Lectures 2-5 Flashcards

1
Q

Absolute date

A

A quantification for how old something is (albeit with error)

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2
Q

Boulder clay

A

Glacial deposit

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3
Q

Cirque

A

Bowl-shaped cavity on hillside with steep, cliff-like tops and shallow bottoms formed by ice

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4
Q

Daughter element

A

Element produced by radioactive decay

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5
Q

Devensian

A

The last glacial period (70Ma)

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6
Q

Diatom

A

Single-celled alga (aquatic plant) with a wall of silica

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7
Q

Dropstone

A

Large rock in fine-grained sediment thought to have been deposited by falling from a melting iceberg

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8
Q

Foraminifera

A

Single-celled aquatic animal with a CaCO3 shell

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9
Q

Freeze-thaw

A

Weathering that results from the expansion and contraction of material as it experiences temperature fluctuations around 0C

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10
Q

Gondwanaland

A

An ancient supercontinent

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11
Q

Green house

A

When Earth is relatively ice-free

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12
Q

Half-life

A

Time taken for one half of the original number of radioactive atoms to decay

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13
Q

Holocene

A

Last 11.7ka interglacial period (in which we live)

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14
Q

Horn

A

Three or more cirques back-to-back

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15
Q

Ice house

A

When Earth had ice at least covering high latitudes

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16
Q

Ipswichian

A

Penultimate interglacial period

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17
Q

Isotopic Age

A

Time since the isoptopic clock was ‘reset’ when isotopes were locked into the minerals (ie crystallisation after melting)

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18
Q

Late-Cenozoic Ice Age

A

Most recent ice age (that we live in)

19
Q

Ordovician Ice Age

A

3rd-most recent ice age

20
Q

Palaeontology

A

Study of fossils

21
Q

Palynology

A

Study of pollen (organic microfossils)

22
Q

Palynomorphs

A

Pollen grains

23
Q

Periglacial

A

Areas surrounding glaciated regions

24
Q

Permafrost

A

Permanently frozen ground

25
Q

Permo-Carboniferous Ice Age

A

2nd most recent ice age

26
Q

Phanerozoic

A

Last ~20% of Earth’s history, during which life boomed

27
Q

Pingos

A

Uplifted frozen hill of permafrost

28
Q

Polygons

A

Patterned ground formed through ice wedge action in permafrost regions

29
Q

Precambrian

A

First ~80% of Earth’s history (little life present)

30
Q

Radioactive decay

A

Spontaneous disintegration of a radioactive element (parent) to a different element/isotope (daughter), giving off energy in the process

31
Q

Radiogenic

A

Formed by radioactive processes

32
Q

Radiometric dating

A

Use of isotopes to provide absolute dates

33
Q

Relative date

A

How old something is in comparison to something else

34
Q

Snowball Earth

A

Theory that Earth was completely covered by ice

35
Q

Stone circles

A

Concentric circles of rock, created in permafrost regions

36
Q

Stratigraphy

A

Study of rock layers

37
Q

Talik

A

Area of unfrozen ground surrounded by permafrost

38
Q

Till

A

Glacial deposit

39
Q

Tuya

A

Volcano that erupted underneath a glacier but melted through ice

40
Q

Varves

A

Regular alternations in lake sediment layers

41
Q

Vesicularity

A

Amount of gas bubbles in magma/lava

42
Q

Volatiles

A

Volcanic gases

43
Q

Geologic calendar/timescale

A

Chronology of events on Earth based on obtaining ages of past events