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Show Minerals of the' McCarthy Grand Magnesium Well, Co., Utah Bronson Stringham University of Utah The McCarthy well was drilled by the American Potash Co. for the purpose of investigating the magnesium content of the Paradox formation which occurs in Grand Co., Utah. The well is situated in section 16, township 22 south, range 19 east, Salt Lake base and meridian. Through the efforts of the University of Utah Research Committee, twenty-eight feet of the core which carries magnesium was received by the University geology de partment for study. Support for the work was generously given by the Research Committee for which acknowledgement is grate fully extended. ... The complete core averaged about 4.5 cm. in diameter but only Y4 of this was received since it had been sawed longitudin ally in quarters, apparently at the drill site. This amount, how Sixteen thin-sections were pre ever, proved adequate for study. pared and observations of these were supplemented by the frag ment oil immersion method of determination with the petrographic microscope. It was found that the minerals halite (NaCI), sylvite (KCI) and carnallite (K MgCIg6H20) were by far the most com mon but considerable anhydrite (CaSO4) and kieserite (K2MgCa2 SO 4H20) were also present. Clastic material included a little quartz, chalcedony, carbonaceous and clayey material and some finely disseminated hematite (FezOg). A discussion of each of ... ... ... these constituents follows: CHEMICAL PRBCIPITATES all specimens studied. Cleavage frag diameter were common and all other 2Yz up minerals were eventually observed to be entirely included within halite crystals. Smooth .but irregularly curved boundaries exist between halite, sylvite and carnallite, Simulating what is corn monly considered "mutual boundaries." Halite was found ments to cm. in ... in Sylvite is less common than halite and usually forms smaller crystals but like halite contains all other minerals included within it. Much dusty hematite causes some sylvite to appear reddish but many clear fragments 'Were observed. Two measurements found the index of refraction to be 1.490. Carnallite crystals ranqed in size from 0.1 cm. to 2 cm. in diameter and seemed to be remarkably free of inclusions except 47 |
