Diatomaceous Clay of Shadrinsky deposit (Kurgan Region)

Kurgan region occupies a leading position among the regions of the Trans-Urals for reserves of opalcristobalite rocks. Diatomaceous clay of Shadrinsky deposit is the largest object of the mineral resource base of the region, located in the 1-1.5 km south-west from the city of Shadrinsk, on the right bank of the river Iset at the deep erosional incision. The results of the research revealed that the rocks forming the productive strata of Shadrinsky deposits are represented with just diatomaceous clay, not tripoli, as previously thought. Diatomaceous clay of Shadrinsky deposit is characterized by diatom complex Pyxilla gracilis top of the upper part of Lower Eocene. The general chemical composition of the rocks is close to diatomite of the major deposits of Trans-Urals. The only significant difference is the lower content of the mineral phases SiO2 and greater clay components. The presence of zeolites, calcium-sodium composition (up to a few %) is detected as part of the impurities; the clay fraction is represented by smectite, kaolinite, mica. The bulk rock contains fragments of diatoms in size from 0.005 to 0.063 mm, fragments of siliceous sponge spicules in the size of 0.027 x 0.061 mm in various states of preservation. Features of material composition and microstructure of diatomaceous clay of Shadrinsky field allow us to consider them as a promising raw material for the production of building and insulating materials.