exam 1 Flashcards

Question

lithosphere

Answer 1

solid but elastic, broken up into plates, including the continents, and move about asthenosphere

Answer 2

liquid magma layers that causes plate movement | -hot spots can break through lithosphere creating island chains

Answer 3

spreading plates away from each other (most underwater), -forms new continental crust as they spread caused by mantle convection

Answer 4

colliding plates, one subducts or goes under the other, can cause uplift -form mountain ranges/earthquakes cause day mantle convection

Answer 5

plate edges grinding past each the run opposite directions caused by mantle convection

Answer 6

lithosphere stretches causing the continental crust too thin. Asthenosphere rises -Volcanoes/fault escarpments

Answer 7

Southwest - East Antarctica connection. When Rodinia was a supercontinent eastern Antarctica and western North America were connected. Based on isotopic geochemistry of equivalent granite found in both places. The isotopic composition developed when the rock formed.

Answer 8

fern-tree, fossil leaf impressions in sedimentary rock from Mt. Wild on Antarctica (255 mya). Also found in India, Australia, South Africa and South America -evidence for continents once being connected, supporting plate tectonics

Answer 9

therapsid dicynodont reptile that survived mass extinctions found in Africa, Antarctica, European Russia & Mongolia by Edwin Colbert -evidence for continents once being connected, supporting plate tectonics

Answer 10

cynodont therapsid found in Antarctica and Africa | -evidence for continents once being connected, supporting plate tectonics

Answer 11

started 180 mya finally Antartica split 32 mya when the South Antartica Peninsula

Answer 12

drakes passage and forming the circumpolar current which initiated cooling (ice started to form) and isolation of the Antarctic continent

Answer 13

180 mya | cryolophosaurs, long-necked sauropods, mosasaurs, plesiosaurs, etc).

Answer 14

mantle blumes

Answer 15

only current that flow around the globe in southern hemisphere -helps isolate antartica

Answer 16

Tectonic plates too small to track, positioned themselves as part of Antarctica such that the Ellsworth Mountains w/ anomalous orientation when Gondwana broke up

Answer 17

(divides east & west Antarctica), and they sit on a plate boundary. -above sea level

Answer 18

sit on a micro pate

Answer 19

started 32 mya -sediment cores at Prydz Bay have glacial boulders and pebbles carried by glaciers and deposited in bay by then. Reach current size/dimensions by 14 mya

Answer 20

4km thick and cover 14 million km^2

Answer 21

pushes it down but when glaciers melt isostatic uplift occurs -evidence in raised beaches, former beaches w/ water-worn cobble/pebbles

Answer 22

burried mountain ranges | west antarctic ice shet rests on rock below sea level

Answer 23

"forzen crusted Dino" | proved antarctic was a forestproof of Gondwana that Ned Colbert found in the 1960's

Answer 24

ice free sedimentary rock place | -lots of paleontology done there

Answer 25

as glaciers melt more heat is absorbed which can open crevasses -very dangerous and difficult to see and navigate

Answer 26

blodzoed dirt lateral: on the outsides medial: in the middle where two come together terminal: at the bottom where they've converged and where they're pushing dirt in front of them

Answer 27

as a glacier moves over rock below it will smooth and polish them. leaves akas in the rock indicating direction of glacial flow

Answer 28

rocks that fall onto a glacier and become deposited in an entirely new area when the glacier melts -coloration and type of rock often doesn't match the geology in the new area causing them to stand out

Answer 29

when the bottom of a glacial melts under pressure, and refreezes when the pressure is relieved

Answer 30

poorly sorted sediments with particles ranging from clay size to boulders.

Answer 31

dirt and rock trapped in a glacier that gets carried to sea and then melts, depositing the debris into the marine sediments

Answer 32

silts that are trapped, not debris

Answer 33

glaciers that extended out into the ocean. they can grind along the bottom (some are free floating) of the ocean when they advance, leaving evidence wfor when they retreat -ross sea ice shelf is massive and due to glacial convergences. it's 100 ft above the water line which is only half as much as below it

Answer 34

caused by the rapid extension of glaciers into the ocean they constantly calve off, but are reformed from behind -Drygalski Ice Tongue

Answer 35

when a glacier calves off (bringing debris) and can break away. Occurs naturally and constantly as a glacier pushes from behind. Includes evaporation from the surface and surface melting/runoff.

Answer 36

Two warming periods, one from the late Miocene to 15 mya and the other from the early Pliocene 5.3 mya to 1.8 mya caused tundra-like growth and dwarf Nothofagus trees to grow. Fossils of the tree were found in the Sirius Formation in the Transantarctic Mountains.

Answer 37

Located next to the Drygalski ice tongue in the Ross Sea, where as snow cover melted, a preserved penguin breeding site was revealed. The breeding site was so well preserved it appears to be only recently abandoned. It may have been abandoned due to food changes or snow coverage.

