Quiz 2 Flashcards
Minerals and rocks that are rich in silica and aluminum and are light colored are
Felsic
Decompression or lowering of pressure, will help rocks
melt
The rate that temperature increases with depth downward into the earth is the
geothermal gradient
According to Bowen’s reaction series, the first silicates mineral to crystalize out of a magma will be Ca-rich plagioclase feldspar and…
olivine
Which of the following minerals (or mineral groups) is not part of the discontinuous series of the Bowen’s reaction series?
gypsum
Polymorphs are different minerals with the same
Chemical Formula
Which is not true of a single silicon-oxygen tetrahedron?
It has 4 silicon atoms
The chain silicate mineral groups are pyroxenes and the
amphiboles
Rocks are more likely to melt
when water is present
An igneous structure that cuts across the bedding in older rocks (is discorant) is called a
dike
An igneous rock made of giant crystals ( up to 10 meters) is called
pegmatite
A felsic extrusive rock would be called
rhyolite
A Phaniritic texture is
entire rock is made of crystals large enough to see with the naked eye “salt and pepper” texture Plutonic or intrusive
An Aphanetic texture is
at least some microscopic crystals, extrusive or volcanic (glassy)
A Porhyritic texture is
2 different sizes of crystals in the same rock
A plutonic rock with an intermediate composition is called
diorite
An igneous rock with pores from expanding gas is
vesicular
Sharp angular lava is called
aa
Sheild volcanoes
are mafic in composition
The most dangerous volcanoes are
composite cones
The type of volcano made entirely of pyroclastic material is
cinder cone
The city of Armero Colombia was destroyed in 1985 by
volcanic mudflows
A lava that erupts underwater would have
pillow structures
A mudflow created by a volcano is called a
lahar
The volcanic gas that illed over 2000 people near Lake Nyos in Africa in 1986 was
carbon dioxide
A nuee ardante is
a glowing cloud of hot gas and ash
Tuff is a rock made from
volcanic ash
The nation that contains extensive flood basalts that formed 65 million years ago is
India
