Final Exam

berm

"bench" in elevation on beach (mound)

cirque

"bowl" carved by the base of a glacier through erosion

surging wave

"kind of like a slump"; occur on the steepest beaches, with smooth wave faces

Primary Coasts/Type 1 Coasts

"non-marine formed shorelines" such as glaciation, stream deposition from deltas, fluctuating sea levels, active volcanism, or organic coasts (reefs, mangroves) "primary fingerprint is NOT oceanic wave action"

roche moutonnee

"rock mountain" formed by glacial erosion; the glacier passing over bedrock causes an asymmetrical form as a result of abrasion on the sloss side and plucking on the lee side; it is smooth in the direction of ice movement

translatory motion

"up and over" towards shore; re-suspends sediment

distribution of heat to the ground due to slope and direction of slope towards sun

(think of the lab where we figured out the glaciers were retreating one way due to the ridge and the path of the sun throughout the day) wet N-facing slope: active layer, colder, permafrost present, freeze/thaw important dry S-facing slope: permafrost missing, freeze/thaw not as important, warmer -----> different ecologies and geomorophologies

filling of tidal inlets

1. streams bring sediment to coast 2. coastal bay becomes filled with sediment as outlet becomes blocked by bar 3. tidal inlets completely filled in, coast straightens, streams diverted elsewhere

migration of barrier islands

1. tidal currents enter inlet 2. inflowing tidal currents deposit sediment in lagoon, sediment builds up behind barrier island; high energy in front of barrier island, low energy behind barrier island 3. barrier island migrates landward and shoreline retreats, so lagoon is same size as before (inlets naturally heal up, years later it will naturally be destroyed again)

Glacial Budgets

A valley glacier could appear at the end of a melt season. Below the snow line, glacier ice and snow have been lost during the melting season. In the zone of accumulation above that line, firn is added to the glacier from the previous winter fall.

Why are there sandy beaches on the east coast and rocky beaches on the west coast?

Active tectonics on the west coast (erosional features) Passive tectonics on the east coast (depositional features)

frost sorting theory 1: Frost Pull

Ground freezes from the top down --> the top of a large pebble is gripped by ice and rises upwards --> lateral pressure causes sediment to slump into the cavity where the pebble used to be --> pebble cannot return downward (this happens multiple times until it is brought to the surface)

Ingredients for making glaciers

Land Snow ***COLD SUMMERS*** Gravity Time

Secondary Coasts/Type 2 Coasts

MARINE PROCESSES ongoing marine erosion and deposition; marine processes are stable for long enough that marine fingerprint overcomes type 1 (non-marine) fingerprint

Relate black/green sand beaches and bowen's reaction series

Mafic minerals compose black and green sand beaches. They are rare because there must be a fairly active volcano near since mafic minerals have low resistance to weathering so continuous deposition of these minerals is needed to maintain black/green sand beaches.

thaw lakes

NOT KETTLES!!! product of thermokarst (polygonal patterns is clue that it is thermokarst and not kettles)

mima mounds

NOT a periglacial landform...just looks like it (look like palsas)

tombolo

When the mainland is attached to an island by a narrow piece of land such as a bar or a spit ("depositional bar behind sea stack because sea stack is being eroded")

icebergs

a block of ice that came from a glacier and is floating in water

collapsing wave

a combination of plunging and surging waves

rock-basin lakes (tarns)

a lake occupying a depression caused by glacial erosion of bedrock

Rayburn's definition of glacier

a large, long-lasting mass of ice, formed on land that moves under the influence of gravity and its own weight

jettys

a pier constructed to keep inlets clear

rock flour (glacial erosion)

a powder of fine fragments produced by the grinding of rock across rock; polishes rock surface; essentially silt and clay sized grains jumbled up

paternoster lakes

a series of circular lakes, formed by glacial erosion, that occur in formerly glaciated valleys

