Keywords Flashcards
Xenoliths
Pieces of country rock within igneous rocks
Kimberlite
Fine grained ultramafic igneous rocks
Oceanic crust
- Rich in Mg and Fe
- Basaltic (dolerite, gabbro)
- 2.9 gcm^-3
- <200Ma
- 5-10km, 7km average
Continental crust
- Rich in Al and Si
- granitic, igneous, sedimentary, metamorphic
- 2.7 gcm^-3
- <4000Ma
- <90km, average 35km
Free Air Anomaly
The higher the altitude the further you are from the centre of the Earth
Bouger Anomaly
For every 10m of mass above sea level, 1mgal is taken off the gravity
Isostacy
Point of equilibrium between the Earth’s lithosphere and asthenosphere, so that the lithosphere ‘floats’ on top of the asthenosphere.
Isostatic rebound
The rising up of land masses that were once depressed by ice
Mesosaurus
Ancestor of an alligator, can’t swim over oceans, travels on land. Found in: South America and Africa
Glossopteris
Plant leaf found in: South America, Africa, India and Antarctica
Lystrosaurus
Ancestor of a Walrus/Seal that couldn’t swim. Found in: Africa, India, Australia and Antarctica
Tillites
Glacial deposits. Found in: South America, Africa, India and Antarctica
Amygdaloidal texture
Texture of a rock where minerals are deposited in vesicles
Batholiths
Large intrusive igneous body, which is at least 100km^2
Pluton
Large intrusive igneous body, which is under 100km^2
Transgressive sills
Sills that step up a bed
Joint
A fracture in a competent rock with no observable movement
Horst
The area formed by the upthrow between two normal faults
Graben
The area formed by the downthrow between two normal faults
Carbonation
Calcite + carbonic acid —> calcium + hydrogen carbonate ions
Hydrolysis
Feldspar + carbonic acid / water —> kaolinite + calcite
What are the three main minerals in sedimentary rocks?
Calcite, Aragonite, Dolomite
Seismic tomography
A technique for 3D imaging of the subsurface of the Earth using seismic waves
What is the sequence of evaporation?
Calcite, Gypsum, Anhydrite, Halite, Sylvite
