Scientific Investigations Map 3079 U.S. Department of the Interior Prepared for the Atlas Of Mars: MTM 35337, 40337 and 45337 Quadrangles U.S. Geological Survey National Aeronautics and Space Administration Pamphlet accompanies map

20° 340° 21° 6000 1000 339° 22° CORRELATION OF MAP UNITS 47.5° 338° 23° 5600 N(2) 337° 24° SURFICIAL PLAINS PLATEAU IMPACT CRATER N(5) Nplsl 5200 336° 25° MATERIAL MATERIAL MATERIAL MATERIAL 335° PERIOD EPOCH 4800 800 c2 Late 4400 47.5° Hpm 47.5° EN-MN Middle 4000 Nplsl Afs 3600 600 47° Nplsu Nplsl Ada Nplsl Ada Early 3200 N(5) N(2) AMAZONIAN 2800 Hpm c1 47.5° 2400 400

47° 47° c3 2000 Nplsl LN Nplsl Late 1600 Nplsu Ada 1200 200 EH Hpm c c2 2 800 47° LH HNps 400 Afs EA HESPERIAN Early 0 0 Ada Nplsu Ada c1 c2 c3 Afs Nplsl Ada Hpm HNps Ncc Npld Nplsu Geologic Units 46° Hpm c1 Figure 2. Plot of crater density data for geologic units in the Nplsu HNps Deuteronilus Mensae map region (see table 1 for data values, error range calculation, and unit names). Solid horizontal lines are breaks between c1 Late Martian periods and dashed horizontal lines are breaks between epochs 0 20 KILOMETERS 46° c as defined by Tanaka (1986): EN–MN, Early to Middle Noachian; LN, 1 Ada Nplsu 46° Hpm Late Noachian; EH, Early Hesperian; LH, Late Hesperian; EA, Early Figure 6. Closed, irregularly shaped depressions (black outline) with polygonal Amazonian. blocks and (or) knobs within a sub-circular basin in the highland plateau. The HNps Ncc basin is roughly defined by the –2,000 m (green) and –2,100 m (yellow) contours HNps from MOLA gridded topography. The knobs and blocks range from a few Ada 46° NOACHIAN Nplsu Middle hundred meters to several kilometers across. The areas between the knobs and blocks are occupied by smooth fill material (unit Afs). Together, the knobs and Npld smooth fill form a hummocky depression floor. The well-preserved impact crater Nplsu Ada 20° near the center of the basin is located at lat 36.8° N., long 22.3° E. Background is Nplsl 45° 47.5° Viking MDIM 2.1 at 256 pixel/degree (NASA/JPL/USGS). North towards top of 25° Nplsu Early c image. 2 Ada 0 5 KILOMETERS c1 Nplsu A′ Figure 10. Bulbous lobe of debris apron material (unit Ada) c 45° 2 Deuteronilus Mensae + Fig. 9 45° DESCRIPTION OF MAP UNITS + Fig. 4 with surface lineations that has flowed through a gap in a c2 mountainous ridge and onto smooth plains material (unit Nplsu SURFICIAL MATERIAL HNps). This lobe, and other prominent lobes nearby, are located Afs Smooth fill material (Late to Early Amazonian)—Smooth deposits surrounding the areas between blocks in an area (40.0° N.) where large apron masses have flowed HNps Nplsu + Fig. 8 and knobs on the floors of closed depressions (lat 36.5° N., long 23.3° E.), covering parts of the floors away from the bases of upper smooth plateau material (unit 45° Nplsu Ada of some impact craters, including Cerulli crater, and the small isolated flats along the rim of Cerulli ). Image center near lat 39.8° N., long 23.0° E. Portion of crater; patches of small knobs within fill deposits below mappable scale are denoted by hachures; THEMIS VIS image V12057009 (NASA/JPL/ASU). North towards top of image. Nplsu grooves in deposits on some impact crater floors follow the curvature of crater walls (lat 36.8° N., long 22.3° E.). Interpretation: Mass-wasted detritus and eolian materials, possibly mixed with ice, that have 44° filled and in some cases, flowed towards the center of low-lying features. Within closed depressions, Nplsu Ada knobs are remnants of eroded blocks and debris from collapse of plateau surface. Within several impact c2 craters, flow convergence at crater center may form concentric grooves; alternatively, grooves may be eroded airfall deposits producing similar concentric patterns (Zimbelman and others, 1989) + + Fig. 5 HNps Ada Debris apron material (Middle to Early Amazonian)—Smooth, lobate deposits surrounding and extending Fig. 15b 44° 44° beyond the bases of mesas, knobs, crater rims, and fretted valley walls; forms bulbous lobes that extend Nplsu Nplsu Ada through breaks in upper plateau material (unit ) (lat 39.8° N., long 23.0° E.) and along margin of HNps Deuteronilus Colles (lat 41.8° N., long 21.2° E.); some surfaces have lineations parallel or transverse to apparent flow direction; some deposits near the slope base are partially covered by one or more apron Nplsu deposits above, forming successive lobate fronts (lat 40.0° N., long 20.5° E.); 1–2 km gap between bases 44° Fig. 15c + of knobs, mesas, and fretted valleys and the apron head are common (lat 40.1° N., long 23.6° E.); materials overlie or embay crater ejecta, knobs, plains, and plateau materials (units Nplsu, Nplsl, Npld, Fig. 13 HNps, Hpm, c1, c2, and c3). Interpretation: Mixtures of ice and mass-wasted detritus that have flowed + block c 1 surfaces Ada Nplsu downslope and covered older units. Apron fronts indicate multiple flow events. Deuteronilus Colles Nplsu 43° Nplsu apron materials may