midterm 1

what is the primary difference between a breccia and a conglomerate?

angularity, breccias are angular and conglomerates are round

which calcium magnesium carbonate mineral is rarely if ever observed in modern depositional environments?

dolomite

what is the primary difference between chert and flint

no difference, these are two names for the same rock

alfred wegener’s evidence for the theory of continental drift was derived from

fossil assemblages

glacial deposits

geologic structures

rock types and ages

true or false: evidence from seismic tomography favors whole mantle connection instead of stratified mantle convection

true

approximately how long ago did the supercontinent pangea exist?

200 million years ago

what is the typical geochemical gradient in a stable continental interior?

30 c/km

match the mineral to the correct group

apatite - phosphate

halite - halide

calcite - carbonate

pyrite - sulfide

ice - oxide

select all of the following characteristics that define a mineral

naturally occurring

solids crystalline

usually inorganic

specified chemical composition

true or false: minerals in phaneritic rocks are visible to the naked eye without the need for a microscope

true

what is the approximate temperature and magnitude at which rocks begin to melt

1000 C

this figure illustrates magnetic anomalies along the axis of the mid atlantic ridge. why are the magnetic anomalies symmetric?

the spreading velocity is equal on both sides of the ridge

rank these sedimentary rocks by the transport energy of their depositions environment: siltstone, conglomerate, sandstone, shale

lowest energy - shale

low energy - siltstone

high energy - sandstone

highest energy - conglomerate

in which of the following places are you most likely to find pillow basalts?

mid ocean ridge volcano

grain sorting in a sediment can be understood as what statistical property of a sediment’s particle size or grain size

variance or standard deviation

match the plate boundary type to the appropriate descriptor

transform - conservative

convergent (continent continent collision) - destructive

convergent (ocean ocean subduction) - destructive

divergent - constructive

true or false: metasomatism is a type of metamorphism where rock chemistry changes primarily due to fluid alteration

true

the delicate tetrahedron building block of silicate minerals has a chemical formula SiO4. if the mineral quartz is composed entirely of silica tetrahedra, why is the chemical formula does quartz SiO2

all oxygen atoms are covalently bonded between silicate tetrahedra

why is there no active volcanism in the himalayas today?

subduction of the indian plate is too shallow

according to Bowen’s reaction series which mineral is the first to crystallize from a melt

olivine

according to Bowen’s reaction series which mineral is the last to crystallize from a melt

quartz

which of the following atomic properties are the most important for element substitution in a mineral lattice

atomic radius and atomic charge

true or false: a granulated rock texture forms in metamorphic rocks subject to high differential stresses

false

what kind of volcanic eruption produced rope like low viscosity pahoehoe lava

hawaiian

which of the following processes are part of sedimentary lithification

compaction, cementation, recrystallization

what is the most abundant group of minerals in the crust and mantle

silicates

true or false: deposition refers to the processes that dislodge particles or rock produced by weathering

true

which type of metamorphism is defined by high temperature and low pressure conditions

contact metamorphism

which is the name for the preexisting rock into which magma is intruded

country rock

the primary difference between a stock and a batholith is

area extent, batholiths are greater than 100 km²

lithospheric plates move at a velocity approximately equivalent to

fingernail growth

how is magma produced at a subduction zone

water reduces the melting temperature along the subduction interface

which physical properties are used to identify minerals

streak

density

luster

hardness

cleavage

true or false: the earths crust includes the entire lithosphere and part of the upper mantle

false

scientists most famous for mapping bathymetry and identifying mid atlantic rift valleys

marie tharp

gold miners in northern california used hydraulic mining to concentrate gold from which type of ore deposit in the sierra nevada mountains

placer deposits