Earth’s Geodynamic Cycle: Rock Formation and Volcanoes
The Geodynamic Cycle: Earth Material Transformation
Also called the Geodynamic Cycle or Rock Cycle, this set of processes explains how Earth materials change and transform geological substances. This cycle relates to erosion and plate tectonics operating over vast temporal scales.
Stages of Rock Formation
The cycle involves various stages, resulting in different rock formations:
Stage 1: Formation of Igneous Rocks
Igneous rocks form when magma cools and solidifies into interlocking crystals. These rocks
Read MoreEssential Building Construction Techniques and Material Properties
Methods of Underpinning
Underpinning involves strengthening or increasing the depth of an existing foundation. The primary methods include:
- Pit Method
- Pile Method
- Miscellaneous Methods
1. Pit Method of Underpinning
In this method, the existing wall is divided into suitable sections, typically measuring about 1.20 m to 1.50 m in width.
Holes are made in the existing wall. Needles with bearing plates are then inserted through these holes and supported on jacks (as shown in diagrams). The pit is excavated,
Read MoreGeological Processes, Mineral Deposits, and Geohazards
Mineral Deposits and Formation Processes
Mineral deposits are concentrations of materials linked to geological processes, requiring sufficient concentration factors to be economically viable.
Geological Processes
These are categorized into two main types:
- Exogenous Processes: External processes (e.g., weathering, sedimentation).
- Endogenous Processes: Internal processes (e.g., volcanism, tectonics).
Endogenous Mineralization
Associated with volcanic construction at plate boundaries (active margins, destructive
Read MoreAcropolis Masterpieces: Erechtheion Architecture and Parthenon Sculptures
Erechtheion: Classical Architecture and Cults
Historical Context and Construction
The Erechtheion belongs to the Classic Period. It is located in the far north of the Acropolis. The construction was entrusted to Mnesikles. The first phase was initiated during the Peace of Nicias, interrupted by the resumption of the Peloponnesian War. The building, the most grandiose Greek Ionic temple built during the time of Pericles, was finally completed in 406 BCE. It was intended to rebuild the temple destroyed
Read MoreGeographical Processes and Landform Development
Geographical Processes: Weathering and Erosion
Key Definitions
Weathering: The rock is broken down and is weakened but does not move.
Erosion: When rock is worn away and moved by forces of nature.
Types of Weathering
Weathering can be categorized as:
- Mechanical
- Chemical
- Freeze-thaw
- Biological
- Onion-skin (Physical)
Chemical Weathering
This occurs when acids in rain and sea/river water react with rock, causing it to wear away.
Freeze-Thaw Weathering
- Water fills a crack in a rock.
- The water freezes and expands.
- The
Essential Definitions of Earth’s Major Geographical Features
Understanding the terminology used to describe the Earth’s surface is fundamental to geography. Below is a comprehensive list of key landforms, water bodies, and terrestrial features, along with their precise definitions.
Landforms and Terrestrial Features
Mountain
A large natural elevation of the earth’s surface.
Hill
A naturally raised area of land, smaller than a mountain.
Valley
A low area of land between hills or mountains.
Plain
A large area of flat land.
Plateau
An area of relatively level high ground.