geol 102 final

rock

solid mass of geological minerals

geological minerals include?

mineral crystals, inorganic mineral solids, fossils

what are the three rock types?

igneous, sedimentary, metamorphic

what rock forming process form igneous rocks?

cooling of the rock

what rock forming processes form sedimentary rocks?

uplift by weathering, erosion, transported, deposited as sediments. sediments compresses and cements into sed. rock

what rock forming process form metamorphic rocks?

high amounts of heat and pressure

which plate boundaries would you find igneous rocks

convergent plate boundary

which plate boundaries would you find felsic rocks

continental crust/hot spots (Yellowstone)

which plate boundaries would you find mafic rocks?

mid ocean ridges,, ocean hotspots (Hawaii)

which plate boundaries would find intermediate rocks?

subduction zones (Mt St Helens)

igneous rock

a type of rock that forms from the cooling of molten rock at or below the surface

what are the two main kinds of igneous rock

intrusive and extrusive

what minerals would you see in a granite

quartz, k-feldspar, biotite, plagioclase feldspar, amphibole

what minerals would you see in a basalt?

plagioclase feldspar, pyroxene

phaneritic texture

Igneous rocks with large, visible crystals because the rock formed slowly in an underground magma chamber.

aphanitic texture

A texture of igneous rocks in which the crystals are too small for individual minerals to be distinguished without the aid of a microscope.

porphyritic texture

An igneous rock texture in which large crystals are scattered on a background of much smaller crystals.

assuming constant pressure, how do changes in pressure or water content influence the melting temperature of the rock?

as water content increases, the melting point decreases

sill

concordant (parallel to) existing layering

dike

discordant

lacolith

sill like body that has expanded upward by deforming the overlying rock

weathering

The breaking down of rocks and other materials on the Earth's surface.

what are the main types of weathering

chemical and mechanical weathering

What are four factors that affect rock weathering rates

physical, chemical, biological

What are the four types of sedimentary rock

clastic, chemical, biochemical, organic

What are the steps in forming a sedimentary rock?

uplift by weathering, erosion, transported, deposited as sediments. sediments compress and cement into sed rock

Describe the relationship between plate tectonics and sedimentary basins

there is a wide range of depositional environments, both on land and in the ocean. In order to be preserved, sediments must accumulate in sedimentary basins, many of which form through plate tectonic processes.

conglomerate formation environment

rivers

conglomerate particle size

coarse

conglomerate mineral composition

quartz, silica, calcium carbonate

Sandstone Formation Environment

beaches, coastal dunes

sandstone particle size

medium

sandstone mineral composition

quartz

shale particle size

fine

shale mineral composition

clay

shale formation environment

lakes, rivers

What are the principle agents of metamorphism in rocks

heat and presure

similarity between marble and limestone

Limestone is a type of rock that exists everywhere in the world. Marble, on the other hand, is a type of rock that is formed by the recrystallization of limestone during the mountain-building process.

Describe how fluids are involved in metamorphism

water is important for two main reasons

- facilitates the transfer of ions between and within minerals increasing the rates at which metamorphic reactions take place

-for moving ions from one place to another

What are the two fluids that are most important in

metamorphism?

water and hot water

What is the temperature range over which metamorphism normally occurs?

250-800

Why doesn't metamorphism generally occur at even higher temperatures?

when a rock is subjected to increased temperatures, certain minerals may become unstable and start to recrystallize into new minerals

Describe how heat and pressure are important in metamorphism

cause the rocks to be bent, folded, crushed, flattened, and sheared

What changes can occur in minerals due to metamorphism?

new minerals grow, with different sizes, shapes, and orientations than those of the original minerals

What common minerals found in metamorphic rocks are not useful as index minerals?

quartz, calcite

schist likely parent rock and grade/type of metamorphism

rock enriched in ferromagnesium minerals such as basalt, low grade regional

slate likely parent rock and grade/type of metamorphism

shale, mudstone, low grade regional

marble likely parent rock and grade/type of metamorphism

limestone or dolomite, regional or contact

amphilobite likely parent rock and grade/type of metamorphism

rock enriched in ferromagnesium minerals such as basalt

where would you find basaltic lava

mid ocean ridges (hawaii)

where would you find andesitic lava

composite cone, stratavolcano

where would you find felsic lava

volcanic domes, pyroclastic flows

which kind of lava is associated with explosive reactions

rhyolite/andesite

basaltic flow

low viscocity (very runny) and long distances

andesitic flow

too viscous too flow far, tends to break up, stratavolcano type

felsic flow

so viscous that it may pile up in a dome shaped mass

caldera cone

give or take 50km in length

cinder cone

smallest out of the cone volcanoes around 0.5km

composite cone

around 6km

what are glaciers made of

compressed, recrystallized snow

what is a glacier

Large, long-lasting river of ice that forms on land, undergoes internal deformation, and creates glacial landforms

glaciers often carry

large sediment beds

where do glaciers form

high elevation, high latitudes (near the poles of the earth)

glacier range in size

large:

glacier range in age

large:

zone of accumulation

The part of a glacial system where snow and ice are accumulating faster than they are melting away.

equilibrium line

the place on a glacier where snow accumulation and melting are in balance, loses mass

crevasses

deep cracks in a glacier or in the earth's surface

zone of wastage

where glacier is melting away and deposited

zone of fracture

the upper portion of a glacier consisting of brittle ice

how do glaciers move?

undergo internal deformation, and create glacial landforms

brittle vs ductile deformation

Brittle:

-Breaks easily

-lower temp

-faster strain

Ductile:

-molded into new shape

-higher temp

-pull apart till thin

basal sliding (ways how ice flows)

The sliding of a glacier over bedrock.

internal flow (ways how ice flows)

Ice crystals deformed by slow displacement; axes become aligned parallel with flow direction like metamorphic rocks

or clastically over the glacier

ice flows from....

high to low ice surfaces

mass balance

relative rate of accumulation and wastage.

what are the two principle types of glaciers

Alpine

Ice Sheet (Continental) cover larger areas, not confined to high elevations. e.g, greenland, antarctica

Alpine glaciers consist of (subtypes)

cirque, valley, and piedmont, temperate, polar, subpolar, icecaps, outlet, ice shelf

temperate glaciers

glaciers that are near their melting point, have meltwater coming off them year round

sublimation

(ice or any solid turns into gaseous water without melting in between)

polar glaciers

temperature is below freezing year round

subpolar glaciers

between polar and temperature climate conditions

experiences seasonal melting and water runoff

ex. Alaska, Canadian Rockies, anywhere it is seasonal.

outlet glaciers

extend outward from continental glaciers or icecaps

ice shelf

where a glacier extends out over water

icecaps

small ice sheets, form at high elevation

erosion for glaciers

v shaped turns into u shaped valley