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Crinoid and ostracod succesion within the Early-Middle Frasnian interval in the Wietrznia quarry, Holy Cross Mountains, Poland

100%

Gluchowski E., Casier J. G., Olempska E.

Acta Palaeontologica Polonica

2006

tom 51

nr 4

695-706

Early–Middle Frasnian ostracods and crinoids from Wietrznia in the Northern Kielce subregion of the Holy Cross area were analyzed. Twenty three ostracod species assigned to thirteen named genera, as well as eighteen crinoid species including the representatives of fifteen stem−based taxa were distinguished. For most of the species open nomenclature is applied. The composition of ostracod assemblage changes from moderately diverse in the lower part of the Palmatolepis transitans Zone to poorly diverse in its higher part. Lack of ostracods in the uppermost part of the Pa. transitans Zone and in the Palmatolepis punctata Zone is noted. The crinoid distribution pattern comprises the interval of relatively high diversity, interrupted in the uppermost part of the Pa. transitans Zone, and the interval of temporary recovery in the lower Pa. punctata Zone. Such distribution patterns point to deterioration of environmental conditions across the Early–Middle Frasnian transition, coinciding with a large−scale C−isotopic perturbation superimposed on intermittent, two−step eustatic sea level rise. On the other hand, impoverished, surviving crinoid faunas and absence of ostracods in the Pa. punctata Zone indicate the overall long−term deterioration of life conditions through the major C−isotope anomaly time span. However, this may also result from synsedimentary tectonic pulses, causing block movements and large−scale resedimentation phenomena on the northern slope of the Dyminy Reef during the basal Middle Frasnian sea level rise.

Ostracods and fore-reef sedimentology of the Frasnian-Famennian boundary beds in Kielce [Holy Cross Mountains, Poland]

88%

Casier J. G., Devleeschouwer X., Lethiers F., Preat A., Racki G.

Acta Palaeontologica Polonica

2002

tom 47

nr 2

Four major microfacies have been recognized in the Psie Górki section and the bioclastic content indicates an open marine environment in the photic zone close to an algal shole. Sedimentological studies point to a regressive episode starting close to the Frasnian–Famennian boundary. The regressive microfacies pattern is revealed by the presence of semirestricted algal microbreccias that compose all of the lower part of the Famennian. The regression was accompanied by meteoric water invasion as the sea level fell. Seventy−six ostracod species are recorded. The ostracod assemblage, dominated by podocopids, belongs to the Eifelian ecotype and is indicative of a well−oxygenated marine environment below fair−weather wave base in the Frasnian part of the section, and of shallower environments in the base of the Famennian. No ostracod assemblage characteristic of hypoxic or semi−restricted water conditions has been recorded. The rate of extinction of ostracod species (>70%) close to the Frasnian–Famennian boundary is comparable with that known on the same level in several other sections investigated in the world. Five new ostracod species are proposed by J.−G. Casier and F. Lethiers: Selebratina vellicata, Samarella? minuta, Bairdiocypris ventrorecta, Acratia pentagona, and “Bairdia” psiegorkiensis.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

2 Casier J. G.

1 Devleeschouwer X.

1 Gluchowski E.

1 Lethiers F.

1 Olempska E.

1 Preat A.

1 Racki G.

1 2006

1 2002

Wyniki wyszukiwania

Crinoid and ostracod succesion within the Early-Middle Frasnian interval in the Wietrznia quarry, Holy Cross Mountains, Poland

Ostracods and fore-reef sedimentology of the Frasnian-Famennian boundary beds in Kielce [Holy Cross Mountains, Poland]