?

?

°80°

DESCRIPTION OF MAP UNITS

Dust mantle —Bright, red material, widespread in map area, interannually 

variable distribution. Unit shown as it appeared in 1977. Interpretation: 

Thin (less than a few meters) dust layer covering underlying units without 

obscuring topographic features. Distribution ephemeral, transported by 

atmospheric suspension and deposited during major dust storms; partly 

removed and redistributed by winds at times.

Dark material—Dark, reddish-gray material in Chasma Australe. Interpretation: 

Dark, saltating sand or agglomerates of dust formed upon erosion of 

layered deposits. Sand may be porous basalt grains eroded from thin layers 

or lenses within layered deposits. Agglomerates may be filamentary 

sublimation residue particles composed of magnetic dust grains (Herkenhoff 

and Murray,1990a)

Layered deposits—Widespread, horizontally layered unit having generally 

smooth surface at available image resolution. Color and albedo intermediate 

between those of dust mantle and dark material (table 1). Interpretation: 

Deposits of dust and water ice in unknown proportions, with lag or 

weathering rind probably covering surface. Unit extensively eroded in 

places; covered by dust mantle in many areas. Color and albedo suggest 

nonvolatile component of layered deposits is composed of bright dust and 

minor dark dust or sand

Upper member, Dorsa Argentea Formation—Forms cratered plains in 

Chasma Australe, marked by few sinuous ridges about 1 km wide and as 

much as 20 km long. Rough topographic grain terminates at contact with 

layered deposits. Interpretation: Volcanic plains exposed by erosion of 

overlying layered deposits to form Chasma Australe. Origin of sinuous 

ridges uncertain—may be volcanic or glacial features (Howard, 1981; 

Tanaka and Scott, 1987; Kargel, 1993)

Contact—Dashed where approximately located or broadly gradational; queried 

where uncertain

Scarp base—Barb points downslope. Dashed where uncertain; forms contact in 

places

Ridge crest

Trough or groove

Crater rim—Showing crest

INTRODUCTION

The polar deposits on Mars are of great interest because they probably record martian 

climate variations (Thomas and others, 1992). The area shown on this map includes polar 

layered deposits with distinct low-albedo features and a sharp boundary between the layered 

deposits and the moderately cratered unit that forms the floor of Chasma Australe. Detailed 

mapping of this quadrangle was undertaken to further investigate the geologic relations 

between the albedo features and the layered deposits and to better constrain the recent 

geologic history of the south polar region. Dark dunes in the north polar region appear to 

be derived from erosion of the layered deposits, but the source of dark material in the south 

polar region is less clear (Thomas and Weitz, 1989). The presence of dark material in the 

brighter, redder layered deposits is paradoxical (Herkenhoff and Murray, 1990a); resolving 

this paradox is likely to result in a better understanding of the origin and evolution of the 

layered deposits and, therefore, the mechanisms by which global climate variations are 

recorded. 

Published geologic maps of the south polar region of Mars have been based on images 

acquired by either Mariner 9 (Condit and Soderblom, 1978; Scott and Carr, 1978) or the 

Viking Orbiters (Tanaka and Scott, 1987). The extent of the layered deposits mapped 

previously from Mariner 9 data is different from that mapped using Viking Orbiter images, 

and the present map agrees with the map by Tanaka and Scott (1987): the floor of Chasma 

Australe is not mapped as layered deposits.

The residual polar ice cap, areas of partial frost cover, the layered deposits, and two 

nonvolatile surface units—the dust mantle and the dark material—were mapped by 

Herkenhoff and Murray (1990a) at 1:2,000,000 scale using a color mosaic of Viking 

Orbiter images. This mosaic and an additional Viking color mosaic were used to confirm the 

identification of the nonvolatile Amazonian units for this map and to test hypotheses for 

their origin and evolution. The colors and albedos of these units, as measured in places 

outside this map area, are presented in table 1 and figure 1. Accurately measuring the color 

and albedo of the units in this map area was not possible due to low signal/noise in the part 

of the red/violet mosaic (corrected for atmospheric scattering) that includes this area 

(Herkenhoff and Murray, 1990a). However, color/albedo unit boundaries in this area are 

visible in color mosaics that have not been corrected for atmospheric scattering effects. 

