Record details

Title
    Geophysical records of dispersed weathering products on the Frasnian carbonate platform and early Famennian ramps in Moravia, Czech Republic: proxies for eustasy and palaeoclimate
Statement of responsibility
    Jindřich Hladil
Other titles
    Late Devonian biotic crisis: ecological, depositional and geochemical records (Variant.)
Author
    Hladil, Jindřich, 1953-
Language
    anglicky
Source title - serial
    Palaeogeography, palaeoclimatology, palaeoecology
Vol./nr.
    Vol. 181
Pages
    p. 213-250
Year
    2002
Notes
    11 obr., 6 s.bibl.
    il.
    Zkr. název ser.: Palaeogeogr. Palaeoclimatol. Palaeoecol.
Subject group
    Anthozoa
    cyklus sedimentační
    devon
    eustáze
    famen
    Foraminifera
    frasn
    jihovýchodní svahy Českého masivu
    karbonátová platforma
    karotáž gama
    magnetická susceptibilita
    magnetit
    moravskoslezské prevariské paleozoikum
    paleoklimatologie
    Stromatoporoidea
    thorium
    uran
    vrt hluboký
    zvětrávání
Geographical name
    Branky (Vsetín)
    Brno-Mokrá
    Bystřice pod Hostýnem (Kroměříž)
    Choryně (Vsetín)
    ČR-Morava
    Rataje (Kroměříž)
    Slavkov u Brna (Vyškov)
    Švábenice (Vyškov)
    Těšany (Brno-venkov)
    Uhřice (Hodonín)
Keyword
    Carbonate
    Czech
    Dispersed
    Early
    Eustasy
    Famennian
    Frasnian
    Geophysical
    Moravia
    Palaeoclimate
    Platform
    Products
    Proxies
    Ramps
    Records
    Republic
    Weathering
Abstract (in english)
   An exceptionally high sea level in Frasnian times (early Late Devonian) changed many peneplained, cratonished and tectonically undisturbed continnetal margins of tropical belts into carbonate platfroms which became covered by thick banks of limestone. The stages marked by very pure carbonates developed during partial sea-level highstands since, when the flooding reached its maximum, the shoreline was distant and conditions for reef growth were good. An increased extension of emerged, flat, coastal areas as coupled with an opposite situaton, when oscillating sea level fell to its momentary minimum and the accomodation space available for accumulation of carbonate material was low. Subaerially exposed surfaces were subject to weathering and the products were dispersed by aeolian or aquatic means to form layers when these weathering materials were trapped in carbonates.
   This overall scenario relating to the trapping of weathering products in pure carbonates was testes at geographically isolated platform with a stableand only sloly subsiding basement (Eastern Moravia, Czech Republic). The amounts of weathering products dispersed in limestone were documented using the combined methods of "gama"-ray logging, "gama"-ray spectrometry and magnetic susceptibility measuring, i.e. according to their radioactivity (K, Th and U) and magnetism (Fe). Six third-order Frasnian eustatic cycles have been inferred from the data, with an estimated period of 1 Ma. The Late Frasnian and especially the Frasnian/Famennian (F/F) transition brought the total destruction or at least a strong overlay on this hypothetical background setting. The record of strong sea-level fluctuations in the F/F interval is shown in strong oscillations and offsets related to pronounced hiatuses and flooding surfaces.
   Such rapid sea-level fluctuation is typical for glacioeustatic control, although the present estimates of the maximum amplitudes are larger than realisable by glaciation events and may be explained in combination with tectonoeustatic models
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    4. 12. 2007
Import date
    8. 8. 2012