Cluster analysis of a regional-scale soil geochemical dataset in northern California

Abstract

A regional-scale soil geochemical study was conducted within a 22,000 km2 area in northern California including the Sierra Nevada, Sacramento Valley, and northern Coast Range. Over 1300 soil samples were chemically analyzed for 42 elements. The distribution of distinct groups of elements demonstrates the interplay of geologic, hydrologic, geomorphologic and anthropogenic factors; however, it is difficult to fully appreciate the complexity of geochemical transport and weathering processes on a landscape-scale in an area of very complex geology with such a large dataset containing more than 40 variables. To examine the data from a perspective of multi-element groupings, cluster analyses were applied to the dataset. The analysis identified several groups of elements whose spatial patterns could be related to specific geologic sources.