Stratigraphy and structure of interior layered deposits in ...forth/publications/Fueten_2008.pdfStratigraphy and structure of interior layered deposits in west Candor Chasma, Mars,

Stratigraphy and structure of interior layered deposits in west Candor

Chasma, Mars, from High Resolution Stereo Camera (HRSC) stereo

imagery and derived elevations

F. Fueten,1 R. Stesky,2 P. MacKinnon,1 E. Hauber,3 T. Zegers,4 K. Gwinner,3

F. Scholten,3 and G. Neukum5

Received 6 December 2007; revised 23 July 2008; accepted 5 August 2008; published 16 October 2008.

[1] Interior layered deposits (ILDs) within western Candor Chasma were studied bymapping lithologies, measuring layer attitudes and comparing the stratigraphy oftwo adjacent mounds. Layering tends to dip in the same direction as the local topographicslope, although at different angles. Regionally consistent attitudes do exist, suggestingpostdepositional block rotations. The stratigraphy of two adjacent mounds correlates,but the thicknesses of the units differ. Most layered material appears to have beendeposited conformably, with one late major unconformity. Several fault populations areidentified and correlate well with regional faults associated with the formation ofValles Marineris. The data suggest that here the ILDs predate the faulting and may beearly basin fill. According to our model for ILD formation, ILDs are depositedsyntectonically during early basin collapse. Subsequent subsidence of surrounding areas,accompanied by little or no sedimentation, left the early deposits as individualmounds, remnants of the former subbasins. Stratigraphic differences between moundsresulted from different subsidence rates of subbasins. A significant change in depositionalenvironment, from depositional to a near cessation of deposition and the onset of amajor erosion event, possibly coincided with the opening of the main Valles Marineristroughs. We further suggest that groundwater played an important role in the formationof sulfates. The youngest unit identified, not including surficial deposits, is likely theresult of a posttectonic, regionally limited volcanic event. If basin collapsecontinued following the cessation of deposition, this model can also account for moundswithin closed basins, such as Hebes.

Citation: Fueten, F., R. Stesky, P. MacKinnon, E. Hauber, T. Zegers, K. Gwinner, F. Scholten, and G. Neukum (2008), Stratigraphy

and structure of interior layered deposits in west Candor Chasma, Mars, from High Resolution Stereo Camera (HRSC) stereo imagery

and derived elevations, J. Geophys. Res., 113, E10008, doi:10.1029/2007JE003053.

1. Introduction

[2] Interior layered deposits (ILDs) occur within severalof the chasmata of Valles Marineris, making up 17% of itstotal area and at least 60% of the volume of all VallesMarineris deposits [Lucchitta et al., 1994], but their originand mechanism of formation are uncertain. Several hypoth-eses for their formation have been proposed, includinglacustrine [Nedell et al., 1987] and eolian [Peterson, 1981]deposition, as well as pyroclastic volcanism in subaerial[e.g., Hynek et al., 2003; Chapman, 2002; Lucchitta, 1987,

1990] or subglacial [Nedell et al., 1987; Chapman andTanaka, 2001; Komatsu et al., 2004] environments. Mostrecently, Rossi et al. [2008] suggested that some light-tonedILD units are large-scale spring deposits. While all theseprocesses would imply that the ILDs are younger than thetroughs in which they formed, other studies [e.g., Malin andEdgett, 2000; Catling et al., 2006] suggest that the ILDs areancient deposits exhumed from below the material formingthe trough walls. Mineralogical data from the OMEGAinstrument on Mars Express show that sulfates are associatedwith many of the ILDs [Gendrin et al., 2005;Mangold et al.,2007a, 2007b], suggesting some water involvement in theformation or later alteration of the ILDs.[3] The chasmata themselves are thought to have devel-

oped as a two-stage process [Lucchitta et al., 1994; Schultz,1998]. Lucchitta and Bertolini [1990] and Lucchitta et al.[1994] proposed that ancestral basins (closed trough depres-sions) with irregular outlines formed prior to the opening ofValles Marineris -related linear troughs. In particular, for thepresent study area, they suggested that the southern portionof Candor Chasma formed as an early ancestral basin, in

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 113, E10008, doi:10.1029/2007JE003053, 2008ClickHere

for

FullArticle

1Department of Earth Sciences, Brock University, St. Catharines,Ontario, Canada.

2Pangaea Scientific, Brockville, Ontario, Canada.3Institute of Planetary Research, German Aerospace Center (DLR),

Berlin, Germany.4Faculty of Geosciences, Utrecht University, Utrecht, Netherlands.5Institute of Geological Sciences, Free University, Berlin, Germany.

Copyright 2008 by the American Geophysical Union.0148-0227/08/2007JE003053$09.00

E10008 1 of 19

http://dx.doi.org/10.1029/2007JE003053

which ILD were deposited later and at least partially withina deep lacustrine environment. Faulting associated with thelater Valles Marineris opening [Schultz, 1998] connected thebasins and created the current pattern of interconnecteddepressions.[4] Mapping of these ILDs throughout Valles Marineris

has largely been limited to identifying their surface proper-ties, with little information about their geometry and atti-tude. Several studies have included measurements ofbedding attitudes [Lucchitta, 2004; Beyer and McEwen,2005; Fueten et al., 2006; Hauber et al., 2006; Zegers etal., 2006; Gaddis et al., 2006], showing that the layeringtends to dip shallowly (typically less than 20�) in thedirection of the topographic slope, suggesting a drapeorigin. Recent measurements [Fueten et al., 2006] revealeda more complicated pattern in west Candor. While down-slope dips are common, some areas show a consistentregional dip that is not related to topography. A majorunconformity is present, indicating significant gaps in thedepositional record.[5] Here, we expand on the work of Fueten et al. [2006]

and develop a model for the formation of these ILDs. Wepropose that ILDs formed during the formation of ancestralbasins and that a major unconformity can be correlated withthe onset of Valles Marineris-related extension.

2. Geological Setting

[6] Within the chasma, the valley floor is a complexseries of mounds and depressions (Figure 1), composed ofvarious layered and massive deposits, as well as more recentsurficial debris (dunes, landslides and crater ejecta). Dom-inating are layered deposits which show a range of layerthicknesses, albedos and erosional characteristics, indicatingdiffering compositions and degrees of competency [e.g.,Komatsu et al., 1993, 2004; Malin and Edgett, 2000] dividethe deposits into three main types: light- to intermediate-toned ‘‘layered’’ units, light- to intermediate-toned ‘‘mas-sive’’ units, and ‘‘thin mesas’’, which consist of dark- tointermediate-toned capping units. Light- to intermediate-toned units differ in their erosional characteristics. Thelayered units tend to exhibit stair-stepped or cliff-benchstructures indicating competency differences within thelayering.[7] Commonly, the ILDs are thought to be younger in age

than the formation of the chasmata themselves (lowerHesperian; e.g., Tanaka [1986]). For this study the area issubdivided into a number of tectonostratigraphic domainsbased on topography, stratigraphy and structure (Figure 2).These domains, labeled A–F for simplicity, tend to bebounded by linear depressions.[8] The imaging spectrometer OMEGA [e.g., Bibring et

al., 2006] has found spectral signatures of pyroxenes,sulfates and iron oxides within the study area. A detailedanalysis of the distribution of these materials throughoutwest Candor Chasma is given by Mangold et al. [2008].Within the study area kieserite is located along the northernslope of the hill within the domain F, throughout much ofdomains C and E, and along the northern boundary of thedomain B. The kieserite cannot be correlated with obviousstratigraphic units and occurs at various elevations, even ontop of mounds. Chasma wall rock to the south and the

domain D are pyroxene-rich regions. Pyroxene-rich signa-tures also occur along the southern slope of the domain Fand in isolated parts of the domain C. Only one minoroccurrence of iron oxides is present within the domain E.