Therefore, while the color and albedo of various units on this map cannot be precisely 

quantified and compared with the values in table 1 and figure 1, color/albedo units can still 

be recognized. Because the resolution of the color mosaics is not sufficient to map these 

units in detail at 1:500,000 scale, contacts between them were recognized and mapped 

using higher resolution black-and-white Viking and Mariner 9 images. 

Only two possible impact craters in the layered deposits have been found in the area 

mapped; both are slightly elongate rather than circular. One, 1.6 km in diameter at lat 86.6°

S., long 268°, was recognized by Plaut and others (1988); the other, about 3 km in 

diameter, is at lat 82.8° S., long 277°. Although the crater statistics are poor (only 16 likely 

impact craters found in the entire south polar layered deposits), these observations generally 

support the conclusions that the south polar layered deposits are Late Amazonian in age 

and that some areas have been exposed for at least 120 million years (Plaut and others, 

1988; Herkenhoff and Murray, 1992, 1994). However, the recent cratering flux on Mars is 

poorly constrained, so inferred ages of surface units are uncertain. 

The Viking Orbiter 2 images used to construct the base were taken during the southern 

summer of 1977, with resolutions no better than 180 m/pixel. (The "less than 100 m per 

picture element" in Notes on Base of the controlled photomosaic base [U.S. Geological 

Survey, 1986] is incorrect.) A digital mosaic of Mariner 9 images was also constructed to aid 

in mapping. The Mariner 9 images were taken during the southern summer of 1971–72 

and have resolutions as high as 90 m/pixel. However, usefulness of the Mariner 9 mosaic is 

limited by incomplete coverage and atmospheric dust opacity. 

PHYSIOGRAPHIC SETTING

The area of this map is mostly within Planum Australe, a plateau about 1,600 km long 

and 1,200 km wide (U.S. Geological Survey, 1989, sheet 1). Its relief is uncertain due to the 

poor geometry of available stereopairs (S.S.C. Wu, oral commun., 1990). The plateau is 

characterized by the smoothly sculptured landforms of the layered deposits (see fig. 2). Part 

of Chasma Australe, a large reentrant in the layered deposits, appears in the northeast 

corner of the map area. 

The topography of the south polar layered deposits has been studied only in the vicinity 

of the residual polar cap, so it is difficult to estimate the total thickness of the layered deposits. Dzurisin and Blasius (1975) combined Mariner 9 radio-occultation and stereophotogrammetric data and found that the region covered by the residual south polar ice cap is 1 to 2 

km higher than the surrounding layered deposits. Areas of relatively complete frost cover are 

typically level, while defrosted scarps slope 1° to 5° overall. In some cases, the scarps form 

low-relief troughs that are asymmetrical in cross section. While photogrammetric data are 

lacking in this map area, brightness variations in several images of the layered deposits suggest that similar topographic relations exist here and in other areas of layered terrain outside 

the region studied by Dzurisin and Blasius (1975). 

STRATIGRAPHY AND STRUCTURE

The oldest unit on this map is the upper member of the Hesperian-age Dorsa Argentea 

Formation (unit Hdu), which forms the floor of Chasma Australe in the northeast corner of 

the map area. The upper member is distinguished from the layered deposits by its numerous 

impact craters, mountains, and sinuous ridges. Tanaka and Scott (1987) used Viking Orbiter 

images to recognize flow fronts in the member outside this map area, indicating a volcanic 

origin. They and others recognized braided and sinuous ridges in the member that have 

been variously interpreted as volcanic, aeolian, tectonic, fluvial, or glacial features (Kargel, 

1993). None of these hypotheses for the origin of these ridges can be ruled out completely 

using observations of the few ridges in this map area, but their occurrence near the south 

pole suggests that ice has been involved in their formation. Better understanding of these 

features will require higher resolution imaging from future spacecraft. The sharp boundary 

between the upper member and the layered deposits at the base of scarps shows that the 

layered deposits overlie the upper member. Layering in the walls of Chasma Australe 

suggests that it was formed by erosion of the layered deposits and that the surface of the 

upper member has been exhumed in the chasma. 