Answer 38

It is the coldest place due to maximum tilt away from the sun and high albedo. The high albedo perpetuates cold conditions as does the elevation above sea level and thick ice sheet that covers the continent. Dryness is due to the constant high pressure from the polar cell, preventing storms from bringing in moisture. Also, cold air holds less moisture.

Answer 39

Some areas are colder than others due to their topography. Inexpressible Island is one of the coldest due to winds coming off of two glaciers behind the island. Air flows downward all around the continent (channeled by valleys and coriolis force).

Answer 40

Katabatic winds form due to cold dense air rapidly moving down valleys (in part due to gravitational force) off the polar plateau with relatively warmer, less dense air above it (creates a pressure difference). These winds can help cause sea ice formation over coastal waters, and open-water areas surrounded by sea ice (polynyas). They are especially strong in summer due to the cold surface air on the ice.

Answer 41

strong windchill which affects local climate, sea ice formation, and movement and erosion, and penguin behavior

Answer 42

rocks and boulders that are sculpted by blowing ie crystals and sand

Answer 43

winds lift sand particles up which are then pulled down by gravity, forming a ballistic path. these particles blast pits into rock.

Answer 44

drifts in snow caused by erosion, wind, and saltation. sastrugi are formed parallell to the wind.

Answer 45

- peninsula up to 50 cm of rain due to receiving warm air currents from the west - temp 1-2 degrees C in Jan. - two flowering plants there - peninsula is more affected by climate change (more melting)

Answer 46

1. frazil ice 2. pancake ice 3. rafting/ridging 4. cementing/consoliation =rough bottomed ice sheet

Answer 47

1. frazil ice 2. grease ice 4. nilas 5. rafting 6. congelation ice =smooth bottomed ice

Answer 48

freshwater ice crystals that form and move to the surface at the end of summer (March). winds from the continent and evaporative cooling at oceans surface reduces the water temp an dice begins forming at -1.8 degrees c and average salinity

Answer 49

forms from frazil ice in calm waters. looks like dark stains on the water surface and lightens with development.

Answer 50

sheets that form from grease ice and cover the oceans surface as a thin layer

Answer 51

rafting occurs when currents or light winds cause nilas to slide over each other. the ice thickens into a smooth-bottomed ice sheet. pockets of waltwater (brine and algae within) get trapped as the ice congels

Answer 52

circular sheets of ice that form from frazil ice in rough waters. these can raft/ridge (ice bends o fractures and piles on itself) before consoliation

Answer 53

newly formed sea ice that's attached to land

Answer 54

not attached to land

Answer 55

ice drfit packed together by winds

Answer 56

large pieces of drift ice

Answer 57

The younger the sea ice the thinner it is. New ice can form between pieces of old ice which causes rafting/ridges on old ice that occurred during formation. New ice is not drinkable (due to brine).

Answer 58

Multiyear ice is over a year old, thicker from congelation on bottom so not always breakable by an ice breaker, but melt water is drinkable as the congelation/compression gets rid of brine. More snow coverage limits light penetration.

Answer 59

When brine gets trapped in the ice the algae within it lays dormant in the winter darkness, but begins growing in the ice with spring light from a greenhouse effect in the ice helping algal growth. This algae is released into the marine food web in summer when the ice starts to melt and stimulates the food chain (more ice = more algae).

Answer 60

as ocean water becomes colder and more saline, it becomes more dense and sinks, creating circulation

Answer 61

Removal of fresh water from the ocean surface when sea ice forms causes water below to be very cold and more saline, so it becomes very dense and sinks.

Answer 62

The Antarctic Convergence is where cold surface waters moving northward form Antarctica meet warm waters, causing the cold waters to sink (more dense). The air temperature changes dramatically as you cross the convergence.

Answer 63

The Antarctic Divergence is between the west wind drift and the east wind drift closer to the Antarctic continent.

Answer 64

This current is flows counterclockwise around the coast of Antarctica, driven by katabatic winds and coriolis force.

Answer 65

Not cold when it comes to the surface due to warm sources (along with poles), and forms an area of open water surrounded by ice (polynya)

Answer 66

Comes from the cold saline water that forms under ice sheets, sinks and moves along the bottom.

Answer 67

This current keeps Antarctic isolated and travels around the entire globe. It is driven by prevailing westerlies (due to the low pressure system) and circulates clockwise around the entire continent. It is the only ocean current that encircles the globe.

Answer 68

Ice shelves are extensions of glaciers into the ocean. They have a hollowed out area below that forms due to warm circumpolar deep water flowing into the front face. They calve off due to ablation and ice sheets form in the front. As ice shelves move they grind along the bottom creating moraines. Grounding lines are formed from these moraines and help to map ice shelf movement.

