Midterm & Glaciers Flashcards

Question

Oldest mineral

Answer 1

Zircon in Australian rock 4.3 Ga

Answer 2

The present is the key to the past The processes that worked in the past are the same as the ones that are observable today, so we can infer what happened in the past from our knowledge of the present

Answer 3

Signs of intrusions and eruptions of magma

Answer 4

Record environmental changes - Mode of transport and environment of deposition i.e. Climate, life, sea level

Answer 5

Record collisions of plates, uplift and erosion of mountains

Answer 6

Age of mammals and flowering plants 65 Ma - present

Answer 7

``` Age of dinosaurs - Development of bipedal movement First birds First mammals First angiosperms ``` 251 - 65 Ma

Answer 8

Cambrian explosion - beginning of the fossil record Life conquers land: plants, lungs, reptilian eggs - All animals are reptilian or amphibious 542 - 251 Ma

Answer 9

Encompasses the time of Earth's history with a lot of diversification of life: "visible life" 542 Ma - Present Palaeozoic, Mesozoic, Cenozoic

Answer 10

Photosynthesis puts oxygen into the air First eukaryotic cells 2,500 Ma - 542 Ma

Answer 11

Earth first becomes habitable First continental crust First life 3,800 Ma - 2,500 Ma

Answer 12

Earth's early life Inhabitable 4,567 Ma - 3,800 Ma

Answer 13

Sedimentary rock makes up a very small portion of the rock on the earth's surface, but it is still very important because it holds important clues about earth's history

Answer 14

Two types: physical and chemical They work in conjunction with one another

Answer 15

Weathering of a rock that results in smaller pieces of the rock - Jointing - Thermal expansion - Wedging by frost, roots, salt - Burrowing

Answer 16

Weathering of rock that results in ions that can be moved away - Dissolution (ex. salt, limestone) - Hydrolysis (ex. feldspar --> clay) - Oxidation (ex. biotite/pyrite --> hematite) - Hydration (ex. clays)

Answer 17

``` Boulder: > 256mm Cobble: > 64mm Pebbles: > 2 mm Sand: > 1/16 mm Silt: > 1/256 mm Mud ```

Answer 18

A mixture of mineral fragments, water, air, and organic matter Bedrock breaks down into regolith, which then mixes with organic matter to create humus

