The phosphatized sponges from the Santonian (Upper Cretaceous) of theWielkanoc Quarry (southern Poland) as a tool in stratigraphical and environmental studies
Authors
Danuta Olszewska-Nejbert
Institute of Geology, University of Warsaw, al. Żwirki i Wigury 93, 02-089 Warszawa
Ewa Swierczewska-Gladysz
Institute of Earth Science, University of Lodz, ul. Narutowicza 88, 90-139 Łódź
Phosphatized sponges from the Santonian of the Wielkanoc Quarry are represented by 11 species of Hexactinosida and 16 species of Lychniscosida. Their species composition is most similar to the Micraster coranguinum Zone fauna (Middle Coniacian – Middle Santonian) of England. Three preservational groups of sponges are distinguished: ‘white’, ‘beige’ and ‘dark’. They are infilled by phosphatized foraminiferal/foraminiferal-calcisphere wackestone and are contained in the marly calcareous inoceramid packstone. The sponges indicate a calm and relatively deep (> 100 m) life environment. After burial, phosphatization and exhumation, the fossil sponges were redeposited in Upper Santonian strata. The ‘white’ and ‘beige’ groups were transported laterally over a very short distance or represent lag deposits. The rolled and crushed sponges of the ‘dark’ group were exhumed and phosphatized more than once. They could be redeposited (reworked) nearly in the same place and/or transported from some longer distances (but not from outside the Cracow Swell). The phosphatized sponges document the former presence in the area of part of theMiddle Coniacian through Middle Santonian succession, which was removed secondarily by subsequent erosion.
