Korelacja lamin w chronohoryzontach wapienia jasielskiego i z wapenia z Zagórza (Karpaty Zewnętrzne)

Grzegorz Haczewski

Abstract


 Tak zwane łupki jasielskie znane są jako regionalny poziom czasowy. Nazwa ta pierwotnie dotyczyła ich dolnego poziomu, a jej obecne, zniekształcone brzmienie nie odpowiada litologii. Autor nazywa

dolny poziom wapieniem jasielskim, górny zaś - wapieniem z Zagórza. Laminy wapienia jasielskiego korelują się na odległości 240 km w jednostkach śląskiej i skolskiej. W wapieniu z Zagorza niektóre laminy są ciągle w jednostce skolskiej i śląskiej polskich Karpat oraz w odległym o 550 km profilu potoku Vinetisu w Rumunii. Ciągłość lamin potwierdza izochroniczność wapieni i umożliwia precyzyjne chronokorelacje, np. pojedynczych turbidytów na duże odległości. Chronohoryzonty wapieni nie powinny być wprowadzane do podziałów litostratygraficznych, gdyż nie są ani warstwami, ani też litosomami, lecz przecinają ukośnie jednostki litostratygraficzne.

 

CORRELATION OF LAMINAE IN CHRONOHORIZONS OF JASŁO LIMESTONE AND ZAGÓRZ LIMESTONE (OUTER CARPATHIANS)

 

Oligocene sequences of the Outer Carpathians, described informally as Menilite-Krosno series, contain thin intercalations of pelitic limestones. The limestones occur at various levels, grouped in several discrete horizons. The most characteristic and widely distributed of these are three horizons situated near one another in the sequence, known as Jasło shales. They are considered as isochronous within the whole area of their occuuence. The author demonstrates a confused character of their name and proposes a name “(laminated) Jasło limestone” for the lower horizon – to conform with their original name introduced by V. Uhlig (1883) and with their lithology. For the upper horizon a name “Zagórz limestone” is proposed.

Correlation of polished sections of Jasło limestone (max. total thickness of limestone layers – 40 cm) reveals a perfect continuity of fine laminae over distances up to 240 km in Silesian and Skole tectonic-facies units. Zagórz limestone shows only crude, indistinct lamination, much less favourable for correlations.

Nevertheless, some elements of stratification within the thickest 4 cm layer appeard to be consistently found in the same position in all correlated sections from Polish Carpathians, while other laminae were less continuous. Those laterally persistent elements are also present in the same order in a sample from southern part of the East Carpathians in Roumania – distant 550 km from the type section in Zagórz.

Continuity of laminae is an important, independent proof of isochroneity of the limestone horizons.

The chronohorizons of Jasło limestone and Zagórz limestone should be not introduced to lithostratigraphic classification, as they do not form individualized lithosomes, are only subordinate intercalations in completely different lithological complexes, and cut diagonally through the boundaries of individual lithosomes, which themselves should be regarded as constitutional elements of a future formal lithostratigraphy.

 


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