The Technique of Serial Correlation Applied to Continuous Series of Element Concentration Values in Homogeneous Rocks

Abstract

A technique of serial correlation is considered for chemical data on series of adjacent specimens from homogeneous mineral deposits and a critical independent sampling interval (I-interval) is evaluated. Values taken at a sampling interval larger than the I-interval are independent in a probability sense, whereas mutual specimen influence is appreciable for smaller sampling intervals. I-intervals have been calculated for element concentration values from three examples. The I-intervals for weight percentages Zn, Ti, and in deposits of sphalerite, titaniferous magnetite, and molybdenite are 23 feet, 15 feet, and 0.5-2 feet, respectively. The examples are in the field of mineral deposits which are generally better sampled, but the theory may be applied to element concentration values in other continuous, homogeneous rocks showing random frequency distribution for a specified element. The I-interval is the one-dimensional equivalent of the PRobable-INfluence CE11 (prince), which indicates the sphere of influence of a certain value. The approximate size of the prince should be considered in sampling problems such as choosing specimen sizes and distances between the individual specimens.