Chapter 2: Rocks, Resources and Scenery Flashcards
Define Geological timescale
The period of geological time since life became abundant 542 million years ago, which geologists have divided into eras and periods.
Define Crust
The outer layer of the earth
Define igneous rock
Rocks formed from cooling of molten lava
Define sedimentary rock
Most commonly, rocks formed from the accumulation of sediment on the sea floor
Define metamorphic rock
Rocks that have undergone a change in their chemistry and texture as a result of heating and pressure
What is the rock cycle?
The connections between the three rock types shown in the form of a diagram
Define weathering
The destruction of rocks in situ, generally caused by the weather
What is mechanical weathering?
Weathering that doses not involve chemical changes
Define scree
Deposits of angular rock fragments found at the foot of rocky outcrops
What is chemical weathering?
Weathering that involves a chemical change taking place
What is biological weathering?
Weathering caused by living organisms such as tree roots or burrowing animals
What is freeze thaw weathering?
Weathering involving the repeated cycles of freezing and thawing
Define pores
Holes in a rock
Define exfoliation
Flaking of the outer surface of rocks mainly caused by repeated cycles of hot and cold
What is solution?
The dissolving of rocks or minerals by rainwater
Define carbonation
The weathering of limestone and chalk by acidic rainwater
What is a batholith?
A huge irregular-shaped mesas of intrusive igneous rock that only reaches the ground surface when the overlying rocks are removed
Define joints
Cracks that may run horizontally or vertically through rock
What is impermeable rock?
A rock that does not allow water to pass through it
What is a tor?
An isolated outcrop of rock on a hilltop typically found in granite landscapes
What is mass movement?
The downhill movement of material under the influence of gravity
What is a cliff?
A steep or vertical face of rock at the coast.
What is permeable rock?
A rock that allows water to pass through it
What is a water table?
The upper surface of underground water
What is a spring
Water re-emerging from the rock onto ground surface. These usually occur as a line of of springs at the base of a scarp slope.
Define vale
In the landscape, a flat plain typically formed on clay
What is an escarpment/cuesta?
An outcrop of chalk compromising a steep scarp slope and a more gentle dip slope
