Geology 1000 Final Exam Review

glacier

stream or sheet of recrystallized ice, flow under the influence of gravity

glacier formation

• winter snow does not completely melt

• snow accumulates on gentle slopes protected from wind

alpine glacier

present in and adjacent to mountainous regions

cirque glacier

fills in bowl-shaped depressions on mountain flanks

valley glacier

flows down valleys

ice caps

cover peaks and ridges

piedmont glaciers

valley glacier emerges from a valley and speads out as lobe/fan on plains

high, low

alpine glaciers move from ____ to ____ elevation

antarctica, greenland

where are continental glaciers found?

outward, from

continental glaciers more ____ from ____ point

zone of accumulation

glaciers grow with snowfall accumulation

zone of ablation

glaciers decrease in size due to melting and calving

glacial advance

accumulation rate exceeds ablation rate

glacial retreat

ablation rate exceeds accumulation

sea ice, glaciers

icebergs originate from ____ or ____

tidewater glacier

continental glacier whose toe is in water

glacial plucking

glacier breaks off fragments of bedrock

glacial abrasion

debris in ice grind away at substrate

roche moutonnée

common erosional feature formed by continental glaciers where asymentrical hills become elongated in direction of flow

cirque

bowl-shaped depression formed due to rockfall

tarns

lakes formed by melted cirques

arete

knife-edge ridge of rock that separated 2 adjacent cirques

horn

mountain peaks surrounded by at least 3 cirques

U-shaped valleys

rivers that erode the channel only, forms ____

fjord

deep U-shaped valley that has been eroded with water

rock flour

finely ground, silt-sized rock fragments

loess

fine, wind-blown sediment

till

unsorted, unstratified sediment left behind by glaciers

depositional landforms

landforms generated from sediment deposited by glaciers

moraines

ridges of till deposited along sides of terminus of a glacier

lateral moraine

sediment dropped on side margins of a glacier

medial moraine

lateral moraines along the sides of 2 merging glaciers join up

terminal moraine

“end” moraine at the furthest limit of glaciation

recessional moraine

sediment deposited at terminus during glacial retreat

kettles

small, nearly circular depressions adjacent to former ice margins

ice age

period of time, in which Earth’s temp cools, promoting extension of continental and alpine glaciers

interglacials

intervals of time between ice ages

pleistocene epoch

glaciations lasted up to 100,000 years, occurred multiple times and separated by ling interglacials

Milankovitch theory

minor changes in Earth’s rotation and orbit can alter amount of solar radiation received at any given latitude can therefore bring about climate change

orbital eccentricity

shape of Earth’s orbital path from elliptical to more circular

axial tilt

inclination of Earth’s axis(23.4º)

plate tectonics

____ are responsible for long-term changes in climate

Milankovitch theory

____ is responsible for intermediate-term changes in climate

variations in solar energy and volcanic activity

____ are responsible for short-term changes in climate

decreased, increased

during glacial periods GHG concentrations ____, during interglacial periods GHG concentrations ____

greenhouse effect

the ability of certain atmospheric gases to trap heat and warm the planet

feedback mechanisms

processes in Earth’s system that respond to a disruption in heat balance, and then act to increase of decrease energy imbalance

albedo

fraction of solar radiation reflected off an object

• example of positive feedback

high albedo

objects light in color reflect more light

low albedo

objects dark in color absorb more radiation

insolation

exposure to sun’s rays

super glacial

period of warming much longer than predicted my Milankovitch cycle

last glacial maximum

the pleistocene ice age peaked ~20,000 years ago

megafauna examples

mammoths, mastodons, giant sloths, saber toothed cats, brown bears wolves, caribou

mammoths

grasslands, grazed on grasses, eliphantidae family

mastodons

woodlands, ate twigs, branches, and leaves

lagerstatten

“storage place”, massive deposit of exceptionally preserved fossils, possibly even containing soft tissues

causes of extinction

• global climate change

• asteroid/comet impact

• volcanic eruption

• new predator/ competitor

paleoclimatology

study of climates that existed during Earth’s previous geologic ages

proxies

paleoclimatology are studied using ____

proxy

preserved environmental feature that can be correlated to direct measures of climatic history

tree rings

Ring thickness is related to yearly temp and precipitation conditions, useful in studying up to 14,000

corals

annual growth bands record temp and salinity conditions, useful in studying up to 500 million years ago

speleothems

geological structure found in caves, formed by accumulation of CaCO₃ minerals from groundwater over time

proxy types

tree rings, corals, speleothems, sediments

dendrochronology

the study of annual tree ring growth

solar heating

sunlight striking an object transforms into thermal energy

heat balance

amount of heat energy that planet radiates back to space is equal to amount received by sun

climate forcing

process that disrupts Earth’s heat balance

climate feedbacks

processes that respond to a disruption in a planet’s heat balance

negative feedback

reduce/dampens a system’s response to a change in heat balance

positive feedback

increases/amplifies a system’s response to an initial change

renewable resource

supply of energy will not be depleted to our use

non-renewable resource

current rates of consumption will use up Earth’s accessible store of an energy source in a matter of decades to centuries

fossil fuels

energy sources formed from the remains of once-living organisms, non-renewable

coal

first fossil fuel used on a larger scale, combustible, brittle, sedimentary rock made of carbon, organic chemicals, quartz, sulfide minerals, and clay

coal formation

1. plant matter in a swamp dies and is buried (anoxic environment with stagnant water)

2. compaction and partial decay produces “peat” (up to 50% C)

3. concentration >50% C is considered “coal”

lignite

soft, brown coal, 50% C

bituminous

dull, black coal, 70% C

anthracite

shiny, black coal, 90%C

terrestrial sed rocks

where is coal found?

underground mining

tunnels/shafts dug underground to access deep coal seams

strip mining

heavy machinery scrapes off sed layers covering coal seam

mountain-top removal

blasting off tops of mountain/hills to uncover buried coal

environmental impacts of coal

• coal has metallic sulfide minerals

• acid rain, mercury fallout, GHG emissions

High energy density

large amount of energy per unit volume

high

oil and natural gas(petroleum) have ____ energy density

low

coal has a ____ energy density

viscocity

resistance to flow

volatility

ability to evaporate

hydrocarbon

chain/ring-like molecules of H and C

long hydrocarbon chains

solid

long hydrocarbon chains example

tar

moderate hydrocarbon chains

liquid

moderate hydrocarbon chains example

crude oil

short hydrocarbon chains

gas

short hydrocarbon chains example

natural gas

natural gas

mixture of lighter hydrocarbon molecules

crude oil

mixture of heavier hydrocarbons molecules that exist in the liquid state

heavy crude

higher proportion of long chain hydrocarbon molecules that are denser and more viscous