Hellas

highlands

Hellas

rim

floor

basin

Hellas

Hellas

Hellas

floor

Hellas rim

A

–38°

–39°

–40°

–41°

–42°

–43°

–44°

–45°

–46°

–47°

280°

279°

270° 270°

280°

–47.5°

278°

277°

276°

275°

274° 273° 272° 271°

270°

–47.5°

–47°

–46°

–45°

–44°

–43°

–42°

–41°

–40°

–39°

–38°

271° 272° 273° 274°

275°

276°

277°

278°

279°

280°

315° 255°

100

75

25

No. of craters with >16 km diameter per 106 km2

AHpc

AHpc

AHpc

HNps

HNps

HNps

HNps

HNps HNps

HNps

HNps

HNps

HNps

HNps

HNps

HNps

HNps

HNps

HNps

HNps

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

HNfis

Hfh

Hfh

Hfh

Hfh

Hfh

Hfh

Hfh

Hfh

AHfs

AHfs

AHfs

AHfs

AHfs

AHvt

AHvt

AHc3

AHc3

AHc3

AHc3

AHc2

AHvD

AHc2

AHc2

AHc2

AHc2

AHc2

AHc2

AHc2

Hc1

Hc1

Hc1

Hc1

Hc1

Hc1

Hc1

Hc1

AHvS

cu

cu

cu

cu

cu

AHvS

Hc1

Hc1

Hc1

AHvD

AHvD

AHvD

HNps

AHvD AHvH

AHvH

AHvH

AHvH

AHvS

AHvS

cf

cf

cf

cf

cf

cf

cf

cf

cf

cf

cf

cf

cf

cf

cf

cf

cu

cu

cu

cu

cu

cu

cu

cu

cu

cu

cu

cu

cu

cu

cu

cu

cu cu

cu

cu

cu

cu

cu

cu

cu

cu cu

cu

cu

cu

cu

cu cu

cu

cu

cu

cp

cp

Nph

Nph

Nph

Nph

Nph

Nph

Nph

Nph

Nph

Nph

Nph

Nph

Nph

Nph Nph

Nph

Nph

Nph

Nph

Nph

Nph

Nph Nph

Nph

Nph

Nph

Nph

Nph

Nph

Nph

Nph

Nph

HNps

Nph

cf

cu

cp

AHvD

Hc1

AHc2

AHc3

AHvH

AHvS

AHpc

HNps

Nph

AHfs

Hfh

HNfis

AHvt

AHpc Hfh HNps

Nph

Nph

HNps

HNps

HNps

HNfis Nph

HELLAS

PLANITIA

Bogia

Quines

Tungla

Santaca

Mliba

H a r m a k h i s

Va l l i s

S u n g a r i

Va l l i s

D a o

Va l l i s

–37.5°

–38°

–39°

–40°

–41°

–42°

–43°

–44°

–45°

–46°

80°

81°

Prepared for the

National Aeronautics and Space Administration

Scientific Investigations Map 3096

Atlas Of Mars: MTM –40277, –45277, –40272, and –45272 Quadrangles

Pamphlet accompanies map

90°

–47.5°

–47°

82°

83°

84°

85°

86° 87° 88° 89°

90°

–47.5°

–47°

–46°

–45°

–44°

–43°

–42°

–41°

–40°

–39°

–38°

–37.5°

89° 88° 87° 86° 85° 84°

83° 82° 81° 80°

20 0 20 40 60 80 100

SCALE 1:1 004 000 (1 mm = 1.004 km ) AT 270° LONGITUDE

TRANSVERSE MERCATOR PROJECTION Prepared on behalf of the Planetary Geology and 

Geophysics Program, Solar System Exploration 

Division, Office of Space Science, National Aeronautics 

and Space Administration

Edited by Jan L. Zigler; cartography by Darlene A. Ryan

Manuscript approved for publication October 14, 2009

Descriptions of nomenclature used on map are 

listed at http://planetarynames.wr.usgs.gov/

KILOMETERS

Planetocentric latitude and east longitude coordinate system shown in black.

