Earth Mat Flashcards - Ch 9

Question 1

Lava commonly erupts from a _________ located in a crater near the summit of the volcano.

Answer 1

central vent

Question 2

Low discharge flank eruptions produce smaller _________ along the summit, side or base of larger volcanoes.

Answer 2

parasitic volcanoes

Question 3

Mauna Kea has _____ parasitic cones

Answer 3

100

Question 4

are large, generally circular to oval depressions caused by subsidence of Earth’s surface. in the context of volcanism

Answer 4

Calderas

Question 5

Magma Loss in caldera formation can be caused by two things

Answer 5

subsurface withdrawal of magma from a shallow chamber as magma migrates to another location,
cataclysmic eruptions that empty the shallow magma chamber.

Question 6

is an intrusive igneous body that is circular, oval or arcuate in plan view and has steep contact

Answer 6

A ring dike or ring dyke

Question 7

, are the product of massive outpourings of low viscosity basaltic lava that envelop hundreds of thousands of square kilometers.

Answer 7

Flood basalts , also known as large igneous provinces (LIP)

Question 8

Mantle Hotspot related LIP

Answer 8

Ontong Plateau, W. Pacific
Kerguelen Plateau, Indian Ocean

Question 9

Continental Flood Plateau

Answer 9

Deccan Traps, India
Siberian Flood Basalts
Karoo, E. Africa
Columbia River/Snake River Plain, N. America

Question 10

Marine and continental
Records break up of pangea

Answer 10

Central Atlantic Magmatic Province (CAMP)

Question 11

consist of a 65,000 km long global network of submarine rift mountains

Answer 11

Ocean ridges

Question 12

Rare examples of surface exposed ocean ridges

Answer 12

Iceland, Galapagos Is., Azores Is.

Question 13

As hot (1100 – 1300 ° C) basaltic magma rises upward and reacts with cold seawater, spheroidal ____________ develop

Answer 13

pillow lavas

Question 14

Ocean ridges also contain _________ that emit lower temperature (100 – 300 ° C) solutions that precipitate light - colored minerals such as calcite, gypsum, barite and quartz.

Answer 14

white smokers

Question 15

are broad, sloping edifices that cover hundreds to thousands of square kilometers with shapes that resemble the defensive shields of ancient warriors.

Answer 15

Shield volcanoes

Question 16

5 Shield volcanoes of the Big Island of Hawaii

Answer 16

Kilauea
Mauna Loa
Mauna Kea
Hualalai
Kohala

Question 17

The Hawaiian eruptions that produce shield volcanoes also generate fiery basaltic___________ several hundred feet high

Answer 17

lava fountains

Question 18

Airborne blobs of liquid lava emitted by fountains are referred to as

Answer 18

spatter

Question 19

Spatter that solidifies at the base of the lava fountains is referred to as

Answer 19

welded spatter or agglutinate deposits

Question 20

Lava fountains that erupt via fissures produce linear ridges called ____________ on either side of the fissure

Answer 20

spatter ramparts

Question 21

are elevated lateral banks that contain the lava flow within stream-like channel.

Answer 21

Lava levees

Question 22

are shallow subterranean tunnels channelling lava beneath thin, solidifi ed basaltic roofs.

Answer 22

Lava tubes

Question 23

lava consists of low viscosity, “ runny ” basaltic lava which produces thin flows with a billowing, rippled and/or ropey surface

Answer 23

Pahoehoe lava

Question 24

More viscous aa lava tends to produce thicker, slower moving lava flows with angular, jagged, fractured surfaces

Answer 24

Aa lava

Question 25

are steep - sided (~30 – 35° ) conical features composed of tephra.

Answer 25

Pyroclastic cones

Question 26

Tephra consists

Answer 26

of volcanic rock fragments of various sizes and compositions emitted during explosive eruptions.

Question 27

Pyroclastic cones composed predominantly of vesicular basaltic material.

Answer 27

Scoria cones

Question 28

Pyroclastic cones consisting of ash, lapilli and bomb - sized particles of various compositions that accumulate as circular to oval - shaped conical volcanoes

Answer 28

Cinder cones

Question 29

are majestic cone - shaped mountains encompassing tens to hundreds of square kilometers in area with slopes ranging from 10 ° to 30°

Answer 29

Composite volcanoes

Question 30

consists of smooth - sided blocks up to several meters in diameter that tumble downslope lithifies as volcanic breccia deposits

Answer 30

Block lava

Question 31

develop when a solidified magma plug is pushed up through the conduit, forming a vertical column on Earth ’ s surface.

Answer 31

Spines

Question 32

are steep - sided, blister - like forms that occur within volcanic craters

Answer 32

Domes

Question 33

Explosive volcanic eruptions produce a vertical plume or eruption column that can be divided into three distinct parts

Answer 33

lower gas thrust Upper convectice thrust Umbrella Region

Question 34

region in the eruption column where material thrust from the vent 100 to 600 m/s

Answer 34

Lower Gas Thrust

Question 35

region in the eruption column where convective rise of heated atmospheric gases and fragments

Answer 35

Upper convective thrust region

Question 36

region in the eruption column where vertrical plume begins to spread laterally as the result of temperature inversions

Answer 36

Umbrella region

Question 37

Two modes of eruptive column behavior ______________ result in two kinds of deposits: pyroclastic fall (air fall) deposits and pyroclastic fl ow deposits.

