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

Troposphere

The troposphere is the layer that contains 20% of all the gases of the atmosphere. Meteorological phenomena, such as clouds and precipitation, take place in the troposphere.

Stratosphere

The stratosphere is the layer that contains the ozone layer. This absorbs much of the Sun's radiation, so temperatures rise in the stratosphere.

Mesosphere

The mesosphere has very low temperatures, reaching -140°C.

Thermosphere

The thermosphere is also known as the ionosphere. Temperatures in this layer are very high.

Exosphere

The exosphere is the outer layer of the atmosphere. Artificial satellites orbit the Earth in the exosphere.

The Earth's crust is made up of three main types of rocks: igneous, sedimentary, and metamorphic.

Igneous Rocks

Igneous rocks are formed when magma (molten rock) cools and solidifies. They can be classified into two main types: intrusive and extrusive.

• Intrusive igneous rocks are formed when magma cools and solidifies slowly beneath the Earth's surface.
• Extrusive igneous rocks are formed when magma cools and solidifies quickly on the Earth's surface.

Sedimentary Rocks

Sedimentary rocks are formed when sediments (pieces of other rocks, minerals, or organic matter) are compacted and cemented together.

• Clastic sedimentary rocks are formed from the accumulation of broken pieces of other rocks.
• Chemical sedimentary rocks are formed from the precipitation

Oceanography: Earth's Marine Realm

Ocean Coverage and Resources

Oceans cover 71% of Earth's surface and hold 97% of its water. They provide crucial resources, including one-third of natural gas and oil, 16% of protein, and 50% of our oxygen.

Maps and Projections

A map is a representation, usually on a flat surface, of a region of Earth or the heavens. A projection is the image of a geometric figure reproduced on a line, plane, or surface.

Types of Maps:

• Political
• Physiographic
• Geologic
• Topographic
• Bathymetric

Ocean Provinces

• Continental Margins: Shallow areas close to shore.
• Deep-Ocean Basins: Deep-water areas farther from land.
• Mid-Ocean Ridge: A submarine mountain range.

Geological Features

Hot spots are plumes originating from the core-mantle boundary.... Continue reading "Oceanography: Exploring Earth's Vast Marine Realm" »

Understanding Soil Exploration: Test Pits & Boreholes

Test Pits and Trial Pits

Test pits, also known as trial pits, are excavations made in the soil to observe and analyze the subsurface layers. These pits are typically dug to a depth of less than 5 meters and have a width of no more than 0.75 to 1 meter. Key requirements for test pit excavation include:

• Wall stability to ensure safety and accurate observation.
• Excavation above the Groundwater Level (GWL) where possible.
• Soil excavation primarily by mechanical means.

Test pits are utilized to explore soil conditions and the sequence of strata up to a depth of 4-5 meters. They also allow for the collection of soil samples for subsequent laboratory testing.

In-Situ Soil Testing Tools

Several tools... Continue reading "Geotechnical Soil Investigation Techniques" »

Warm Area Biomes

Origin of Terrestrial Atmospheres

Venus, Earth, and Mars received their atmospheres through outgassing. Chemical reactions caused CO₂ on Earth to dissolve in oceans and go into carbonate rocks, like limestone. Mars lost much of its atmosphere through impacts.

Formation of the Maria

• The Moon once had a molten interior.
• Several large impacts made huge crater basins.
• This “runny” lava filled in the basins.

Mercury: A Dead Planet

• No atmosphere.
• Has no maria, but small lava plains.
• Has fewer craters than the Moon.
• Craters are shallower than the Moon's due to higher gravity on Mercury.
• Evidence for tectonic processes.
• Evidence for ice at the North Pole.

Mars: Mountains and Canyons

• Mountains and canyons.
• Volcanoes.
• Thin atmosphere.
• No plate tectonics; volcanoes

Jovian Planets and Their Numerous Moons

Jovian planets are known for their abundance of moons. We can categorize these moons into three groups:

Moon Classifications

1. Small Moons: These moons, less than 300 km across, lack a spherical shape and are likely captured asteroids.
2. Medium Moons: Ranging from 300 to 1,500 km in diameter.
3. Large Moons: These moons exceed 1,500 km in diameter. Both medium and large moons likely formed like planets from the "mini-Solar nebulae" surrounding the Jovian planets.

Jovian moons primarily consist of ice. Due to the lower melting point of ice compared to rock, less heating is needed to create molten cores. This allows for volcanism and tectonics to occur. Tidal heating, another significant heat source, plays a crucial... Continue reading "Exploring the Jovian Moons: A Comprehensive Guide" »

Write the schedule of the main big bang events.