Informace o publikaci
Původ spessartinem bohatých granátů v drobách Drahanské vrchoviny
| Autoři | |
|---|---|
| Rok publikování | 2003 |
| Druh | Článek ve sborníku |
| Konference | Moravskoslezské Paleozoikum 2003 |
| Fakulta / Pracoviště MU | |
| Citace | |
| Klíčová slova | spessartine rich garnets; provenance; Drahany Culm; Czechoslovakia |
| Popis | Studies of garnet geochemistry by electron microprobe is widely applicable in solving problems of provenance. Spessartine-rich garnet is rather less common then other main garnet species which makes it a provenance sensitive indicator. This paper presents example that show the value of spessartine-rich garnets in provenance study of Lower Carboniferous sediments of Drahany Upland. Polymict garnet assemblages of Drahany Upland (Protivanov-, Rostání- and lower part of Myslejovice Formation, Goniatite zones Peg a Goa) with various mixture of garnet geochemistry contain more than 20% of spessartine-enriched garnets. The change into pyrope-almandines predominant oligomict assemblages (upper part of Myslejovice Formation, Goniatite zones Gob a Gog) is characteristic among others by a sudden decrement of spessartine-rich garnets below 5% and reflects changes in provenance. It is commonly believed that the clastic material originates from crystalline terrains situated West of Culm sedimentary basin. The study of spessartine-enriched garnet geochemistry in polymict garnet assemblages provides cogent evidence of supply clastic material from northern situated geological units (Silesicum and Orlice-kladsko Crystalline Unit). The youngest sediments (polymict garnet assemblages) were not ever supplied by the Silesicum and Orlice-kladsko Crystalline Unit but material came from West. Certain part of spessartine-enriched garnets can arise from recycled older Culm sediments. |