3. Methodology and Data Sets

[9] The primary tool used for understanding the structureand tectonics of this region is measurement of the layeringattitudes, done using the software package Orion. Fueten etal. [2005] discuss the methodology in detail.[10] The data used for this study are HRSC stereo images

[Jaumann et al., 2007] from Mars Express orbit 2116. Thenadir panchromatic orthorectified image was processed to12.5 m/pixel resolution. Stereo images were used to calcu-late the elevations to a resolution of 50 m/pixel [Gwinner etal., 2005; Scholten et al., 2005]. Orion uses bilinearinterpolation to compute the intermediate elevations neededto match the nadir image resolution. Subsequently, a CTX[Malin et al., 2007] image mosaic for the area was con-structed and registered to the HRSC DTM. In addition toHRSC images, we used topographic data from the MarsOrbiter Laser Altimeter (MOLA) [Zuber et al., 1992] andimage data from the Mars Orbiter Camera (MOC) [Malin etal., 1992], as well as from the High Resolution ImagingScience Experiment (HiRISE; McEwen et al. [2007]).[11] Layer attitudes were calculated by sampling the

elevations along visible contacts and computing the best-fit plane through the three-dimensional set of points. Theaverage sample spacing was 50 m or more, often 100–150 m, equal to or greater than the DTM resolution. Themeasured end-to-end trace lengths were typically from600 m to 11 km, with an average length of 2.6 km. Weconclude that the measurements are largely independent andlittle biased by the procedure used to produce the DTM.Even where the higher-resolution CTX images were used,these restrictions were maintained.[12] For all data presented here, the maximum deviation

of the point furthest from the calculated plane is less than1.5% of the plane’s trace length. For all planes with dipsgreater than 2�, the dip error is less than the dip of the plane,with an average dip error of 1.7 degrees. Layer measure-ments are presented in Figure 3. Measurements for massiveand layered units, which are described in detail later, aredifferentiated for clarity.

4. Lithologies and Layer Attitudes

[13] This portion of west Candor Chasma had mostrecently been mapped by Lucchitta [1999] who suggestedthat ILDs in this area are of Hesperian or Amazonian age.The deepest part of the chasma is in the northeastern part ofour area (domain D) where layered material is covered bydeposits which appear to be darker. The layering attitudecould be measured in a minor depression and it indicatesthat the layering is nearly horizontal. We focus primarily onthe lithologies that make up the topographically elevatedmounds and subdivide the rock units based on their beddingand competency characteristics, adopting the terminologyproposed by Malin and Edgett [2000]. For the purpose ofour work, the lithology can broadly be classified intomassive units and layered units.

E10008 FUETEN ET AL.: INTERIOR LAYERED DEPOSITS, MARS

2 of 19

E10008

4.1. Massive Units (MU)

[14] The best exposed outcrops (Figure 4A) of units thatappear massive at HRSC image resolution (10–20 m/pixel),but display fine layering at MOC (few meters per pixel,Figures 4B and 4C) andHiRISE (25–32 cm/pixel, Figure 4D)resolutions, respectively, occur in domains B, C and E.They are resistant to erosion, normally display spur-and-gully erosional features and have a steeper topographicprofile than layered units. They form a ridged topography,with ridges often parallel to strike where it can be mea-sured. In HRSC images, layering thickness is on the orderof tens of meters and layers appear to occur in packagesseveral hundred meters in thickness. Where the outcroppermits, layer attitudes can be measured with great con-stancy over distances of several kilometers. In domains B

and C, massive units are conformably overlain by layeredunits (Figure 4B). The exposures of massive units do notcoincide with the sulfates and high-calcium pyroxenesdetected by the OMEGA spectrometer [Mangold et al.,2008]; their composition is therefore unknown.[15] There are five distinctive outcroppings of massive

units which form mesas. One, which had been tentativelydescribed by Fueten et al. [2006] as a basement unit, isunfortunately not completely covered by the 2116 HRSCimage and DTM. Elevation traces across the four mesascompletely covered by the DTM were used to estimate theirelevation above background topography. Although a slop-ing background topography and debris aprons make anexact thickness measurement difficult, we suggest that anestimate of 800–900 m is reasonable, as illustrated in

Figure 1. West Candor Chasma is outlined on a MOLA shaded relief image of Valles Marineris,showing the connected basins and the regional structural attitudes that define and control the basinsystem. The study area within west Candor is outlined on an HRSC mosaic image.


3 of 19

E10008

Figure

2.

(A)HRSC

orbit2116false-colorim

age.

(B)Color-coded

topographic

map

withelevationcontours.Domain

boundariesandnam

esareoverlaid

onboth

images.


4 of 19

E10008

Figure 5A. For the fifth mesa, not entirely covered by theimage, approximately 900 m is our best estimate for itsthickness (Figure 5E).[16] The vertical thickness estimates presented in Figure 5

need to be corrected for the measured dip of the units toobtain true stratigraphic thicknesses which are less than thevertical estimate. For MU1 to MU4 with dip values ofapproximately 15� the difference between an estimated800m vertical height and the corresponding stratigraphic

thickness is less than 25 m and thus within the range ofestimated error for arriving at the original vertical measure-ment. However, attitude measurement on MU5 indicatesteep dips of 22� and 33� to the northeast, representingamong the steepest measurements in the area. These valuescorrespond reasonably well to steep measurements of 29.7�and 41.6� reported by Fueten et al. [2006], made using alower resolution DTM. Using a dip value of 30� for MU5

Figure 3. Lithology and layer attitudes, using standard symbols to represent the layer strike (long line)and dip (short tick with number).


5 of 19

E10008

indicates that an estimated vertical thickness of 900 mcorresponds to a stratigraphic thickness of 780 m.[17] On the basis of their common appearance, thickness

and lack of interbedded finely layered units within them, wesuggest that these free-standing MU mesas are the remnantsof a single, competent member. The best estimates for thethickness of this unit are between 750–800 m. Because oftheir location within the stratigraphic column, as will bediscussed later, these freestanding mesas will be referred toas the Upper MU member.