be eroded remnants of an ancient central peak structure. Gaps may represent upper c2 margin retreat or downslope advance of the apron mass with cessation of supply Fig. 12 + HNps Nplsu PLAINS MATERIAL HNps Hpm Mottled plains material (Late to Early Hesperian)—Topographically variable materials with bright 43° 43° flat-topped surfaces and surrounding lower dark hummocky surfaces; margins of some bright surfaces Nplsu bounded by scarps; hummocky surfaces have small knobs in some locales (lat 45.8° N., long 20.5° E.); where adjacent to smooth plains (unit HNps), elevation is similar along the contacts; surfaces are topographically below both smooth plateau units (Nplsu and Nplsl). Interpretation: Origin of this unit Ada Nplsu 43° is unknown, but could be related to erosion and redistribution of plateau materials, a transition from c2 Afs highland plateau to northern lowlands terrain, or a dark smooth fill material covered with bright patches of Lyot crater (lat 50.5° N., long 29.3° E.) ejecta c 2 HNps Smooth plains material (Early Hesperian to Late Noachian)—Smooth, relatively featureless materials c2 Fig. 10 + with regions of variable albedo north of continuous cratered highlands; exhibits scattered clusters of Afs 42° c3 Deuteronilus Ada small circular to irregular knobs (denoted on map by hachures); dark streaks appear to extend beyond c Afs 1 the margin of some dark albedo regions (lat 46.0° N., long 21.2° E.); where adjacent to mottled plains Hpm Interpretation Ada HNps (unit ), elevation is similar along the contacts. : Eroded plateau material (units Nplsu 0 1 KILOMETER c1 Nplsu, Nplsl, and Npld) deposited in low-lying areas, mixed and (or) covered with eolian deposits. + Fig. 11 42° 42° Patchy dark albedo areas covered with thin dust mantle that is modified by eolian activity, producing Nplsu wind streaks Figure 7. Portion of a closed depression in the highland Nplsu Afs Colles plateau with smooth fill material (unit ) occupying areas Fig. 15a + PLATEAU MATERIAL between adjacent blocks of upper smooth plateau material (unit Nplsu). Two surfaces along the edge of one block are clearly Npld Dissected plateau material (Middle Noachian or older)—Portions of continuous cratered highlands with 42° visible, suggesting that plateau materials may be layered in sinuous channels; elongate depressions and secondary crater fields associated with Cerulli crater are places. The block also stands higher along this edge, suggesting common; channels are concentric to a sub-circular basin and well-preserved impact crater near lat 36.8° that it is tilted down into the smooth fill deposits along the HNps Nplsu N., long 22.3° E.; where adjacent to upper smooth plateau material (unit ), the materials are at opposite edge. Image center near lat 36.6° N., long 23.2° E. Interpretation 0 10 KILOMETERS similar elevations. : Ancient highland plateau modified by impact cratering and fluvial Portion of MOC NA image E1200224 (NASA/JPL/MSSS). 41° Afs activity. Channels may be related to fluvial dissection from fluid migration within impact-fractured Ada + Fig. 6 North towards top of image. Figure 11. Lobate debris apron material (unit Ada) extending c2 plateau materials c2 Ada Nplsu Nplsu Upper smooth plateau material (Middle Noachian or older)—Portions of continuous cratered highlands Fig. 7 + downslope and to the northeast from an escarpment has flowed HNps around small knobs (arrows) of upper smooth plateau material that are smooth with minor sinuous channels south of the plateau margin and polygonal mesas north of Nplsu the plateau margin; elevation and crater density of mesa top surfaces generally decrease northward; large (unit ). Curved lineations transverse to the apparent flow 41° direction along upper apron slopes could be ridges of material Nplsu 41° elongated depressions within continuous highlands contain irregular blocks or knobs of the original surface (lat 36.5° N., long 23.3° E.); where in contact with lower smooth plateau material (unit Nplsl), displaced upwards. Image center near lat 38.8° N., long 22.5° Ada E. Portion of THEMIS VIS images V11146004 and c this unit is positioned above unit Nplsl (lat 46.6° N., long 21.4° E.), forming a layered sequence of Nplsu 1 plateau materials revealed in polygonal mesas. Interpretation: Ancient highland plateau modified by V10834007 (NASA/JPL/ASU). North towards top of image. impact cratering, minor fluvial activity, and surface collapse above volatile-rich zones. Mesas are in-situ 41° Nplsu remnants of plateau beyond continuous margin. Knobs are smaller, more eroded remnants of the plateau. Knobs in Deuteronilus Colles may be remnants of a central peak from an impact structure Deuteronilus Mensae Nplsl Lower smooth plateau material (Middle Noachian or older)—Portions of cratered highlands above A surrounding plains (units HNps and Hpm) that are smooth with few impact craters; elevations of 40° Ada Nplsu mesa-like surface tops are consistently between –3,700 