medial moraine

a single long ridge of till on a glacier, formed by adjacent lateral moraines joining and being carried down-glacier; "run right down the center"; tend to show 2+ glaciers next to each other that got together

hanging valley

a smaller valley that terminates abruptly high above a main valley; can make waterfalls

baymouth bar

a spit that covers access to a bay since the area behind it fills with sediment

kame terrace or kame moraine

a terrace made of sorted sediment deposited by meltwater streams that formed against a previous ice margin

riprap/seawall

a wall of stones that protects shorelines

glacial erosion under the glacier

abrasion and plucking, bedrock polished and striated, rock flour washes out of glacier, polishing and rounding, striations on rock

open system pingos

all about groundwater slower need enough pressure from groundwater flow to keep feeding the system "icy magma chamber from regular GW flow" discharge and recharge groundwater keeps feeding the central ice core

stream deltas

alluvial (river) processes; delta is riverbed building itself out to sea level

Ice is...

always moving forward and we're always shedding material off the front even it its advancing

erratic

an ice-transported boulder that came from somewhere else not nearby

periglacial landforms (what do you need?)

annual average temperatures below freezing, land, and non-glaciated

ogives

annual markers of ice flow (distance between them is annual movement of ice) "an alpine glacier thing" ogives begin at the knickpoint, each "U" represents one year of movement over the knickpoint darker pattern in these is due to higher concentration of dirt from melting at thinner ice (usually in warmer months) the center of the ice gets ahead of the edges

foreshore

area between high and low tide

mountain landscape features after glaciation

aretes horn cirque rock basin lakes (tarns) rock step hanging valley U-shaped valley

mountain landscape features during glaciation

aretes horn truncated spurs glacier triangular facets

glacier cross section

as you go deeper, density increases plastic deformation (permanently deforms glacier) behavior is different for ice sheets vs. alpine glaciers (alpine not as thick, density increases with little depth)

backshore

between high tide and where the storm can reach

kettle

big holes in outwash caused by the melting of a block of ice that was surrounded by sediment

plucking (glacial erosion)

bits of other rock in ice can erode underlying rock, which can be picked up by the ice due to the PMP; pressure on the boundary between the bedrock and ice can break off bedrock

ground moraine

blanket of till deposited during glacial retreat

drumlins

bodies of till shaped into smooth hills; direction of ice flow is in direction where the long axis "points" towards (ex: in this picture ice flow direction is -->)

block field/"felsenmeer"

boulder fields that are/have been actively moving on almost no slope whatsoever "a river of slow-moving boulders"

valley train

braided outwash that travels down a valley

human impacts on coastlines

break waters, groins, and jettys all cause deposition of sediment somewhere; development destroys vital shoreline vegetation; water and petroleum pumping cause problems

disruption of ice

can cause significant ground collapse --> loss of habitat

rock glaciers

can result from 2 processes: 1. (glacial) glacier nearly melts away --> leaves only rocks 2. (periglacial) permafrost area. mass wasting --> sorted pile of rocks --> freeze/thaw results in a pile of rocks on a slope

Tides

caused by gravitational forces of sun and moon

u-shaped valley

characteristic cross-profile of a valley carved by glacial erosion; "in equilibrium with geometry of ice"; glacier is more viscous and "domes up" and focuses energy across wider area to form these

headlands

cliffs that jut into the sea

frost sorting theory 2: Frost Push

cold penetrates into the ground --> large stones have ice formed around them faster than surrounding soil (due to stone having greater thermal conductivity) --> stone is forced upwards --> sediment slumps into cavity where stone was (this happens multiple times until it is brought to the surfacce)

flood tides

coming in (to shore)

biological processes- coral reefs

corals try to keep up with sea level since they need to be in an area where light can penetrate the water column

brittle deformation

cracking and moving

ice: hexagonal crystal system

crystal structure like a mineral, ice IS a mineral. have one long axis (c-axis) and multiple short axes (a-axes) much easier to deform along short axes (a-axes)

