Stone Age to Iron Age: Evolution of Materials and Technology
Stone Age
Materials Used in the Stone Age:
Paleolithic inhabitants made their first tools from a limited variety of rocks and minerals. These materials shared certain properties: hardness, toughness, fragility, and a conchoidal fracture. The variety in composition led to compounds, in some areas, with silicon. Siliceous materials were accessible where limestone was not present. The first tools were crude, but later the technique was perfected, resulting in more complex and useful tools. Fire was discovered
Read MoreEarth’s Structure, Rocks, Minerals, and Soil Formation
The Earth: A Unique Planet
Key characteristics of the Earth include:
- Presence of oxygen
- Temperature ideal for human life
- Abundance of water
Geosphere: Earth’s Internal Structure
Crust
The crust is the outermost layer of the Earth, where life unfolds. It represents only 2% of our planet’s volume. Its thickness is about 30km, and its temperature ranges from 22°C to 400°C.
Mantle
The mantle is the most voluminous layer, making up 82% of the Earth’s volume. It has a thickness of about 2870 km and is divided
Read MoreLandforms: Classification, Relief Types, and Geological Processes
Landform Classification and Interpretation
1 – When we observe a landscape, we perceive different elements simultaneously. The relief is the aspect of the Earth’s surface, regardless of biotic elements.
Descriptive Classification of Landforms
Landforms are classified by their appearance:
- Mountain: Isolated relief with a large gap between its base and top.
- Cerro: Isolated relief with little unevenness.
- Gorge or Throat: Narrow valley bottom featuring steep walls on either side.
- Plateau: Isolated, flat-topped
Plate Tectonics: Earth’s Dynamic Crust and Seismic Activity
**Borders Neutral**
Borders neutral: Only collide and slide; therefore, the lithosphere is neither created nor destroyed. They can have volcanism. Example: San Andreas Fault.
**Tapering Edges**
Tapering edges: Also called destructive edges. The oceanic crust is destroyed. Their types are:
- Ocean-continent: The oceanic crust is introduced into the continental crust, which makes mountains climb (Andes).
- Ocean-ocean: The oceanic crust is introduced into a mixed crust (Japan).
- Continent-continent: Both are
Earth’s Magnetic Field and Rock Magnetization: Key Concepts
Earth’s Magnetic Field and Rock Magnetization
Types of Rock Magnetization
a) Sedimentary Rock (Detrital Remanent Magnetism)
Origin: Magnetic minerals align with the Earth’s magnetic field during sediment deposition. This alignment is locked in when the sediment lithifies into rock.
Example: Magnetite in sandstone aligns during deposition and retains the Earth’s magnetic field direction.
b) Metamorphic Rock (Thermoremanent Magnetism)
Origin: During metamorphism, rocks heat up and lose their magnetization.
Read MoreEarth and the Universe: Formation, Movements, and Relief
1st Item: The Earth and the Universe
1. The Earth, a Planet of the Solar System
The universe contains all celestial bodies in space: stars, planets, satellites, asteroids, and comets. Stars are celestial bodies with their own light and heat, grouped into galaxies. Planets do not have their own light and form planetary systems around a star. The solar system is composed of eight planets and the Sun. The Earth is a planet in the solar system, shaped like a sphere flattened at the poles. Its surface
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