Major and trace elements in pyropealmandine garnets as sediment provenance indicators of the Lower Carboniferous Culm sediments, Drahany Uplands, Bohemian Massif

ČOPJAKOVÁ, Renata a Petr SULOVSKÝ. Major and trace elements in pyropealmandine garnets as sediment provenance indicators of the Lower Carboniferous Culm sediments, Drahany Uplands, Bohemian Massif. Lithos. 2005, roč. 82, 1-2, s. 51-70. ISSN 0024-4937.

Základní údaje

Originální název

Major and trace elements in pyropealmandine garnets as sediment provenance indicators of the Lower Carboniferous Culm sediments, Drahany Uplands, Bohemian Massif

Název česky

Major and trace elements in pyropealmandine garnets as sediment provenance indicators of the Lower Carboniferous Culm sediments, Drahany Uplands, Bohemian Massif

Autoři

ČOPJAKOVÁ, Renata (203 Česká republika, garant) a Petr SULOVSKÝ (203 Česká republika)

Vydání

Lithos, 2005, 0024-4937

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Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10500 1.5. Earth and related environmental sciences

Stát vydavatele

Česká republika

Utajení

není předmětem státního či obchodního tajemství

Impakt faktor

Impact factor: 2.243

Kód RIV

RIV/00216224:14310/05:00030977

Organizační jednotka

Přírodovědecká fakulta

UT WoS

000229418400004

Klíčová slova anglicky

Garnet chemistry; Trace elements; Granulites; Lower Carboniferous Culm Basin; Provenance; Bohemian Massif

Štítky

Bohemian massif, garnet chemistry, granulites, Lower Carboniferous Culm Basin, provenance, trace elements

Příznaky

Mezinárodní význam, Recenzováno

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Anotace

V originále

The Lower Carboniferous Culm Basin is part of the European Variscan foreland basin. Garnet is an abundant heavy mineral at all stratigraphic levels of the Culm sediments (the Protivanov, Rozstání and Myslejovice Formation from base to top). This paper compares the major element (electron microprobe) and trace element (LA-ICP-MS) compositions of garnet for the purpose of studying the provenance of the Culm sediments. The polymict garnet assemblages ranging from the Protivanov to lower part of the Myslejovice Formation (Goniatite zones Pe-Go) pass into oligomict ones dominated by pyropealmandine garnets (uppermost part of the Myslejovice Formation; Goniatite zones Go-Go). As the predominant low-grossular pyropealmandines from oligomict garnet assemblages are very uniform and homogeneous in major element composition, we studied their trace element composition and zoning. Pyropealmandine garnets are poor in LREE and show enrichment in HREE; the chondrite-normalized patterns are almost flat from Dy to Lu and show a significant negative Eu anomaly, typical for granulite-grade garnets. Major element compositions of detrital low-grossular pyropealmandines can only be matched with some granulites and garnetiferous felsic gneisses of the Bohemian Massif. Garnets from granulites cropping out at the present-day erosion level of the Bohemian Massif have usually higher Ca and/or lower Mg contents. The major and trace element compositions and zoning patterns of pyropealmandine garnets from the upper part of the Myslejovice Formation compare well with garnets from the Miroslav granulites and small Moldanubian granulite bodies west of the Třebíč Massif. The Moldanubian granulites are commonly associated with mantle-derived peridotites and eclogites. The presence of detrital Cr-spinels with high Cr# and low Mg# (single grains of Cr-spinels and fine-grained kelyphitic intergrowths of Cr-spinel with chlorite) comparable with spinel types from Moldanubian peridotites could indicate the joint occurrence of peridotites, serpentinized peridotites, and granulites at the erosion level of the Bohemian Massif during the deposition of the uppermost Culm sediments (325 Ma). While the older Culm sediments (polymict garnet assemblages) represent the accumulation of clastic material from the northern and north-western areas (Moravo-Silesian and Lugian Zone), the uppermost Culm sediments (oligomict garnet assemblages) contain material from western and south-western areas (Moldanubian Zone and Moravian Nappe); the general influx of clastic material changed as a result of clockwise rotation of the eastern part of the Variscan belt during this time span (340325 Ma).

Česky

The Lower Carboniferous Culm Basin is part of the European Variscan foreland basin. Garnet is an abundant heavy mineral at all stratigraphic levels of the Culm sediments (the Protivanov, Rozstání and Myslejovice Formation from base to top). This paper compares the major element (electron microprobe) and trace element (LA-ICP-MS) compositions of garnet for the purpose of studying the provenance of the Culm sediments. The polymict garnet assemblages ranging from the Protivanov to lower part of the Myslejovice Formation (Goniatite zones Pe-Go) pass into oligomict ones dominated by pyropealmandine garnets (uppermost part of the Myslejovice Formation; Goniatite zones Go-Go). As the predominant low-grossular pyropealmandines from oligomict garnet assemblages are very uniform and homogeneous in major element composition, we studied their trace element composition and zoning.