Petrografické složení a sedimentární prostředí klastických sedimentů spodního paleozoika (kambrium - devon)

Mgr. Helena Gilíková, Ph.D.

Doctoral thesis

Petrology composition and sedimentary environments of the Lower clastic sediments

Abstract:

Abstract Petrology composition and the sedimentary environments of the Lower Paleozoic ( Cambrian-Devonian) clastic sediments In this work the siliciclastic sediments of the Lower Cambrian and Lower-Upper Devonian are studied. These sediments are directly overlying the southern part of the Brunovistulicum. The main part of these clastics can be found under the sediments of the Carpathian nappes and the Carpathian foredeep. Except the sediments recorded in the logs also the sediments from some small outcrops were studied in the area of Brno, Tišnov and Znojmo. It deals with terrestrial sediments they were deposited in distal or medial part of the alluvial fan. From the discovery of the trace fossils and marine microfossils in Cambrian but also Devonian sediments we can consider the deposition of the sediments in shallow marine area of alluvial fan deltas or braided deltas. Although we can find in some old studies that there is no difference between the Cambrian and Devonian sediments some particular dissimilarities were identified based on new and detailed studies done on these sediments. From the petrological point of view it is possible to separate (Skoček 1980) the sediments of the Cambrian from those recognized like Devonian into three sections. The lower section which is formed by immature sediments - arcose and arcosic sandstones now contains also the Cambrian sediments. They are characterized by bigger representation of the mesostable and unstable minerals in HMA (Heavy Minerals Assemblage). The middle and upper section is build by Devonian sediments. In the middle section compare to upper one very mature sedimetns can be found. In the upper section some of the unstable components in the admixture were identified. In HM (Heavy Minerals) association ultrastable minerals predominate in both sections. From the detritic garnets in the Cambrian and Devonian sediments plentifully spessartine – almandine garnets and pyrope-almandine garnets can be found. Most part of detritic tourmaline group corresponds to schorl-dravite and by aluminium rich schorl-dravite chemical composition. In the boulder material of the Cambrian and Devonian sediments except quartz also some fragments of the granitic and metamorhosed rocks are recognized. From the comparative studies done on garnets and tourmalines and some potential source rocks of the Brno Massif can be learn that material was derived from the different stratigraphical stages and rocks with the same composition similar to the garnets and pegmatites of western part of the Brno Massif, rhyolites of the metabasic zone and gneisses from the metamorphic mantle of the Brno Massif.

Abstract:

Abstract Petrology composition and the sedimentary environments of the Lower Paleozoic ( Cambrian-Devonian) clastic sediments In this work the siliciclastic sediments of the Lower Cambrian and Lower-Upper Devonian are studied. These sediments are directly overlying the southern part of the Brunovistulicum. The main part of these clastics can be found under the sediments of the Carpathian nappes and the Carpathian foredeep. Except the sediments recorded in the logs also the sediments from some small outcrops were studied in the area of Brno, Tišnov and Znojmo. It deals with terrestrial sediments they were deposited in distal or medial part of the alluvial fan. From the discovery of the trace fossils and marine microfossils in Cambrian but also Devonian sediments we can consider the deposition of the sediments in shallow marine area of alluvial fan deltas or braided deltas. Although we can find in some old studies that there is no difference between the Cambrian and Devonian sediments some particular dissimilarities were identified based on new and detailed studies done on these sediments. From the petrological point of view it is possible to separate (Skoček 1980) the sediments of the Cambrian from those recognized like Devonian into three sections. The lower section which is formed by immature sediments - arcose and arcosic sandstones now contains also the Cambrian sediments. They are characterized by bigger representation of the mesostable and unstable minerals in HMA (Heavy Minerals Assemblage). The middle and upper section is build by Devonian sediments. In the middle section compare to upper one very mature sedimetns can be found. In the upper section some of the unstable components in the admixture were identified. In HM (Heavy Minerals) association ultrastable minerals predominate in both sections. From the detritic garnets in the Cambrian and Devonian sediments plentifully spessartine – almandine garnets and pyrope-almandine garnets can be found. Most part of detritic tourmaline group corresponds to schorl-dravite and by aluminium rich schorl-dravite chemical composition. In the boulder material of the Cambrian and Devonian sediments except quartz also some fragments of the granitic and metamorhosed rocks are recognized. From the comparative studies done on garnets and tourmalines and some potential source rocks of the Brno Massif can be learn that material was derived from the different stratigraphical stages and rocks with the same composition similar to the garnets and pegmatites of western part of the Brno Massif, rhyolites of the metabasic zone and gneisses from the metamorphic mantle of the Brno Massif.

Keywords

Východoevropská platforma, brunovistulikum, kambrium, devon, sedi mentologie, těžké minerály, provenience, East European Craton, brunovistulicum, Cambrian, Devonian, sedi mentology, heavy minerals, provenance

Language used: Czech

Date on which the thesis was submitted / produced: 13. 12. 2007

Thesis defence

• Date of defence: 13. 12. 2007
• Supervisor: doc. RNDr. Jindřich Hladil, DrSc.
• Reader: prof. RNDr. Jiří Kalvoda, CSc., prof. RNDr. Jan Zapletal, CSc.

Masaryk University

Faculty of Science

Doctoral programme / field:
Geology (4-years) / Geological Sciences