Volcanism In The Solar System

Question 0

How does volcanism occur on earth and where?

Answer 0

Source rock - fertile (fe-rich) peridotite
Heat source - radioactive decay
Fractionation - invisible liquid, partial melting & fractional crystallisation (enriching the fluid I’m silica making it more explosive)
Surface - 70% of earth is MORB. Hotspots & subduction

Question 1

Where has volcanism occurred and where is it occurring in the solar system?

Answer 1

Past activity - moon, mercury, Venus, Mars, Jupiter (iced satellite)
Active - Io, Tritan, Encaludus
Partial melting of ice - Ganymede & Europa (Jupiter), Enceladus (Saturn), Tritan (Neptune)

Question 2

What are the 2 styles of eruptions?

Answer 2

Effusive - basic composition, low viscosity and a volatile poor magma (Hotspots and MORB)
Explosive - intermediate to acid composition. High in silica meaning viscous but also volatile rich (subduction)

Question 3

The study of terrestrial volcanic systems helps us understand extra-terrestrial volcanic systems. What main features can be in Hawaii and how can they help us understand volcanism in the solar system?

Answer 3

Terrestrial features - lava flows, channels (needing a high discharge rate), lava tubes (roofing and the draining), fissures, dykes, craters, calderas, cinder cones, pyro clastic aprons, debris flows
Understanding - size of fields, dimensions if channels, dispersal of pyroclastics
Lava - AA radar bright, pahoehoe radar dark

Question 4

Size of average lava flows on Mars, Jupiter and Venus OR smallest to biggest?

Answer 4

Moon - <3km - Domes
Mars - 10km - Olympos Mons
Jupiter - 150km - Io
Venus - 400km

Question 5

How does gravity and atmospheric pressure effect volcanism?

Answer 5

Gravity - buoyant forces causes magma to rise. The distribution of the magma
Atmospheric pressure - enhances convective cooling. Controls degassing
Higher atmospheric pressure - the DECREASE in plume height but the INCREASE in volatiles

Question 6

Volcanism on Venus?

Answer 6

85% volcanic flows
No plate tectonics - slow cooling which means a warmer mantle which means a weak convections implying from the warm mantle periodical catastrophic resurfacing event
Features - candi (channels - sediment, water and/or lava), mountains, domes, CORONAE (inner circular plateau, raised rim and bounded by circular trough or moat)

Question 7

Mars volcanism?

Answer 7

Cooling - a single plate with a thick rigid lithosphere. Volcanic activity and associated tectonisim can only have occurred in early time
Eruption style - extensive volcanic plain followed by Evidence of phraetomagmatic eruption (evidence of water)
Tectonic association - Thorsis volcanoes (Olympos Moms - nested caldera, levels, channels, lobate flow front) - immense size of shield volcanoes implies mantle plumes
Thorsis - volcanic plain
Patera - Ceranius Tholus (prolonged eruption, butterfly impact crater, lava channel and delta) formed by basal melting which flooded the crater forming a temporary lake (Caleb et al., 2007)

Question 8

What ages can be obtained from a volcanic eruption (youngest to oldest) and how can they be obtained?

Answer 8

Crystallisation age - age of magmatic event (U-Pb)
Cosmic ray age - time of flight from cosmic ray spallation generating
Terrestrial age - time residing on the earth
(D. Moor et al., 2013)