The layered deposits (unit Al) are recognized by their distinct bedded appearance and 

intermediate color and albedo; they appear to be the youngest bedrock unit in the south 

polar region (Herkenhoff and Murray, 1992, 1994). The horizontal to subhorizontal beds 

that make up the layered deposits are especially well exposed on this map around Chasma 

Australe. Similar layered exposures have been recognized in the north polar layered deposits 

(Cutts, 1973; Cutts and others, 1976; Blasius and others, 1982; Howard and others, 

1982). In both polar regions, layers are apparent in such places because of their terraced 

topography, especially where accented by differential frost retention (Herkenhoff and 

Murray, 1990b). Photoclinometric analysis of an exposure of layered deposits outside the 

map area (Herkenhoff and Murray, 1990b) indicates that similar layers are 100 to 300 m 

thick, but thinner layers, if present, cannot be detected due to limitations in image 

resolution. Thinner layers (14 to 46 m thick) were found by Blasius and others (1982) in the 

north polar layered deposits, which suggests that finer layering may also exist in the 

southern polar deposits. Slopes of as much as 20° occur outside this map area between 

nearly horizontal terraces at lat 87.0° S., long 346° (Herkenhoff and Murray, 1990b). No 

definite angular unconformities have been found within the south polar layered deposits 

(Herkenhoff and Murray, 1992, 1994), unlike the north polar deposits, where better image 

resolution allows them to be recognized (Cutts and others, 1976). As described in the next 

section, water ice in the layered deposits is probably protected from solar heating and 

sublimation by a weathering rind or lag deposit on the surface. 

Structural deformation in this area and in nearby quadrangles (Herkenhoff and Murray, 

1992, 1994) appears to be minimal or absent, as no faulting or folding has been observed. 

The scarps and troughs in the layered deposits are interpreted as erosional rather than 

structural features because of the lack of folded or offset layers. An unusually steep, irregular 

scarp is present in the layered deposits at lat 83.3° S., long 297°, near the upper edge of 

the flank of a low-relief trough. The scarp appears to be fluted, with individual flutes as much 

as 1 km across, in a Mariner 9 image with 91 m/pixel resolution. This scarp is barely visible 

as a bright line in the best Viking Orbiter image of this area (383B27). Similar bright lines 

that are visible in other parts of this Viking image are mapped as scarps, but in most cases 

they cannot be seen in Mariner 9 images of the same area, perhaps due to greater 

atmospheric opacity. Such steep scarps were not found in either MTM −90000 (Herkenhoff 

and Murray, 1992) or MTM −85080 (Herkenhoff and Murray, 1994). Unlike the steep 

scarps in the north polar layered deposits (Thomas and Weitz, 1989), these scarps do not 

appear to be the source of dark, saltating material. Either the dark material has been 

removed from the area by winds since the last episode of scarp retreat or erosion is 

continuing and dark material is simply not exposed in these scarps. Higher resolution images 

of these features from future Mars missions are needed to determine their origin and role in 

layered deposit evolution. 

