Notes, summaries, assignments, exams, and problems for Geology

Structure of the Earth

Earth consists of four concentric layers: inner core, outer core, mantle, and crust. The crust is made up of tectonic plates, which are in constant motion. Earthquakes and volcanoes are most likely to occur at plate boundaries.

Inner Core

The inner core is in the center and is the hottest part of the Earth. It is solid and made up of iron and nickel with temperatures reaching 5,500ºC.

Outer Core

The outer core is the layer surrounding the inner core. It is a liquid layer, also made up of iron and nickel. Temperatures are similar to the inner core.

Mantle

The mantle is the widest section of the Earth, with a thickness of approximately 2,900km. It is made up of semi-molten rock called magma.

Crust

The crust is the outer layer of... Continue reading "Structure of the Earth and Plate Tectonics: A Comprehensive Guide" »

• Pollution is the addition of a substance or an agent to an environment by human activity, at a rate greater than that at which it can be rendered harmless by the environment and which has an appreciable effect on the organism within it.

• Basically… contamination of nature which affects living organisms.

• Substances exposed to the atmosphere and littering by humans.

POINT SOURCE POLLUTION (Coming from a direct source)

• The pollutants are coming from clear identifiable sources: sewage into a river.

• Easier to see who is polluting.

• Easier to manage and monitor.
  

NON-POINT SOURCE POLLUTION (NPS)

• Release of pollutants from numerous sources: car fumes, etc.

• Almost impossible to detect the origins of the pollutants.

• Rain can collect various forms of nitrates and

Collapse

Collapse is the reduction in wood size during drying before fiber saturation. It manifests as a corrugated surface due to crushed wood tissues and sometimes internal lens-shaped cracks. Collapse occurs in some wood species when dried slowly at high temperatures or humidity, or during rapid outdoor drying. It's more intense on radial cut faces than tangential ones. This defect causes significant wood loss during surfacing and reduces mechanical strength. Tangential shrinkage is greater than radial shrinkage, often separating wood tissues parallel to the weaker radial parenchyma cells. The pith is also susceptible to damage, developing cracks and crevices. In eucalyptus, avoid sawing the pith to achieve good quality dried products.

Drying... Continue reading "Wood Defects and Degradation" »

Trenches:

A narrow, deep depression in the sea floor.

Ridges:

A long narrow hilltop mountain range or watershed.

Disagreement with Alfred and Changed Opinion

Wegener's hypothesis was not widely accepted because he could not explain how the continents moved. In the late 1950s and 1960s, scientists were able to put together the evidence and concluded that the continents did drift.

Layers of the Earth

The innermost layer, the core, is mostly iron. The pressure at the inner core is more than a million times that at Earth's surface. The layer outside is the mantle, though it is thought to be solid, it is very hot, near the melting point of the rocks. The crust is the outermost, and therefore best-known, layer of Earth.

Theory of Plate Tectonics

The theory... Continue reading "Trenches, Ridges, and Plate Tectonics: Exploring Earth's Geology" »

Natural Disasters

• Avalanche

• Drought

  Drought is the unusual dryness of the soil caused by levels of precipitation.

• Earthquake

  An earthquake is the result of a sudden release of energy.

• Famine

• Flood

  A flood is an overflow of water that covers the earth.

• Hurricane

• Landslide

• Tornado

  A tornado is a column of violent rotating air.

• Tsunami

  A tsunami consists of huge waves caused by an underwater earthquake or a volcanic eruption.

• Volcano

  Volcanoes can cause widespread destruction and consequent disaster in various ways.

• Wildfire

Weather

• Blizzard

• Cloudy

• Damp

• Dry

• Foggy

• Hailstones

• Heatwave

• Icy

• Rainy

• Snowy

• Stormy

• Sunny

• Thunder and Lightning

• Warm

• Wet

• Windy

Preindustrial Societies

Hunter-Gatherer Societies

Hunting, fishing, and gathering fruits and roots were essential for survival in hunter-gatherer societies. These societies had very little impact on the environment.

Agricultural Societies

Agricultural societies formed larger groups. The agricultural revolution transformed the way resources were obtained through:

• Plant species cultivation
• Hydraulic work (reservoirs, dykes, terraces, canals, and channels)

The impact on the environment was relatively small.

Industrial Societies

Industrial Revolution

From the 18th to the 20th century, a new economic model emerged based on the mass production of goods using enormous amounts of energy. This led to serious environmental problems, including the over-exploitation... Continue reading "Environmental Issues and Sustainable Solutions" »

Localitation:

• Amazon
• Congo
• Indonesia

Temperature:

• High around 25º all months
• Hot weather

Spaciouness:

• Low temperature
• Less than 3º

Precipitation:

• High and regular more than 2000 mm

Vegetation:

• Rainforest
• Central Africa
• India
• Central America
• Surrounds the Equatorial climate

Temperature:

• High more than 20º all months
• Hot weather

Spaciouness:

• A few between (3º-10º)

Precipitation:

• Irregular, two seasons: summer and Winter
• High 1000 mm
• More than 2000 mm

Vegetation:

• Tropical Gallery Forest
• Sahara
• Kalahari

Temperature:

• High temperature
• Average temperature higher than 20º

Spaciouness:

• Big spaciouness termal
• Differents
• Day/night
• Summer/winter

Precipitation:

• Low (< than 200 mm)
• Irregulars

Vegetation:

• Just Oasis

Localitation:

• Occidental Europe
• South Coast of Chile
• West of Canada
• New Zealand

Temperature:

Types of Stress

• Compression: pressure from both sides
• Tension: pressure from pulling apart
• Shear: opposite pressure, land grinding past other land

Strength of the Crust

The strength of the continental crust (quartz and feldspar) increases with depth then weakens.

• Brittle (surface/less depth, temp, and pressure): stress makes rock fracture, but rock remains intact
• Ductile (more depth, temp, and pressure): stress makes rock flow in solid state, rock resists deformation.

Joint

The crack where the rock was pulled apart

Stresses that form joint:

• Burial and tectonic forces: force from every side of the rock, straight cracks
• Cooling and contraction: ex-when mud dries it cracks
• Unloading: pressure in an uplift, mountain

Fault

Rocks have slipped passed one another

Movement

•What makes up a beach?

Whatever is locally available. This could be boulders, sand, mud, biological material. Whatever is near.

•What are the 3 different ways sand can move along the beach?

- Perpendicular via swash (up the beach) or backwash (goes back to the ocean)

- Parallel to the beach via longshore currents

•What is the difference between a summertime and wintertime beach?

Summertime beach has mostly swash and a wide sandy beach. Wintertime beach has a lot of wave activity so the beach is narrower and backwash dominates.

•What are the two major types of shores and their characteristics?

Erosional- California. Will see cliffs. Over two plates

Depositional- Miami. Will see barrier islands. Over a single plate.

•Which coast is experiencing... Continue reading "cgghjk;" »