Wyniki wyszukiwania - BazTech

1

Campanian (Late Cretaceous) hexactinellid sponges from the white chalk of Mielnik (Eastern Poland)

Olszewska-Nejbert D., Świerczewska-Gładysz E.

Acta Geologica Polonica

|

2011

|

Vol. 61, no. 4

383-417

EN

The taxonomic description of the Campanian (Upper Cretaceous) hexactinellid sponges from the white chalk of Mielnik, eastern Poland, is presented. The fauna comprises 19 species belonging to 15 genera, representing by the Hexactinosida and Lychniscosida. The species Polyopesia macropora is described as new. They represent a typical sponge assemblage of the North European Province. Most of the specimens are strongly phosphatized (85% of the material), less common are grey-beige, slightly phosphatized specimens (11%), and distinctly rarer are specimens infilled with white chalk (3%) and silicified specimens (1%). Phosphatization was the dominant fossilization process of the hexactinellid sponges in the white chalk of Mielnik.

2

The phosphatized sponges from the Santonian (Upper Cretaceous) of the Wielkanoc Quarry (southern Poland) as a tool in stratigraphical and environmental studies

Olszewska-Nejbert D., Świerczewska-Gładysz E.

Acta Geologica Polonica

|

2009

|

Vol. 59, no. 4

483-504

EN

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.

3

Pochodzenie sfosfatyzowanych gąbek z warstwy dańskiego piaskowca glaukonitowego z Nasiłowa (dolina środkowej Wisły)

Świerczewska-Gładysz E., Olszewska-Nejbert D.

Przegląd Geologiczny

|

2006

|

Vol. 54, nr 8

710-719

EN

The sponge fauna from the Danian glauconitic sandstone as exposed at Nasiłów, contains all species known from the underlying Upper Maastrichtian siliceous chalk and, additionally, some species not documented hitherto from the latter unit. The stratigraphic ranges of the all studied sponges indicate their Late Maastrichtian age; there are no Danian sponges in the glauconitic sandstone. Two assemblages of sponges may be distinguished in the glauconitic sandstone, based on the analysis of the infilling of their interspicular space: 1) sponges infilled with phosphatized siliceous chalk and 2) sponges infilled with phosphatized glauconitic siliceous chalk. Petrographic study indicates that the host deposit of the first assemblage was a siliceous chalk. The second type originated from a glauconitic siliceous chalk unit, probably equivalent to the so-called Żyrzyn Beds of Late Maastrichtian age. The glauconitic chalk orginally overlain the siliceous chalk at Nasiłów, but has been subsequently eroded. Detailed analysis of the relations between two types of infillings allows to distinguish a latest Maastrichtian stage of erosion after deposition of the siliceous chalk, not recognised by previous authors. In this erosional stage, phosphatized sponges originally embedded in siliceous chalk were re-exposed and subsequently buried during the deposition of the glauconitic siliceous chalk unit.

4

Early diagenetic collapse and injection microstructures in phosphate nodules of the Brentskardhaugen Bed (Jurassic) in Spitsbergen

Krajewski K.

Bulletin of the Polish Academy of Sciences. Earth Sciences

|

2000

|

Vol. 48, nr 2

209-229

EN

Fossiliferous phosphate nodules in the condensed Brentskardhaugen Bed (Toarcian-Bathonian) in Spitsbergen show common collapse and injection microstructures associated with stages of phosphatization of biogenic carbonate skeletal remains. These structures provide supporting evidence for the nature of early phosphate replacement of biogenic carbonate in clastic condensed environment of the Jurassic Spitsbergen shelf. The replacement process consisted in phosphate cementation of the original skeletal surfaces and internal skeleton pore spaces. Stages of early diagenetic dissolution of biogenic carbonate and reworking events in the depositional environment led, however, to complex and variable infillings of skeletal moulds. Interplay of recurrent events of phosphate emplacement into sediment, carbonate dissolution, and mechanical reworking of fossiliferous phosphate nodules accounts for a broad spectrum of phosphatic replacement microstructures in the original biogenic carbonate.