Tectonic landformsTectonic landforms

• Global distribution• Extension

Long and narrow graben (“simple grabens“)Complex graben systems (“rifts“)

• CompressionWrinkle ridgesLobate scarps

• Strike-slip faults• Outlook: Implications for geophysics

• Global distribution• Extension

Long and narrow graben (“simple grabens“)Complex graben systems (“rifts“)

• CompressionWrinkle ridgesLobate scarps

• Strike-slip faults• Outlook: Implications for geophysics

Review papers:

• Tanaka et al. (1991) • Banerdt et al. (1992)

Review papers:

• Tanaka et al. (1991) • Banerdt et al. (1992)

Blattverschiebung (strike-slip fault, wrench fault)linkslateral

com

pres

sion

exte

nsio

n

western hemisphere eastern hemisphere

from Banerdt et al. (1992)

Global distribution

Extensional features (graben)Cross-cutting relationshipsExtensional features (graben)Cross-cutting relationships

10 km10 kmNN

Simple grabenSimple graben

l o n g a n d n a r r o w g r a b e n

l o n g a n d n a r r o w g r a b e n

HRSC 3D-view

fromAnderson et al. (2001)

Southwestern part of Tharsis (Daedalia Planum, Terra Sirenum)

from Wilson and Head (2002)

Radiating, long and narrow simple graben

from Wilson and Head (2002)

Surface expression forgiant radial dike swarms?Terrestrial analog:Mackenzie Dike Swarm (Canada)

from Wilson and Head (2002)

Alternative view:local volcanism and smaller dike swarms [Mège et al., J. Geophys. Res., 2002)

Description: Multiple 'grabens' in Canyonlands. The Grabens are a system of linear collapsed valleys caused by the movement of underlying salt layers towardCopyright © Martin Miller, University of Oregon

Canyonlands National ParkCanyonlands National Park

• often considered to be a terrestrial analog forlong and narrow Martian grabens

• but: deformation due to (relatively shallow)ductile salt layers

• often considered to be a terrestrial analog forlong and narrow Martian grabens

• but: deformation due to (relatively shallow)ductile salt layers

fromSchultz et al. (2000), after Tanaka et al., J. Geophys. Res. 96 (1991)

a) Faulting at bimaterialinterface (e.g., mega-regolith overbasalt)

b) Faulted upperlayer separated bysills fromdetachment zonefrom undeformedsubstrate

c) Graben wedgefalling into space-accomodatingtensile crack

d) Graben faultsnucleated be dikedilatation at depth

Schultz: Modelle langer und schmaler Gräben

Simple grabens on Marsthin-skin vs. thick-skin tectonics

Previous view: symmetric, strainconcentrated above the

décollement

Current view: asymmetric, faultscontinue to depth as network

from:Schultz, LPSC XXXI (2000)

after Watterson et al., J. Struct. Geol. 20 (1998)

"Hourglass" model forplanetary grabens

fromSchultz et al. (2000)

1000 m1000 m

13.0°N, 103.2°W13.0°N, 103.2°W

Collapse pitsnortheast flank of volcano, Ascraeus MonsCollapse pitsnortheast flank of volcano, Ascraeus Mons

no raised rims, no ejectano raised rims, no ejecta

Tantalus Fossae –Pit craters associated with faultingTantalus Fossae –Pit craters associated with faulting

38.2°N, 103.8°W38.2°N, 103.8°W

p i t c r a t e r c h a i n („c a t e n a“)

p i t c r a t e r c h a i n („c a t e n a“)

~3 km~3 km

diameters up to > 4 kmvolumes up to > 7 km3

Wyrick et al., J. Geophys. Res. 109 (2004)

diameters up to > 4 kmvolumes up to > 7 km3

Wyrick et al., J. Geophys. Res. 109 (2004)

Ferrill et al., GSA Today 14 (2004):dilatational normal faulting and collapse

Ferrill et al., GSA Today 14 (2004):dilatational normal faulting and collapse

• Crosscutting relationships

• pristine morphology

• Lack of sediment accumulation

• on the bottom

• Crosscutting relationships

• pristine morphology

• Lack of sediment accumulation

• on the bottom

activeformation

today?

activeformation

today?

Intensely fractured terrainClaritas FossaeIntensely fractured terrainClaritas Fossae

HRSC 3D-view

HRSC 3D-view

HRSC 3D-view

HRSC 3D-view

Tempe Fossae:Are they comparable

to a terrestrialcontinental rift?

fromHauber & Kronberg (2001)

Complex grabensystems (“rifts“)

fromHauber & Kronberg (2001)

Tempe Fossae

tectonic sketch map

Topographic (MOLA-)Profilesacross the Tempe Rift

from Hauber & Kronberg (2001)

re-activation of older structuresfrom Hauber & Kronberg (2001)

from Hauber & Kronberg (2001)

com

pres

sion

exte

nsio

n

western hemisphere eastern hemisphere

from Banerdt et al. (1992)

Global distribution

Image examples from:Montesi and Zuber,J. Geophys. Res. 108 (2003)

Viking

MOC

wrinkle

ridge

common landforms on Mars, the Moon (maresurfaces), and Venus

Terrestrial analogs:Regularly spaced

anticlinal ridges assurface expression of

folding and thrust faulting(Yakima Fold Belt,

Columbia River Basalts)

Wrinkle ridge topographyDifferent spacing reflecting different lithospheric properties?

from: Watters, Icarus 171 (2004

Wrinkle ridge topographyfrom: Watters, Icarus 171 (2004

wrinkle

ridge

wrinkle

ridge

Structural modelsproposed forplanetary wrinkleridgesa) Buckle folds with nucleations

of thrust faults [Watters, 1988]

b) Simple thrust fault c) Conjugate thrust fault

[Allemand & Thomas, 1992; Mangold et al., 1998]

d) Fault-bend fold [Suppe, 1983; Suppe & Connors, 1992]

e) Fault-propagation fold[Mercier et al., 1997]

fromSchultz, J. Geophys. Res. 105 (2000)

Wrinkle ridges

Blind thrust model[Schultz, 2000]

overalldirection ofthrusting

Questions• Depth of faulting: Thin- or thick-skinned

tectonics?

• Geometry and number of faults?

• Importance of folding?

• Mechanical model of Watters (2004): thin-skinneddeformation of upper crustal material, singlethrust fault with listric geometry

• Outlook: MARSIS radar on Mars Express will investigate shallow crustal structure

Wrinkle ridges

• Typical for plate tectonics on Earth (e.g., San Andreas fault, North Anatolian fault)

• Evidence on Mars is very rare (Schultz, Nature, 1989)

Lateral movements(strike-slip faults)

200 m

Tectonic faultsIus Chasma

Tectonic faultsIus Chasma

500 m500 m8°N, 7°WLayers in western Arabia Terra

faultsfaults

Outlook (1)

• Improved understanding of potentially seismic regions on Mars

• Mapping of faults

• Assessment of fault ages

DLR

Outlook (2)• Previous work

demonstrates that themagnitude of displacementaccommodated alongfaults with slip surfacesscales with theirhorizontal (map) lengths

• HRSC will improve theknowledge of length-displacementrelationships

• crustal properties

from Schultz et al., LPSC XXXII (2001)