The dark material (unit Ad) and the dust mantle (stipple) unconformably overlie the 

other map units, indicating relatively recent deposition by saltation and from atmospheric 

suspension, respectively. The location of dark material in topographic depressions here and 

elsewhere in the south polar region indicates that it is transported by saltation (Herkenhoff 

and Murray, 1990a; Herkenhoff and Murray, 1994), but image resolution is insufficient to 

resolve dune forms. Deposition or redistribution of this unit may be continuing. The unit 

may be composed of sand-size particles or low-density aggregates of dust grains. The very 

low thermal inertias in this region deduced by Paige and Keegan (1994) indicate that solid 

sand grains are not abundant in the map area. The dark material is therefore more likely 

composed of low-density aggregates of dust particles or very porous grains of basalt. We 

cannot distinguish between these two hypotheses using the available data in the map area. If 

the dark material is made of solid or porous sand grains rather than sublimation residue 

particles, codeposition of dust and sand to form the layered deposits is implied. Saltating 

sand will inject dust into suspension, so the dust must somehow be cemented to permit 

codeposition with sand (Herkenhoff and Murray, 1990a). 

The bright, red dust mantle does not appear to obscure topography, so it is probably no 

more than a few meters thick. Furthermore, the extent of the dust mantle changed in many 

places during the 3 Mars years between the Mariner 9 and Viking Missions, indicating that it 

is ephemeral (Herkenhoff and Murray, 1992, 1994). Its boundary is mapped here as it 

appeared during the Viking Mission in 1977. A new Viking Orbiter 2 color mosaic of the 

study area, taken during orbit 358, was constructed using controlled images provided by T. 

Becker of the U. S. Geological Survey in Flagstaff. Analysis of this color mosaic indicates 

that the bright, red unit extends beyond the layered deposits, supporting our previous 

interpretation of this unit as a dust mantle (Herkenhoff and Murray, 1990a). This 

interpretation is consistent with thermal modeling of Viking IRTM data that shows that the 

thermal inertia of the surface of the layered terrain is very low (Paige and Keegan, 1994). 

The boundary between the dust mantle and the layered deposits in the northwest corner of 

the map appears streaked in many cases. These streaks may be unique to this area, as they 

have not been seen in nearby quadrangles (Herkenhoff and Murray, 1992, 1994). The 

direction of the streaks is roughly parallel to the dip of the flanks of the large troughs in the 

layered deposits, suggesting that gravity has played a role in their formation. However, the 

overall slopes of the trough flanks are probably very low (less than 5°), so the streaks are 

unlikely to be solely the result of mass movement. 

GEOLOGIC PROCESSES AND HISTORY

The polar layered deposits are widely believed to have been formed through deposition 

of water ice and dust, modulated by global climate changes during the last few million to 

hundreds of million years (Murray and others, 1972; Cutts, 1973; Soderblom and others, 

1973; Cutts and others, 1976, 1979; Squyres, 1979; Toon and others, 1980; Carr, 1982; 

Howard and others, 1982; Pollack and Toon, 1982; Plaut and others, 1988). However, the 

details of the relation between theoretical variations of Mars' orbit and axis and geologic 

observations are not clear (Thomas and others, 1992). In particular, the apparent contrast in 

ages of the north and south polar layered deposits, as indicated by their different crater 

densities (Cutts and others, 1976; Plaut and others, 1988), is paradoxical. The geology of 

this quadrangle illustrates some of the processes that are important in the evolution of the 

southern deposits. 

The differing crater densities and the contact relations between the layered deposits and 

the upper member of the Dorsa Argentea Formation seen in this quadrangle indicate that 

the layered deposits postdate the upper member. With the exception of areas covered by the 

residual polar ice cap, the south polar layered deposits appear to have undergone net 

erosion in the recent geologic past. A larger fraction of the north polar layered deposits is 

covered by the north polar residual ice cap, so erosion of the northern deposits can occur 

only in the relatively small areas that are free of perennial ice. Solar heating of the exposed 

deposits causes sublimation of the water ice within them (Toon and others, 1980; Hofstadter 

and Murray, 1990), probably forming a lag deposit of nonvolatile material. Such a 

nonvolatile layer would protect underlying water ice from further sublimation. Herkenhoff 

and Murray (1990a) proposed that minor amounts of dark magnetic dust exist in the layered 

deposits along with the bright, red dust mantle that covers much of the martian surface. The 

magnetic dust may preferentially form filamentary sublimation residue particles (Storrs and 

others, 1988) that eventually break free of the surface and saltate, ejecting the remaining 

dust into suspension. Dark particles 100 microns to 1 mm in size will continue to saltate 

until trapped by an obstacle or depression, where they could form isolated patches of the 

dark material. Eventual destruction of such particles could allow the dark dust to be recycled 

back into new layered deposits from atmospheric suspension. 

