Geology Exam 2 Flashcards
Flood basalt eruptions are fed by..?
long fissures/dikes
how was the crater at crater lake formed?
collapse of overlying rocks into an emptied magma chamber
when melting forms magma…
partial melting produces a magma that is more felsic than the source
Which of the following is Not a rock typically found with calderas?
- welded rhyolite
- tuff
- granite
- gabbro
gabbro!
how do volcanic neck forms
- erosion of the volcano, leaving behind the solidifed conduit inside the volcano
- erosion of overlying rock layers exposing the conduit below the volcano
This is the solid upper part of the Earth, including the crust and uppermost mantle
lithosphere
what class of mineral forms when the element O is bonded with a metal, as in the mineral hematite?
oixdes
what are the two main ways that minerals are put together in rocks?
crystalline verus clastic
magnetite and hematite occur together in layered sedimentary rocks called?
banded iron formations
what type of mineral is garney?
silicate mineral
what class of mineral form when the element Si is bonded with element O, as in the mineral quartz?
silicates
what is composed of the smallest sedimentary clasts?
shale
which of the following is a common characteristic of carbonate rocks?
they commonly have a dissolved apperance
because shales are easily eroded, the areas where they are exposed typically
have soft slopes and soil cover
how does an angular unconformity form?
older rocks are tilted, eroded, and overlain by younger rocks
what lived during the Mesozoic era?
dinosaurs
oldest rocks found are from the
precambrian era
what is punctuated equilibrium
a hypothesis that explains how new organisms or new characteristics can appear suddenly in the fossil record
James Hutton came up with..
the concept that geologic processes operating at present are the same processes that operated in the past
oceanic plateaus form from basaltic volcanism originating from
hot spots
the majority of transform boundaries are found
in conjunction with mid-ocean ridges
what is the ultimate source of food for animals living around deep-sea hydro thermal vents
bacteria that break down hydrogen sulfide
most oceanic plateaus are..
constructed by volcanic eruptions probably over mantle pumes
forms in low-temperature environments, at or near Earth’s surface
Clastic
forms in high-temperature environments; minerals are interlocking
crystalline
A rock that is unusually rich in some commodity that might be valuable
mineral deposit
contains enough of a commodity to be mined at a profit
ore deposit
contains (CO3)^2
carbonates
calcite and dolomite
carbonates
contains oxygen bonded with metals
oxides
contains (S)^2 bonded with Fe, Pb, Zn, or Cu
sulfides
pyrite and galena
sulfides
contains (S04)^2 plus an element like Ca
sulfates
gypsum
sulfates
contains a metallic element, such as Na or K
Halides
is the percentage or concentration of the valuable commodity in a rock
the grade
CaSO42H2O, can be scratched with fingernail; typically gray, white, or clear
gypsum
PbS; distinctive metallic-gray cubes with cubic cleavage; high specfic gravity
Galena
FeS; pale bronze to brass-yellow; commonlu forms cube-shaped crystals
Pyrite
what is detritus
is loosened and transported clastic material
detrital
describes deposits of detritus
this occurs when rocks are heated locally and have little associated deformation
contact metamorphism
involves heating and deformation over large areas
regional metamorphism
granite and rhyolite are
felsic
diorite and andesite
intermediate
basalt and gabbro
mafic
peridotite
ultramafic
rock made mostly of calcium carbonate; may contain fossil shells and coral skeletons
limestone
very soft rock of calcium carbonate created by remainns of mirco organisms
chalk
mostly forms when seawater evaporates in tidal flats and narrow seas; the material in sheetrock
gypsum
conglomerate
rounded pebbles and sand and finer particles between larger clasts
Breccia
angular pebbles and coobles and finer particles between larger clasts
