Tectonic Processes, Rocks and Landform Development
What you must know
Earth's crust is divided into plates that move on the mantle. At divergent boundaries plates separate; at convergent boundaries one plate subducts; at conservative boundaries they slide. These produce earthquakes, volcanoes, fold mountains and ocean trenches. The Bahamas lies on a stable carbonate platform away from major plate margins, so it has no active volcanoes and few earthquakes.
Concepts to master
The rock cycle; igneous, sedimentary and metamorphic rocks; weathering (physical, chemical, biological); erosion; deposition; and karst processes. Limestone is sedimentary, formed from calcium carbonate, and dissolves in weakly acidic rainwater to create caves, stalactites, stalagmites, sinkholes and blue holes.
Traps in questions
Do not place the Bahamas on a plate boundary. Do not confuse weathering (breakdown in situ) with erosion (transport away). Do not call limestone igneous. Remember that earthquakes are measured on the Richter scale but damage is described by the Mercalli scale.
Rule of thumb
For rock questions, name the rock, its origin and one Bahamian example. Example: limestone - sedimentary, formed from compacted coral and shell fragments - makes up most of The Bahamas and dissolves to form blue holes.