Geology Lab Practical

what three geological observations did darwin make in his travels?

- formation of volcanos - rising of the andes by earthquakes -fossil relatives of modern species

what does the term metamorphic grade refer to?

-age of a metamorphic rock -the degree to which a metamorphic rock's protholith has changed - whether a metamorphic rock has an igneous or sedimentary protholith

the presence of water_______

-lowers the melting temp during flux melting -helps the magma rise towards the surface -causes explosive volcanic eruptions

3 observable properties of a mineral

-luster -hardness -odor

what must be true in order for an ore mineral occurrence to be economically valuable?

-natural processes must have concentrated the desired element to greater degree than its avg crustal abundance -there must be enough of the ore mineral to make extraction profitable -the sale price of the element must be greater than the costs of mining and extraction

3 characteristics of a mineral

-naturally occurring -solid -chemical composition

at which location is volcanic activity abundant?

-oceanic ridges - subduction zones

where does most of the earth's volcanic and earthquake activity occur?

at the edges of the lithosphere plates and at hotspots

intrusion of granite into layers of sedimentary rock would cause

contact metamorphism

in the plate tectonic model, where is large scale compressional stress found?

convergent plate boundaries

mohs hardness scale describes the relative hardness of a mineral not absolute hardness, this means that:

diamond will scratch talc but talc cant scratch a diamond

the latitude of a location is based on the

equator

metamorphic rocks can be made from what parent rocks?

igneous sedimentary metamorphic

what does earth's magnetic field generate?

lines of force that parallel the earth's surface at the equator

where does new lithosphere form? and where is it consumed?

midocean ridges; subduction zones

what is true of a clastic sedimentary rock?

minerals crystallize from molten materials

direction of 315 degrees in the azimuth system corresponds to ...

northwest

well rounded grains in a clastic sedimentary rock indicate?

numerous collisions between particles during extensive transportation

in an anticline, the ______ rocks are exposed in the center of the fold, and bed typically dip ______ from one another

oldest; toward

the longitude of a location is based on the

prime meridian

grain size of an igneous rock is determined by

rate of cooling

collision of two continental plates would cause

regional metamorphism

what changes take places during physical weathering?

rocks are broken into smaller pieces

difference between sill and dikes

sills are parallel to layering in surrounding rocks while dikes cut across them

the texture of a rock includes the ________________ of its constituent grains

size, shape, and orientation

Earth's surface was primarily formed from _____________ events

slow occurring

igneous rocks form by:

solidification of magma at the surface or within the earth

where are intermediate igneous rocks most commonly found?

subduction zones

the presence of footprints in a sedimentary rock is compatible with origin in all of the following environments except:

the floor of the atlantic ocean

foliation and lineation are terms that describe:

the orientation of mineral in metamorphic rocks

where is large scale tensional stress found?

transform faults

cross bedding and ripple marks are the result of ______ during depostion

water or wind currents

in a syncline, the ______ rocks are exposed in the center of the fold, and bed typically dip ____ from one another

youngest; away from