[18] A distinctive darker resistant cap unit (CU, identifiedas AHire by Lucchitta [1999]) forms the approximately50 m thick cap on the central mound of domain F andhas been shown to unconformably overlie layered material[Lucchitta, 2004; Fueten et al., 2006]. It is preservedprimarily along a south-west-facing slope with a sharp breakat the ridge of the mound and appears to have limitedregional extent. CTX imagery (P01_001443_1740_XN_06S074W) draped over the HRSC DTM shows that thesteep slope contains fine layering which is truncated at ashallow angle by the cap rock (Figures 6A and 6B).

Figure 4. (A) HRSC image 2116 showing primary locations of massive units with layer attitudes. Thefeatures labeled MU 1–5 are isolated MU mesas, which are discussed in more detail in the text. (B)The lower MU in domain B, as shown in the topographic profile a–b of Figure 10 (MOC M20/00189,2.92 m/pixel). (C) The lower MU in domain C, as displayed in the topographic profile c–d ofFigure 10 (MOC R09/00035, 4.49 m/pixel). (D) Fine layering within HiRISE image PSP_00380_1740(25 cm/pixel).


6 of 19

E10008

Figure 5. (A–D) Detailed HRSC 2116 images and topographic profiles across MU mesas, identified asshown. The locations are indicated in Figure 4A. The vertical exaggeration in all cases is a factor ofabout 7. (E) Detailed HRSC 2116 image and topographic profiles across MU5. The location is indicatedin Figure 4A. The vertical exaggeration is a factor of about 7.


7 of 19

E10008

Spectrographic measurements using the Mars ExpressOMEGA instrument shows a strong pyroxene signature[Mangold et al., 2008], indicating that this unit is mostlikely a basaltic unit, either a flow or a pyroclastic depositthat has become well lithified. This unit dips 6–8� to thesouthwest (Figure 3), compatible with the attitude of itsexposed top surface. This fact likely indicates that, here, thisunit has been little eroded since its formation.

4.2. Layered Units (LU)

[19] Layered units occur throughout the area. UsingHiRISE image TRA_000836_1740, Okubo and McEwen[2007] demonstrated that sub-surface fluid flow was

responsible for the alteration of fractures present withina layered sequence of ILD material with a kieseritesignature. This outcrop is within our domain C.[20] Layered units are characterized by alternating dark

and light layering on the meter scale, and are less resistantto erosion than the massive units. Layered units often showa stair-stepping or terracing erosion surface, as described byMalin and Edgett [2000], suggesting alternating high andlow erosional competencies. In domains B and C, packagesof layered units alternate conformably with massive units(e.g., Figure 4B).[21] Domain A appears to be entirely composed of

layered units. Attitudes near the southern end where they

Figure 5. (continued)

Figure 6. CTX image mosaic overlaid on HRSC DTM. Two perspective views of the cap unit (CU)overlying the layered unit in the southeastern part of domain F. The layers dip by up to 20� toward thenortheast and east on the north and east sides, respectively, of the southwest-dipping cap unit. Layering isshown as dashed lines. The image within the inset has been significantly enhanced to illustrate therelationship.


8 of 19

E10008

could be measured indicate 5�–15� dips toward the south tosouthwest.[22] Along the southern edge of domain B where the strata

are well exposed in cross section, Layered units appear inthree packages, separated by massive units. Here, at lowelevations, attitudes dip consistently approximately 5�–10�toward the SE. These attitudes are compatible with those ofmassive units in the same locations. At higher elevationstoward the northwest portion of domain B, the dips becomeshallower and show more variability in direction, which tendto mimic local topographic slope. The determination ofstrike becomes more sensitive to the placement of datapoints at shallow attitudes, which explains some of thevariability in strike. At the northwest end of domain B,attitudes gradually change to a more easterly dip.[23] Fueten et al. [2006] suggested that an elliptical

feature (Figure 6A) within the layered unit in the north partof domain F was consistent with a gentle fold, suggested tobe draping of a layered unit over a local block. Theseattitude measurements are confirmed and show further thatthe layering becomes more easterly in dip on the east side ofthe mound.

4.3. Layering Attitude Summary

[24] With some notable exceptions discussed below, theattitude measurements (Figure 3) are regionally consistentwithin each topographically defined domain, but varybetween domains. Dip directions are to the south in domainA, to the east in domain E, to the northeast in domain C, andnearly horizontal within the domain D. Within domain B,layer attitudes change from southerly trends on the westernmargin to easterly trends in the eastern portion of thisdomain. Most dip values are in the range of 5�–10�, whiledips in some localities such as the domain F and mesaMLU5 may reach 20�–30�. In most cases, dip directionparallels the topographic slope, while the dips themselvesare generally either steeper or shallower than the slope.Only in a few places is the topographic slope parallel to thelayering. As can be expected from conformable units, mostmeasurements of massive and layered units in close geo-graphic proximity are consistent.[25] Layer attitudes in the domain F show the greatest

variability. The capping unit CU dips 6–8� to the southwest(Figure 3), which differs from the attitudes of the underlyingunits, but is compatible with the attitude of its exposed topsurface. The layered units below this cap have some of thesteepest dips measured in this study and dip approximately20�–25� to the northeast. Within the linear depressionforming the western boundary of the domain C, somelayered units dip to the southwest, in contrast to allsurrounding measurements.

4.4. Stratigraphy

[26] Layered and massive units are present in domain Band C, and appear to be conformable with each other. To beable to compare units in both blocks and determine therelative stratigraphic position of all units, we attempt todevelop the generalized stratigraphy of the recognized unitsby taking the upper and lower contacts of packages oflayered and massive units from the topographic profiles(Figure 7). Only a few locations allow for an adequate crosssection of the stratigraphic column. Figure 7 shows the

attempt to measure and correlate the stratigraphy. Crosssections AB, CD and EF show the apparent dip. Because theprofile EF in domain B is parallel to strike direction, itappears horizontal in cross section. Because of uncertaintiesin locating contacts, all thickness values are rounded to 50 mincrements.[27] Section AB and CD are approximately parallel to the

dip direction in the domain C. Section AB includes MU1,which forms the highest stratigraphic level within thisdomain, while section CD provides the best detailed infor-mation for the lower stratigraphy. The simplest stratigraphy,compatible with the topographic profile for this region, isconstructed by fitting layers of 5� (section CD) and 7�(section AB) dip, which agrees well with the direct dipmeasurements of 5�–10�.[28] Section EF in domain B is composed entirely of

