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

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;" »

1. Internal Geologic Agents

Internal geologic agents, such as the movements of lithospheric plates, earthquakes, and volcanic eruptions, shape the Earth's relief. The energy source that drives these processes is the heat stored inside the Earth. Evidence of this heat is the geothermal gradient, defined as the increase in temperature with depth. This heat originates from:

• The collision of planetesimals during the Earth's formation
• The disintegration of radioactive elements

2. Movement of Lithospheric Plates

From a dynamic perspective, the Earth can be divided into three layers:

• Lithosphere: The rigid outermost layer composed of the crust and a portion of the upper mantle (from 0 to 100 km).
• Mesosphere: The rest of the mantle, a semi-liquid layer.
• Endosphere:

Oil and Gas Well Cementing Fundamentals

Cementing is a critical process in oil and gas well construction, ensuring well integrity, safety, and efficient hydrocarbon production. It involves pumping a cement slurry down the wellbore to fill the annulus between the casing and the formation, or to plug zones within the well.

Key Functions of Well Cementing

In oil and gas wells, the primary functions of cement are crucial for well integrity and longevity:

1. Provide zonal isolation, preventing fluid migration between different formations.
2. Support the axial load of casing strings, ensuring their stability and preventing collapse.
3. Protect casing against corrosive fluids and external pressures from the formation.
4. Support the wellbore, enhancing its stability

Ozone Depletion

Ozone depletion is a steady decline of about 4 percent in the total amount of ozone in Earth's stratosphere. There is also a much larger springtime decrease in the stratospheric ozone around Earth's polar regions. The latter phenomenon is referred to as the ozone hole.

Causes of Ozone Depletion

The main cause of the ozone hole is man-made chemicals, especially man-made halocarbon refrigerants, solvents, propellants, and foam-blowing agents (CFCs, HCFS, halons). These compounds are transported into the stratosphere by wind. Once in the stratosphere, they release halogen atoms through photodissociation, which catalyze the breakdown of ozone (O₃) into oxygen (O₂).^[3] Both types of ozone depletion were observed to increase as emissions... Continue reading "Ozone Depletion and the Greenhouse Effect" »

Florida's Aquifers

1. 150 to 70 million years ago (MYA), sediment formed on basement rock, becoming the bedrock (limestone and related rocks and shells).

2. 70-25 MYA: Various sea level fluctuations occurred during a major hot period, and sedimentation continued.

Biscayne Bay Aquifer

• Unconfined surficial aquifer
• Depth ranges from 0 feet in the west to 260 feet in the east

Floridian Aquifer

• Larger, deeper, and older than the Biscayne Bay Aquifer
• Confined in South Florida
• Unconfined in North Florida
• Saline water in South Florida

3. The Floridian Aquifer was formed between 150-25 MYA.

4. The Biscayne Bay Aquifer was formed between 2 MYA - 125,000 years ago (TYA).

• Pollution, seepage, and contamination
• Overuse (unnecessary wasting of water)

Coastal Water

1. Freshwater... Continue reading "Florida's Coastal Ecosystems: Aquifers, Marine Life, and Seagrass" »

The Natural and Human Causes and Consequences of River Flood: Flooding in Bangladesh (LEDC) 1998

Bangladesh has been formed by deposition from three main rivers: the Brahmaputra, the Ganges, and the Meghan. The sediment from these and over 50 other rivers forms one of the largest deltas in the world, with up to 80% of the country located on the delta. As a result, much of the country is just a few meters above sea level and is under threat from flooding and rising sea levels. Bangladesh has a very dense population growth (nearly 2.7% per annum). Almost all of Bangladesh's rivers have their source outside of the country. For example, the drainage basin of the Ganges and Brahmaputra covers 1.75 million km2 and includes the Himalayas, the Tibetan... Continue reading "Causes and Consequences of River Flooding in Bangladesh: A Case Study" »