longshore current

current produced as water flows parallel to coastline

hook

curved spit created when there is a secondary wind

intragranular shifting (glacier movement)

deformation along crystal axial plane occurs if its freezed into ice; you need sufficient pressure for this

formation and growth of glaciers

diagenetic process; fluffy flakes pile up and have lots of air in them, they are not dense, but if you keep piling snow up then the snow will be altered from pressure to a more dense state

intergranular shifting (glacier movement)

differential movement between ice grains occurs if the grains aren't that "locked" or "fused", like firn (lower pressure situation)

lunate fracture or crescentic gouge

direction where gouge gets deeper is direction of ice flow

lateral moraine

elongate mounds of till which form along the sides of a valley glacier

fjords

elongated, deep and narrow sea amid steep land; a U-shaped undersea valley surrounded by mountains; longer than it is wide

Wave refraction with uneven shorelines?

erosion where it sticks out (headland), deposition in beaches (where it goes back; see pic in notes)

continental glaciation

exists where a large part of a continent is covered by glacial ice

closed system pingos

faster, rapid ground underneath is talik (thawed) lake drains somehow --> saturated unfrozen ground exposed to cold temps --> freezes and expands --> suddenly grows

glacial flow

fastest ice motion occurs at the surface near the center of the glacier (least amount of frictional drag)

Albany Pine Barrens (field trip, state glacial history)

fine sand; parabolic dunes; low pressure system has winds moving in counterclockwise fashion to create these; climate was dry, windy, and had little vegetation when the dunes were created; shallow lacustrine (lake) deposits (well-sorted sand); LAKE ALBANY WAS HERE!--> lake regressed--> only sand after drying out, no vegetation; this dune likely formed shortly after glacial Lake Albany retreated because that is when plants began to establish

spit

finger-looking ridge of sand deposited where longshore drift encounters deeper water

sea arch

forms when two sea caves erode completely through the headland

alpine glaciation

found in mountainous regions; VERY sensitive to climate change

glacial erosion above glacier

frost wedging, erosion by glaciers steepens slopes

stone circles

geometric patterns of sediment that are naturally occurring

faceted (glacial erosion)

given a flat surface by abrasion

glacial outwash

glacially eroded, sorted sediment that has been transported by meltwater typically, the sediment becomes finer grained with increasing distance from the glacier terminus (sand, silt, clay farther downstream and coarser grained sediment closer to the glacier) (subglacier=till, midglacier=gravel, further away=silt and clay) (the only way dropstones end up in silt and clay lake deposits are if it came from an iceberg)

formation of kettles

glacier retreats and leaves behind chunks of dead ice --> heat melts the glacier and outwash is carried down the glacier --> outwash flows over the dead ice and forms a new layer of ground --> the dead ice continues to melt until they're completely gone --> kettle formed (outwash is still there and makes up sides of kettle)

isostatic rebound

glaciers cause rebound by causing depressions --> glacier retreats --> land rebounds (trying to reach equilibrium); causes a "smear of raised beaches"

Where do glaciers develop?

glaciers develop where all of the annual snow doesn't melt away in the summer (polar regions, heavy winter snowfall, high elevations, 85% in Antarctica, 10% in Greenland)

eustatic sea level change due to glaciers (CLIMATE)

glaciers lower sea level slowly glaciers melt quickly and sea level rises

receding glaciers

glaciers with negative budgets that grow smaller and their edges melt back

advancing glaciers

glaciers with positive budgets that push outward and downward at their edges

ebb tides

going out (to ocean)

permafrost

ground frozen throughout the year

passive continental margins

have broad continental shelves and beaches with spit

snow line

height above sea level where glacier is at equilibrium; equilibrium line; ELA (equilibrium line altitude, point at which accumulation=melting)

Ice always moves from ____ to ___ pressure

high; low

features of glaciers game link

https://www.purposegames.com/game/features-of-glaciers-game?l=14754

Stop 4 (field trip, state glacial history)

huge wall of clay, inside of wall near bottom are varves of fine sand and clay repeated with random large rocks; as you go up side of cliff, layers get smaller and smaller; proglacial lake depositional environment; as ice retreats we get less and less deposits --> smaller varves

chatter marks/crescentic fractures

ice frozen onto bed puts stress on rock A series of small, closely spaced, crescentic grooves or scars formed in bedrock by rocks frozen in basal ice as they move along and chip the glacier's bed. The horns of the crescent generally point down glacier.