m and –3,800 m; albedo generally darker than Nplsu plains in Viking Orbiter data; where in contact with upper smooth plateau material (unit Nplsu), this unit is positioned below unit Nplsu (lat 46.6° N., long 21.4° E.). Interpretation: Stratigraphically lower portion of ancient highland plateau in relation to Nplsu materials Ada 40° Nplsu 40° IMPACT CRATER MATERIAL HNps Ada c c 3 Well-preserved crater material (Early Amazonian to Late Hesperian)—Pronounced, continuous rim 1 Ada with significant relief relative to surrounding surfaces and continuous ejecta blanket; ejecta blankets 32.5° Nplsu commonly have rampart margins (lat 42.4° N., long 22.4° E.); many crater floors are covered by surficial smooth fill material (unit Afs). Interpretation: Deposits exhibiting little degradation that form ejecta, 40° rims, and floors of impact craters Nplsu Figure 3. Location map for figures 4–13 and 15A–C. Image center locations are HNps c2 Moderately degraded crater material (Late to Early Hesperian)—Continuous rim with minor relief Nplsu approximate. Topographic profile A–A′ is shown for figure 14. Background relative to surrounding surfaces and continuous to semi-continuous ejecta blanket; ejecta blankets have Viking MTM mosaic at 50 m/pixel. smooth to pitted surfaces; many crater floors are covered by younger surficial smooth fill material (unit 39° Nplsu Afs). Interpretation: Deposits exhibiting moderate degradation that form ejecta, rims, and floors of impact craters Nplsu c1 Highly degraded crater material (Early Hesperian to Middle Noachian)—Partial to discontinuous rim c 1 with little or no relief relative to surrounding surfaces; some ejecta blankets could only be identified from brightness differences in THEMIS daytime IR data (lat 42.7° N., long 21.0° E.); some crater floors 39° 39° are covered by younger surficial smooth fill or debris apron material (units Afs and Ada). Interpretation: Deposits exhibiting extensive degradation that form ejecta, rims, and floors of impact Ada c 2 craters Ncc Npld Cerulli crater material (Late to Middle Noachian)—Pronounced, continuous rim with significant relief HNps Afs Ada Nplsu 39° relative to surrounding surfaces and continuous ejecta blanket; numerous channels along crater interior Nplsl walls (lat 32.8° N., long 22.1° E.) and outer portions of ejecta blanket; secondary craters and crater fields c1 from the impact scattered throughout ejecta blanket and on adjacent plateau materials (units Nplsu and Nplsl); linear grooves radial to crater center; crater floor and low-lying regions within rim materials Nplsu 0 1 KILOMETER Nplsu covered with surficial smooth fill material (unit Afs). Interpretation: Moderately degraded deposits that 38° c2 form ejecta, rim, and floor of Cerulli crater Figure 8. Dark patchy area within a topographic low in smooth c3 HNps Contact—Dashed where approximately located; short dashed where inferred plains material (unit ). The dark materials appear to be a thin mantle covering the plains surface with wind streaks Crater rim radiating away from its edges, indicating recent eolian activity. 38° Npld —Showing crest. Dashed where approximately located, short dashed where inferred; D > 4.5 38° km Alternatively, the dark material may underlie the brighter Nplsl Ada material and is exposed by dust devil activity. Note that the Crater rim—Showing crest; 3 < D < 4.5 km Nplsu Ada streaks cross local topographic obstacles such as small impact c2 craters. Image center near lat 46.0° N., long 21.2° E. Portion of Nplsu Afs Npld Crater central peak 0 5 KILOMETERS 38° MOC NA image E0401347 (NASA/JPL/MSSS). North Rimless crater towards top of image. c2 Npld Figure 12. Lobes of debris apron material (unit Ada) that extend from the mound along the margin of Deuteronilus c2 Crater ejecta rampart scarp Colles and onto adjacent smooth plains material (unit HNps). Closed depression—Showing margin Knobs of upper smooth plateau material (unit Nplsu) 37° c c 2 2 surrounded by debris apron material may be the remains of a Afs Scarp—Hachures point downslope central peak from a large impact structure. Image center near lat c 1 Nplsu 41.8° N., long 21.2° E. Portion of THEMIS VIS image Afs Radial groove c V09636012 (NASA/JPL/ASU). North towards top of image. 3 c2 0 5 KILOMETERS 37° Afs 37° Wrinkle ridge Afs Npld Flow lineation Figure 4. Polygonal mesa consisting of upper smooth plateau Npld material (unit Nplsu) on top of lower smooth plateau material Hpm (unit Nplsl) with exposure of Nplsl surfaces along the mesa Nplsu c Groove Nplsl 3 scarp. The shared contacts and vertical sequence of these two Afs 37° Channel Nplsl Nplsu units suggests that they are related. surfaces may be exposed lower layers of plateau materials. Image center near lat Nplsu Nplsu Graben 46.6° N., long 21.4° E. Portion of THEMIS VIS image Afs V13954002 (NASA/JPL/ASU). North towards top of image. Flow front—Arrow indicates flow direction Ada 36° Hpm Nplsl c1 Afs Secondary crater field

