The formation of the South Tharsis Ridge Belt: Basin and Range-style extension on early Mars?

Ezgi Karasözen, Jeffrey C. Andrews-Hanna, J. M. Dohm, R. C. Anderson

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The South Tharsis Ridge Belt (STRB) is located along the northeastern edge of Terra Sirenum and partially surrounds the southwestern part of Tharsis in an arc. It consists of 29 large ridges separated by distances 130 to 260 km, with average relief of 1.5 km above the surrounding plains. Because the STRB is among the oldest tectonic features associated both spatially and developmentally with Tharsis, it may provide key information on the early evolution of Tharsis and possibly pre-Tharsis processes. Earlier studies concluded that the ridges formed through compressional tectonism. However, the shape, size, and separation of the ridges support the interpretation that the STRB resembles the extensional Basin and Range Province on Earth. Both regions are characterized by series of parallel mountain ranges separated by broad valleys. In this study, we evaluate both extensional and compressional hypotheses for the origin of the ridges using evidence from topography, deformed craters, crustal thickness models, and strain modeling. Though neither interpretation explains all aspects of the ridges, the topography of the ridges and crustal thinning associated with the western part of the ridge belt support an extensional origin. Strain models predict that Basin and Range-style wide rifting would be expected for early Martian conditions. This extension may have been initiated by plume-induced uplift in the early stages of Tharsis formation, but the large amount of extensional strain inferred in the western STRB must have been accommodated by compression elsewhere, possibly in the heavily deformed craters of western Terra Sirenum.

Original languageEnglish (US)
Pages (from-to)916-943
Number of pages28
JournalJournal of Geophysical Research: Planets
Volume121
Issue number6
DOIs
StatePublished - Jun 1 2016
Externally publishedYes

Keywords

  • Basin and Range
  • Mars
  • South Tharsis Ridge Belt
  • Tharsis
  • tectonics

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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