The above scenario is consistent with the color, albedo, and geology of the units 

mapped here. The thin dust mantle appears to be a temporary feature, perhaps deposited 

during a great global dust storm such as that observed in 1971. Where the dust has been 

removed by winds, the water ice in the layered deposits is protected from further sublimation 

by a weathering rind of dust and dark residue particles. The streaks observed in the 

northwest corner of the map are interpreted as the result of local removal of the dust mantle 

by saltation of dark material. The orientation of the streaks is consistent with the direction of 

strong off-cap winds expected during the southern summer, when seasonal CO2 frost is 

subliming rapidly. The atmospheric boundary layer may be affected by the presence of the 

low-relief troughs, perhaps reducing its ability to maintain saltation. In any case, this area is 

a prime target for future exploration. 

ACKNOWLEDGMENTS

This map and text benefited substantially from reviews by Henry Moore and Ken 

Tanaka. The research described in this publication was carried out by the Jet Propulsion 

Laboratory, California Institute of Technology, under a contract with the National 

Aeronautics and Space Administration. 

REFERENCES CITED

Blasius, K.R., Cutts, J.A., and Howard, A.D., 1982, Topography and stratigraphy of 

martian polar layered deposits: Icarus, v. 50, p. 140-160.

Carr, M.H., 1982, Periodic climate change on Mars: Review of evidence and effects on 

distribution of volatiles: Icarus, v. 50, p. 129-139.

Condit, C.D., and Soderblom, L.A., 1978, Geologic map of the Mare Australe area of 

Mars: U.S. Geological Survey Miscellaneous Investigations Series Map I–1076, scale 

1:5,000,000. 

Cutts, J.A., 1973, Nature and origin of layered deposits of the martian polar regions: 

Journal of Geophysical Research, v. 78, p. 4231-4249.

Cutts, J.A., Blasius, K.R., Briggs, G.A., Carr, M.H., Greeley, Ronald, and Masursky, 

Harold, 1976, North polar region of Mars: Imaging results from Viking 2: Science, v. 

194, p. 1329-1337.

Cutts, J.A., Blasius, K.R., and Roberts, W.J., 1979, Evolution of martian polar landscapes: 

Interplay of long-term variations in perennial ice cover and dust storm intensity: Journal 

of Geophysical Research, v. 84, p. 2975-2994.

Dzurisin, Daniel, and Blasius, K.R., 1975, Topography of the polar layered deposits of 

Mars: Journal of Geophysical Research, v. 80, p. 3286-3306.

Herkenhoff, K.E., and Murray, B.C., 1990a, Color and albedo of the south polar layered 

deposits on Mars: Journal of Geophysical Research, v. 95, no. B2, p. 1343-1358. 

———1990b, High resolution topography and albedo of the south polar layered deposits 

on Mars: Journal of Geophysical Research, v. 95, no. B9, p. 14,511-14,529.

Herkenhoff, K.E., and B.C. Murray, 1992, Geologic map of the MTM -90000 area, 

Planum Australe region of Mars: U.S. Geological Survey Miscellaneous Investigations 

Series Map I–2304, scale 1:500,000.

Herkenhoff, K.E., and B.C. Murray, 1994, Geologic map of the MTM −85080 area, 

Planum Australe region of Mars: U.S. Geological Survey Miscellaneous Investigations 

Series Map I–2391, scale 1:500,000.

Hofstadter, M.D., and Murray, B.C., 1990, Ice sublimation and rheology: Implications for 

the martian polar layered deposits: Icarus, v. 84, p. 352-361.

