Igneous Rocks - Test 1

Which of the following is the term used for molten rock inside the Earth?

magma

What is the term used for igneous rocks in which the crystals are too small to be seen by the unaided eye?

aphanitic

igneous rocks with large crystals surrounded by smaller crystals are said to have a __ texture

porphyritic

Which of the following is a type of volcanic glass which is full of gas bubbles?

vesicular

which of the following is NOT a type of igneous rock?

marble

What term is used to refer to igneous activity which occurs at the Earth’s surface?

A & D (extrusive and volcanic)

Which of the following rocks would have the highest silica content?

gabbro

Which of the following types of igneous rocks would have the lowest silica content with very high concentrations of iron and magnesium?

ultra-mafic

Which of the following is an example of an extrusive igneous rock?

rhyolite

Which of the following types of igneous rocks most commonly forms the floor of the oceans?

basalt

Which of the following locations would be the most likely place for a rock with a phaneritic texture to form?

deep inside the crust

what type of texture MUST granite have?

phanaritic

Which of the following is the aphanitic equivalent of granite?

rhyolite

What term is applied to igneous rocks with many gas bubbles in them?

Vesicular

Which type of igneous rock make up the majority of the continental crust?

granite

Why are lava flows typically finer grained than intrusive igneous rocks?

The extrusive magma cools quickly so the mineral grains do not have time to grow

A __ is an open cavity in a volcanic rock that was filled by a gas bubble when the lava was still mainly liquid

vesicle

According to Bowen’s Reaction Series, which mineral would you expect to see as a phenocryst in a porphyritic basalt?

olivine

what is the last mineral to crystallize as a body of magma cools?

quartz

__ has the same mineral composition as andesite but different texture

diorite