Geo-111 Chapter 5 Quiz

Put the following minerals in the correct order that they will crystallize from a magma: potassium feldspar pyroxene olivine amphibole biotite

1. Olivine 2. Pyroxene 3. Amphibole 4. Biotite 5. Potassium Feldspar

The site on the figure below that would mostly likely form a rock that is coarse-grained is:

A. A

The main difference between granite and rhyolite is [a], whereas the main difference between granite and gabbro is [b].

A. a: crystal size, b: mineral composition

Match each igneous rock with its correct texture: a. coarsely crystalline b. finely crystalline c. vesicular d. glassy

A. coarsely crystalline -- 1. peridotite B. finely crystalline -- 3. andesite C. vesicular -- 4. scoria D. glassy --2. obsidian

Match each igneous rock with its correct composition: a. felsic b. intermediate c. ultramafic d. mafic

A. felsic -- 2. rhyolite B. intermediate -- 4. diorite C. ultramafic -- 3. peridotite D. mafic -- 1. gabbro

What is the most likely composition of igneous rocks formed at Site D (continental volcanic arc)?

A. felsic to intermediate

Referring to the graph below, which of the following changes in conditions would cause melting of a solid rock?

A. from A to B

The change in temperature that occurs with depth in the Earth is called the ______________________.

A. geothermal gradient

Increasing the pressure on rocks tends to ___________ the melting temperature of minerals.

A. increase

The presence of many mineral crystals will tend to ____________ the viscosity of a magma.

A. increase

Small holes formed in igneous rocks when gases escaped are called _________________.

B. Vesicles

__________________ brings hot rocks upward through the asthenosphere beneath mid-ocean ridges.

B. convection

Having a more felsic composition will tend to ____________ the viscosity of a magma.

B. decrease

Increasing the temperature will tend to ____________ the viscosity of a magma.

B. decrease

Water tends to _____________ the melting temperature of minerals.

B. decrease

What is the most likely composition of igneous rocks formed at Site E (volcanic island arc)?

B. intermediate

When melting forms magma

B. partial melting produces a magma that is more felsic than the source

[a] is magma that flows on the Earth's surface. If the magma solidifies at the surface, the igneous rock that forms is generally referred to as [b]. The general term for a magma that solidifies at depth (below the Earth's surface) is [c].

C. a: Lava, b: extrusive, c: intrusive

A very large pluton that covers more than 100 km2 is called a _________________.

C. batholith

What generally happens when subduction-derived magma encounters thick continental crust?

C. the magma interacts with the crust, forming felsic or intermediate compositions

The larger crystals in a porphyritic igneous rock that are surrounded by a finer grained matrix are called ____________.

D. Phenocrysts

The layering of sediments, pillow basalts, sheeted dikes, and gabbro in the oceanic crust is collectively termed an ________________ complex.

D. ophiolite

__________________ occurs when heavy minerals form in a magma and sink to the bottom of the magma chamber.

E. crystal settling

A horizontal intrusion of magma between existing layers of rock is called a _____________.

E. sill

Match each site on the map with the correct plate tectonic setting in the Quiz Me question below: a. ocean-continent convergent b. hot spot in a continent c. oceanic divergent d. ocean-ocean convergent e. hot spot in an ocean

a. ocean-continent convergent -- b. hot spot in a continent -- c. oceanic divergent -- d. ocean-ocean convergent -- e. hot spot in an ocean --