Economic Geology, Volume 10

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Economic Geology Publishing Company, 1915 - Geology

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Page 130 - SF, Copper in the red beds of the Colorado Plateau region : US Geol. Survey Bull. 260, pp. 221-232, 1905.
Page 60 - BUTLER, BS, and GALE, HS, Alunite — a newly discovered deposit near Marysvale, Utah: US Geol.
Page 114 - EMMONS, WH, and LANEY, FB, Preliminary report on the mineral deposits of Ducktown, Tenn.: Bull.
Page 20 - The region was then covered by a body of water probably cut off from the sea, and salt or highly alkaline. The alkaline waters by some means gained access to the heated portions of the syenite and dissolved its minerals. The heated waters returned to the surface heavily charged with the constituents of the syenite in solution. They were still efficient solvents, however, and acted upon the syenite at the surface, removing most of the silica along with the lime and alkalies, but leaving the alumina...
Page 36 - DEPOSITS. A study of the general geology, chemistry, and mineralogy of the deposits has led to the following conclusions: 1. The bauxite and associated clays are the products of surface weathering of the syenite by normal processes of rock decomposition, and are in no sense chemical sediments. Bauxite deposits occurring on the syenite surface have developed in situ from the syenite. The deposits developed in situ from the syenite show evidence of downward secondary concentration of alumina. Bauxite...
Page 112 - The apically-truncated stocks are monzonitic to diorritic in composition, the deeper truncated stocks have the composition of granodiorite to granite. The ore deposits associated with the laccoliths and deeper truncated stocks have been of comparatively slight commercial importance, while associated with the apically-truncated stocks are deposits of great value. It is believed that the lack of large deposits associated with the laccoliths is due to the fact that after intrusion they were sealed off...
Page 242 - Uraninite or pitchblende occurs in nature (a) in small amounts in granite pegmatites and (b) in intimate association with commoner metallic minerals in a few ore deposits. Quartz Hill, near Central City, is the one important locality in the United States and one of the few in the world that exemplifies the second mode of occurrence. For a number of years a small and sporadic production has come from this locality and has been used mainly in experimental work and for museum specimens. Pitchblende...
Page 42 - In many instances it has been necessary to remove the upper eighteen inches or two feet of high silica ore before mining. This increase in silica toward the surface may be due to an actual downward secondary concentration of alumina. Those portions of kaolin and halloysite which persist after the main portion of the kaolinized syenite has been altered to bauxite are the dense impervious parts. Bauxite is soluble in surface solutions to a certain extent and on being dissolved and carried downward...
Page 41 - The gradation from syenite to kaolin is shown by numerous analyses to be of a normal type of surface weathering. In the following table are analyses of samples from the same locality. No. 1 is fresh syenite from the cut near the Lantz Mine. No. 2 is partially kaolinized syenite. No. 3 is completely kaolinized syenite containing some bauxite, and No. 4 is bauxite. TABLE I.
Page 95 - BOUTWELL, JM, Economic geology of the Bingham mining district, Utah: US Geol. Survey Prof. Paper 38, 1905.

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