Answer 37

– convective thrust and gravitational collapse–

Question 38

occurs when the thrust region plume exhibits buoyancy

Answer 38

Convective thrust

Question 39

_of the plume occurs due to negative buoyancy initiation of pyroclastic flows

Answer 39

Gravitational collapse

Question 40

deposits are produced by airborne pyroclasts propelled upward in an eruption column

Answer 40

Pyroclastic fall (air fall)

Question 41

lateral sequence of air fall particales from nearest to farthest

Answer 41

Bombs and breccia settle first and closest, smaller particles slow and farthest Solidifies deposits grades upward from brccias to lapili tufts and lastly fiend tuffs Distal ash - sized particles are deposited and later compacted and cemented together as ash fall tuffs

Question 42

deposits generally lack stratification and are poorly sorted chaotic mixtures of clast sizes are deposited rapidly.

Answer 42

pyroclastic flow

Question 43

Three major types of pyroclastic flows are recognized:

Answer 43

Pyroclastic Surges Pumice Flows Nuee Ardentes

Question 44

Pyroclastic flow very low density, extremely hot, gaseous flows ash - to lapilli - size particles; 100 km/h Low densities allow surges to defy gravity and climb upwards

Answer 44

Pyroclastic surges

Question 45

Pyroclastic flow low to moderate density, hot vesiculated flows Siliceous pumice flows produce light - colored, vesicular ignimbrites Andesitic to basaltic flows produce vesicular scoria flow.

Answer 45

Pumice flows

Question 46

Pyroclastic flow fluidized mixtures of hot, incandescent rock fragments and gases 1000C at 150 km/h High density, vesicle - poor block and ash pyroclastic flow deposits are generated

Answer 46

Nuées ardentes (French for “ fiery clouds ”)

Question 47

Siliceous pumice flows produce light - colored, vesicular _________

Answer 47

ignimbrites

Question 48

are volcanic mudflows up to tens of meters thick with the consistency of wet cement.

Answer 48

Lahars

Question 49

Lahars can form at three different times:

Answer 49

Synchronous with volcanism (syn-eruption lahars) and active pyroclastic flow. After volcanism has ceased (early post - eruption lahars) slopes of dormant or inactive volcanoes (late post - eruption lahars)

Question 50

The 1991 Mt Pinatubo (Philippines) eruption involved both ________ and _______ lahars

Answer 50

syn-eruption and post -eruption

Question 51

are large volcanic features that lack the typical, highly elevated landform associated with most volcanoes.

Answer 51

Rhyolite caldera complexes

Question 52

Rhyolite calderas are known as __________; since low depression calderas are the signature aspect,

Answer 52

inverse volcanoes

Question 53

After eruption of rhyolite calderas, they can emit smaller scale eruptions over long time intervals and experience regional uplift, referred to as

Answer 53

“resurgence”

Question 54

eruption involving both magma and heated groundwater magma below water table

Answer 54

Phreatomagmatic eruptions

Question 55

Volcanic features produced by phreatomagmatic eruptions include

Answer 55

tuff rings, tuff cones (both positive) and maars (negative).

Question 56

gently sloping, circular structures composed of stratified, glassy volcanic debris and scoria explosive eruption of basalt in a lake, beach or wetland environment. Reworked shallow water cinder cones

Answer 56

Tuff rings

Question 57

circular volcanic cones formed by the eruption of basalt in water smaller and steeper features Less explosive eruption, short durations

Answer 57

Tuff cones

Question 58

low relief volcanic craters that form by shallow explosive phreatomag matic eruptions volcanic crater filled with water to create either a freshwater or saline lake

Answer 58

Maars

Question 59

The eruption of heated water and steam without magma, characterizes phreatic eruptions

Answer 59

Phreatic eruptions

Question 60

groundwater heated by proximity to magma

Answer 60

Hot springs

Question 61

eruptive hot springs that eject fountains of heated water periodically

Answer 61

Geysers

Question 62

Eruptions begin as fissures, evolving to central vent flows and the generation of large shield volcanoes. Fiery basaltic lava fountain eruptions, quiet lava flows, and cinder cones are also generated.

Answer 62

Hawaiian

Question 63

Persistent fissure eruption of low viscosity basaltic lava flows. Prolonged quiet eruptions may generate lava plateaus and flood basalts.

Answer 63

Icelandic

Question 64

Explosive, steam-blast eruptions with lava flows and pyroclastic debris.

Answer 64

Surtseyan (phreatomagmatic)

Question 65

Surtseyan eruptions are named after the volcanic island of _____, which rose above sea level on November 14, 1963.

Answer 65

Surtsey

Question 66

Periodic bursts ("burps") of moderately explosive eruptions (less than 5 km high). These eruptions contain great concentrations of pyroclastic fragments and incandescent basaltic lava flows.

Answer 66

Strombolian

Question 67

Explosive eruptions of basaltic to rhyolitic viscous lava. Large volumes of volcanic ash plumes (less than 25 km high) and pyroclastic debris.

Answer 67

Vulcanian

Question 68

Violent eruptions of volcanic debris ejected, scattering ash over thousands of square kilometers

Answer 68

Vesuvian

Question 69

Tephra eruptions emit immense ash clouds over 11 km in height into the stratosphere.

Answer 69

Plinian

Question 70

Violent tephra eruptions with volumes greater than 1 km³ and ash cloud heights ranging from 25 to 55 km

Answer 70

Ultraplinian