Answer 19

Small rock particles that have the potential to become, but are not yet, soil

Answer 20

Soil that is able to support life

Answer 21

``` Zone of leaching - - Topsoil (O & A1) - Transition (A2) Zone of accumulation - Subsoil (B) Bedrock (C) ```

Answer 22

Thin Occasionally has hard salt/calcite crust

Answer 23

Thick laterite soil, but very nutrient deprived | - No B horizon, but Al-rich A2

Answer 24

The products of physical weathering Described based on size, composition, roundness, sorting of clasts, and cement type (quartz or calcite) E.g. - Conglomerate/breccia - Sandstone/arkose - Siltstone - Mudstone/shale

Answer 25

As sediment moves farther from the source, it gets more "mature" - more spherical, better sorted, higher proportion of resilient minerals

Answer 26

Rocks that are formed from chemical precipitation E.g. - Evaporites (rock salt/gypsum, saltwater evaporation) - Tavertine (chemical limestone) - Banded iron formation: very old

Answer 27

Rock formed from the remains of prehistoric organisms - Limestone (calcite shells) - Chert (shells of plankton like radiolaria, diatoms) - Coal (plant debris)

Answer 28

Has a recognizable bottom and top Generally relate to one depositional event

Answer 29

Surface that separates two beds | Can be gradational or abrupt

Answer 30

Contacts between beds that are beside one another Can be: - Pinched out - Interfingering - Gradational

Answer 31

A series of beds

Answer 32

A distinctive (and mappable) series of strata Often named based on the place it was discovered and the rock type (e.g. Toronto Limestone)

Answer 33

Laid down with no interruption

Answer 34

A break in the geologic record

Answer 35

Disturbance of rock caused by burrowing animals (ex. worms, clams)

Answer 36

Deposition within a current of water or wind Results in cross-bedding

Answer 37

Beds within which the coarsest sediment was deposited first and the finest sediment last Happens in turbid water

Answer 38

Impressions made on the base of a bed where a dense sediment (sand/pebbles/boulders) overlaid a much softer sediment (mud/silt)

Answer 39

Scours dug into the top part of a bed get filled in by later strata, taking a cast of the scour marks

Answer 40

Terrestrial: - Rivers - Lakes - Glacial - Sedimentary basins Marine - Deltas - Beaches - Shallow water - Carbonate reef - Deep ocean

Answer 41

Distinct sedimentary characteristics reflect distinct processes Our knowledge of present-day sedimentary environments can allow us to reconstruct palaeoenvironments from sedimentary rocks

Answer 42

The cycle of where water is stored and where/how it moves

Answer 43

Freshwater accounts for only 3.5% of earth's water Of this freshwater, only 0.3% is surface water - the majority is ice cap/glacier and groundwater Of surface water, most is contained in lakes

Answer 44

1. Irrigation (39.6%) 2. Thermoelectric Power (39.3%) 3. Public and Domestic Use (13.5%) 4. Industrial Use (5.3%) 5. Aquaculture (1.1%) 6. Mining (0.6%) 7. Livestock (0.5%)

Answer 45

A drainage network that collects water from a broad region AKA watershed

Answer 46

The highland or ridge that separates one watershed from another

Answer 47

The patterns that water tends to follow when draining from a source into the basin - Dentritic - Radial - Structurally controlled

Answer 48

Resemble the branches on a tree Form on a land with uniform substrate

Answer 49

Water drains radially from a centre point Generally happens when the source is the high point of a conical mountain

Answer 50

Water follows the path of the well-defined topography underneath I.e. through joints, along valleys

Answer 51

Measures the elevation, sediment load, water load, or water velocity of a river against the distance from its source

Answer 52

Occurs through scouring, breaking, lifting, abrasion, and dissolution Depends on discharge and sediment content

Answer 53

Looks like the intertwining hairs in a braid - Large volume of bedload - Banks erode very easily - Shifting bars

Answer 54

Looks like a snake winding across the landscape - Mostly suspended load - Cohesive banks - Cutbanks, point bars, oxbow lakes - Erosion takes place on the outer edges of meanders

Answer 55

The area of sediment deposition on the inside of the meanders of a river

Answer 56

Lakes that have been formed when a meander of a river cuts in so close that it cuts itself off

Answer 57

Sediment carried within the body of a river; smaller particles that the water is able to float along with it

Answer 58

Sediment that is dragged, bounced, or rolled along the bed of a stream; larger particles that can only be moved by a large amount of force

Answer 59

Ions that are dissolved in the stream and carried along with it

Answer 60

Typically form steep V-shaped valleys

Answer 61

River downcuts into the ground, leaving a "terrace" of raised ground surrounding its floodplain

Answer 62

Particularly turbulent water with a rough surface; forms when: - Water flows over steps or large clasts in the channel floor - Channel abruptly narrows - Gradient abruptly changes

Answer 63

Forms where the gradient of a stream becomes so steep the water free-falls down the stream bed

Answer 64

Gently sloping apron of sediment Forms when a fast-moving stream abruptly emerges from a confined space and spreads out, slowing down and quickly dropping its sediment load

Answer 65

Accumulation of sediment in a pair of low ridges on either side of a stream

Answer 66

When the volume of water flowing exceeds the capacity of the stream channel and flows over into the floodplain areas on either side of the stream

Answer 67

Gradient deposition, with larger clasts deposited closer to shore and finer clasts further out; clasts are well-sorted and rounded Contain marine fossils and tend to become siltstone/mudstone

Answer 68

Shallow marine environments that contain a large amount of carbonate shell debris Indicate the presence of a reef

