Światowe i regionalne zdarzenia w zapisie stratygraficznym pogranicza franu i famenu Gór Świętokrzyskich
Abstract
STRATIGRAPHIC RECORD OF GLOBAL AND REGIONAL EVENTS ACROSS THE FRASNIAN-FAMENNIAN BOUNDARY IN THE HOLY CROSS MOUNTAINS
Summary
The Upper Devonian of the Holy Cross Mts is a deepening upward sequence. The successive facies turnovers are mostly abrupt, especially within the relatively elevated central region, but they do not correlate even over a short distance. Synsedimentary block faulting ( e.g. Fig. 1), resulting in the stepwise disintegration of the carbonate platform, is mainly responsible for these considerable differences of the stratigraphic record. This is in a contradiction to the previously proposed regularity of some relative sea level changes over the southern Poland. Usually there is no marked facies turnover at the Frasnian-Famennian boundary, in places where i t does not fall into a wide stratigraphic gaps. However, narrow gaps within the condensed crinoid and cephalopod limestones are situated in this position, and the limestones analogous to the Kellwasserkalk locally occur within the basinal facies (Płucki). Flat pebbles conglomerates are also common near this boundary, but they occur a relatively large stratigraphic interval, and individual layers are very impersistent (Fig. 3).
The succession of conodont biofacies (Figs 4- 6) is however very similar to that explained by the eustatic sea level changes and known from the Frasnian of the Ardennes, and widely recognized across the Frasnian-Famennian boundary. The pelekysgnathid peaks below and above the icriodid maximum across the F/F boundary suggest, that the late Frasnian and the early Famennian pelekysgnathids occupied a deeper environment than did contemporaneous icriodids, and than it was previously supposed.
Summary
The Upper Devonian of the Holy Cross Mts is a deepening upward sequence. The successive facies turnovers are mostly abrupt, especially within the relatively elevated central region, but they do not correlate even over a short distance. Synsedimentary block faulting ( e.g. Fig. 1), resulting in the stepwise disintegration of the carbonate platform, is mainly responsible for these considerable differences of the stratigraphic record. This is in a contradiction to the previously proposed regularity of some relative sea level changes over the southern Poland. Usually there is no marked facies turnover at the Frasnian-Famennian boundary, in places where i t does not fall into a wide stratigraphic gaps. However, narrow gaps within the condensed crinoid and cephalopod limestones are situated in this position, and the limestones analogous to the Kellwasserkalk locally occur within the basinal facies (Płucki). Flat pebbles conglomerates are also common near this boundary, but they occur a relatively large stratigraphic interval, and individual layers are very impersistent (Fig. 3).
The succession of conodont biofacies (Figs 4- 6) is however very similar to that explained by the eustatic sea level changes and known from the Frasnian of the Ardennes, and widely recognized across the Frasnian-Famennian boundary. The pelekysgnathid peaks below and above the icriodid maximum across the F/F boundary suggest, that the late Frasnian and the early Famennian pelekysgnathids occupied a deeper environment than did contemporaneous icriodids, and than it was previously supposed.