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

Danish medical bulletin

Kalvoda J¹  Frýda J¹  Becker RT¹  Hartenfels S¹  Kumpan T¹  Bábek O¹  Matys Grygar T¹ 

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关键词: Famennian;    Tournaisian;    Hangenberg Events;    gamma-ray spectrometry;    magnetic susceptibility;    element geochemistry;    stable carbon isotope geochemistry;   

DOI  :  

学科分类：医学（综合）

来源: Den Almindelige Danske Laegeforening

【 摘 要 】

Petrophysical (gamma-ray spectrometry, magnetic susceptibility) and geochemical (X-ray fluorescence spectrometry and inorganic carbon isotope geochemistry) methods are used for stratigraphic correlations and palaeoenvironmental interpretations of the Devonian-Carboniferous boundary interval in the northern part of the Rheinisches Schiefergebirge, Germany. Sections at Oese, Oberrodinghausen and Drewer were studied in the stratigraphic range from the Famennian Upper expansa Zone to the Tournaisian Lower crenulata Zone. The Famennian Wocklum Limestone reveals distinctive cyclicity in the limestone and shale arrangement, whose primary origin has been supported by correlation with K/Al ratio changes. Lower-order K/Al cyclicity follows bundles of alternating layers. On the other hand, Zr/Al cyclicity is rather independent on facies and K/Al and duration of Zr/Al cycles was estimated to be 370 ka, which is close to 405 ka eccentricity. Correlations of the curve patterns of Computed Gamma Ray, U/ThGRS, bulk magnetic susceptibility, K/Al, Zr/Al, S, and Mn proxies have been employed for regional correlation. Our dataset confirms previous palaeoenvironmental interpretations of the Hangenberg Events and additionally provides information on gradual decrease in a bottom oxygenation just prior the events. Peaks in redox and palaeoproductivity proxies (U/Th, Cu+Ni+Zn+Pb) occur in the Hangenberg Black Shale in all studied sections. Although sedimentation of the Hangenberg Black Shale took place during the deepening step, the enhanced palaeoproductivity and hypoxia to anoxia were the main cause of its deposition. An interregional correlation of the Devonian-Carboniferous intervals from the northern Rhenish Massif, Moravian Karst and Carnic Alps was carried out and underlines the potential for further chronostratigraphic definitions.

【 授权许可】

Unknown