Late Archean basement in the Bangenhuken Complex of the Nordbreen Nappe, western Ny-Friesland, Svalbard |
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| Authors: | Fredrik J. Hellman David G. Gee Patrik Witt-Nilsson |
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| Affiliation: | F. J. Hellman, Dept. of Mineralogy and Petrology, Lund University, Sölvegatan 13, SE-223 62 Lund, Sweden (currently at Scancem Research AB, Box 104, SE-62030 Slite, Swede;D. G. Gee &P. Witt-Nilsson, Dept. of Geophysics, Uppsala University, Villavägen 16, SE–752 36 Uppsala, Sweden. |
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| Abstract: | The rocks of western Ny-Friesland, northern Svalbard, are part of a tectonostratigraphy including four thrust sheets, each composed mainly of orthogneisses overlain by younger metasedimentary rocks. Previous geochronological studies have shown that the orthogneisses are dominated by ca. 1750 Mya granitoids. This study of a quartz-monzonite in one of the thrust sheets, the Nordbreen Nappe, yields a single-zircon U-Pb ion-microprobe age of 2709 Ø 28 My. This is the oldest rock unit so far reported in the Svalbard Caledonides. However, age-determinations on detrital zircons in the metasediments of western Ny-Friesland have shown that Late Archean rocks were prominent sources. The new ages presented here provide the first evidence of a local source for these sedimentary rocks. |
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