Answer 69

these are icebergs that are flat-topped because they have broken off of ice shelves

Answer 70

the area was open water until 27,000 BP until the ice shelf began advancing

Answer 71

two huge pieces of the iceshelf broke off blocking currents in the southern ross sea and causing extensive sea ice coverage. This prevented deep water upwelling and changed ocean dynamics. Penguin colonies that needed open water access to breaches were nearly abandoned until the bergs broke up and open water returned.

Answer 72

Located on the west Antarctic Peninsula it began breaking up in 2002. The rapid collapse was due to climate change and indicates that the peninsula is more affected by climate change than East Antarctica.

Answer 73

highly productive and are formed via warm water upwelling in a localized area

Answer 74

formed by katabatic winds pushing sea ice away from coast

Answer 75

adding heat to change the conditions | -open ocean polynyas

Answer 76

maintaining heat | -coastal polynyas

Answer 77

katabatic winds are constantly cooling the ocean surface (enhancing ice formation) but are also blowing away the newly formed sea ice allowing more sea ice to form. -occurs in coastal polynyas

Answer 78

A coastal polynya that formed from winds coming off the polar plateau. It persists through the winter and has allowed open water and beach access for breeding penguins for thousands of years in the Ross Sea

Answer 79

Stable isotopes ratios of oxygen in water are especially useful as a proxy for past temperatures (H & ) have stable isotopes

Answer 80

water evaporates from cold periods and is deposited and stored in glacial ice on land, leaving more o the heavier 180 isotopes in the ocean. Reverse occurs in warm periods

Answer 81

the ratio of heavy to light isotopes compared to a standard x 1000, measure per 1000 (per mil), not per 100 as in percentage

Answer 82

Concentration of 180 ions in precipitation decreases with temperature and from the equator to the poles

Answer 83

Colder periods show an increase in the light oxygen isotope in the ice and increases heavy isotope in the oceans indication a smaller ratio. Warming periods see the reverse indicating a larger ratio

Answer 84

where the ice is the thickest and has the least amount of ablation. This is usually in the middle of the plateau and the flattest area with the least amount movement

Answer 85

Summer: layers are lighter due to larger grain size that don't pack as closely as a result winter layers: darker because the grains are smaller and light is reflected differently

Answer 86

1. you can count annual rings (summer or winter) 2. you can use known volcanic ash, dust, or other signature that have been dated elsewhere 3. you can use dust with radioactive uranium isotopes with a known decay rate

Answer 87

oldest ice core dated at -800,000 years old. There may be older ice cores dating back around 1,500,000 years in East Antartica

Answer 88

CO2 is a proxy for past air temperature and can reflect changes in plant biomass Methane (CH4) can reflect amount of wetland decay in warmer periods N2O Can reflect soil microbial activity Compared to earths atmosphere today -all increase as temp increases

Answer 89

78% N 21 % O .035% CO2,CH4,H2O

Answer 90

solar radiation is mostly lost or reflected. the solar radiation that enters earths atmosphere is absorbed at the surface, then radiated back to the atmosphere as infrared radiation. The heat in this radiation is trapped by trace gases. This creates a warm blanket over the planet and is necessary for life. Increasing trace gases means more heat is trapped, increasing global termpatures.

Answer 91

CO2 in ice cores provides a glimpse into the past and how gases changed in the atmosphere naturally over time. Warming and cooling cycles are due to solar radiation cycles (CO2 traps IR...

Answer 92

there have been cycles of increases and decreases due to natural climate change. we are in a cycle of rapid temperature increase that is occurring too fast for most organisms to adapt/evolve to cope with change.

Answer 93

Has one of the longest modern records of measuring CO2 in the atmosphere (since 1958). The site is good because it minimizes human contamination and is at a high elevation. Annual cycles of increase and decrease are due to seasonal change (little to no photosynthesis in the winter). Record shows that the amount of CO2 in the atmosphere today is increasing rapidly.

Answer 94

There is natural warming and cooling from slight changes in solar radiation caused by the Earth's elliptical orbit and wobbling around the sun, which results in slight changes in solar radiation reaching the Earth's surface. Insolation is another name for radiation. Cycles of climate change from this are now known in cycles of 41,000, 100,000, 400,000 years.

Answer 95

Sea level drops with glacial periods (colder) CH4 varies with CO2

Answer 96

Two hemispheres see opposite trends in climate change over time. This is due to the north having more glacial (freshwater) discharge into the ocean which causes different responses in ocean/global currents there. For example some places will warm and others will cool as a response to changes in ocean currents and gyres

Answer 97

The international geophysical year began in 1957-1958 with 67 countries participating at the end of the cold war. Sputnik 1 was launched by USSR in 1959. Knowledge was gained about how magnetic fields interact with/prevent comsic rays and solar winds.

