Overview
This lecture covers essential geographical terms and landforms, explaining their formation, characteristics, and examples to enhance understanding of Earth's diverse physical features.
Major Landforms & Their Formation
- Mountains form from tectonic plate movements (e.g., Himalayas through plate convergence).
- Snow-capped Mountains appear cold at the top due to thinner atmosphere and lower temperatures.
- Glaciers develop from accumulated, compressed snow in high latitudes/altitudes, move slowly, and are freshwater sources.
- Volcanoes form where tectonic plates converge or diverge, allowing magma to erupt.
- Plateaus are elevated flat areas, created by tectonic uplift or volcanic eruptions.
- Buttes and Mesas are isolated hills with flat tops, formed from plateau erosion.
Water-Based Landforms
- Rivers originate from elevated regions, eroding land to form valleys and transporting sediment.
- Deltas develop where rivers slow and deposit sediment at the mouth (e.g., where rivers meet seas).
- Lakes are inland water bodies; can be open (drain via rivers) or closed (lose water via evaporation).
- Oceans cover 71% of Earth's surface, formed by Earth’s cooling and water accumulation.
- Seas are smaller, shallower, and partly surrounded by land compared to oceans.
Coastal & Marine Features
- Coasts are where land meets water, shaped by waves, tides, and sediment deposits.
- Gulfs and bays are large sea inlets; gulfs are deeper, bays are semicircular.
- Straits are narrow waterways connecting two larger bodies; channels are wider.
- Islands are land surrounded by water; archipelagos are groups of islands.
- Atolls are ring-shaped coral islands enclosing a lagoon.
- Cliffs are steep rock faces, mainly on coasts.
- Beaches consist of sand and pebbles, constantly reshaped by waves.
Other Unique Landforms
- Deserts are dry regions with low rainfall; include hot, rainshadow, coastal, and polar deserts.
- Oases are fertile spots in deserts with groundwater at the surface.
- Rainforests have high rainfall and biodiversity, mainly in tropical regions.
- Prairies/Grasslands are flat, fertile lands dominated by grasses; called different names worldwide.
- Tundra is a cold, treeless, high-latitude or high-altitude region.
- Canyons and valleys are deep land cuts formed by river or glacier erosion.
- Basins are low-lying depressions, sometimes filled with water.
- Peninsulas are surrounded by water on three sides; capes are narrow land extensions into water.
- Isthmuses are narrow strips of land connecting two larger land areas.
- Marshes (grassy) and swamps (woody) are wetlands; sounds are large sea inlets wider than fjords (fjords carved by glaciers).
- Sand dunes are mounds shaped by wind in deserts and beaches.
- Waterfalls form where rivers drop from hard to soft rock layers.
Key Terms & Definitions
- Tectonic Plate — Large slab of Earth's crust moving atop the mantle.
- Glacier — Slowly moving mass of ice formed by compacted snow.
- Delta — Landform at a river mouth from sediment deposition.
- Strait — Narrow waterway connecting two larger water bodies.
- Archipelago — Group or chain of islands.
- Atoll — Ring-shaped coral reef island enclosing a lagoon.
- Isthmus — Narrow land connecting two larger land masses.
- Marsh — Wetland dominated by grasses.
- Swamp — Wetland with trees and woody plants.
Action Items / Next Steps
- Review and memorize key terms and their characteristics.
- Study examples of each landform on a world map.
- Prepare questions for clarification on specific terms or processes.