Morphology (glacier classification)

ice profile and topography -alpine: controlled by topography -ice sheet/ice cap: independent of topography; moving out from a central location -piedmont: alpine glacier that flows onto flat area and spreads out; "combination of alpine and ice sheet"; "fans out, and the fan behaves like an ice sheet, an alluvial fan of ice at lower elevation, and behaves like an alpine at high elevation"

sea stack

if top of arch collapses, it leaves a single column

stone stripes

in areas where the ground is on a slope, these are caused by gravity where material is moving downslope in waves; "soil creep through freeze/thaw and permafrost slopes" (doesn't take much of a slope to occur)

wave dispersion

in deep water, longer waves travel faster than shorter ones and will gradually leave the shorter ones behind; "they sort themselves out on their way to shore" (this is why on the beach near the shore the waves are short and why they're long further into sea, due to depth!)

pro-glacial

in front

eustatic sea level change due to mid ocean ridges (CLIMATE)

increase in MORs --> increase in temp of water --> sits higher up in asthenosphere --> increase in sea level (isostasy) sea level drops if activity slows and MORs become smaller

fringing reef

initially surround land, grow seaward

thermokarst

karst topography formed by melting of ground ice underlain by permafrost (ground collapses) (looks like a sinkhole); freeze/thaw is a big player in physical weathering in active layer and above (sharp boundary between active layer and permafrost)

Gravel Pit (field trip, state glacial history)

lake deposits over pre-existing glacial deposits (glacier-->deep lake-->shallow lake); clay under well-sorted medium sand indicates depositional environment of deep lake to shallow lake to shoreline (glacial geomorphology with coastal processes); REGRESSION OF LAKE ALBANY; well-sorted sediment indicates high energy fluvial environment; kame deposits and kame terrace indicate high energy, lots of water, and lots of sediment; esker deposit indicates fluvial under glacier

palsas

like pingos but much smaller and occur in groups in boggy areas bogs form --> freeze --> trap organic gases (ex: methane) --> if it melts, those gases are released (positive feedback climate issue) thick vegetation and organic matter regulates the soil temperature --> small individual blocks of ice that grow in places where there's positive pore water pressure

atoll

little circular reef island where volcano used to be

esker

long sinuous ("snakey") ridge of water-deposited sediment (common with ice sheets) (formation of this is usually perpendicular to recessional moraines)

terminus

lower edge of a glacier; at the end of glacier; the ice margin IN THE DIRECTION WHERE ITS MOVING

biological processes- mangroves

mangrove stands; mangrove forests have trees that are adapted to saltwater

Dynamics (glacier classification)

mass balance (the balance between accumulation and ablation) -advancing: positive mass balance -stagnating: negative mass balance -neutral: equilibrium mass balance; terminus and ELA are staying in place (related to climate, can change)

outwash

material washing out from glacier that's full of sediment (transported by meltwater)

Airy Equation

mathematical equation to describe wave movement in different water depths if depth decreases --> velocity decreases and wavelength decreases --> height increases (H:L ratio. higher ratio --> steepened waves --> waves crash; has to do with angle of repose)

recrystallization (glacier movement)

melting and refreezing of ice crystals, related to Pressure Melting Point

Modern glacier distribution

mostly limited to polar regions most of the Earth's freshwater is bound up in Antarctic Ice Sheet

pingos

mound made in permafrost areas where the center is a big block of ice; pingo grows as ice block in center grows

plastic flow

movement that occurs within the glacier due to the plastic/deformable nature of the ice itself; cold-based glaciers usually, dependent on pressure

