DETRITUS FROM VARISCAN LOWER CRUST IN ROTLIEGEND SANDSTONES OF THE INTRA-SUDETIC BASIN, SW POLAND, REVEALED BY DETRITAL HIGH-PYROPE GARNET

作者：Biernacka Julita^*

来源：Annales Societatis Geologorum Poloniae, 2012, 82(2): 127-138.

• Permian
• Sudetes
• sandstone
• provenance
• detrital garnet
• granulite

It is well established that pebbles in the Sudetic Permian conglomerates were derived from the nearby Variscan massifs of upper-crustal composition. How ever, the provenance of the sand-size grains re mains enigmatic. Electron microprobe analyses (EMPAs) of detrital garnet from up per Rotliegend conglomerates and sand stones ex posed at Golisk, the Intra-Sudetic Basin, showed a distinct assemblage dominated by high-pyrope (high-grossular) almandine, typical of high-grade metamorphic rocks, such as high-pressure granulites. These results, coupled with a previously reported population of similar detrital garnet in the stratigraphically equivalent conglomerates and sand stones of the Karkonosze Piedmont Basin, suggest regional in put of detrital lower-crustal material. This detritus was derived ultimately either from the Moldanubian Zone of the Bohemian Massif, or from high-grade rocks of the Orlica-Snieznik Massif that were ex posed in the Carboniferous-Permian. Permian siliciclastic rocks might have covered a large part of the Sudetes. During the Me so zoic and Palaeogene, these rocks might have been recycled further, contributing high-pyrope garnet, as an accessory mineral, into siliciclastic rocks of the Sudetes and their foreland.

• 出版日期2012