Planetographic latitude and west longitude coordinate system shown in red.

Geologic Map of MTM –40277, –45277, –40272, and –45272 Quadrangles, Eastern Hellas Planitia Region of Mars

By

Leslie F. Bleamaster, III,1, 2 and David A. Crown1

2010

1

Planetary Science Institute, Tucson, AZ

2

Trinity University, Geosciences Department, San Antonio, TX AMAZONIAN HESPERIAN NOACHIAN PERIOD

SEQUENCE OF MAP UNITS AND VOLATILE ACTIVITY

RIM ASSEMBLAGE FLOOR ASSEMBLAGE VALLIS AND CHANNEL MATERIAL CRATER MATERIAL VOLATILE ACTIVITY

Hellas Planitia

Paleo-lakes?

Fluvial channels

Dao, Harmakhis, 

and Sungari Valles 

Gullies and 

ice-rich flows 

Figure 6. MOLA DEM (left) and Viking MDIM 2.1 (right) showing several truncations along Dao Vallis on 

the eastern rim of Hellas basin. Image locations shown on map. See map symbol explanation at end of 

Description of Map Units.

Figure 1. (A) Hellas Planitia extends across ~50° in longitude (long ~46° to 95° E.) and more than 20° in 

latitude (lat ~32° to 55° S.). The –4,000 m elevation contour roughly defines the topographic depression of 

the Hellas basin. (B) MTM –40277, –45277, –45272, and –40272 quadrangles traverse the eastern rim of 

Hellas Planitia and display ~3 km of relief, including the transition from rim to floor. Mars Orbiter Laser 

Altimeter (MOLA) DEMs (128 px/degree, ~464 m/pxl). Note locations of informally named features 

discussed in report.

Figure 2. MOLA 128 pixel/degree DEM with contour intervals or shorelines: 

–6,900 m, –5,800 m, and –3,100 m (Moore and Wilhelms, 2001, 2007) and –1,800 

m (Crown and others, 2005). Shorelines follow and are characterized by distinct 

changes in surface morphology, including crater retention.

Figure 3. Graphical representation of N(5) (black) and N(16) (red) size 

frequency distributions for major geologic units. N(16) scale is 

nonlinear, but age divisions (Tanaka, 1986) correlate with N(5) 

divisions. Periods: N, Noachian; H, Hesperian; A, Amazonian. Epochs: 

E, Early; M, Middle; L, Late.

Figure 4. Parts of THEMIS daytime IR I07937005 (A; image center, lat 47.42° 

S., long 277.23° W.) and nighttime IR I08018008 (B; image center, lat 35.07° S., 

long 275.54° W.) images illustrate the morphologic and thermophysical differences between the smooth (HNps) and hummocky (Nph) plains materials (line 

connects common crater in each image; image widths ~30.5 km). Image locations 

shown on map.

DESCRIPTION OF MAP UNITS

RIM ASSEMBLAGE

Channeled plains material (Amazonian to Hesperian)—Smooth to 

irregular surfaces characterized by small-scale sinuous channels, 

ridges, and scarps; lightly cratered. Type Locality: (lat 45.5° S., long 

271.3° W.). Interpretation: Sediments deposited as result of erosion of 

surrounding highlands to the east and of Hellas Planitia rim terrain; 

redistributed to form smooth and scoured (to the east) surfaces. 

Uncertainty regarding exact location of contact with unit HNfis results 

from presence of poorly consolidated sediments and Amazonian 

mid-latitude mantling deposits. Some contributions of sediments and 

volatiles may be related to development of Reull Vallis to the east of the 

map area or Hellas Planitia paleolakes

Smooth plains material (Hesperian to Noachian)—Plains of slight to 

moderate relief cut by narrow, sinuous channels and linear to arcuate 

troughs. Forms low-relief plateau with a moderate albedo in Viking and 

THEMIS visible datasets; exhibits ridges and curvilinear to irregular 

scarps, many along the margins of Dao Vallis. Stipple pattern marks 

regions of downdropped blocks of smooth plains material that preserve 

primary surface characteristics. Type Locality: lat 41° S., long 273.8° 

W.; blocks at lat 38.8° S., long 272.8° W. Interpretation: Sedimentary 

deposits derived from surrounding terrains and possible volcanic material; large irregular blocks represent initial stages of canyon widening 