alternating layered and massive units. A change in layerattitudes, from southeasterly to easterly across this domainmakes the construction of a simple stratigraphic columnmore complex. A measurement of the central layered unityields a thickness of 350 m, while the upper layered unit hasa minimum thickness of approximately 200 m. The eastdipping massive unit (Figure 7, hatched area on map inset),which has a thickness of approximately 200 m near locationF, is stratigraphically above the layered unit if projectedaccording to its attitude. This agrees with observationswithin the image that the massive unit overlies the layeredunit. However, as the topography of domain B descendsbeyond location F along section line EF, the elevation ofthis massive unit is at the same elevation as the morewesterly layered units. As outlined above, we suggest thatthe massive unit attitude reflects a regional change withinthis domain and place the massive unit stratigraphically ontop of the layered unit, in accordance with observation andstructural projection.[29] To obtain the best match between the sections and

allow for the simplest correlation of the massive unitsoutlined in the map area, two stratigraphic sections arecorrelated along the upper contact of the uppermost layeredunits in both sections. Hence we suggest that the cappingmassive unit in domain B can be correlated with the massiveunit below the free standing MU mesa in domain C.[30] A comparison of the two stratigraphic sections indi-

cates significant differences between the two domains. Thelowest massive unit within domain C, for which thethickness can be determined accurately, is 50% thicker thanthe thickest equivalent unit within domain B. The lowest-most exposed unit in domain B is a layered unit.[31] Even though the unconformable cap unit CU does not

outcrop along the sections, it is illustrated in the compositesection in its presumed position. As erosion has removedmuch of the upper MU member and CU is clearly uncon-formably emplaced, we tentatively suggest that the eventthat caused the erosion of the upper MU member is the sameas that represented by the unconformity in domain F.

5. Faulting and Lineaments

[32] Numerous studies have documented the existence offaults within VM [Schultz, 1995, 2000; Mege and Masson,1996; Schultz and Lin, 2001; Peulvast et al., 2001] andample evidence exists for multiple fault sets within this area.


9 of 19

E10008

We suggest that linear depressions and planar scarps seen inthis area are regionally significant faults. In most cases thisinference is supported by observations made at smallerscales. As outlined below, most structural features can begrouped into two sets, each appearing to follow a regionaltrend. These two dominant trends are approximately parallelto the south and west walls of west Candor Chasma(Figure 1). In the absence of geochronological data or clearcross-cutting relationships no clear age relationships be-tween the features can be established. Features of similarorientation, corresponding to the two regional trends, havebeen grouped together for discussion purposes althoughthey may have different ages.

[33] Arguably the most significant structural trend in thearea is oriented NW–SE, at approximately 120� which isparallel to the south wall of the chasma and the overallValles Marineris trend (Figure 1). This trend also parallelsthe major linear topographic low within western CandorChasma. Within the study area, topographic depressions ofthat attitude form the boundaries of domains A, B, C, D(Figures 8 and 9). The edge of the elevated topographywithin the area is marked by a sharp boundary (C–Dboundary) trending 120�.[34] On a finer scale, seen in HiRISE images, this

boundary is marked by a series of parallel joints(Figure 8B) and fracture sets of that attitude are visible

Figure 7. Cross sections through the domains B and C with the interpreted stratigraphy, projected usingthe apparent dip angles. The upper right stratigraphic sections show the suggested stratigraphy in domain(left) B and (right) C areas. The composite section includes the unconformable cap unit (CU) which is notpresent in the profiles and is primarily based on the profile for domain C. The erosion level in domain F isunknown, hence the placement of CU is not intended to indicate the level of erosion but merely thatdeposition occurred following the erosion. On the basis of data from section E to F, an FU may be a basalunit. The MU placed at the top of the E–F section does not appear in the section but is projected fromalong the traverse further east beyond point F.


10 of 19

E10008

within domain D (Figure 8C). Fractures (Figure 8D) and asignificant offset (Figure 8E) parallel to the linear depres-sion that marks the boundary between domains B and Care visible within HIRISE images.[35] Within the southern portion of the area, two planar

scarps (Figure 9B) occur within massive units along the SEedge of domain B. A NW–SE trending fault is visiblewithin HiRISE image PSP_001641_1735 (Figure 8C).Fractures trending approximately 100�–110� are also visi-ble within CTX image P01_001443_1740_XN_06S074Won the east side of domain F (Figure 9D). Here close-spacedfractures occur at the bottom of the mound high in thestratigraphic section of the finely layered unit.[36] The second prominent set of structural features trends

SW–NE (�40�–070�) and is thus approximately perpendic-ular to the first set. Many regional-scale features show thistrend, including the walls forming the blunt end of westernCandor Chasma (Figure 1). Linear topographic depressions(Figure 10) oriented at 040� mark the northwestern andsoutheastern boundary of domain B. Fractures of that attitudecan be identified within HiRISE images at several locations,(Figures 10C to 10E), including near several 040�-trending

linear breaks visible within the lowerMU (Figure 10B). In thesouthwestern portion of the area, fractures considered to bepart of this set, though trending closer to 060�, are present inHiRISE images PSP_002129_1735 and PSP_001641_1735(Figure 11).[37] Two prominent planar scarps, which trend approxi-

mately E–W, are oblique to these regional trends. Both dipapproximately 30� to the north and are in close proximity toeach other (Figures 12A, 12C, and 12D) within whatappears to be the same competent massive unit. A cleartruncation of finely layered units, parallel to the base of thescarp (Figure 12B), is visible near the northern scarp. Wesuggest that these scarps are large east–west trending faults.

6. Discussion

[38] Any complete model for the geological history ofthis area must account for all observations presented here,the primary ones being:[39] 1. Layer attitudes primarily follow the regional

topographic slope.

Figure 8. Various examples of NW–SE trending features. (A) Major linear features trending about 120�within the northern portions of the study area. (B) Parallel joints and (C) fractures within HiRISE imagePSP_00380_1740. (D) Fracture with offset within HiRISE image TRA_000836_1740. (E) Offset inHiRISE image PSP_002692_1745.


11 of 19

E10008

[40] 2. The stratigraphic sections between adjacent blocksdiffer. There is no exposed equivalent within domain B forthe thick lower massive unit found in domain C.[41] 3. The sedimentary units alternate between compe-

tent massive and less competent layered units, which itselfis composed of alternating thinner beds of competent and

incompetent material. No significant unconformity can beidentified within this LU/MU package.[42] 4. A significant erosional event affected at least the

upper MU member. This event required the removal of atleast 750–800 m of stratigraphic section, leaving isolatedmesas behind.

Figure 9. (A) Linear features trending 120� within the southern portions of the study area. (B) 3D viewof planar scarps within the HRSC image. (C) Offset within the HiRISE image PSP_001641_1735.(D) Multiple offsets within the CTX image P01_001443_1740_XN_06S074W.


