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

By Rodrigue, Christine M. | Journal of Geoscience Education, November 2011 | Go to article overview

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


Rodrigue, Christine M., Journal of Geoscience Education


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. © 2011 National Association of Geoscience Teachers. [DOI: 10.5408/1.3604826]

INTRODUCTION

This paper presents an exercise that uses Mars Exploration Rover geochemical data to teach principal components analysis (PCA) for geomorphic or geological zonation. The data come from the Spirit rover's Alpha Particle X-ray Spectrometer (APXS), which collected spectra from 93 rocks and soil samples (Geliert et al, 2006) during its travel over three distinctive zones on the floor of Gusev Crater. These zones consisted of a cratered basaltic plain, the West Spur of the Columbia Hills with bedded materials and evaporites, and the northwest side of Husband Hill where very diverse aqueous and acid-aqueous altered rocks and soils were found. PCA is a data reduction technique that has increasingly been used in the geosciences since the early 1960s, making its acquaintance of value in the education of geoscience majors. The APXS data can make the technique memorable to such majors as it produces a coherent zonation from 15 different oxides and elements.

A classic task in the geosciences is zonation of complex surface patterns into areal units and demarcating transition zones or boundaries between them, often along a transect in the field. So, for example, a soil catena can be zoned by changes in soil particle size, underlying bedrock and regolith, topographic relief, drainage, erosion and deposition processes, weathering, organic matter, and geochemistry (Milne 1935; Bushneil, 1942; Webster, 1973; Raynolds et al, 2006). Ground-penetrating radar can be used along a transect to infer subsurface stratigraphy for geological mapping (Baker and JoI, 2007). An environmental ecotone might be zoned by field sampling of soils and censusing of species presence and abundance along a transect. For example, a transect could be taken down a catena, across a wetland-upland interface, or through a seasonal surface water and groundwater boundary (Fortin et al, 2000).

Zonation can be vertical and temporal in geological usage, not just horizontal and spatial in mapping usage. So, for example, fossils, grain size, bulk density, and geochemistry can be used for temporal zonation and sequencing of stratigraphie units (e.g., Patterson et al, 2000; Brown and Pasternack, 2004; Peterson et al, 2008).

Zonation, then, is a common task in the field and laboratory activities of geoscientists. The process can seem superficially straightforward, but the zoning schemes that result can color analytic results. Complications include scale, edge effects, spatial autocorrelation, and aggregation effects. These distortions and biases are collectively called the Modifiable Areal Unit Problem or MAUP (Dark and Bram, 2007) or the analogous Modifiable Temporal Unit Problem (MTUP). The MTUP is less commonly discussed, largely in criminology contexts (e.

The rest of this article is only available to active members of Questia

Sign up now for a free, 1-day trial and receive full access to:

  • Questia's entire collection
  • Automatic bibliography creation
  • More helpful research tools like notes, citations, and highlights
  • Ad-free environment

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

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

Settings

Typeface
Text size Smaller Larger
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Full screen

matching results for page

Cited passage

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited passage

Welcome to the new Questia Reader

The Questia Reader has been updated to provide you with an even better online reading experience.  It is now 100% Responsive, which means you can read our books and articles on any sized device you wish.  All of your favorite tools like notes, highlights, and citations are still here, but the way you select text has been updated to be easier to use, especially on touchscreen devices.  Here's how:

1. Click or tap the first word you want to select.
2. Click or tap the last word you want to select.

OK, got it!

Thanks for trying Questia!

Please continue trying out our research tools, but please note, full functionality is available only to our active members.

Your work will be lost once you leave this Web page.

For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

Already a member? Log in now.