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High-Potash Dikes in The Homestake Mine, Lead, South Dakota

Noble, James A. (1948) High-Potash Dikes in The Homestake Mine, Lead, South Dakota. Geological Society of America Bulletin, 59 (9). pp. 927-940. ISSN 0016-7606. doi:10.1130/0016-7606(1948)59[927:hdithm];2.

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Widely scattered bodies of Tertiary intrusive porphyry crop out in the northern Black Hills, in greatest abundance in a circular area of about 10-mile radius with Lead and the Homestake Mine at the center. Five rock types are represented: rhyolite; quartz monzonite; monzonite; grorudite; and phonolite. A swarm of rhyolite dikes in the Homestake Mine comprise rocks of two distinct compositional types: so-called low potash rocks with about equal parts of orthoclase, albite, and quartz; and high potash rocks which consist of orthoclase and quartz. There are no ferro-magnesian minerals in either type of rock. While only a few other occurrences of rocks of the high potash type have been described, it does not seem possible to dismiss this rock type from a genetic classification on the basis of inaccurate description. Three possible modes of origin for similar rocks have been proposed: selective assimilation of potash-rich wall rocks; hydrothermal introduction of potash; or, most probably, normal differentiation with strong reaction, followed by hindered reaction (Bowen, 1928).

Item Type:Article
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URLURL TypeDescription[927:hdithm];2DOIArticle
Additional Information:© 1948 Geological Society of America. Manuscript received by the Secretary of the Society, August 19, 1947.
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Caltech Division of Geological Sciences468
Issue or Number:9
Record Number:CaltechAUTHORS:20220325-703103300
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Official Citation:James A. Noble; High-Potash Dikes in The Homestake Mine, Lead, South Dakota; 59 (9): 927–940. doi:[927:HDITHM]2.0.CO;2
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:114073
Deposited By: Tony Diaz
Deposited On:25 Mar 2022 17:27
Last Modified:25 Mar 2022 17:27

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