Glacier

must be on land, must have ice, and ice must be "alive" (actively deforming) --> moving under gravity from its own mass

Northern hemisphere polar ice

not a glacier because it is not on land

spilling wave

occur on gently sloping beaches, where the crest breaks and spills down the face of the wave

extending flow

occurs when the gradient of the underlying rock surface steepens and the glacier responds by accelerating and becoming thinner; this can happen over knickpoints

compressive flow

occurs when there is a reduction in the subsurface gradient and the glacier slows down and thickens due to the build up of ice (upwards movement)

eustatic sea level change due to ocean temperature (CLIMATE)

ocean water can thermally expand or contract

transverse crevasses

ogives; bending across ice fall

superglacial

on top

crevasses

open fissures (cracks) in a glacier caused when it passes over a steep part of the valley floor and moves faster than the upper part of the rigid zone of ice which cannot stretch to move as rapidly as the underlying ice. Being brittle, the ice of the rigid zone is broken by tension/normal stress; they only go down to where the brittle/plastic boundary is

moraine

pile of glacial sediment that marks the end of ice; "till as a landform"

human-induced problems with melting permafrost

pipelines thaw out ground beneath them (from providing heat to keep the material being transferred viscous to flow) railroad tracks can warp landscape significantly heat in buildings transfers to ground--> destabilizes ground --> destruction

divergent/convergent plate boundaries

possess steep continental shelves

frost sorting

preferentially bringing the bigger material to the top by the freeze/thaw process; grain-size sorting

wave-cut bench

produced when waves undercut headland

end moraine

ridge of till piled up along the front edge of a glacier; the outermost end moraine

truncated spurs

ridges that have triangular facets produced by glacial erosion at their lower ends

sea cave

rock was weak --> physical erosion --> sea cave (produced when waves are refracted against the side of headland)

mountain landscape features before glaciation

rounded ridges rounded peaks V-shaped valley

striations (glacial erosion)

scratches in the rock in the direction of ice movement

gelifluction

seasonal freeze-thaw action upon permafrost soils which induces downslope movement (causes stone stripes)

barrier reef

separated from coast by a lagoon

Cohoes Falls (field trip, state glacial history)

shale and greywacke (not too structurally sound); waterfall has not moved at all in complete historical documentation--> knick point must have been carved under a much higher discharge regime (Mohawk cannot provide this, so it must have formed during the time of the Iro-Mohawk); Mastodon found here is key to the timing (as the pothole it was found in couldn't have formed until this waterfall was forming)

arete

sharp ridges that separate adjacent glacially carved valleys

tectonic uplift

sharper than isostatic rebound; causes uplifted coastal terraces

flute

small ridge protected by a rock from glacier/water that shows direction of ice flow; long, linear ridges; sub-glacial landform

Snow to Ice

snowflakes--> granular snow --> firn (in between snow and ice) --> glacier ice (fusion of grains, density of ice is reached) almost like going from a sand to a sandstone (due to fusion and increase of density of particles)

where do drumlin fields occur?

somewhere near the end of the ice margin

wedges

splitting apart frozen ground through time due to freeze/thaw (they just grow and grow and grow; positive feedback)

radial crevasses

spreading in all directions; piedmont glaciers

beach

steepest part of the foreshore

groins

structures designed to trap sand as it is moved down the beach by the longshore drift; stabilize beaches (but also cause erosion on the opposite side, where sand is not being trapped)

kame deposit

superglacial deposit; a lake was held in place by ice on both sides which then melted and left deposits (ice was previously holding deposits in place)

local sea level change (TECTONICS)

tectonics can raise or lower local sea level glacial isostatic equilibrium changge can raise or lower local sea level