due to fracturing, sapping, collapse, and possible devolatilization

Hummocky plains material (Noachian)—Irregular surfaces of moderate 

relief; moderately to heavily cratered and cut by numerous channels 

and scarps; mottled appearance with high-standing knobs, ridges, 

troughs, and layered outcrops along scarps; low albedo relative to 

smooth plains material (unit HNps) in Viking and THEMIS visible 

images; highly variable thermophysical signature in THEMIS infrared 

images. Diamonds indicate layered materials observed in highresolution MOC images, see figure 5. Type Locality: lat 38.1° S., long 

275.3° W. Interpretation: Sedimentary and volcanic deposits with 

some remnants of rugged highlands. Irregular surface morphology, 

albedo, and thermophysical mottling result from deformation, deflation, fluvial downcutting, scarp retreat, and collapse of layered, possibly water/ice-rich, materials. Heavily cratered inselberg on floor of 

Hellas Planitia (lat 46° S., long 275.5° W.) represents lateral continuation of rim assemblage underneath smooth floor deposits (unit HNfis); 

Hellas basin floor exposure displays both old, degraded crater rims, as 

well as superposed fresh craters, indicating some removal of a cover 

material, possibly unit AHpc. Current surface morphology appears to 

be dominated by aeolian deflation, devolatilization, and collapse

FLOOR ASSEMBLAGE

Smooth fill material (Amazonian to Hesperian)—Smooth, relatively 

featureless surface in Viking and THEMIS visible images, confined to 

topographic depressions marking the extensions of Harmahkis Vallis 

onto Hellas Planitia. Depressions have sinuous to braided nature. Type 

Locality: lat 42.9° S., long 275.5° W. Interpretation: Significantly thick 

deposits (enough to obscure hummocky nature of unit Hfh) of fine 

material resulting from mass wasting and aeolian deposition

Hummocky floor material (Hesperian)—Irregular surface with moderate 

relief, specifically near concentrations of narrow troughs, found 

adjacent to and around scarp-bound mesas of smooth interior floor 

within Hellas Planitia (unit HNfis). Outcrops contained within 

topographic depressions at terminus of Harmahkis Vallis. Superposed 

by smooth fill material (unit AHfs). Type Locality: lat 42.8° S., long 

276.5° W. Interpretation: Combination of remnant smooth interior 

deposits, Harmakhis Vallis terminal deposits, and underlying rock 

material. Represents breakup and removal of smooth interior deposits; 

includes materials mass-wasted from adjacent mesas

Smooth interior floor material (Hesperian to Noachian)—Broad annular 

region in eastern Hellas Planitia characterized by smooth to irregular 

surfaces (in Viking and THEMIS data) with rectilinear to polygonal 

ridge patterns, moderately to heavily cratered. Locally forms scarpbound mesas. Clearly embayed by terminal deposits from Dao Vallis 

(unit AHvt) but has gradational boundary with channeled plains (unit 

AHpc) to the east and with other vallis materials (units AHvD, AHvH, 

AHvS). Stipple pattern marks area of anomalously high retention of 

small to moderately sized craters, including those with dark albedo and 

thermophysical characteristics similar to those of unit Nph. Type 

Locality: lat 46.7° S., long 274.4° W. Interpretation: Sedimentary and 

volcanic materials eroded from eastern Hellas Planitia rim and deposited on basin floor. Deposits drape underlying topography and wrinkle 

ridges; localized removal of material exposes older striated ejecta 

blankets and rugged wrinkle-ridge morphology. Some ridges form 

circular patterns consistent with buried crater rims. Materials possibly 

transported through proto-Dao and proto-Harmahkis Valles (and other 

vallis systems) and deposited in a widespread lacustrine environment 

across the basin floor. Current outcrop pattern, specifically near 

Harmakhis Vallis, controlled by paleolocation of Harmakhis’ terminal 

branches. Larger, superposed craters penetrate deep enough to excavate 

the underlying unit Nph materials; relatively smaller craters of unit 

Nph are morphologically subdued (several craters completely 

blanketed by surficial materials but maintain topographic expression as 

circular ridges). Widespread mantling by aeolian fines and atmospheric 

frosts, especially south of latitude 40° S.

