Wiek formacji skalskiej dewonu świętokrzyskiego
Abstract
ON THE AGE OF THE SKAŁA FORMATION (DEVONIAN OF THE HOLY CROSS MTS)
Summary
The pelagic tentaculite species Nowakia otomari Boucek, indicative for its own zone has been found In the Brachiopod Shale and Microcyclus Shale of the Skały Formation. Holy Cross Mts. Poland. N. otomari occurs also in Bohemia in the Srbsko Formation being abundant in its lower part - Kacak shales ( 12). However, the underlying Chotec Limestone contains the tentaculites of N. sulcata lineage, which cannot be ancestral for N. otomari (12, 29). The question arises whether the appearance of N. otomari, certainly an effect of expansion of distribution area, was synchronous in the Holy Cross Mts. and Bohemia. It is suggested that development of N. otomari took place in the allopatric, in relation to N. sulcata, lineage and that the appearances and disappearances of these two lineages in Mid-Europe were results of ecological competition between them. Taking into account palaeogeographic factors it can be expected that invasion of the Holy Cross Mts. area by N. otomari should occur not earlier than of Bohemia. Therefore, the Brachiopod Shale of the Skały Formation is not older than the Karak shales, which contain ammonites of C. crispiforme Zone, and most probably it is of latest Eifelian or earliest Givetian age.
Summary
The pelagic tentaculite species Nowakia otomari Boucek, indicative for its own zone has been found In the Brachiopod Shale and Microcyclus Shale of the Skały Formation. Holy Cross Mts. Poland. N. otomari occurs also in Bohemia in the Srbsko Formation being abundant in its lower part - Kacak shales ( 12). However, the underlying Chotec Limestone contains the tentaculites of N. sulcata lineage, which cannot be ancestral for N. otomari (12, 29). The question arises whether the appearance of N. otomari, certainly an effect of expansion of distribution area, was synchronous in the Holy Cross Mts. and Bohemia. It is suggested that development of N. otomari took place in the allopatric, in relation to N. sulcata, lineage and that the appearances and disappearances of these two lineages in Mid-Europe were results of ecological competition between them. Taking into account palaeogeographic factors it can be expected that invasion of the Holy Cross Mts. area by N. otomari should occur not earlier than of Bohemia. Therefore, the Brachiopod Shale of the Skały Formation is not older than the Karak shales, which contain ammonites of C. crispiforme Zone, and most probably it is of latest Eifelian or earliest Givetian age.