Use of Geochemistry Data Collected by the Mars Exploration Rover Spirit in Gusev Crater to Teach Geomorphic Zonation through Principal Components Analysis

Abstract

This paper presents a laboratory exercise used to teach principal components analysis (PCA) as a means of surface zonation. The lab was built around abundance data for 16 oxides and elements collected by the Mars Exploration Rover Spirit in Gusev Crater between Sol 14 and Sol 470. Students used PCA to reduce 15 of these into 3 components, which, after quartimax rotation, very strikingly divided the surface traversed by Spirit's into three distinct zones. Students then used such concepts as the Bowen reaction series, typical minerals in Earth's basalts and andesitic arcs, the periodic table, and the Goldschmidt classification, together with Pancam images from Spirit and the Mars Orbiter Camera, to interpret the surfaces over which the rover moved. Students found this foray to Mars a challenging but enjoyable project, and it made PCA memorable to them long after the class had ended. Some variant on this lab could work for multivariate statistics courses in geology, geography, and environmental science, as well as advanced courses in the content of those disciplines, particularly those dealing with zonation.