12 of 19

E10008

[43] 5. Individual blocks of layered deposits appear to bebounded by faults, with differential displacements havingtaken place between these smaller blocks.[44] 6. Mounds of layered deposits show signs of internal

deformation. Fractures visible within HiRISE images arepresent at all stratigraphic levels. Their attitude appears tocorrelate well with regionally significant linear depressionsand scarps.[45] The observations above clearly indicate that the

formation of interior layered deposits cannot be a late-stageor postdeformation event. Valles Marineris most likely didnot develop in a single tectonic episode. Rather, ancestralbasins formed some time prior to the opening of rift-likelinear chasms [Lucchitta et al., 1994; Schultz, 1998;Peulvast et al., 2001]. In the case of Candor Chasma,Lucchitta et al. [1994] suggested that the southern portionopened as an ancestral basin and that if the depositsformed in a lacustrine setting, a water depth of severalkilometers was necessary. For this reason, they suggestedthat a volcanic origin is more likely for interior layereddeposits. We agree that they are most likely associatedwith the ancestral basin formation, but suggest that the

deposits were emplaced syntectonically during the basinformation, rather than after it. At any time, the depositionalsurface need not have been very far below the regionalelevation of the surrounding plateau.

6.1. Deposition

[46] The subsiding floor of an ancestral basin would havebeen enclosed by a number of bounding faults which wouldhave accommodated the downward displacement of thebasin floor. Given the size of the areas occupied by deposits,the minimum basin size would have been on the order ofhundreds to thousands of square kilometers. A slab of crustof that size would not likely have maintained its integritywhile being displaced downward several kilometers. It ismuch more likely that the crust of the basin fractured into anumber of smaller segments, which we suggest to be on theorder of several square kilometers in area. The subsidenceitself would then have taken place with differential displace-ments between these smaller blocks, some subsiding fasteror further than others. This implies that the subsiding floorwould have developed an irregular topography during thesubsidence.

Figure 10. Linear features trending NE–SW. (A) Large-scale lineaments overlaid on HRSC image2116. (B) Detailed view of HRSC 2116 from the northeastern edge of domain C showing several crossfractures, each beginning and ending between paired arrows. (C) Fractures in domain C seen in theHiRISE image TRA_000836_1740. (D) Fractures, indicated by the arrows, from the HiRISE imagePSP_002696_1745. (E) Fractures within the HiRISE image PSP_003830_1740.


13 of 19

E10008

[47] It is also reasonable to assume that deposition ofmaterial within a juvenile ancestral basin occurred as soonas a topographic depression had developed, especially asMars is thought to have been more active during theHesperian period. This assumption implies that depositsfilled the basin as the floor subsided, eliminating the needfor several kilometers of water depth. There is no directevidence that the basins were, in fact, filled with water,either continuously or intermittently. The observed erosionevent, as discussed below, is more likely the result of fluiderosion. However, that does not imply that all depositionwithin the basins took place within a lacustrine environ-ment. Certainly, crater ejecta, ashfall and spring deposits arepossible contributors and cannot be discounted.[48] The observation that the lower portion of the strati-

graphic sequences in domains B and C do not match inthickness is directly compatible with this model of basinformation. If domain C subsided faster during early basinformation, it may well have accumulated a thicker lowermassive unit than the adjacent domain B.[49] We suggest then that the individual mounds of

layered deposits formed as small basins, or more likelysmall subbasins within a larger basin, which subsided andwere filled during subsidence. The observed dips may bepartially the result of draping over basement topography asthe basins developed. However, differential basin subsi-dence and tilting could also have produced minor rotationand tilting of the basin blocks, and thus account for some ofthe present dips.[50] Our observations also put some constraints on the

mode of formation of the sediments. Two key factors needto be included in any sedimentary model used to explain theILDs: the presence of fine layered material with contrastingcompetencies and the alternation of thick packages oflayered and massive units. These features point to system-atic changes of source or depositional conditions, with twoperiods of cyclicity, short periods during deposition of the

fine layering and a superimposed long period producing thealternation of layered and massive units. Nedell et al. [1987]used the short-period cyclicity to argue for lacustrinedeposition; however, the interbedded thick competent unitsare more difficult to explain in this way.[51] A further point to make here is that the sequence of

deposits, alternating between massive and layered units, issimilar in the two areas where we can determine thestratigraphic sections, except that the units are thicker inone (domain C) than the other (domain B). This observationimplies that the source of sediment is the same for bothareas. If, as we suggest, domain C subsided faster thandomain B, then either domain C received a greater rate ofsediment influx or the deposition surface was very close tothe topographic level of the surrounding plateau. Withoutknowing the sediment source, we cannot choose betweenthese two possibilities.

6.2. Tectonism

[52] The opening of the rift-like portion of Valles Mari-neris must have been accompanied by faulting and subsi-dence [Schultz, 1998]. Faulting associated with thistectonism would have used pre-existing crustal-scale frac-tures, where possible. A composite tectonic map containingthe major proposed faults with cross section is presented inFigure 13. We suggest that the planar scarp along theboundary between domain C and D most likely representsfault motion related to Valles Marineris opening. Anylayered deposit north of this boundary was displaceddownward. The fact that the floor has very little topographicexpression suggests that such buried layered deposits didnot have much topographic expression or that the floordeposits are quite thick. Hence we suggest that the majorlineaments discussed above are basin faults, with somebeing reactivated during Valles Marineris opening. Sincethe scarp along the northeast edge of domain C is up to600 m in height, the vertical component of displacement

Figure 11. Linear features trending NE–SW. (A) Large-scale lineaments overlaid on the HRSC image2116. (B) Fractures within the HiRISE image PSP_002129_1735. (C) Fractures within the HiRISE imagePSP_001641_1735. White arrows and black arrows indicate fractures of the two main regional sets.


14 of 19

E10008

during Valles Marineris tectonism may be quite significanton reactivated faults, perhaps on the order of several kilo-meters. Tectonism-related displacement of fault blockswould also have led to rotation. However, because of thelimited amount of extension actually produced during VallesMarineris opening [Mege and Masson, 1996; Schultz,1995], the amount of rotation would also have been limited.[53] Two regions within the area provide some evidence

for rotation. With the exception of MU5 which appears todip 20�–30�, most layer dips observed in the study area areless than 20�. If, as we suggest, MU5 is located on a faultactive during Valles Marineris opening, the high dip angleof MU5 is most likely the result of fault-related rotationduring this late stage.

[54] We also suggest that the shallow northeast dipobserved within domain C is partially the result of a rotationor tilt toward the northeast (a clockwise rotation about ahorizontal axis oriented approximately at 300�). Our pro-posed mode of deposition can account for different strati-graphic sequences for different subbasins, but is unlikely toaccount for the formation of the observed narrow lineardepressions, as they would be filled easily. We showedearlier that the 120� linear depression bounding domains Band C is fault-related. A minor rotation of domain C along a300�-trending horizontal axis, i.e., a tilt to the northeast,could result in the opening of a tensile region in the area ofthe depression (Figure 13). Such a proposed rotation wouldrequire oblique or transform motion along bounding faults,motion that in the simplest case would be approximately

Figure 12. Linear features trending E–W. (A) HRSC image 2116 showing the location of the detailedviews. (B) Fine layering is truncated along a linear contact, indicated by the arrow. (C, D) Planar scarpsare interpreted as east–west trending faults, shown in these detailed oblique projections of HRSC 2116,viewed looking toward the west.


