|
Mount St. Helens is… A basaltic cinder cone An explosive stratovolcano A basaltic shield volcano A small, welded tuff cone |
An explosive stratovolcano |
|
Which one of the following shows the correct order (left to right) of decreasing magma viscosity? Rhyolite, andesite, basalt Andesite, rhyolite, basalt Basalt, rhyolite, andesite Basalt, andesite, rhyolite |
Rhyolite, andesite, basalt |
|
Which of the following are usually the most abundant gases emitted during basaltic volcanism? Chlorine and sodium Neon and ammonia Oxygen and nitrogen Water vapor and carbon dioxide |
Water vapor and carbon dioxide |
|
Which of the following statements best describes Shiprock, a famous volcanic feature in New Mexico? The eroded remains of a volcanic pipe and radiating dikes An extinct, massive, rhyolite volcanic dome A very recently, active basaltic cinder cone An extinct, highly symmetrical, composite volcanic cone |
The eroded remains of a volcanic pipe and radiating dikes |
|
A _______________ is the largest, discordant body of intrusive, igneous rock Lopolith Laccolith Batholith Stock |
Batholith |
|
____________ magma is the most abundant type erupted at oceanic spreading centers Granitic Basaltic Andesitic Pegmatitic |
Basaltic |
|
The _________ ocean basin is rimmed by the most subduction zones Atlantic Indian Pacific Arctic |
Pacific |
|
Which of the following is associated with deep mantle hot spots? Vesuvius and the other volcanoes of Italy The volcanoes of Hawaii and the Quaternary activity in Yellowstone National Park The very young cinder cones scattered across the southwestern United States Mt. St. Helens and other volcanoes of the Cascade Mountains |
The volcanoes of Hawaii and the Quaternary activity in Yellowstone National Park |
|
Which type of basaltic lava flow has a fairly smooth, unfragmented, ropy surface? Aa Pegmatitic Pahoehoe Scoria |
Pahoehoe |
|
The Columbia Plateau in Washington and Oregon is… A thick stack of welded-tuff layers An extensive, thick accumulation of successive eruptions of flood basalts A caldera filled with rhyolitic lava flows A field of large stratovolcanoes |
An extensive, thick accumulation of successive eruptions of flood basalts |
|
What volcanic events formed Crater Lake, Oregon? When did it take place? A powerful explosion blew away the top of a stratovolcano; 10 million years ago The crater of a large, extinct cinder cone filled with water; 5 million years ago Landslides and volcanic mudflows dammed the Mazama River; 500 years ago Caldera collapse followed major ash and pyroclastic-flow eruptions; 6000 years ago |
Caldera collapse followed major ash and pyroclastic-flow eruptions; 6000 years ago |
|
The average composition of rocks comprising a large composite cone or stratovolcano is similar to a (an) _____________ magma Basaltic Ultramafic Andesitic Rhyolitic |
Andesitic |
|
Massive, gently sloping volcanoes built of successive, basaltic lava flows are called _____________. Examples are found on the Hawaiian Islands. |
Shield volcanoes |
|
Volcanic bombs originate… As erupted magma blobs that partly congeal before falling to the ground As laser-guided, granite blocks launched from a supersonic jet As blocks of volcanic rock broken off from an erupting volcanic crater As ash particles that join together in the eruptive plume and fall as cobble-sized objects |
As erupted magma blobs that partly congeal before falling to the ground |
|
Which of the following factors tend to increase the explosive potential of a magma body beneath a volcano? High viscosity and high dissolved gas content High viscosity and low dissolved gas content Low silica content and low viscosity Low viscosity and low dissolved gas content |
High viscosity and high dissolved gas content |
|
A _____________ is an intrusive, igneous body that is tabular and concordant (parallel) with adjacent rock layers. Laccolith Dike Pluton Sill |
Sill |
|
Ash and lapilli are different sized pyroclastic particles. False |
True |
|
Small basaltic cones built from ejected lava fragments during one, short, eruptive episode are called __________. Composite/stratovolcanoes Cinder cones Volcanic domes |
Cinder cones |
|
Which one of the following statements is not true? Melting temperatures of silicate rocks increase with increased pressure Melting temperatures of silicate rocks are lowered by small amounts of water Basaltic magmas in general have higher temperatures than rhyolitic magmas When magma reaches the surface, its dissolved gas content cannot escape |
When magma reaches the surface, its dissolved gas content cannot escape |
|
Why would a plume of solid silicate rock rising slowly from deep in the mantle begin melting as it neared the base of the lithosphere? The rock heats up and contracts at lower pressures, causing it to liquefy The lowered pressures cause rapid heat loss accompanied by melting Volcanoes at the surface heat up the ascending plume as it approaches the magma chamber Temperatures remain high as lowered pressures decrease melting temperatures |
Temperatures remain high as lowered pressures decrease melting temperatures |
|
Vents that emit only heated, volcanic gases and water are called fumaroles. False |
True |
Share This
Flashcard