VALLIS AND CHANNEL MATERIAL

Vallis terminal material (Amazonian to Hesperian)—Irregular surface; 

moderate albedo in Viking and THEMIS visible images; minor 

topographic rise at lobate margins. Type Locality: lat 39.75° S., long 

278.25° W. Interpretation: Sedimentary material deposited at mouth of 

Dao Vallis by fluvial, nival, glacial, and (or) debris-flow processes. 

Represents the most recent contributions of material from the rim to the 

floor

Channel floor material (Amazonian to Hesperian)

Member 3 (Amazonian to Hesperian)—Smooth surfaces in elongate, 

sinuous channels; low albedo. Occurs on floors of youngest throughcutting canyons and channels superposing the vallis terminal material 

at the mouth of Dao Vallis. Type Locality: lat 39.6° S., long 277.8° W. 

Interpretation: Fluvial, aeolian, and (or) mass-wasted materials deposited in narrow topographic lows

Member 2 (Amazonian to Hesperian)—Smooth surfaces in truncated 

channel segment. Channels typically have narrow, sinuous form, but 

also show widening in some locations as open canyons. Type Locality: 

lat 39.05° S., long 275° W. Interpretation: Channel floor containing 

deposits of fluvial, aeolian, and (or) mass-wasted material; widening 

caused by wall collapse. Channel segments reflect drainage along 

Hellas Planitia rim; some may represent abandoned pathways of Dao 

Vallis paleochannels

Member 1 (Hesperian)—Smooth surfaces in truncated channel 

segments. Occurs along trend of several small surface channels. Channels typically have narrow, sinuous form but also show widening in 

some locations as open canyons. Type Locality: lat 39.3° S., long 274° 

W. Interpretation: Channel floor containing deposits of fluvial, aeolian, 

and (or) mass-wasted material; widening caused by wall collapse. 

Channel segments reflect drainage along Hellas Planitia rim; some may 

represent abandoned pathways of paleochannels

Dao Vallis floor material (Amazonian to Hesperian)—Smooth materials 

on floor of elongate, relatively steep walled, sinuous canyon; linear and 

curvilinear features parallel canyon margins. Type Locality: lat 39.4° 

S., long 273.55° W. Interpretation: Materials derived from surrounding 

units, canyon walls, and (or) aeolian deposition; modified by smallscale deflation and redistribution. Lineations may be related to flow of 

water/ice-rich materials downcanyon or due to convergence of debris 

shed from adjacent walls

Harmakhis Vallis floor material (Amazonian to Hesperian)—Smooth 

materials on floor of elongate, relatively steep walled, sinuous canyon; 

surface lineations and chains of pits parallel canyon margins. Type 

Locality: lat 41.9° S., long 271.6° W. Interpretation: Materials derived 

from surrounding units, canyon walls, and (or) aeolian deposition, 

modified by small-scale deflation and redistribution; lineations either 

from flow of water/ice-rich materials downcanyon or from 

convergence of debris shed from adjacent walls; pits from loss of 

volatiles or from collapse of surface materials over subsurface volatile 

pathways

Sungari Vallis floor material (Amazonian to Hesperian)—Smooth materials on floor and at terminus of narrow, elongate, sinuous canyon. Type 

Locality: lat 40.25° S., long 272.15° W. Interpretation: Canyon floor 

containing deposits of fluvial, aeolian, and (or) mass-wasted material

CRATER MATERIAL

Crater-fill material (Amazonian to Noachian)—Smooth, relatively 

featureless surfaces on crater floors. Some surfaces have lineated and 

concentric patterns and (or) lobate margins extending from crater walls. 

