Exam 14: Mass Wasting: the Work of Gravity

_________are dissolved in melts at depth but they have a tendency to evolve and vaporize at lower (atmospheric) pressure and drive volcanic processes.

Which of the following is the dominant feldspar in basalt?

Mafic rocks like basalt and gabbro________ .

Which of the following igneous rocks usually exhibit aphanitic texture?

Plutonic rocks are emplaced at depth yet they can be seen at the Earth's surface due mainly to__________

The aphanitic equivalent of diorite is

A(n) ______texture would be most unlikely to occur in an extrusive igneous rock.

Tabular sills and lava flows often have regular geometric grids of vertically oriented, thermal shrinkage cracks called_______ .

What are vesicles?

What phenocryst minerals would you expect to find in a porphyritic andesite?

What do pumice and obsidian have in common?

The mechanism of selectively removing the minerals which melt at the lowest temperature is_____

When magma cools and consolidates without growth of mineral grains, it is

What is the rock colour (total % of dark minerals) of a typical gabbro or basalt?

What would you call an aphanitic, vesicular, black rock having small pale green phenocrysts of olivine and small white lath shaped phenocrysts of plagioclase?

Which igneous rock or magma has the lowest silica (SiO2) content?

When a rock has a two- stage cooling history (slow then fast) or has minerals that crystallized at different temperatures and grew at different rates it is___________ .

Which of the following igneous rocks exhibit phaneritic texture?

Exceptionally coarse grained felsic plutonic rocks that are rich in rare minerals and trace elements are probably___________ .

A _________is the largest, discordant body of intrusive, igneous rock.