Quaternary geology Flashcards

Question

What happens to the amount of incoming solar radiation during the Milankovitch cycles?

Answer 1

It varies: Eccentricity varies over 100,000 years Obliquity varies over 4,000 years Precession varies over 26,000 years

Answer 2

a) it amplifies the levels of radiation b) it diminishes the levels of radiation

Answer 3

Currently, the summer is at aphelion. It is 7% cooler than if it was at perihelion. The winter is at perihelion. It is 7% warmer than if it was at aphelion. In 13,000 years, the winter will be at aphelion. It will be 7% cooler. The summer will be at perihelion. It will be 7% warmer.

Answer 4

EQUATOR: sun energy (IR radiation) is concentrated over a smaller area and has less atmosphere to go through POLES: sun energy is spread out over a larger area due to the natural curvature of the Earth, and has to travel through more atmosphere

Answer 5

OBLATE SPHERE - Gravity is much stronger at the poles because they are closer to the core = lower ocean sea levels - Ocean sea levels are higher at the equator because they are further from the core = less gravity - Gravitational potential energy = higher at the equator because higher sea levels

Answer 6

Because the equator water is warmer more salt will dissolve, and more evaporation makes surface waters saltier

Answer 7

1. At the equator, the water is warmer and saltier 2. The warm salty water moves into colder waters near the poles 3. As it cools, it becomes denser and so sinks and a conveyor belt is set up 4. Cooler water returns to the warm water in a deep sea current

Answer 8

Thermohaline circulation transfers energy from the equator to the poles - this makes milder climates in the north, increasing precipitation in Northern Latitudes - this falls as snow, causing an increase in albedo - results in global cooling, sets up a positive feedback cycle

Answer 9

ACC - Antarctic Circumpolar Current

Answer 10

The gap between North and South America meant that the warm water flowed through the Panama Gap so no warm water came to Europe - this made Northern Latitudes much colder When the Drake Passage was closed, no current could flow round Antarctica so there could be no snow in Antarctica because warm water was transported South

Answer 11

a) 50 million years ago b) 15 million years ago

Answer 12

air masses (e.g. Hadley Cells) - rising air near the equator, flow towards the poles at high altitudes, sinking air around 30 degrees latitude, and return flow towards the equator

Answer 13

GLOBAL COOLING e.g. Himalayas 1. Stops warm air getting further North - stops warming the poles - high altitude = clouds rise, snow, albedo, positive feedback cycle... 2. Increase SA for weathering which locks away CO2 H2O + CO2 --> H2CO3 (carbonic acid) - made when rainwater dissolves carbon dioxide, and the acid then falls on the mountains - oxidation: olivine + CA --> iron + ions - hydrolysis: plagioclase + CA --> kaolinite (china clay) + Ca3+ + CO3 2- - carbonation: CaCO3 (limestone calcite) + CA --> Ca2+ + 2HCO3-

Answer 14

NE face of mountains North face because it is colder, so there is more snow and less melting. The South face gets the most sun (it rises in East and sets in West so the whole face gets it too) so snow cannot be supported, there will be less of it and there will be more melting. East side because the prevailing wind is from the South West, so the wind will blow the snow away from the West side of the mountain.

Answer 15

- protracted cold period - major expansion of ice sheets and glaciers

Answer 16

- number of glacials - when there was a severe cold climate - when glaciersand ice sheets advanced - ice sheet coverage in mid-latitudes because most deposits are not lithified, they are often rich in fossils: leaves, insects, seeds, pollen, fungi spores

Answer 17

Warm interval where temperatures were at high or higher than now - characterised by the development of mixed (temperate) woodland

Answer 18

shorter cold episodes where local ice advances occurred

Answer 19

relatively short period of thermal improvement during a glacial phase - temperatures not as warm as today, climax vegetation was boreal woodland

Answer 20

- the Sahara used to be a mosaic of lakes and oases with vegetation - eustatic sea level change - waxing and waning of ice sheets raising and lowering sea level (creates land bridges e.g. Bering Land Bridge connecting N. America to Asia)

Answer 21

Tropical Sub-tropical Temperate Boreal

Answer 22

- treeless tundra - (mammoth) steppe (cool, unforested grassland) - large herbivores roamed land (mammoths, reindeer, bison)

Answer 23

- broadleaved deciduous woodland and grassland - Britain: warm loving insects, large mammals such as hippos in the Thames and short-tusked elephants in Trafalgar Square, southern rivers contain molluscs that now thrive in Nile Valley

Answer 24

We can find different evidence in Britain which allows us to understand the previous stadials, interstadials, glacials and interglacials. BUT the evidence is usually fragmented e.g. The Ipswichian interglacial was the last interglacial, with an average temp 1-2 degrees warmer than today, with hippos in the Rhine and Thames. Sea level 6-9m higher than today.

Quaternary geology Flashcards

(48 cards)