Sediment provenance and dispersal in a deep marine foreland basin: the Lower Carboniferous Culm Basin, Czech Republic

Abstract

The Lower Carboniferous Culm Basin of the Czech Republic represents the most easterly and southerly part of the European Variscan foreland basin system. The NNE–SSW-trending basin is exposed along the eastern flank of the Bohemian Massif. It contains up to 7.5 km of deep marine sediment deposited as an axial turbidite system sourced from south/southwest of the basin. Heavy mineral data and clast types indicate that for much of the Viséan, sediment was sourced from a predominantly low-grade metamorphic terrane and Viséan limestones. In the latest Viséan, a progressive change in source material is recorded by an increase in high-grade metamorphic detritus. Studies of Variscan nappe pile emplacement along the eastern flank of the Bohemian Massif allow an assessment of the relationship between basin development and nappe emplacement. Basin initiation coincided with underthrusting of high grade metamorphic (Moldanubian) nappes at 340 Ma. Sedimentation was synchronous with nappe emplacement throughout the Viséan which resulted in uplift and erosion of a low grade metamorphic terrane. Moldanubian nappes were exhumed at approximately 330 Ma when high grade metamorphic detritus entered the basin. Two phases of northward-directed sediment progradation are recognized. Sediment progradation is considered to be related to changes in drainage basin size and/or climatic fluctuations within the Variscan Orogen, since sediment is inferred to have been supplied to the basin axially rather than laterally and subsidence curves show no significant change in subsidence rates. In contrast to many models of foreland basin sediment distribution, filling of the Culm Basin was largely independent of tectonic activity adjacent to the basin margin and/or of subsidence rate changes. Sedimentation in the Culm Basin commenced 10–15 Ma earlier than the rest of the Variscan foreland, and records the first impact of the northwardly propagating Variscan Orogen in northern Europe.

U-Pb zircon age of the Krásné Loučky tuffite: the dating of Visean flysch in the Moravo-Silesian Paleozoic Basin (Rhenohercynian Zone, Czech Republic)

“…More abun dant Cambro-Ordovican grains are con sis tent with the age of granitoids in the Desná Dome (Kröner et al, 2000). These results are in agree ment with the in ter pre ta tion of heavy min eral as so ci a tions de scribed by Hartley and Otava (2001), who identi fied their source in strata and in meta-ig ne ous rocks.…”

“…This is the re sult of sys tem atic work by three most dis tin guished post-World War II in ves ti ga tors of this area and is widely ac cepted. The zonation of heavy min er als in the flysch strata de scribed by Hartley and Otava (2001) also sup ports this di vi sion of the stra tig ra phy. The Moravice For ma tion is clas si fied as be long ing to goniatite zones Goa 2-3 to Gob mu (Kumpera, 1983).…”

“…The Moravice For ma tion is clas si fied as be long ing to goniatite zones Goa 2-3 to Gob mu (Kumpera, 1983). In terms of the con tent of heavy min er als, the lower part of the Moravice For ma tion be longs to the Lower Heavy Min eral Zone, and the mid dle be longs to the Mid dle Heavy Min eral Zone, while the up per sec tion ranges up to the bot tom of the Up per Heavy Min eral Zone (Hartley and Otava, 2001). …”

“…Purkyòová (2003) there fore in ter preted the plant thanatocoenosis as be ing of Early Car bon if er ous age with out youn ger flo ral el e ments. In terms of the oc cur rence of heavy min er als (Karkusz, 1989) and their uti li za tion for lo cal stra tig ra phy (Hartley and Otava, 2001), the quarry lies in the Lower and at the tran si tion to the Mid dle Heavy Min eral Zone (Fig. 1).…”

Provenance study of Permian non-marine sandstones and conglomerates of the Krkonoše Piedmont Basin (Czech Republic): exotic marine limestone pebbles, heavy minerals and garnet composition

“…In garnets 3 and 23 a weak prograde zonality can be observed. There is a slight increase in xMg from the Moldanubian garnets were recycled from Carboniferous, it can be inferred that the Moldanubian Zone was exposed to erosion during the Late Carboniferous, as indicated by the data from Kulm in central Moravia (Dvořák 1973, Hartley & Otava 2001, Kotková et al 2007.…”