Rb-Sr whole-rock isotopic study of late Archaean and early Proterozoic granitoid intrusions, Kainuu, eastern Finland

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Authors:Halliday, A. N.; Luukkonen, E. J.; Bowes, D. R.
Author Affiliations:Primary:
Univ. Mich., Dep. Geol. Sci., United States
Volume Title:Bulletin of the Geological Society of Finland
Source:Bulletin of the Geological Society of Finland, 60(2), p.107-113. Publisher: Geological Society of Finland, Helsinki, Finland. ISSN: 0367-5211
Publication Date:1988
Note:In English
Summary:A tonalite-granodiorite-granite suite emplaced during a late Archaean deformational phase yields a six-point isochron age of approx 2500 m.y. and an initial 87 Sr/ 86 Sr of 0.7044. A rapakivi-type granite suite emplaced after the late Archaean episode and before the emplacement of early Proterozoic Jatulian dolerites yields a six-point isochron age of approx 2290 m.y. and an initial 87 Sr/ 86Sr of 0.7036. Both ages are approx 150-200 m.y. younger than corresponding U/Pb mineral ages for the same rock: the difference is interpreted as representing continued isotopic homogenization prior to uplift, although the mechanism for such large scale, fluid phase mass transfer is not well understood. [R.E.S.]
Subjects:Absolute age; Archean; Dates; Geochronology; Granites; Granodiorites; Igneous rocks; Intrusions; Neoarchean; Paleoproterozoic; Plutonic rocks; Precambrian; Proterozoic; Rb/Sr; Upper Precambrian; Whole rock; Europe; Finland; Kuhmo Finland; Oulu Finland; Scandinavia; Western Europe; Eastern Finland; Hyrynsalmi; Kainuu
Abstract Numbers:90M/0010
Record ID:1992064102
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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