Howard, A.D., 1981, Etched plains and braided ridges of the south polar region of Mars: 

Features produced by basal melting of ground ice? [abs.], in Reports of Planetary 

Geology Program—1981: National Aeronautics and Space Administration Technical 

Memorandum 84211, p. 286-288.

Howard, A.D., Cutts, J.A., and Blasius, K.R., 1982, Stratigraphic relationships within 

martian polar cap deposits: Icarus, v. 50, p. 161-215.

Kargel, J.S., 1993, Geomorphic processes in the Argyre-Dorsa Argentea region of Mars, in

Abstracts of papers submitted to the Twenty-fourth Lunar and Planetary Science 

Conference, Houston, March 15-19, 1993: Houston, Lunar and Planetary Institute, p. 

753-754.

Murray, B.C., Soderblom, L.A., Cutts, J.A., Sharp, R.P., Milton, D.J., and Leighton, R.B., 

1972, Geological framework of the south polar region of Mars: Icarus, v. 17, p. 328-

345.

Paige, D.A., and Keegan, K.D., 1994, Thermal and albedo mapping of the polar regions of 

Mars using Viking Thermal Mapper observations: 2. South polar region: Journal of 

Geophysical Research, v. 99, p. 25,993-26,013.

Plaut, J.J., Kahn, Ralph, Guinness, E.A., and Arvidson, R.E., 1988, Accumulation of 

sedimentary debris in the south polar region of Mars and implications for climate 

history: Icarus, v. 76, p. 357-377.

Pollack, J.B., and Toon, O.B., 1982, Quasi-periodic climate changes on Mars: A review: 

Icarus, v. 50, p. 259-287.

Scott, D.H., and Carr, M.H., 1978, Geologic map of Mars: U.S. Geological Survey 

Miscellaneous Investigations Series Map I–1083, scale 1:25,000,000.

Soderblom, L.A., Malin, M.C., Cutts, J.A., and Murray, B.C., 1973, Mariner 9 observations 

of the surface of Mars in the north polar region: Journal of Geophysical Research, v. 

78, p. 4197-4210.

Squyres, S.W., 1979, The evolution of dust deposits in the martian north polar region: 

Icarus, v. 40, p. 244-261.

Storrs, A.D., Fanale, F.P., Saunders, R.S., and Stephens, J.B., 1988, The formation of 

filamentary sublimate residues (FSR) from mineral grains: Icarus, v. 76, p. 493-512.

Tanaka, K.L., and Scott, D.H., 1987, Geologic map of the polar regions of Mars: U.S. 

Geological Survey Miscellaneous Investigations Series Map I–1802-C, scale 

1:15,000,000. 

Thomas, Peter, Squyres, Steven, Herkenhoff, Ken, Howard, Alan, and Murray, Bruce, 

1992, Polar deposits on Mars, in Kieffer, H.H., Jakosky, B.M., Snyder, C.W., and 

Matthews, M.S., eds., Mars: Tucson, University of Arizona Press, p. 767-795.

Thomas, P.C., and Weitz, Catherine, 1989, Sand dune materials and polar layered deposits 

on Mars: Icarus, v. 81, p. 185-215.

Toon, O.B., Pollack, J.B., Ward, William, Burns, J.A., and Bilski, Kenneth, 1980, The 

astronomical theory of climatic change on Mars: Icarus, v. 44, p. 552-607.

U.S. Geological Survey, 1986, Controlled photomosaic of the MTM −85280 area, Planum 

Australe region of Mars: U.S. Geological Survey Miscellaneous Investigations Series 

Map I–1843, scale 1:500,000.

———1989, Topographic maps of the western, eastern equatorial, and polar regions of 

Mars: U.S. Geological Survey Miscellaneous Investigations Series Map I–2030, three 

sheets, scale 1:15,000,000.

