On the quantitative estimation of some factors of placers formation (case study of stanniferous placers of Mongolian mountain areas)

Abstract

Using analysis of variance (factorial) and correlative technique the relative significance of different factors of placers formation for stanniferous placers dimensions at the MPR territory was determined as follows: order of the stream, the valley of which contains the placer - 30,2%, distance from the placer to the mineral source - 20,6%, stream density within the drainage basin where the placer is formed - 12,0%; loose sediments thickness - 9,7%, type of mineral source - 6,8%, all the rest factors - 8,0%, total significance of the considered factors combinations - l3,4%. Form, degree and direction of correlation between the factors under discussion and placers scale are estimated using coefficient of correlation.

According to calculated data the most prospective areas for large 'tin placers search are parts of overdeepened valleys of III-IV order situated within 4 km from mineral sources in the drainage basin with stream density about 1,1-1,3 km per km².