Siarka i jej główne minerały w iłach poznańskich (górny neogen) oraz ich wpływ na barwę osadu
Abstract
Sulphur and its main minerals in the Poznań Clays (upper Neogene) – their influence on the sediment colour.
A b s t r a c t. The Poznań Clays, which are a well-known but still informal lithostratigraphic unit in the Neogene of the Polish Lowlands, contain sulphur and its minerals. Native sulphur was found in them for the first time, whilst pyrite, gypsum and jarosite were documented using various research methods. Native sulphur is present only in the microcrystalline form, and pyrite as the framboids. Gypsum is very well developed in the form of both micro- and macrocrystals, often as twins. In turn, jarosite was found macroscopically in the field exposure and confirmed by mineralogical research methods. Generally, sulphur minerals mentioned above do not affect the colour of the studied sediments. This is due to their trace amounts and microcrystalline form in the sediment (sulphur, pyrite). However, the gypsum has the same colour as the surrounding Poznań Clays due to its transparency or the admixture of other mineral components. Only jarosite, macroscopically yellow or orange together with goethite, can affect the colour of the sediment if it is present in significant amounts.
A b s t r a c t. The Poznań Clays, which are a well-known but still informal lithostratigraphic unit in the Neogene of the Polish Lowlands, contain sulphur and its minerals. Native sulphur was found in them for the first time, whilst pyrite, gypsum and jarosite were documented using various research methods. Native sulphur is present only in the microcrystalline form, and pyrite as the framboids. Gypsum is very well developed in the form of both micro- and macrocrystals, often as twins. In turn, jarosite was found macroscopically in the field exposure and confirmed by mineralogical research methods. Generally, sulphur minerals mentioned above do not affect the colour of the studied sediments. This is due to their trace amounts and microcrystalline form in the sediment (sulphur, pyrite). However, the gypsum has the same colour as the surrounding Poznań Clays due to its transparency or the admixture of other mineral components. Only jarosite, macroscopically yellow or orange together with goethite, can affect the colour of the sediment if it is present in significant amounts.