Abstract:

Making use of the R-type factor analysis for the measurement of stream sediment survey in Western Zhejiang area，six representative factors have been extracted out.Combined with the regional geological background，this paper has discussed the elemental association which could reflect these six factors and drawn the distribution map for the factor score.It helps to provide better parameters for classifying the elemental association types and geochemical subareas.Results show that：Factor 1，with a combination of Cu，Mo，U and Zn，is the major ore-forming elements in this area；Factor 2，with a combination of As，Pb，Ag，is a series of mesothermal-low temperature elements； Factor 3，with a combination of Bi and W，belongs to a series of hypothermal elements；Factor 4，combinated with B,F and Sn is a characteristic of tin-bearing granite，F and B play a vital role as mineralizer；Factor 5，association of radioactive element Th and U；for factor 6，Au is gotten in and Hg is gotten out during regional mineralization.Besides，factor 1 to factor 6 have showed a remarkable zonation on the site of the small granitic rock mass at Yanshanian period（corresponding to some metallogenic specificity） and the trunk fracture zone for metallogenesis，and there is an approximate results between factor 1 to factor 6 and clustering analysis.

Key words: elemental association, factor analysis, stream sediment survey, geochemistry