15 of 19

E10008

perpendicular to the rotation axis. The two scarps trendingapproximately east–west could serve that purpose (Figure 13),though we have no direct evidence for an oblique motion.

6.3. Unconformities and Erosion

[55] No evidence was found for any significant uncon-formities within the LU/MU package. While it cannotbe stated that deposition throughout the package wascontinuous, the continuity of layers and the lack of erosionalhorizons that cut layers argue against significant erosionalevents during the time of LU/MU deposition. If the freestanding MU mesas represent the remnants of a continuousunit, a minimum estimate of its regional extent would bebetween 600 and 800 km2. To create the free standing MUmesas would require the removal of most of this 800 m thickregionally extensive unit. Such a massive erosional event is

clearly different from the deposition-dominated period pre-ceding it. We propose that this event marks a significantchange in the environment of Candor Chasma and possiblyValles Marineris as a whole.[56] A significant angular unconformity exists between

cap unit CU and the underlying material. CU appears to beof limited extent, its boundaries cannot be correlated withany tectonic features and there is no evidence that it hasbeen affected by any deformation. Hence we suggest that itwas deposited very late in the geological history, possiblyafter tectonic activity had ceased.

6.4. Timing of Events

[57] In the absence of crater counts or other geochrono-logical data, we can only determine relative timing andsequence of events. We propose that ILD deposition

Figure 13. Composite tectonic diagram, overlaid on HRSC image 2116 with topographic contours,illustrating major faults, as discussed in the text. The vertical cross section AB has been constructed toillustrate the rotation of domain C relative to A and the presumed vertical throw of the fault betweendomain C and D. A hypothetical ILD-basement contact has been added to illustrate offsets in the crosssection. The dips are based on those of the ILD strata. Offsets and rotations have been exaggerated forclarity. The sense of horizontal motion along E–W faults is postulated to accommodate rotation ofdomain C.


16 of 19

E10008

occurred simultaneously with ancestral basin formation andmost likely continued throughout basin formation. Currentlyelevated mounds of layered deposits correlate with individualsubbasins, each of which followed its own subsidence path.The fact that free-standing MU5 appears to be rotated by aValles Marineris opening-related fault suggests that deposi-tion of the LU/MU package was complete prior to VallesMarineris related tectonic activity.[58] The significant erosion event following deposition of

the LU/MU package represents a major change in the localenvironment. Given the severity of the event, it is temptingto place it at the beginning of Valles Marineris opening.Opening of chasmata would provide passages for largeamounts of erosion products and possibly the mechanismsfor rapid erosion. A more open system of chasmata wouldalso make it difficult to deposit significant thicknesses ofmaterial locally on elevated locations. Since at least onechasma, Hebes, retained its closed basin form while stillcontaining a significant isolated ILD, a simple increase inerosion cannot account for the observations. The sedimen-tary conditions must also have changed. An intriguingpossibility is that water disappeared as a possible trans-port/deposition medium at that time, perhaps because VallesMarineris opening created a new connected network ofpassageways that drained away the water from the surfaceof the Tharsis crust. Whatever is the cause, it appears thatsubsidence continued in Valles Marineris with little or nodeposition other than the products of wall rock erosion andcollapse and wind transport. The idea of chasma formationwith and without deposition was first proposed by Lucchittaet al. [1994], but not developed further.[59] The unconformable cap unit CU is the last ILD unit

to be emplaced and appears to have been affected only byerosion. We suggest that it postdates the main phase ofValles Marineris tectonism and may not be part of the ILD,in the strictest sense.

6.5. Sulfate Occurrences

[60] As pointed out above, the appearance of kieseritecannot be correlated with a particular lithology or strati-graphic level. Kieserite is not pervasive throughout CandorChasma [Mangold et al., 2008] and, while the condition forthe formation of the detected kieserite is under debate, itslack of widespread abundance suggests that the conditionsare localized. We have suggested that LU and MU unitsfrom domain B and C formed under similar conditionsduring basins subsidence, but kieserite is common withinthe domain C, but mostly absent from the domain B. Hencewe suggest that it is unlikely that kieserite is a primarymineral formed during deposition.[61] If Valles Marineris opening did open a drainage

network as suggested above, it is difficult to envisagestanding water to the elevation at which kieserite is foundin an interconnected chasma network. This constraint makesa groundwater origin for the kieserite units more likely. Theobservation of Okubo and McEwen [2007] of fluid alter-ation along fractures in domain C demonstrates the presenceof groundwater. We suggest then that kieserite may be theresult of alteration or may have formed as spring deposits,as suggested by Rossi et al. [2008]. An alteration scenariodominated by groundwater also seems to be very plausible

on the basis of recent global hydrologic modeling[Andrews-Hanna et al., 2007].

6.6. A Model of ILD Formation

[62] As ILDs are common throughout Valles Marineris, ageneralized model of ILD formation should provide ahypothesis which can be tested in other locations. Accord-ing to our model, layered deposits initially form as basin fillduring the formation of ancestral basins (Figure 14). Basinfloor collapse proceeded by differential displacement ofkilometer-sized fault blocks. Basal layered material coveredthe fault blocks by passive draping and hence may havebeen deposited at a small angle, rather than horizontally.The mode of deposition is unknown, but either aqueous oraerial deposition are feasible. This model of gradual basinfloor collapse does not require deep standing water at anytime during the collapse. Indeed, if deposition rate is closeto subsidence rate there is no room for significant waterdepth. Differential displacement of subbasins also resultedin differences in the stratigraphy between sub-basins.Deeper subbasins may have accumulated a thicker sequenceof deposited material, as demonstrated in domain C above(Figures 14B and 14C). Even though fine layered unitsalternate with more massive layered units, the depositionalenvironment throughout basin formation appears not tohave been interrupted by significant periods of erosion, asno significant unconformities can be identified.[63] We postulate that this deposition environment

changed significantly during Valles Marineris opening.Valles Marineris related faulting most likely used existingzones of weakness where possible and led to verticaldisplacement of fault blocks (Figure 14D). In west CandorChasma it also appears to correlate with a significanterosion event. If basins were filled by water, opening adrainage network by faulting could indeed lead to erosionand transport of significant amounts of ILD material. In aclosed chasm, such as Hebes, any water, probably not alarge amount at any time, may well have drained outthrough fractures, though it may have lacked the erosivepower of the open chasm.[64] While it is tempting to attribute post-Valles Marineris

faulting to Valles Marineris opening–related processessensu stricto, it is not certain that basin collapse did notcontinue as well. If, for example, Hebes basin continued tocollapse, growing in an outward fashion following the endof significant deposition, it would attain its current topog-raphy. The elevated ILD marks the site of the originalancestral basin which collapsed early and was filled. Partsof the basin with little or no ILD material formed after theenvironment favorable for deposition ceased to exist. Smallbasins devoid of layered material or basins with asymmet-rically distributed deposits might be explained this way.[65] While processes such as subaerial deposition could

certainly have continued during the erosional event andValles Marineris opening, the present erosional surface iscomposed largely of the eroded MU/LU units. If a signif-icant thickness of material had been deposited on top of theeroded MU/LU units, then these too would have to havebeen eroded subsequently. This would require a seconderosion event capable of removing significant amounts ofstratigraphy. In the absence of evidence for such a second-ary erosion event, we suggest that the opening of Valles