Pressure Melting Point

temperature at which ice melts at a given pressure with enough pressure, a solid can turn into a liquid by pushing the molecules close enough together, once the object is liquid, you can lose resistance to flow that the solid object has, then you can easily move (this usually happens at the bottom of the glacier); once it moves, pressure is released and it becomes solid again

Thermal (glacier classification)

temperature of the ice relative to PMP -temperate: ice is at or near PMP "wet based glaciers"; slides easily -polar: ice is below PMP most of the time "cold based glaciers"; requires plastic deformation for ice to move -sub-polar: ice is always below PMP "frozen based glaciers"; only moves through inter-/intra-granular deformation. ONLY plastic deformation (related to climate, can change)

chevron crevasses

tension

talik

thawed area due to variations in insolation (because of things like vegetation, presence of open water, or albedo of rock/vegetation/water/etc.)

zone of wastage

the lower part of the glacier where ice is lost or wasted by melting, evaporation, and calving (split and shed); where losing > gaining; zone of ablation

tidal bulges

the moon's gravitational field attracts water to the side of earth nearest it, creating a high tide on the side of the Earth nearest it, and a corresponding bulge on the opposite side. The areas between the bulges repel the water, leading to low tides

negative budget

the opposite of positive budget (amount of ice and water lost is greater than amount of snow gained, glacier recedes) (margin recedes)

South Pole

the physical pole placed here is no longer exactly at the south pole because the ice is moving, therefore the south pole is a glacier

horn

the sharp peak that remains after cirques have cut back into a mountain on several sides

basal sliding

the sliding of the glacier as a single body over underlying rock; low friction; usually with warm-based glaciers "slides on the base"

frost heave and formation of stone circles

the soil and stones move upwards due to ice crystals and frost heave --> the soil moves downwards due to melting but ice crystals beneath the stones stop them from returning to their original position --> uneven heating and cooling causes the ground to rise up "as a frozen bubble" and stones roll down to the bottom of the slope --> formation of stone cirlces

Ice sheet

the thickest part of a glacier is where the most precipitation is; the ice flows in all directions (think of pouring syrup on a table)

rigid zone

the upper part of the glacier where ice grains are locked and move together

collapsed pingo

thermokarst lake with ring around it

varve

two thin layers of sediment, one dark (silt/clay) and one light (sand) representing one year's deposition in a lake (if each couplet represents a year--> seasonal variations)

sub-glacial

under

ablation/wasting

under the influence of gravity, glacier ice moves downward and is eventually lost of wasted

till

unsorted and unstratified glacial sediment deposited by glacial ice

oscillatory motion

up and down (deeper water)

zone of accumulation

upper part of the glacier with a perennial (enduring) snow cover; where mass is gained

movement of valley glaciers

valley glaciers move downslope under the influence of gravity and their own weight

wave refraction

velocity of wave slows down as it gets closer to shore due to friction --> waves come in having crests nearly parallel to the coast ("you slow down water waves and this changes the angle at which it travels")

rip current

water pools up, enough mass of water builds up and it "rips out" into the ocean quickly and powerfully

ice wedge polygons

wedging out polygons of frozen ground

plunging wave

well over the angle of repose; more erosion occurs because energy is focused over a small area (occur where the beach is steeper, and are characterized by a steep wave face with the crest curling over the top)

positive budget

when the amount of snow a glacier gains is greater than the amount of ice and water it loses and it expands (margin advances)

brittle/plastic transition

where flow begins and brittle deformation (crevasses) end

longitudinal crevasses

widening; spreading width

What does the nature of waves depend on?

wind velocity wind duration fetch (length of water over which a given wind has blown)

τ=ρgt sinα

τ= critical shear (constant) ρ= density of ice (constant) g= gravity (constant) Given perfectly plastic deformation with a constant yield stress of 1 bar: t sinα=τ/ρg OR 1/ρg=t sinα= Constant (if slope increases then thickness decreases; ice going over an ice fall will thin due to an increase of slope, this increases the likelihood of deep crevasses)