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1

The genetical types of caves in the Polish lowlands

100%
Urban J., Ciborowski T., Paternoga J., hercman H., Sujka G.
Nature Conservation
|
2007
|
tom 63
85-94
2

Catagenic ankerite replacing biogenic calcite in the Marhogda Bed [Jurassic], Sassenfjorden, Spitsbergen

100%
Krajewski K. P.
Polish Polar Research
|
2002
|
tom 23
|
nr 1
85-99
3

Removal of cadmium and lead from aqueous solution by calcite

100%
Yavuz O., Guzel R., Aydin F., Tegin I., Ziyadanogullari R.
Polish Journal of Environmental Studies
|
2007
|
tom 16
|
nr 3
467-471
The removal of toxic cadmium(II ) and lead(II ) from aqueous solutions was investigated using calcite, which is inexpensive and widespread over the globe, as the effective inorganic adsorbent. The experimental data of the removal equilibrium were correlated by either the Langmuir or Freundlich equations. Results indicate that the Langmuir model gave a better fit to the experimental data than the Freundlich equation. Maximum adsorption capacities were determined as 18.52 mg/g Cd and 19.92 mg/g Pb for natural calcite at 25°C, respectively.
4

Comparing the effect of phytoplankton and a charophyte on calcite precipitation in lake water: experimental approach

100%
Kufel L., Rymuza K.
Polish Journal of Ecology
|
2014
|
tom 62
|
nr 3
Primary producers are able to strongly affect calcium budget in hardwater lakes. The relative contribution of phytoplankton and charophytes to water decalcification (by precipitation of calcium carbonate) is, however, unclear. In this study we checked the effect of natural phytoplankton community and a charophyte (Nitellopsis obtusa) on the decline of calcium concentration in experimental outdoor conditions. The experiment was carried out in original lake water and two variants of enrichment with inorganic nitrogen and phosphorus to test the changing efficiency in decalcification by both primary producers. At low nutrient concentrations, N. obtusa was responsible for calcium decline in original lake water by 12 mg Ca+2 dm–3 during 20 days of experiment. In these conditions the effect of phytoplankton was negligible. In lake water enriched with nutrients, the exponential growth of phytoplankton led to the decrease of calcium concentration from initial 35 mg Ca+2 dm–3 to 9 mg Ca+2 dm–3 in the same time period. The maximum effect of N. obtusa was the same as in original lake water but manifested itself earlier to decline in the end of experiment. Supersaturation of water with calcium carbonate was always more than threefold and saturation index reached 27 in mixed cultures of phytoplankton and N. obtusa in lake water enriched with nutrients. In this context we hypothesise on a possible role of charophytes as nucleation sites necessary for calcite precipitation. Based on our own and literature data we also discuss expected immobilisation of phosphate incorporated in calcite precipitated by the growth of phytoplankton and N. obtusa.
5

The calcareous speleothems in the pseudokarst Jaskinia Slowianska-Drwali cave, Beskid Niski Mts., Poland

80%
Urban J., Margielewski W., Zak K., Hercman H., Sujka G., Mleczek T.
Nature Conservation
|
2007
|
tom 63
119-128
6
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Nanostructural and geochemical features of the Jurassic isocrinid columnal ossicles

80%
Stolarski J., Gorzelak P., Mazur M., Marrocchi Y., Meibom A.
Acta Palaeontologica Polonica
|
2009
|
tom 54
|
nr 1
69-75
Calcite isocrinid ossicles from the Middle Jurassic (Bathonian) clays in Gnaszyn (central Poland) show perfectly preserved micro− and nanostructural details typical of diagenetically unaltered echinoderm skeleton. Stereom pores are filled with ferroan calcite cements that sealed off the skeleton from diagenetic fluids and prevented structural and geochemical alteration. In contrast with high−Mg calcite skeleton of modern, tropical echinoderms, the fossil crinoid ossicles from Gnaszyn contain only 5.0–5.3 mole% of MgCO₃. This low Mg content can be a result of either a low temperature environment (ca. 10℃) and/or low Mg/Ca seawater ratio. Both conditions have been proposed for the Middle Jurassic marine environment. Occurrence of Mg−enriched central region of stereom bars of Jurassic columnal ossicle of Chariocrinus andreae is consistent with the concept of magnesium ions involvement in earliest growth phases of calcium carbonate biominerals.
7
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Content available

Aragonitic rostra of the Turonian belemnitid Goniacamax: arguments from diagenesis

70%
Dauphin Y., Williams C. T., Barskov I. S.
Acta Palaeontologica Polonica
|
2007
|
tom 52
|
nr 1
The hypothesis that belemnitid rostra are formed by primary biogenic low−Mg calcite is widespread. However, the coexistence in the same rostrum of both aragonitic and calcitic components has been reported in true belemnites (Goniocamax, Turonian). A combined microstructural and chemical composition study of the comparison of shells with undisputed mineralogy from the same site as the Turonian Goniocamax, shows that these aragonitic shells display the effects of diagenetic alteration. These observations favour the hypothesis that belemnite rostra are composed of primary aragonite, rather than low−Mg calcite, and are consistent with all other cephalopod shells. Calcitic and aragonitic rostra are also known in other Dibranchiata such as Triassic Aulacocerida and Eocene Belopterina. Diagenetic changes such as shown here may clearly affect palaeo−environmental interpretations based on carbonate shells.
8

"Miękkie nacieki" w jaskiniach

70%
Gradzinski R., Radomski A.
Wszechświat
|
1957
|
nr 07
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