Astrogeology Research Program

Prepared for the National Aeronautics and Space Administration

U.S. Geological Survey
Scientific Investigations Map 2934
version 1.0

Geologic Map of the MTM –20272 and –25272 Quadrangles, Tyrrhena Terra Region of Mars

By Scott C. Mest and David A. Crown


thumbnail view of map


Mars Transverse Mercator (MTM) –20272 and –25272 quadrangles (lat 17.5°–27.5° S., long 270°–275° W.) cover part of the highlands of Tyrrhena Terra north of Hellas Planitia. The surface of the Tyrrhena Terra region records a complex history of impact cratering and modification by fluvial and eolian activity. The map area consists primarily of intercrater plains, impact crater material, and crater floor material. An extensive valley network, Vichada Valles, as well as several smaller networks, dissects the northern part of the map area. The abundance and widespread nature of fluvial features within the map area have significant implications for past Martian environmental conditions. The degraded terrains surrounding Hellas Planitia provide constraints on the role and timing of volatile-driven activity in the evolution of the highlands. The geologic history of this area may have been influenced not only by the presence of Hellas Planitia but also by other buried impact basins.

Download this map as a ~41" x 37" PDF file (sim2006-2934.pdf; 15.7 MB)

Download the accompanying pamphlet as a 15-page PDF file (sim2934pamphlet.pdf; 388 kB)

For questions about the content of this report, contact Ken Tanaka

Download the Version history

Download a current version of Adobe Reader for free

| Help | PDF help | Publications main page | Other Planetary Maps |
| Geologic Division | Astrogeology Research Program |

This report is also available in print from:

USGS Information Services, Box 25286,
Federal Center, Denver, CO 80225
telephone: 888 ASK-USGS; e-mail:

Accessibility FOIA Privacy Policies and Notices

Take Pride in America home page. FirstGov button U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: Michael Diggles
Page Last Modified: November 14, 2007