Uwagi o paleoekologii fauny wapienia muszlowego NE obrzeżenia Gór Świętokrzyskich
Abstract
REMARKS ON PALEOECOLOGY OF FAUNA OF THE MUSCHELKALK AT NE MARGIN OF THE HOLY CROSS MTS
Summary
Muschelkalk rocks from NE margin of the Holy Cross Mts (Fig. 1) are highly varying in facies development (Fig. 2). Benthic fauna, useful for paleoecological analyses (Table 1), occurs in crinoid, organodetrital, knobby and wavy limestones. Individual assemblages of fossils were found to be related to each of these types of limestones, making it possible to reconstruct turbulence of bottom waters and nature of substratum. It was found that:
- organodetrital limestones were forming in zones of activity of bottom currents, i.e. those characterized by vivid development of suspension-eating epifauna;
- knobby limestones were originating due to penetration of sediment by mud-eating infauna and areas of their sedimentation was related to zones of stagnant bottom waters and unconsolidated substratum;
- wavy limestones were forming in transitional zones between areas of sedimentation of organodetrital and knobby limestomes;
- crinoid limestones were forming in the remaining areas, characterized by development of crinoid fauna.
Distribution of fauna in the sections (Fig. 2) reflects repeat changes of hydrodynamic conditions and, therefore, distribution of areas of development of individual faunistic assemblages on seafloor, i.e. areas of sedimentation of individual types of sediments. Attempts were made to explain these changes in terms of small depth of sedimentary basin. This interpretation is supported by character of assemblages of bivalves (5) and Rhizocorallia (9) and taphonomy of ceratitids (17). Storm deposits indicate some catastrophic episodes, destroying life on seafloor due to lowering of waving base down to the seafloor surface. Each episode of that type could form a new hydrodynamic pattern and, therefore, change of areas of sedimentation of individual types of limestones. This may explain marked facies differentiation of the strata.
Summary
Muschelkalk rocks from NE margin of the Holy Cross Mts (Fig. 1) are highly varying in facies development (Fig. 2). Benthic fauna, useful for paleoecological analyses (Table 1), occurs in crinoid, organodetrital, knobby and wavy limestones. Individual assemblages of fossils were found to be related to each of these types of limestones, making it possible to reconstruct turbulence of bottom waters and nature of substratum. It was found that:
- organodetrital limestones were forming in zones of activity of bottom currents, i.e. those characterized by vivid development of suspension-eating epifauna;
- knobby limestones were originating due to penetration of sediment by mud-eating infauna and areas of their sedimentation was related to zones of stagnant bottom waters and unconsolidated substratum;
- wavy limestones were forming in transitional zones between areas of sedimentation of organodetrital and knobby limestomes;
- crinoid limestones were forming in the remaining areas, characterized by development of crinoid fauna.
Distribution of fauna in the sections (Fig. 2) reflects repeat changes of hydrodynamic conditions and, therefore, distribution of areas of development of individual faunistic assemblages on seafloor, i.e. areas of sedimentation of individual types of sediments. Attempts were made to explain these changes in terms of small depth of sedimentary basin. This interpretation is supported by character of assemblages of bivalves (5) and Rhizocorallia (9) and taphonomy of ceratitids (17). Storm deposits indicate some catastrophic episodes, destroying life on seafloor due to lowering of waving base down to the seafloor surface. Each episode of that type could form a new hydrodynamic pattern and, therefore, change of areas of sedimentation of individual types of limestones. This may explain marked facies differentiation of the strata.