Defintions —> Keywords Flashcards
Pieces of country rock within igneous rocks
Xenoliths
Fine crystal size ultramafic igneous rocks
Kimberlites
- Rich in Fe and Mg
- Basaltic (Dolerite and Gabbro)
- 2.9 gcm^-3
- < 200Ma
- 5-10km thickness (average = 7km)
Oceanic crust
- Rich in Al and Si
- Granitic (igneous, metamorphic, sedimentary)
- 2.7 gcm^-3
- < 4000Ma
- < 90km (average = 35km)
Continental crust
The higher the altitude, the further you are from the centre of the Earth
Free Air Anomaly
Minus 1mgal from the gravity for each 10m above sea level
Bouger Anomaly
The point of equilibrium between the lithosphere and asthenosphere where the lithosphere ‘floats’ on top of the asthenosphere
Isostacy
The rising up of land masses that were once depressed by ice
Isostatic rebound
Ancestor of an alligator, couldn’t swim far, travelled on land. Found in South America and Africa
Mesosaurus
Plant leaf, found in South America, Africa, India, Australia and Antarctica
Glossopteris
Ancestor of walrus/seal, couldn’t swim. Found in: Africa, India and Antarctica
Lystrosaurus
Glacial deposits, found in: South America, Africa, India, Australia and Antarctica
Tillites
Texture of a rock where minerals are deposited in vesicles
Amygdaloidal texture
Large intrusive igneous body, > 100km^2
Batholith
Large intrusive igneous body, < 100km^2
Pluton
A sill which steps up a bed
Transgressive sill
A fracture in a competent rock with no observable movement
Joint
The area formed by upthrow between two normal faults
Horst
The area formed from downthrow between two normal faults
Graben
Calcite + carbonic acid —> calcium + hydrogen carbonate ions
Carbonation
Feldspar + carbonic acid (water) —> kaolite + calcite
Hydrolysis
What are the three main minerals in sedimentary rocks
Calcite, Aragonite and Dolomite
A technique for 3D imaging of the subsurface of the Earth, using seismic waves
Seismic tomography
Calcite, gypsum, anhydrite, halite, sylvite
Sequence of evaporation