Hummocky texture in smooth fill material (unit Afs) Nplsu c2 Nplsu 36° 36° Knobby texture in smooth plains material (unit HNps)

Ribbed texture

Npld

36° Hpm c2 15° 20° 25° 30° 35° 40° Ada Afs gap

35° ARABIA 45° 45337 0 20 KILOMETERS Mamers Mensae c2 Deuteronilus Figure 9. Northern portion of map region with mottled plains (unit Hpm) and polygonal mesas of smooth plateau materials 35° 35° Ismeniae (units Nplsu and Nplsl). The mottled plains unit is Fossae topographically variable consisting of bright, flat-topped Ncc 40° surfaces and lower dark hummocky surfaces. Arrows denote 40337 Nplsu the scarps along the margins of several bright surfaces. Image c3 35° center near lat 46.8° N., long 22.5° E. Portion of Viking MTM mosaic at 50 m/pixel. North towards top of image. Nplsu Afs TERRA c3 Valles c 2 c2 35° 35337 34° ARABIA Afs c1 c 2 Npld TERRA Ada Figure 5. Alcoves (arrows) along the scarps of a polygonal mesa of upper Nplsu Cerulli smooth plateau material (unit ). The smooth materials within some 0 5 KILOMETERS 34° 34° alcove floors have minor surface lineations and (or) raised lobate fronts, Afs indicating downslope flow of materials similar to lobate debris aprons (unit Figure 13. Ribbed pattern of ridges (shown by stipple pattern c 30° Ada 1 ). Note the approximate 1-km gap between the base of the mesa and the on map) along the margin of debris apron materials (unit Ada). c 0 125 KILOMETERS Ncc 1 head of the apron mass. The gap may have formed by upper margin retreat Partial retreat of the apron margin or apron deposition over an Afs Nplsu 34° 0.9 –4.4 KILOMETERS or advancement of the apron mass with cessation of debris supply from the uneven pre-existing surface (for example, see ejecta from source area. Black lines across image are data gaps. Image center near lat c Figure 1. Regional view of Deuteronilus Mensae (lat 30°–48° N., long 15°–40° E.) with MTM nearby well-preserved impact crater [unit 3] underlying the 44.4° N., long 22.5° E. Portion of THEMIS VIS image V01310004 apron deposits) may have produced the ribbed appearance. quadrangles 35337, 40337 and 45337 outlined in white. The approximate location of the Arabia (NASA/JPL/ASU). North towards top of image. shoreline as defined by Clifford and Parker (2001) shown in orange. Most of the shoreline coincides Image center near lat 42.7° N., long 23.3° E. Portion of Afs with the highland-lowland boundary scarp. Viking MDIM 2.1 at 256 pixel/degree 0 5 KILOMETERS THEMIS VIS image V13592007 (NASA/JPL/ASU). North 33° towards top of image. Afs (NASA/JPL/USGS) merged with 128 pixel/degree gridded MOLA topographic data in simple c2 cylindrical projection.