17 of 19

E10008

Marineris coincided with the end of significant deposition.There is evidence of relatively minor deposition followingthat opening. On the basis of its limited extent and strati-graphic location, we suggest that a late localized minorvolcanic event may be responsible for the deposition of capunit CU.[66] The model of ILD formation as outlined above can

be tested by examining the structure and stratigraphy ofother layered deposits. One would expect draped layering,evidence of faulting and a significant change in the depo-sitional environment, possibly associated with a majorerosional event in open chasmata.

7. Conclusions

[67] It is proposed that mounds of interior layered depos-its within west Candor Chasma originated as syntectonicbasin fill during ancestral basin collapse. Differences instratigraphy between adjacent mounds result from differen-tial collapse of subbasins. The depositional environment,which produced in excess of 1.5 km of apparently nearly

conformable layered material, changed during the VallesMarineris opening. The change in environment is markedby a cessation of deposition and by a major erosional event.Spectral signatures of kieserite occur in several locations,not directly related to specific stratigraphic layers, suggest-ing that groundwater may have played an important role inthe formation of kieserite. Groundwater entering the ances-tral basins soon after their initial subsidence, perhaps form-ing shallow ponds or playas, may have altered some, but notall layered deposits. The stratigraphically highest unit CUwas most likely emplaced very late as the result of localvolcanic activity. The model presented accounts for theobservations in the study area. In addition it can alsoaccount for the present day geometries of ILDs in closedbasins such as Hebes.[68] This study demonstrates the importance of including

both structural and image analysis in unraveling the com-plex history of this part of Mars. Knowledge of the layeringattitudes and stratigraphy is crucial to understanding thesequence of events and can lead to testable models for thedevelopment of similar ILD deposits.

Figure 14. A schematic model of ILD formation. Offsets and rotations have been exaggerated forclarity. See the text for details.


18 of 19

E10008

[69] Acknowledgments. We thank the HRSC Experiment teams atDLR Berlin and Freie Universitaet Berlin and the Mars Express Projectteams at ESTEC and ESOC for their successful planning and acquisition ofdata, as well as for making the processed data available to the HRSC team.We also want to thank the MOC, MOLA, and HiRISE teams for makingtheir data available. Two constructive thorough reviews by Baerbel Luc-chitta and Ross Beyer helped to substantially improve the manuscript. Thisproject was partially funded by an NSERC discovery grant to F. Fueten.Pangaea Scientific thanks Paul Budkewitsch and Canada Centre for RemoteSensing for support of ORION under contract NRCan-01-0102. We thankM. Lozon for preparing the illustrations.

ReferencesAndrews-Hanna, J. C., R. J. Phillips, and M. T. Zuber (2007), MeridianiPlanum and the global hydrology of Mars, Nature, 446, 163–166.

Beyer, R. A., and A. S. McEwen (2005), Constraints on the origin of finelayers in Ganges Mensa and Hebes Mensa, Mars, 31st Lunar Planet. Sci.Conf., Abstract 1070.

Bibring, J.-P., Y. Langevin, J. F. Mustard, F. Poulet, R. Arvidson, A. Gendrin,B. Gondet, N. Mangold, P. Pinet, and F. Forget (2006), Mineralogical andaqueous Mars history derived from OMEGA/Mars Express data, Science,312, 400–404.

Catling, D. C., S. E. Wood, C. Leovy, D. R. Montgomery, H. M. Greenberg,C. R. Glein, and J. M. Moore (2006), Light-toned layered deposits inJuventae Chasma, Mars, Icarus, 181, 26–51.

Chapman, M. G. (2002), Layered, massive, and thin sediments on Mars:Possible Late Noachian to Late Amazonian tephra?, in Volcano-Ice Inter-actions on Earth and Mars, edited by J. L. Smellie and M. G. Chapman,Geol. Soc. Spec. Publ., London, 202, 273–203.

Chapman, M. G., and K. L. Tanaka (2001), Interior trough deposits onMars: Subice volcanoes?, J. Geophys. Res., 106(E5), 10,087–10,100.

Fueten, F., R. M. Stesky, and P. MacKinnon (2005), Structural attitudes oflarge scale layering in Valles Marineris, Mars, calculated from MarsOrbiter Laser Altimeter data and Mars Orbiter Camera imagery, Icarus,175(1), 68–77.

Fueten, F., R. Stesky, P. MacKinnon, E. Hauber, K. Gwinner, F. Scholten,T. Zegers, and G. Neukum (2006), A structural study of an interiorlayered deposit in southwestern Candor Chasma, Valles Marineris,Mars, using high resolution stereo camera data from Mars Express,Geophys. Res. Lett., 33, L07202, doi:10.1029/2005GL025035.

Gaddis, L. R., J. Skinner, T. Hare, R. Kirk, T. Titus, L. Weller, andG. Neukum (2006), Morphology and morphometry of Ceti Mensa, WestCandor Chasma, Mars, 37th Lunar Planet. Sci. Conf., Abstract 2076.

Gendrin, A., et al. (2005), Sulfates inMartian layered terrains: The OMEGA/Mars Express view, Science, 307, 1587–1591.

Gwinner, K., F. Scholten, M. Spiegel, R. Schmidt, B. Giese, et al. (2005),Hochauflosende Digitale Gelandemodelle auf der Grundlage von MarsExpress HRSC-Daten, Photogramm. Fernerkund. Geoinf., 5, 387–394.

Hauber, E., et al. (2006), An integrated study of interior layered deposits inHebes Chasma, Valles Marineris, using MGS, MO, and MEX Data, 37thLunar Planet. Sci. Conf., Abstract 2022.

Hynek, B. M., R. J. Phillips, and R. E. Arvidson (2003), Explosive volcan-ism in the Tharsis region: Global evidence in the Martian record,J. Geophys. Res., 108(E9), 5111, doi:10.1029/2003JE002062.

Jaumann, R., et al. (2007), The high-resolution stereo camera (HRSC)experiment on Mars Express: Instrument aspects and experiment conductfrom interplanetary cruise through the nominal mission, Planet. SpaceSci., 55, 928–952.

Komatsu, G., P. E. Geissler, R. G. Strom, and R. B. Singer (1993), Strati-graphy and erosional landforms of layered deposits in Valles Marineris,Mars, J. Geophys. Res., 98(E6), 11,105–11,121.