Answer 69

Fine sediments are deposited along the shores Sediment ripples due to being deposited within a current - cross bedding Sandstone, siltstone, shale

Answer 70

Present as thick sequences where deeper-water sediments slowly grade into river sediments

Answer 71

Area of groundwater where all pores are filled with water - no air

Answer 72

Line that separates the saturated zone of groundwater from the unsaturated zone

Answer 73

Area above the water table where water partially fills the pores in the ground but not fully

Answer 74

Actual amount of space there is in between particles that can be filled by water

Answer 75

Connectivity between pores - allows water to flow within a substance

Answer 76

Will always flow from high to low hydraulic head

Answer 77

Potential energy available to drive the flow of a given volume of groundwater at a location

Answer 78

Sediment rocks that transmit water easily Provides water to wells

Answer 79

Sediment/rock that does not transmit water easily and therefore slows it down

Answer 80

When water is pumped out a well too quickly and the water table sinks down around the well, forming a pointed-down cone shape

Answer 81

A network of underground caves that have been carved out of limestone by water Collapse of these caves causes a landscape of sinkholes or limestone spires

Answer 82

Circular depression in the ground that happens when an underground cave collapses

Answer 83

Formations that grow in caves from the accumulation of dripstone Stalactite: hangs from the ceiling Stalagmite: emerges from the ground Limestone column: happens when a stalactite and stalagmite merge

Answer 84

Where a surface stream enters into a crack or hole and travels for some time in underground caves

Answer 85

Contaminants can enter the groundwater and then travel within the water, potentially ending up in well water

Answer 86

Expressed as a ratio (e.g. 1:500,000) Means that one unit measured on the map is equal to 500,000 units on the ground - 1 cm = 500,000cms or 5km in reality

Answer 87

Connect all points of equal height above a certain datum (usually sea level)

Answer 88

Height difference between two subsequent contour lines

Answer 89

Represents the topography and geological structures on a specific line across the earth

Answer 90

Universe Transverse Mercator Uses Northing and Easting instead of Latitude and Longitude

Answer 91

Distance to the equator (km)

Answer 92

Measured to a central meridian (degrees)

Answer 93

Position on a sphere measured in degrees For true-north, north is 0%, south is 180%

Answer 94

Area of glacier where ice accumulates and begins to flow downhill

Answer 95

Area of glacier where ice melts and begins to recede AKA zone of ablation

Answer 96

Advances if accumulation > wastage | Retreats if accumulation < wastage

Answer 97

Basically a river of ice flows down a mountain side into a valley

Answer 98

Pile of debris deposited by a glacier Lateral moraines: Formed along the edges Medial moraines: Formed where two glaciers meet, run in the middle of the composite Terminal moraines: Formed at the toe of the glacier

Answer 99

U-shaped Formed because the glacial abrasion/plucking both lower the floor of the valley and bevel its sides

Answer 100

Residual edge of a rock that resembles the edge of a knife Pointy edge of the mountainous region surrounding the valley

Answer 101

Glacially eroded hill, elongate in direction of flow - Upstream part = gentle slope (rasping) - Downstream edge = steep slope (plucking)

Answer 102

Snake-like ridges of sand and gravel that form when sediment fills meltwater tunnels at the base of a glacier

Answer 103

Streamlined, elongate hills that have been molded by the flow of a glacier

Answer 104

Long gouges, grooves, or scratches within the bedrock over which a glacier passes - Caused by rasping of large clasts that are being carried along with the glacier

Answer 105

A boulder or cobble that was picked up by a glacier and deposited hundred of kilometres away from the outcrop from which it detached

Answer 106

A mixture of unsorted sediment deposited by glaciers

Answer 107

Trapping of solar heat inside the Earth's atmosphere by carbon dioxide and other greenhouse gasses that absorb infrared radiation Changes the average temperature on earth from -19 to +15 degrees Celsius

Answer 108

Caused by: - Greenhouse effect - Variation in earth's orbit/tilt/precession - Thermohaline circulation - Albedo

Answer 109

Over the coure of 100,000 years, earth's orbit will change from more eccentric (more oval) to less eccentric (more circular) Changes the length of seasons and variability in temperature

Answer 110

Over a period of 41,000 years, the tilt of earth's rotational axis changes from 22.1° and 24.5° and back again Changes the variability in temperature across the planet - more variability with more tilt

Answer 111

Over 23,000 years, the north pole changes from pointing to the North Star to Vega

Answer 112

The rising and sinking of water within the oceans, driven by differences in water density - Change in density due to differences in temperature and salinity (colder/more saline = denser) Circulation involves both surface and deep-water ocean currents - Water in polar areas sinks and flows along the bottom of the ocean toward the equator Prevention of thermohaline circulation shuts down the Gulf Stream

Answer 113

The reflectivity of a surface - Ice is highly reflective, so lots of ice = less heat absorbed Increasing albedo causes cooling, decreasing albedo causes warming

Answer 114

Today, temperature is fairly cold in comparison to how it has been in the past - There have been multiple ice ages in the past We can also record past CO2 levels from ice cores taken from the Antarctic

Midterm & Glaciers Flashcards

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