ČOPJAKOVÁ, Renata and Radek ŠKODA. Detritické a autigenní REE minerály v sedimentech kulmu Drahanské vrchoviny, jejich význam pro studium provenience klastického materiálu a procesů diagenese (Detrital and authigennic REE minerals from Culm sediments of Drahany Uplands, their significance for provenance study of clastic material and diagenetic processes). Acta Musei Moraviae, Sci. Geol. Brno: Moravské zemské muzeum, 2006, vol. 91, No 1, p. 105-127, 105-129. ISSN 1211-8796.
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Basic information
Original name Detritické a autigenní REE minerály v sedimentech kulmu Drahanské vrchoviny, jejich význam pro studium provenience klastického materiálu a procesů diagenese
Name (in English) Detrital and authigennic REE minerals from Culm sediments of Drahany Uplands, their significance for provenance study of clastic material and diagenetic processes
Authors ČOPJAKOVÁ, Renata (203 Czech Republic, guarantor) and Radek ŠKODA (203 Czech Republic).
Edition Acta Musei Moraviae, Sci. Geol. Brno, Moravské zemské muzeum, 2006, 1211-8796.
Other information
Original language Czech
Type of outcome Article in a journal
Field of Study 10500 1.5. Earth and related environmental sciences
Country of publisher Czech Republic
Confidentiality degree is not subject to a state or trade secret
RIV identification code RIV/00216224:14310/06:00036849
Organization unit Faculty of Science
Keywords in English authigenic minerals; rhabdophane-(Ce); synchysite-(Ce); thorogummite; monazite alteration; diagenesis; Drahany Upplands
Tags International impact, Reviewed
Changed by Changed by: doc. Mgr. Radek Škoda, Ph.D., učo 21802. Changed: 19/10/2009 18:22.
Abstract
Electron microprobe study of mineral chemistry, chemical age and alteration of detrital monazite as well as composition and textural position of authigenic REE minerals - rhabdophane-(Ce), synchysite-(Ce) and thorogummite - have been carried out on the samples of clastic Culm sediments from the Drahany Uplands. Detrital monazite is commonly homogeneous in BSE, only it exceptionally shows an irregular zoning. Some monazite grains are replaced by apatite and hydrated REE-minerals propagating from rim inwards and along fractures. Three different stages of detrital monazite alteration were observed: the first stage is characterized by minor depletion of heavy REE (Gd, Dy, Er), Y, Th and Pb, but it does not show any significant deviations in the ideal stochiometry. The second stage is accompanied by strong depletion of Gd, Dy, Er, Y, Th, U and Pb, the stochiometry is disrupted and totals decrease up to 98-96 wt. percent of oxides. The last stage is characterized by depletion of light REE (La, Ce) and all above mentioned elements. Grade of alteration positively correlates with intensity of diagenesis from the Myslejovice to the Protivanov Formation. Unaltered detrital monazite from all stratigraphic units and monazite from pebbles in the Račice conglomerates were used for U-Th-Pb electron microprobe dating. Majority of detrital monazite from Protivanov, Rozstání and lower part of Myslejovice Formation displays Viséan age (339 err 15, 331 err 19 and 335 err 14 Ma, respectively). Monazite from clasts of mica-schist, orthogneiss and aplite yield similar ages: 330 err 21 Ma, 332 err 22 Ma and 331 err 17 Ma, respectively. Three small grains of monazite gave late Devonian age 373 err 49 Ma. One detrital monazite from lower part of Myslejovice Formation yielded Precambrian age 603 err 65 Ma, which is similar to the Moravo-Silesian Zone (Brno Batholith or orthogneisses protholite). Monazite dating does not support beginning of sedimentation at the border Tournai/Viséan and diachronous deposition of the flysch formations. It also suggests similar stratigraphic range of the Protivanov, Rozstání and Lower part of Myslejovice Formation.
Abstract (in English)
Electron microprobe study of mineral chemistry, chemical age and alteration of detrital monazite as well as composition and textural position of authigenic REE minerals - rhabdophane-(Ce), synchysite-(Ce) and thorogummite - have been carried out on the samples of clastic Culm sediments from the Drahany Uplands. Detrital monazite is commonly homogeneous in BSE, only it exceptionally shows an irregular zoning. Some monazite grains are replaced by apatite and hydrated REE-minerals propagating from rim inwards and along fractures. Three different stages of detrital monazite alteration were observed: the first stage is characterized by minor depletion of heavy REE (Gd, Dy, Er), Y, Th and Pb, but it does not show any significant deviations in the ideal stochiometry. The second stage is accompanied by strong depletion of Gd, Dy, Er, Y, Th, U and Pb, the stochiometry is disrupted and totals decrease up to 98-96 wt. percent of oxides. The last stage is characterized by depletion of light REE (La, Ce) and all above mentioned elements. Grade of alteration positively correlates with intensity of diagenesis from the Myslejovice to the Protivanov Formation. Unaltered detrital monazite from all stratigraphic units and monazite from pebbles in the Račice conglomerates were used for U-Th-Pb electron microprobe dating. Majority of detrital monazite from Protivanov, Rozstání and lower part of Myslejovice Formation displays Viséan age (339 err 15, 331 err 19 and 335 err 14 Ma, respectively). Monazite from clasts of mica-schist, orthogneiss and aplite yield similar ages: 330 err 21 Ma, 332 err 22 Ma and 331 err 17 Ma, respectively. Three small grains of monazite gave late Devonian age 373 err 49 Ma. One detrital monazite from lower part of Myslejovice Formation yielded Precambrian age 603 err 65 Ma, which is similar to the Moravo-Silesian Zone (Brno Batholith or orthogneisses protholite). Monazite dating does not support beginning of sedimentation at the border Tournai/Viséan and diachronous deposition of the flysch formations. It also suggests similar stratigraphic range of the Protivanov, Rozstání and Lower part of Myslejovice Formation.
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