Abstract
Welin, E., Christiansson, K., and Nilsson, Ö.: Rb‐Sr age dating of intrusive rocks of the Haparanda suite. Geologiska Föreningens i Stockholm Förhandlingar. Vol. 92, pp. 336–346. Stockholm, September 30, 1970. The infracrustal rocks of the Haparanda suite range in composition from gabbro to granodiorite and are considered to be synkinematic intrusions into the folded Svecofennian‐Karelian supracrustals. Rb‐Sr investigations on eight whole rock samples and five minerals indicate an isochron age of 1880 m. y. and an initial Sr87/Sr86 ratio of 0.706. This ratio implies that the analyzed intrusive rocks were not derived by melting of ancient sialic crust. Two biotites included in the calculation fit the isochron within the limits of error and indicate that a subsequent addition or subtraction of Rb or Sr in the rocks has not taken place due to later metamorphism or weathering.
Published Version
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