MARS TECTONICS & VOLCANOLOGY Zachary Gallegos University of New Mexico / Mars One

Mars Orbiter Laser Altimeter Map

Plate Tectonics Lithospheric plates sliding on the asthenosphere, above the mantle Exists on Earth Theory proposed in the early 1900’s Does it exist on other bodies in the solar system?

Plate Tectonics Recycles material Regulates the atmosphere CO 2 sequestration and output Linked with mantle convection Push new material to surface at divergent boundaries Pulls old material into the Earth at convergent boundaries

Tectonics of Earth Picture of plates

Plate boundaries Divergent Spreading apart Convergent Moving together Strike-slip Sliding past

Divergent Mid-Atlantic ridge Oceanic East African Rift Continental Rio Grand Rift Continental

Convergent Mariana Islands/Trench oceanic-oceanic Pacific Northwest oceanic-continental Himalayas continental-continental

Strike-slip San Andres fault right lateral

Plate Tectonics of Mars

Tectonics of Mars Mars seems to lack global, Earth-like tectonics Too small? Not enough water? Large scale faulting HUGE scale rifting

Topography Mars’ planetary dichotomy Not tectonic in origin Bolide impact, water resurfacing Slow sloping at the dichotomy not pronounced Earth’s dynamic lithosphere Tectonic in origin Steeply sloping at the margins Continental and oceanic crust

Magnetics Mars lacks a current magnetic field Magnetic reversals recorded on Earth

Magnetics Possible magnetic reversals recorded in early Martian crust

Interior of Mars Smaller/colder Less water

Faulting Tectonic movement Normal (extension) Reverse (compression) Strike-slip (lateral)

Faulting on Mars Thrust faulting Amenthes Rupes Normal faulting Circum-Tharsis Strike-slip faulting?? Within Valles Marineris

Faulting on Mars Circum-Tharsis Extensional faulting

Valles Marineris Giant tectonic fissure in the crust Not the result of plates Result of Tharsis uplift Length: > 4,000km Width: > 200km Depth: > 7km Largest known valley in the solar system

Valles Marineris Nearly ¼ or the planets circumference Nine times longer than the grand canyon

Vallis Marineris

Volcanology Study of volcanoes Volcanoes bring new material to the surface from below Lava, ash, gas

Volcanology of Earth Most of Earth’s volcanism is related to plate tectonics Divergent and convergent boundaries

Volcanology of Mars No planetary tectonics Shield forming Hot spot volcanism (e.g. Hawaii) Mostly basaltic in compositions From ultramafic komattiatic to dacitic

Rocks and Minerals Mars has a different volcanic signature than Earth

Why Basalt? Hot spot volcanism produces basalt

Volcanism and Tectonics With no tectonics, volcanoes grow to enormous size

Montes Mons are large shield volcanoes Earth analogue: Hawaii Gentle slopes < 6° Ascraeus Mons Pavonis MonsArsia Mons

Tholi Tholus is a term for smaller, dome shaped volcanoes Older than Mons Buried by later flows Steeper flanks Different material than Montes? Less material than Montes?

Patera Term given to small volcanoes with large calderas Latin translation: shallow drinking bowl Larger calderas than the tholi Probably represent larger volcanoes Buried beneath flows and sediment

Rootless Volcanoes & Pseudocraters Show no sign of magma conduit Analogues on Earth erupt due to a magma body flowing over a surface or subterranean water source

Martian Volcanic Provinces

Tharsis Largest volcanic province on Mars 25% of the planets surface Avg. 7-10km above datum Youngest flows on Mars

Tharsis Arsia Mons

Olympus Mons Largest mountain in the solar system Height: > 22km Diameter: > 500km Slope: ~ 4° 6 nested calderas 3.5km deep

Alba Mons North of Tharsis buldge Very low slopes ~.5° 1600km across Rises 3km above plains

Elysium Second largest volcanic province 1,700x2,400 km Elysium Mons 13km high Hecates Tholus North Albor Tholus South

Syrtis Major 1200km across 2km high 2 calderas Nili Patera, Meroe Patera Silica rich rocks Dacite & Granite Isidis Basin

Highland Patera Near the Hellas impact basin Impact induced volcanism along fractures?

Arabia Terra Low relief Patera Structures that look like Earth’s supervolcanoes e.g. Eden Patera

Questions?

Geography of Mars

Volcanic Provinces

Exploration Sites