Commune: Chęciny (pow. kielecki, woj. świętokrzyskie) , Piekoszów (pow. kielecki, woj. świętokrzyskie)
Framework element or context represented:
Sequence of Upper Devonian and Lower Carboniferous in the Paleozoic core of the Świętokrzyskie (Holy Cross) Mts, Kielce subregion.
Primary geological/geomorphological interest:
Lithostratigraphic sequence, paleontological site.
Comparative assessment justification:
One of the best outcrop of the Devonian-Carboniferous boundary with sequence of sediments which illustrates evolution and drowning of the northern margin of the Polish-Moravian Middle-Upper Devonian platform, useful for interregional analyses; the best exposure of Devonian syndepositional karst in Poland.
Protection status and accessibility:
Partly proposed for protection, partly well accessible.
Character of site: Active quarry and other artificial outcrops.
Area: 10 ha
Altitude: 200-270 m a.s.l.
Lithology: conglomerates, breccias, limestones, shales, silstones, claystones, clays
Discipline: Palaeobiology, Palaeoenvironment, Stratigraphy of Phanerozoic
Process Age: *all periods
Bedrock Age: Carboniferous, Devonian, *all periods
Description of primary interest:
The rocks crop out in the northern face of the quarry and at adjacent Todowa Grząba hill. The lower part of the quarry face is formed of the Frasnian stromatoporoid and amphiporoid limestones of the Kowala Fm. They represent lagoonal-peritidal facies with horizons of paleosols and karst pipes. The subaerial episodes belong to Lofer type cycles of sedimentation, generated by rhytmic changes of subsidence of the platform margin close to tectonically deepening basin. The Frasnian is overlain by the Fammenian with low-angle discordance documenting tectonic event and abrasion. Fammenian is represented with condensed (up to 1 m) sequence of crinoid-cephalopod limestones. The Carboniferous rests on the Fammenian without discordance or directly on the Frasnian, levelling the Late Devonian paleo-surface. Several metres thick the Upper Tournaisian-Lower Visean claystones, bearing limestone beds and pyroclastic material, contain rare reworked fossils. The Lower-Middle Visean Zaręby Beds are composed of green-black siliceous shales (up to 25 m) bearing phosphate nodules and microfossils. They were deposited in deep-water, partly anoxic environment. Outcropped in Todowa Grząba hill, the Middle-Upper Visean limestones (up to 25 m), represent facies equivalent of the Lechówek Beds. Their sequence starts from breccia with clasts of the Frasnian-Visean rocks, passing upward to biodetrital, crinoid limestones abounding in fauna (corals and brachiopods). The limestones are interpreted as gravity flow sediments moved from shallow platform to deep basin. They are overlain and surrounded by clayey-sandy Lechówek Beds with siliceous and phosphatic concretions and pyroclastic material.
Literature:
BEŁKA Z., SKOMPSKI S. 1988–Mechanism of sedimentation and facial location of the Coal Limestone in southwestern Holy Cross Mts (English sum.) Przegl. Geol. 36, 8: 442-448. BEŁKA Z., SKOMPSKI S., SOBOŃ-PODGÓRSKA I. 1996–Reconstruction of a lost carbonate platform on the shelf of Fennosarmatia: evidence from Visean polymictic debrite, Holy Cross Mts, Poland. In: Strogen P., Somerville I.D., Jones G.L. eds., Recent advances on Lower Carboniferous geology. Geol. Soc., Spec. Publ. 107: 315-329. DEVONIAN REEFS ... 1993–Devonian reefs of Poland. Acta Palaeont. Pol., 37 (1992), 2-4: 85-428. MIGASZEWSKI Z. 1995–Occurrence of pyroclastic rocks in the Lower Carboniferous of the Holy Cross Mts (Central Poland) (English sum.). Przegl. Geol. 43, 1: 7-11. RACKI G., NARKIEWICZ M. 2000–Tectonic versus eustatic controls of sedimentary development of the Devonian in the Holy Cross Mts., Central Poland (English sum.). Przegl. Geol. 48, 1: 65-76. SKOMPSKI S., SZULCZEWSKI M. 2000–Lofer-type cyclothems in the Upper Devonian of the Holy Cross Mts (Central Poland). Acta Geol. Pol. 50, 4: 393-406. SZULCZEWSKI M. 1995–Depositional evolution of the Holy Cross Mts. (Poland) in the Devonian and Carboniferous – a review. Geol. Quater. 39, 4: 471-488. SZULCZEWSKI M., BEŁKA Z., SKOMPSKI S. 1996–The drowning of a carbonate platform: an example from the Devonian-Carboniferous of the southwestern Holy Cross Mts, Poland. Sediment. Geol. 106: 21-49. SZULCZEWSKI M., SKOMPSKI S. 1995–Stop 4. Ostrówka quarry. In: Szulczewski M., Dvořak J. eds., Evolution of the Polish-Moravian carbonate platform ... Guide to Exc. B4. 13th Intern. Congr. on Carboniferous-Permian. XIII ICC-P. 28.08-2.09.1995. Pol. Geol. Inst. Warszawa: 20-23.