Komatsu, G., G. G. Ori, P. Ciarcelluti, and Y. D. Litasov (2004), Interiorlayered deposits of Valles Marineris, Mars: Analogous subice volcanismrelated to Baikal Rifting, Southern Siberia, Planet. Space Sci., 52, 167–187.

Lucchitta, B. K. (1987), Recent mafic volcanism on Mars, Science, 235,565–567.

Lucchitta, B. K. (1990), Young volcanic deposits in the Valles Marineris,Mars?, Icarus, 86, 476–509.

Lucchitta, B. K. (1999), Geologic Map of Ophir and Central Candor Chas-mata (MTM-05072) of Mars, U.S. Geological Map, I-2568.

Lucchitta, B. K. (2004), A volcano composed of light-colored layereddeposits on the floor of Valles Marineris, 35th Lunar Planet. Sci. Conf.,Abstract 1881.

Lucchitta, B. K., and M.L. Bertolini (1990), Interior structures of VallesMarineris, Mars, 20th Lunar Planet. Sci. Conf., Abstract 590–591.

Lucchitta, B. K., N. K. Isbell, and A. Howington-Kraus (1994), Topogra-phy of Valles Marineris: Implications for erosional and structural history,J. Geophys. Res., 99(E2), 3783–3798.

Malin, M. C., and K. S. Edgett (2000), Sedimentary rocks of early Mars,Science, 290, 927–1938.

Malin, M. C., G. E. Danielson, A. P. Ingersoll, H. Masursky, J. Veverka,M. A. Ravine, and T. A. Soulanille (1992), Mars observer camera,J. Geophys. Res., 97(E5), 7699–7718.

Malin, M. C., et al. (2007), Context camera investigation on board the MarsReconnaissance Orbiter, J. Geophys. Res., 112, E05S04, doi:10.1029/2006JE002808.

Mangold, N., et al. (2007a), An overview of the sulfates detected in theequatorial regions by the OMEGA/MEX spectrometer, 7th Int. Conf.Mars, Abstract 3141.

Mangold, N., A. Gendrin, C. Quantin, B. Gondet, J.-P. Bibring, V. Ansan,Ph. Masson, G. Neukum, OMEGA Team, and HRSC Co-InvestigatorTeam (2007b), Sulfate-rich deposits in West Candor Chasma, 38th LunarPlanet. Sci. Conf., Abstract 1643.

Mangold, N., A. Gendrin, B. Gondet, S. LeMouelic, C. Quantin, V. Ansan,J.-P. Bibring, Y. Langevin, P. Masson, and G. Neukum (2008), Spectraland geological study of the sulfate-rich region of West Candor Chasma,Mars, Icarus, 194, 519–543, doi:10.1016/j.icarus.2007.10.021.

McEwen, A. S., et al. (2007), Mars Reconnaissance Orbiter’s High Resolu-tion Imaging Science Experiment (HiRISE), J. Geophys. Res., 112,E05S02, doi:10.1029/2005JE002605.

Mege, D., and P. Masson (1996), Amounts of crustal stretching in VallesMarineris, Mars, Planet. Space Sci., 44, 749–782.

Nedell, S. S., S. W. Squyres, and D. W. Andersen (1987), Origin andevolution of the layered deposits in the Valles Marineris, Mars, Icarus,70, 409–441.

Okubo, C. H., and A. S. McEwen (2007), Fracture-controlled paleo-fluidflow in Candor Chasma, Mars, Science, 315(983), doi:10.1126/science.1136855.

Peterson, C. (1981), A secondary origin for the Central Plateau of HebesChasma, in Proc. 12th Lunar Planet. Sci. Conf., Part B, pp. 1459–1471,Pergamon Press, New York.

Peulvast, J.-P., D. Mege, J. Chiciak, F. Costard, and P. L. Masson (2001),Morphology, evolution and tectonics of Valles Marineris wallslopes(Mars), Geomorphology, 37, 329–352.

Rossi, A. P., G. Neukum, M. Pondrelli, S. Van Gasselt, T. Zegers, E. Hauber,A. Chicarro, and B. Foing (2008), Large-scale spring deposits on Mars?,J. Geophys. Res., 113, E08016, doi:10.1029/2007JE003062.

Scholten, F., et al. (2005), Mars Express HRSC data processing—methodsand operational aspects,Photogramm. Eng. Remote Sens., 71, 1143–1152.

Schultz, R. A. (1995), Gradients in extension and strain at Valles Marineris,Mars, Planet. Space Sci., 43, 1561–1566.

Schultz, R. A. (1998), Multiple-process origin of Valles Marineris basinsand troughs, Mars, Planet. Space Sci., 46, 827–834.

Schultz, R. A. (2000), Fault-population statistics at the Valles Marinerisextensional province, Mars: Implications for segment linkage, crustalstrains, and its geodynamic development, Tectonophysics, 316, 169–193.

Schultz, R. A., and J. Lin (2001), Three-dimensional normal faulting mod-els of the Valles Marineris, Mars, and geodynamic implications, J. Geo-phys. Res., 106(B8), 16,549–16,566.

Tanaka, K. L. (1986), The stratigraphy of Mars, Proc. Lunar Planet. Sci.Conf. 17th, Part I, J. Geophys. Res., 91, suppl., E139–E158.

Zegers, T. E., W. Dabekaussen, E. Hauber, K. Gwinner, F. Scholten,F. Fueten, R. Stesky, P. MacKinnon, G. Neukum, and HRSC Co-Investi-gator Team (2006), 3D structural analysis of Ophir Chasma based onHRSC image data and stereo-derived DTM, 37th Lunar Planet. Sci. Conf.,Abstract 1605.

Zuber, M. T., D. E. Smith, S. C. Solomon, D. O. Muhleman, J. W. Head,J. B. Garvin, J. B. Abshire, and J. L. Bufton (1992), The Mars Observerlaser altimeter investigation, J. Geophys. Res., 97(E5), 7781–7797.

��F. Fueten and P. MacKinnon, Department of Earth Sciences, Brock

University, 500 Glenridge Avenue, St. Catharines, ON, Canada L2S 3A1.([email protected])K. Gwinner, E. Hauber, and F. Scholten, Institute of Planetary Research,

German Aerospace Center (DLR), Rutherfordstr. 2, 12489 Berlin,Germany.G. Neukum, Institute of Geological Sciences, Free University, Mal-

teserstr. 74-100, 12489 Berlin, Germany.R. Stesky, Pangaea Scientific, R.R.#5, Brockville, ON, Canada K6V 5T5.T. Zegers, Faculty of Geosciences, Department of Earth Sciences,

Utrecht University, Budapestlaan 4, 3508 TA Utrecht, Netherlands.


19 of 19

E10008

Documents

Stratigraphy and structure of interior layered deposits in ...forth/publications/Fueten_2008.pdfStratigraphy and structure of interior layered deposits in west Candor Chasma, Mars,