##### U.S. Geological Survey     Geologic Investigations Series I-2763

## **Geologic   Map of MTM –45252 AND –45257 Quadrangles, Reull Vallis Region of Mars**

### *By***Scott C. Mest and David A. Crown**

| **INTRODUCTION**

Mars Transverse         Mercator (MTM) quadrangles –45252 and –45257 (latitude 42.5°         S. to 47.5°        S., longitude 250° W. to 260° W.) cover a portion of the highlands         of Promethei Terra east of Hellas        basin (fig. 1). The map area consists of heavily cratered ancient highland         materials having moderate        to high relief, isolated knobs and massifs of rugged mountainous material,         and extensive        tracts of smooth and channeled plains. Part of the ~1,500-km-long Reull         Vallis outflow system (fig.        2) is within the map area. The area also contains surficial deposits,         such as the prominent large        debris aprons that commonly surround highland massifs. Regional slopes         are to the west, toward        the Hellas basin, as indicated by topographic maps of Mars (U.S. Geological         Survey, 1989; Smith        and others, 1999). Approximately 60% of the surface of Mars is covered         by rugged, heavily cratered        terrains believed to represent the effects of heavy bombardment in the         inner solar system ~4.0        billion years ago (Murray and others, 1971; Schubert and others, 1992;         Tanaka and others, 1992).        Much of this terrain, including that within the map area, records a long         history of modification by        tectonism, fluvial processes, mass wasting, and eolian activity. The presence         of fluvial features to        the east of Hellas basin, including Reull Vallis and other smaller channels,         has significant implications        for past environmental conditions. The degraded terrains surrounding Hellas         basin provide        constraints on the role and timing of volatile-driven activity in the         evolution of the highlands. Current        photogeologic mapping at 1:500,000 scale (see also Mest and Crown, 2002)         from analysis of        Viking Orbiter images complements previous geomorphic studies of Reull         Vallis and other highland        outflow systems, drainage networks, and highland debris aprons, as well         as regional geologic        mapping studies and geologic mapping of Hellas basin as a whole at 1:5,000,000         scale (Crown and        others, 1992; Mest, 1998; Mest and Crown, 2001; Pierce, 2001; Leonard         and Tanaka, 2001). Viking        Orbiter image coverage of the map area generally ranges from 160 to 220         m/pixel; the central        part of the map area is covered by higher resolution images (~47 m/pixel).         Crater size-frequency        distributions have been compiled to constrain the relative ages of geologic         units and determine the        timing and duration of inferred geologic processes. |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

 

| **File         Name**                                                                                                                                   | **Description**                                 | **File         Size** |
|---------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------|-----------------------|
| i2763.pdf                                                                                                                                               | Portable       Document Format file of this map | 44.6         MB       |
| This       map is 46 x 42 inches and is best reproduced on a large-format plotter at       600 dpi or greater. The PDF provided can be viewed on screen |

Download a current   version of Adobe Acrobat Reader for free

| Help   | PDF help   | Geopubs main page | I-map   | 

For questions about the   content of this report, contact Scott Mest

This map   is also available from:

USGS Information   Services, Box 25286,   Federal Center, Denver, CO 80225  telephone: 303-202-4210; e-mail: infoservices@usgs.gov

----

Carolyn Donlin

Privacy Statement
Disclaimer
Accessibility

| Department   of the Interior | U.S. Geological Survey   | Geologic Division | Astrogeology   |