Element composition of ground water and speleothem “moon milkˮ in a karst cave Proshchal’naya (Far East)

Object of research.The aim of this work was the comparative analysis of element composition of groundwater (drip, fracture), water from the interior of the watercourse in a karst cave Proshchal’naya (Khabarovsk Territory) and the surface water of the nearest river Sagdy-Selanka. The great interest was the study of speleothem (dropstones) “moon milk” in the cave Proshchal’naya.Materials and methods.Speleothem “moon milk” was investigated with a scanning electron microscope (EVO-40HV, CarlZeiss, Germany) and silicon-drift x-ray detector X-MAX 80 мм2 . By ICP-MS method a comparative analysis of element composition of groundwater (drip, fracture), water from an internal stream in the cave Proshchal’naya and surface water of the river Sagdy-Selenka were carried out.Results.Maximum concentrations of calcium, iron and manganese was installed in the spring, between drip and fracture water and magnesium – in flowing waters (inland watercourse caves and Sagdy-Selanka R.). It was determined that visually plastic and homogeneous mass of speleothem “moon milk” is heterogeneous and contains various microstructures. Tubular microstructures were represented by richer elemental compo sition (C, O, Ca, Fe, Mn, Si, Al, and S) compared with club-shaped formations (C, O, Ca, and Na). The binding matrix in the composition of the “moon milk” were reticular structures similar to actinomycente mycelium and bacterial films. Findings. The results of studies conducted in a monsoon climate may be interesting for researchers which study karst processes in other climatic zones.