A high-resolution, multiproxy stratigraphic analysis of the Devonian–Carboniferous boundary sections in the Moravian Karst (Czech Republic) and a correlation with the Carnic Alps (Austria)

Abstract

A multidisciplinary correlation of the Devonian–Carboniferous (D–C) boundary sections from the Moravian Karst (Czech Republic) and the Carnic Alps (Austria), based on conodont and foraminifer biostratigraphy, microfacies analysis, field gamma-ray spectroscopy (GRS), carbon isotopes and element geochemistry, is presented in this paper. The study is focused on the interval from the MiddlePalmatolepis gracilis expansaZone (Late Famennian) to theSiphonodella sandbergiZone (Early Tournaisian). In Lesní lom (Moravian Karst), a positive δ13C excursion in theBisphatodus costatus–Protognathodus kockeliInterregnum from a distinct laminated carbonate horizon is correlated with a carbon isotope excursion from the Grüne Schneid section of the Carnic Alps and is interpreted as the equivalent of the Hangenberg black shales and a local expression of the global Hangenberg Eventsensu stricto. Higher up at both sections, a significant increase in the terrigenous input, which is inferred from the GRS signal and elevated concentrations of terrigenous elements (Si, Ti, Zr, Rb, Al, etc.), provides another correlation tieline and is interpreted as the equivalent of the Hangenberg sandstone. Both horizons are discussed in terms of relative sea-level fluctuations and palaeoceanographic changes. Recent studies show that conodont biostratigraphy is facing serious problems associated with the taxonomy of the first siphonodellids, their dependence on facies and discontinuous occurrences of protognathodids at the D–C boundary. Therefore, the correlative potential of geochemical and petrophysical signatures is high and offers an alternative for the refining of the problematic biostratigraphic division of the D–C boundary.

Petrophysical and geochemical signature of the Hangenberg Events: an integrated stratigraphy of the Devonian-Carboniferous boundary interval in the Northern Rhenish Massif (Avalonia, Germany)

“…The selected petrophysical and geochemical proxies reveal similar patterns between the sections described herein and those previously studied in the Moravian Karst (Lesní lom, Mokrá and Křtiny quarries; Kumpan et al 2014a) and Carnic Alps (Grüne Schneid; Kaiser et al 2006, Kumpan et al 2014aFig. 17).…”

“…A decrease in terrigenous proxies (CGR, Zr/Al and Al) and increase in redox-sensitive U/Th and Mn take place just below the Hangenberg Black Shale Event in the high praesulcata Zone. U/Th reaches positive peaks and K/Al decreases in the Hangenberg Black Shale Event, coeval with δ 13 C positive excursion (Kaiser et al 2006, Kumpan et al 2014a). Increase in detrital proxies (CGR, Zr/Al or Al) related to the Hangenberg Sandstone Event is well correlated among the above-mentioned sections.…”

“…Glacigenic deposits documented in South and North America, South and possibly Central Africa were dated by palynomorphs as synchronous with the sea-level fall (Isaacson et al 1999(Isaacson et al , 2008Streel 2002;Caputo et al 2008;Brezinski et al 2008Brezinski et al , 2010. Incised valleys infilled by siliciclastics were documented in Morocco ) and the siliciclastic intervals overlying the Hangenberg Black Shale Event horizon in the Central Hunan (Hance et al 1994), in Ohio and Kentucky (Coleman & Clayton 1987) or Moravian Karst (Kumpan et al 2014a), as well as in the studied sections from the Rhenish Massif (Bless et al 1993, see Kaiser et al 2011 andreferences therein). Inevitably for such a sea-level drop, gaps of variable stratigraphic extent are known from DCB in many places, e.g., Belgium (Hance et al 1994, Kumpan et al 2014b, Spain (García-Alcalde & Menédez-Alvarez 1988), Colorado (Myrow et al 2013) or Kentucky (Coleman & Clayton 1987).…”

Conodonts across the Devonian/Carboniferous boundary in SE Sardinia (Italy)

“…Several sections are under investigation around the world, both restudying already known localities (i.e. Mossoni et al 2013, Kumpan et al 2014) and exploiting new ones (i.e. Bahrami et al 2011, Becker et al 2013, Girard et al 2014, Kumpan et al 2014, Kalvoda et al 2015.…”

The Devonian/Carboniferous boundary in the Holy Cross Mountains (Poland)

“…This phe nom e non was linked with a large-scale gla cial ep i sode in the south ern hemi sphere, causing rel a tively rapid sea level fall (Streel et al, 2000;Sandberg et al, 2002;Caputo et al, 2008;Isaacson et al, 2008;Kalvoda et al, 2013;Kumpan et al, 2013).…”