Afs 33° 33° Ncc 65° 65° MC–1 A A' 32.5° Figure 14 (right). Topographic profile from the continuous highlands to the Meters Meters outermost polygonal mesas shows the same relative elevation of near-boundary Continuous Near-Boundary Far-Boundary Cerulli Afs Afs –1500 –1500 c1 33° mesas and highland plateau, but a difference in elevation of some far-boundary Highlands Mesas Mesas 340° MC–3 MC–6 mesas. Profile location (A–A') is shown in Figure 3. This difference, and the –2000 –2000 20° 339° general decrease in crater density northward from the continuous plateau, can be 21° 338° 32.5° MC–4 MC–5 –2500 –2500 South attributed to an erosional event that removed the upper portion of upper smooth 22° 337° 30° 30° 23° 336° plateau material (unit Nplsu). Alternatively, the difference may be related to the –3000 Ada Ada –3000 335° Nplsu, Npld Nplsu 24° general decrease in plateau elevation towards the north (plateau slopes down Nplsu Nplsu 25° 300° 60° HNps into the lowlands). Profile extracted from 128 pixel/degree (~463 m/pixel) –3500 –3500 gridded MOLA topographic data. Descriptions of nomenclature used on map are SCALE 1:1 004 000 (1 mm = 1.004 km ) AT 350° LONGITUDE Prepared on behalf of the Planetary Geology and –4000 –4000 listed at http://planetarynames.wr.usgs.gov/ TRANSVERSE MERCATOR PROJECTION Geophysics Program, Solar System Exploration 45 x Vertical Exaggeration MC–10 MC–11 MC–12 MC–13 20 0 20406080100 Division, Office of Space Science, National Aeronautics and Space Administration Edited by Theresa Iki; cartography by Darlene A. Ryan KILOMETERS 270° 315° 0° 45° 90° Planetocentric latitude and east longitude coordinate system shown in black. Manuscript approved for publication June 6, 2009 0° 0° Planetographic latitude and west longitude coordinate system shown in red.

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MC–18 MC–19 MC–20 MC–21 Figure 15 (left). Four common surface textures observed on lobate debris aprons are (1) smooth with minor pits, (2) knobby, (3) lineated, and (4) ridge and valley. These textures likely formed within an ice-rich dust 2 mantle on apron surfaces. In the left image (A), surface textures are evident along the edges of small craters 300° 60° and their floors are generally smooth, indicating the presence of mantling material. Modification of the 1 2 mantle may have occurred from a combination of ice sublimation, which released the bound dust grains and –30° –30° A C MC–26 MC–27 eolian activity that removed the dust. Images – and their approximate center locations are portions of MOC NA M0402347 (lat 38.3° N., long 23.6° E.), E2100663 (lat 44.3° N., long 22.2° E.), and E1202901 (lat Geologic Map of MTM 35337, 40337, and 45337 Quadrangles, 3 4 4 MC–25 MC–28 43.2° N., long 23.4° E.) (NASA/JPL/MSSS). 3 Deuteronilus Mensae Region of Mars 2 MC–30 Any use of trade, product, or firm names in this publication is for descriptive By –65° –65° purposes only and does not imply endorsement by the U.S. Government. 4 For sale by U.S. Geological Survey, Information Services, Box 25286, 1 1 A B C Federal Center, Denver, CO, 80225, 1–888–ASK–USGS Frank C. Chuang and David A. Crown QUADRANGLE LOCATION 1Planetary Science Institute Digital files available at http://pubs.usgs.gov/sim/3079 Photomosaic showing location of map area. An outline of 0 500 METERS 0 500 METERS 0 500 METERS Tucson, AZ 85719-2395 2009 1:5,000,000-scale quadrangles is provided for reference. Printed on recycled paper