Type Locality: lat 41.1° S., long 272.65° W. Interpretation: Fluvial, 

aeolian, and (or) mass-wasted deposits accumulated on the crater floor; 

lobate margins and lineated features most likely from downslope flow 

and primary deposition; concentric patterns possibly from episodic 

deposition and (or) erosion

Crater material, undivided (Amazonian to Noachian)—Fresh to highly 

eroded rim, floor, and ejecta materials. Ejecta deposits commonly 

lobate; some have pedestal morphology and striated ejecta blankets. 

Some are superposed on and some protrude through Hellas floor 

materials. Crosshatch pattern indicates dark-albedo material (in 

Viking and THEMIS visible datasets) within ejecta blankets. Type 

Locality: lat 43.8° S., long 276.25° W. Interpretation: Material 

displaced and redeposited by impacts; low-albedo material excavated 

from unit Nph

Crater-peak material (Hesperian to Noachian)—Rugged, topographically elevated, uneven material near centers of impact craters. Type 

Locality: lat 44.3° S., long 276.75° W. Interpretation: Material uplifted 

during lithospheric rebound of basement rock during impact event

Contact—Dashed where approximately located; dotted where buried. 

Internal contact delineates deposits of different impacts

Ridge crest

Subdued ridge crest—Visible in MOLA topography

Scarp top—Hachures point downslope

Narrow trough

Narrow channel

Valles floor lineations

Crater ejecta lineations

Crater rim—Showing crest. Dashed where buried

Crater central peak

Subdued crater rim

Location, finely layered outcrop

Collapsed plains

Anomolously high concentration of mantled craters

Dark albedo ejecta material

Figure 7

Figure 6

Figure 4A

Figure 4B

Figure 5. A comprehensive search of all MOC narrow-angle images within a 20° 

by 20° area (A; lat 30°–50° S., long 270°–290° W.) of the eastern rim reveals 

layered deposits at each of the locations identified by a yellow dot. Parts of MOC 

narrow-angle images E2000151 (B; image center, lat 41.27° S., long 275.71° W.) 

and E2200427 (C; image center, lat 41.09° S., long 275.21° W.) show intricate 

curvilinear patterns found in finely layered deposits concentrated in the 

hummocky plains material (Nph) of the rim assemblage (image widths ~3 km). 

Red line, –5,000 m contour.

0 10 KILOMETERS

Figure 7. Part of MOC wide-angle image M1202662 shows what may be the 

only traceable vallis deposits on the floor of Hellas Planitia. Arrows point to the 

raised margins. Parallel nature of the incised channel and the deposit margins 

suggest that the two are genetically linked (image width ~113 km). Image 

location shown on map.

0 10 KILOMETERS

–7,000 m Inset

–8,200 m Globe

–4,000 m

4,000 m

5,000 m

–20°

–60°

–1,800 m

–3,100 m

–5,800 m

–6,900 m

–8,200 m

45° 105°

400

300

200

No. of craters with >5 km diameter per 106 km2

100

0

MN

LN

EH

LH

EA

MC–21

MC–5

MC–6

MC–7

MC–12 MC–13 MC–14 MC–15

MC–1

MC–20 MC–22 MC–23

MC–27

MC–28

MC–29

MC–30

QUADRANGLE LOCATION

Photomosaic showing location of map area. An outline of 

1:5,000,000-scale quadrangles is provided for reference.

60°

60° 120°

120°

0°

30°

65°

0° 45° 90° 135° 180°

–30°

–65°

0°

30°

65°

–30°

–65°

Any use of trade, product, or firm names in this publication is for descriptive 

purposes only and does not imply endorsement by the U.S. Government.

For sale by U.S. Geological Survey, Information Services, Box 25286, 

Federal Center, Denver, CO, 80225, 1–888–ASK–USGS

Digital files available at http://pubs.usgs.gov/sim/3096

Printed on recycled paper

–4,000 m

–6,400 m

U.S. Department of the Interior

U.S. Geological Survey

A B

B C

–47.5°

–37.5°

90°

80°

A B