Mineralogy and micropalaeontology of the Kinnekulle altered volcanic ash bed (Ordovician) at Pääsküla, North Estonia

Investigation of subsurface tunnels in Paaskula Hillock revealed outcrops of the 27-cmthick Kinnekulle altered volcanic ash bed. Preliminary X-ray diffractometric study showed that the dominating minerals are potassium feldspar and illite-smectite. Palaeontological investigations revealed abundant scolecodonts in the bed, suggesting the infaunal mode of life for some Ordovician polychaete worms. In the studied area, the limestone block above the Kinnekulle bed could have been shifted along the bed due to the pressure of advancing continental ice sheet in the Quaternary.