3,800-Myr granitic gneiss in south-western Minnesota

S. S. Goldich; C. E. Hedge

doi:10.1038/252467a0

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3,800-Myr granitic gneiss in south-western Minnesota

S. S. Goldich·C. E. Hedge

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Abstract

WE have previously arrived at an age of 3,550 Myr for granitic 1 gneiss in the vicinities of Morton and Montevideo in the Minnesota River valley, south-western Minnesota. We now report new Rb–Sr analyses (Table 1) and an age of 3,800 Myr for the fine grained foliated phase of the Montevideo Gneiss of Lund 2 . The rocks have undergone a complex history of metamorphism which remains to be deciphered, but the age determinations reveal that the geological mapping and previous interpretations did not provide a proper basis for sampling.

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Source-reported bounding extent: 43.43696596521823° to 45.29034662473613° latitude; -96.50390625° to -93.33984375° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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S. S. Goldich, C. E. Hedge. 1974. 3,800-Myr granitic gneiss in south-western Minnesota. https://doi.org/10.1038/252467a0

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