Figure 1. Violet Lambert albedo plotted against red Lambert albedo for three 

surface units in vicinity of south residual polar cap of Mars (exposures outside map 

area). Lambert albedos derived by dividing observed reflectance (corrected for 

atmospheric scattering) by cosine of incidence angle. Error bars represent 

combination of 13 percent uncertainty in absolute albedos and sampling errors in 

5×5-pixel areas. Albedo variations along lines of constant red-to-violet ratio (R/V) 

mainly due to slope differences (Herkenhoff and Murray, 1990a). Colors of units are 

consistent with colors of similar units in north polar region (Thomas and Weitz, 

1989). 

INTERIOR —GEOLOGICAL SURVEY, RESTON, VA—1998

Prepared on behalf of the Planetary Geology Program, Solar System Exploration Division,

Office of Space Science, National Aeronautics and Space Administration

Edited by Derrick D. Hirsch; cartography by Mike Dingwell

Manuscript approved for publication December 2, 1996

Base from U.S. Geological Survey, 1986 .

GEOLOGIC MAP OF THE MTM –85280 QUADRANGLE, PLANUM AUSTRALE REGION OF MARS

By

Ken Herkenhoff

1998

Prepared for the

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

ATLAS OF MARS

1: 500,000 GEOLOGIC SERIES

PLANUM AUSTRALE REGION—MARS

M 500k −85/280 G, 1998

MAP I–2595

Dust mantle (stipple) 0.04 – 0.05 0.14 – 0.18 3.2 – 3.8

Dark material (unit Ad) 0.02 – 0.05 0.04 – 0.10 1.8 – 2.1

Layered deposits (unit Al) 0.03 – 0.05 0.10 – 0.13 2.5 – 3.2

For sale by U.S. Geological Survey, Information Services,

Box 25286, Federal Center, Denver, CO 80225

120° 150° 180° 210°

240°

unconformity

Number of craters

 larger than 2 km

in diameter per million

 square kilometers*

SYSTEM

AMAZONIAN

HESPERIAN

Less than

5

7

10

400

800

CORRELATION OF MAP UNITS

 *Plaunt and others, 1988

Dust mantle

Layered deposits

Dark material

EXPLANATION

0 0.05 0.1 0.15

RED LAMBERT ALBEDO

0

0.02

0.04

VIOLET LAMBERT ALBEDO

R/V = 2

R/V = 3

R/V = 4

Unit Violet Red R/V

Table 1. Lambert albedos and colors of surface units in the south polar region

(Herkenhoff and Murray, 1990a). Ranges indicate variations in color and

albedo among various areas sampled

260°

265°

270°

275°

280°

285°

290°

295°

300°

−82.5°

−83°

−84°

−85°

−86°

−87°

−87.5°

300° 295° 290° 285° 280° 275° 270° 265° 260°

−87.5°

−87°

−86°

−85°

−83°

−82.5°

−84°

West

East

South

North

PLANUM

ANGUSTUM

P L A N U M

Chasma Australe

AUSTRALE

MTM −85080

I–2391

MTM −90000

I–2304

CAVI

ANGUSTI

MTM −85280

I–2595

MTM −85000

Figure 2. Index map showing location of major physiographic features and 1:500,000-scale maps 

in Planum Australe region completed or in progress in Mars Geologic Mapping Program. Mars 

Transverse Mercator (MTM) numbers indicate latitude and longitude of center of maps. I–number 

indicates published map. 

Promethei

Rupes

270°

300°

30° 0° 330°

90°

x

x

x

x

x

x

-

-

-

-

-

--

-

--

-

60°

Ad

Al

Hdu

Hdu

Ad

Ad

Hdu

Hdu

CHASMA 

 AUSTRALE

Al

Al

Al

Al

Al

Al

Al

Al

Al

Al

Al

Al

Al

Al

Al

Al

Al

Ad

Al

Hdu

 KILOMETERS

SCALE 1:500 000 (1 mm = 500 m ) AT -87.5° LATITUDE

POLAR STEREOGRAPHIC PROJECTION

10 0 10 20 30 40 50 60 80 90 70 100