Igneous 1

Question 1

Ultramafic

Answer 1

<44%SiO, Peridotite, Microperidotite, Komatite, <5% plagioclase/augite/olivine,
mantle ONLY

Question 2

Mafic

Answer 2

55-45%SiO, Gabbro, Dolerite, Basalt, plagioclase/hornblende/augite/olivine,
constructive boundaries

Question 3

Intermediate

Answer 3

66-55%SiO, Diorite, Microdiorite, Andesite, quartz/plagioclase/biotite/hornblende,
destructive boundaries

Question 4

Silicic

Answer 4

> 66%SiO, Granite, Microgranite, Rhyolite, quartz/feldspar/micas,
destructive boundaries

Question 5

Grain Size

Answer 5

Coarse- >3mm
Medium- 0.1-3mm
Fine- <0.1mm

Question 6

Grain Classification

Answer 6

euhedral, anhedral, groundmass, porphyritic, phenocrysts

Question 7

Rock Classification

Answer 7

granular, vesicular, frangmental/tuff

Question 8

Structures

Answer 8

Pillow lava, Columnar jointing, Amagdales, Pahoehoe, Aa, Xenoliths

Question 9

Bodies of Lava

Answer 9

Pluton- magma chamber
Sill- concordant to beds
Dyke- discordant to beds

Question 10

Basic Magma

Answer 10

partial melting of mantle peridotite, very fluid, high temperatures >1000, low viscosity, constructive boundary, non explosive eruptions,

Question 11

Intermediate Magma

Answer 11

wet partial melting above subduction zone, viscous, lower temperatures <800, frequent eruptions, destructive boundary

Question 12

Acid Magma

Answer 12

partial melting of continental crust, high gas content, very viscous, low temperatures 700, highly explosive eruptions, convergent boundary

Question 13

Sill vs Lava Flow

Answer 13

sill- 2 baked margins, medium grained, 2 chilled margins
lava flow- surface structures, fine grained, 1 baked margin

Question 14

Volcano Types

Answer 14

shield, fissure, cinder cone, caldera, stratovolcano

Question 15

Volcanic Hazards

Answer 15

lava, blasts, sector collapse, ashfall, lahars, gases, pyroclastic flows, pyroclastic debris

Question 16

Predicting Eruptions

Answer 16

measuring temperatures, low magnitude earthquakes, surface fractures, expanding gradient, gas spectrometers, steam vents, shallow earthquakes, steam eruptions, ground deformation, gravity anomalies, thermal anomalies, gas emissions, seismic activity, lava dome