny and Grinnell Formations in the Whitefish and southwestern Clark Ranges (Price, 1964), and the Appekunny, Grinnell and upper...

... of the Povungnituk Group ( Francis et al. 1983 , St. Onge & Lucas 1994 ). Some of the mineralized complexes appear to represent channelized sheet-flows ( e.g., Cross Lake), whereas others appear to represent lava channels or very shallow sills with lateral “levee” facies breccias and peperites ( Lesher 1999...