Material composition of Miocene sediments of the Saitovo sand-gravel deposit (Southern Pre-Urals)

We studied Middle-Late Miocene sediments on the example of representative section in the South part of Ashkadar-Sukhaylya Neogene bed. The first data of mineralogical-geochemistry investigations of Miocene limnic sediments of Saitovo sand-gravel deposit were presented. In the section of quarry of deposit two gravel-pebble and two silt-sandy packs were distinguished. The rocks were mainly composed of quartzite clasts (to 95 %). In the fine fractions of sands with X-Ray diffraction method clay minerals were found: kaolinite, chlorite, illite. The accumulation of gravel-pebble packs reflected formation through tectonically active setting of source of detritus. During stagnant tectonic settings fine-clastic rocks were formed through destruction of coarse material and as well as through other sources (ancient kaolin/illite weathering crusts). High value of chemical weathering index (Al2O3/(Al2O3+CaO+Na2O+K2O)molec 100 = 90) of rocks indicated their formation under warm humid conditions of climate. Completed investigation allowed not only to characterize Miocene sediments source of detritus, but also to define the pre-Urals Miocene geology history.