ABSTRACT

Sidewall cores from wells are a good source of data for paleoecological analyses because they are free from downhole contamination often present in the cutting samples. Samples available from any one faunal zone are usually from a wide variety of depositional environments and different wells. Sample Ordering is ideal for analyses of such a data set.

The Sample Ordering program uses an algorithm to place each sample in order along an ecological gradient. Data supplied are the relative abundance of each species and the designation of one species which will have its maximum abundance at one of the ecological extremes.

The result is a compact display which shows the relative abundance of each species with respect to each other along the ecological gradient. This enables a quick comparison of the ecological range of extinct species with those believed to have occupied similar environments during much of the Tertiary.

Analysis of a set of Pleistocene core samples is used here to establish the environment of the extinct Trimosina sp., and to construct a detailed water-depth interpretation for the interval cored.