Understanding Watersheds: Key Elements and River Basin Types
Understanding Watersheds
A watershed encompasses several key elements:
Watershed Divide
The watershed divide is a line that delineates the watershed, marking the boundary between it and adjacent watersheds. Precipitation on either side of the divide flows into different rivers. It’s also known as the divortium aquarum.
The Main River
The main river is typically defined as the watercourse with the greatest volume of water (average or maximum), the longest length, or the largest drainage area. Defining
Read MoreUnderstanding Tectonic Stress, Deformation, and Geological Structures
Tectonic Stress and Strain
Tectonic Stress
Rock may be subjected to three types of stress:
- Compression: These forces cause shortening and thickening of the rocks. These pressures originate from convergent plate margins and transform faults.
- Tension: These forces produce stretching and thinning of the rocks. They can also arise when rocks are released from compressive stress.
- Shear: These are pressures acting on a surface in opposite directions. Shear stress is developed at faults and along plate boundaries.
Solar Energy: Impact on Earth, Meteorology & Uses
Solar Energy and Earth’s Processes
The Sun emits energy created by nuclear reactions. Geological agents are natural systems that produce erosion, mass movement, and sedimentation. Hot water moves due to temperature differences.
When land and water absorb sunlight, they warm up. Some areas of the Earth receive more solar energy than others. Around the Equator, the rays are perpendicular to the ground. At the poles, the rays are oblique.
Atmospheric and Oceanic Currents
Air (ocean) currents are movements
Read MoreMagma Formation, Transport, and Volcanic Processes
Magma Formation and Volcanic Processes
Mid-Ocean Ridges
Thinning of lithosphere due to slab pull forces from the denser and older subducting slab. Adiabatic decompression drives melting of the mantle. Production of primitive basalt (~50% SiO2) called Mid-Ocean Ridge Basalt, or MORB. Volcanism is generally effusive (not explosive), producing voluminous basaltic lava flows and pillow lavas.
Continental Rifts
Melting due to thinning of the lithosphere, decompression-driven. More alkaline basalt than MORB
Read MorePlate Tectonics: Convergence, Subduction, and Dynamics
Plate Convergence and Subduction Zones
Oceanic-Oceanic Plate Convergence
Occurs when the oceanic lithosphere cools and thickens as it moves away from the ridge. Eventually, it breaks and subducts.
Characteristics of subduction zones:
- Great bow.
- Intense magmatism, resulting in a string of volcanic islands on the overriding plate.
- Tectonic erosion.
- Melting of the oceanic crust as it enters the sub-lithospheric mantle.
- The overriding plate experiences relatively low pressure, which means:
- Sediments are subducted
Understanding Chemical Equations: Balancing, Types, and Calculations
Understanding Chemical Equations
The Matmata method of equalization in chemical equations involves ensuring that the number of atoms of each element is equal on both sides of the equation.
Methods for Balancing Chemical Equations
The method involves testing coefficients for the elements involved. This begins by adjusting coefficients for elements involved in the compounds.
Types of Chemical Reactions
- Decomposition or Chemical Analysis: AB → A + B
- Synthesis: A + B → AB
- Displacement or Replacement: AB