Answer 98

due to lack of atmospheric interference. Early studies were focused on magnetic fields, cosmic rays and development of communications. We now have a better understanding of the different atmospheric layers, interactions, and solar events.

Answer 99

the field exists due to earths solid iron core surrounded by liquid magma. the magnetic poled reverse every million years or so. Early research focused on navigation at sea, later interests developed on radio waves for communicaiton

Answer 100

the poles reverse every million years or so. they migrate up to 40 miles/year due to constant movement of the magma. compasses are never exact due to this movement

Answer 101

temerpature decreases as altitude increases but it increases as the ozone layer because ozone traps heat

Answer 102

temp increase at this layer. this is where auroras occur due to charged particles being accelerated outward into upper atmosphere

Answer 103

occur in the ionosphere due to charged particles being accelerated outward to upper atmosphere

Answer 104

Antarctica is a good place to deploy instrument because of it's large polar plateau across latitudes and once they are up there there is minimal interference

Answer 105

Antarctica is ideal for telescopes due to the extreme cold 1) The cold prevents water vapor in the air that would distort view 2) Reduced interference of infrared radiation from ground to scope due to high albedo 3) Reduced aerosols/pollutants 4) No light pollution 5) The stable bedrock means there's little seismic activity Telescope set up at South Pole station in the 1970s gives us some of the best images of cosmic/solar events. Gave us a better understanding of cosmic rays.

Answer 106

neutral subatomic particles that originate with radioactive decay, emitted from nuclear reaction in the sun, or from black holes. Need a large array to detect the particles making the Antarctic environment ideal. they help to understand process in the sun as well as early universe after the big bang

Answer 107

when neutrinos interact with ice to produce a blue flash

Answer 108

followed the AMANDA model (built in the 1990s) It was build between 2005-2010 for hundreds of millions of dollars at South Pole station to detect neutrinos

Answer 109

They were first discovered in Antarctica in 1911 (1000s found since). They preserve extremely well in ice. They'll melt down into moving glaciers, and bubble up to the surface when they hit a mountain range (Transantarctic Mountains). They stand out very well on the white surface forming meteorite fields. They provide information on the moon, mars and how asteroids form.

Answer 110

O3 molecules are constantly forming & breaking apart in the stratosphere 15-25 km above the surface and react with UV light. O2 -> 2O O3 -> O2 + O O + O2 -> O3 O + O3 -> 2O2 (formed) (destroyed) Early earth's atmosphere lacked ozone and any protection from UV rays so there was no terrestrial life. About three billion years ago marine life began evolving deep in the ocean (safe from the UV). It took 2.5 billion years for enough O3 to accumulate in the atmosphere to establish an equilibrium of O3 being created to O3 being destroyed which protected the surface enough from UV light to allow terrestrial life to evolve.

Answer 111

CFCs breakdown in polar stratospheric clouds. In the winter clouds form with ice crystals at -78ºC. CFCs and N2O bind to the ice crystals and remain there through the winter. In the spring the ice melts and the chemical reaction occurs releasing free Cl. The chlorine reacts with O3. ClO + O2 -> Cl + 2O2 2O3 -> 3O2 One chlorine atom breaks down 100,000 O3 molecules before washing out of the atmosphere.

Answer 112

form above Antarctica every winter in extreme cold and darkness, formed of ice crystals that capture CFCs and hep release free chlorine in the spring that destroys ozone

Answer 113

Antarctica is the idea place for cfc to breakdown due to extremely cold temps and stratospheric clouds that are not in the arctic. the ozone hole is technically a thinning of the ozone, not an actual hole.

Answer 114

the ozone decline started in 1985. The station was founded during IGY. They sent balloons up to measure ozone and noticed a decline in 1977. Around the hole that would form in the spring/early summer they found chlorine (not a naturally occurring element in the atmosphere)

Answer 115

body of water between south America's Cape Horn and south shetlands islands of antartica

Answer 116

Decrease in CO2, ocean currents, ice dated back 500,000 years (some 1 mya under dry valleys) Organisms found during the warming period were no longer found in fossil record past this point

Answer 117

Island located at tip of the Antarctic Peninsula, sedimentary rocks extensive, snow-free, lots of erosion (see lots of marine fossils) Earliest penguin-like fossil from Palaeocene in New Zealand (61 mya), evolved in the southern hemisphere from a flying ancestor 15-20 fossil species on Seymour Island (fully formed, some 6 ft tall), Eocene or 50 mya Seymour fossils indicate niche for penguins was established in the Southern Ocean by Eocene, marine ecosystem must have been highly productive/rich to support the diversity of penguins at that time Gap in penguin record until Miocene (10 mya), diverse record in South America