Glossary

Adit
A horizontal passage or tunnel to enter an underground mine

Andesite
A type of intrusive volcanic rock

Aphanitic
Rock texture where crystals are too small to be seen by the naked eye

Argillic
A type of alteration of rock leading to the formation of clay minerals

Batholith
A large body of intrusive igneous rock

Breccia
Fragmental rock with angular components

Dextral fault movement
Where the block on the far side appears to have moved to the right

Disseminated
Containing small discreet grains of sulphides

Epithermal
Ore body formed at shallow depths from ascending hydrothermal solutions

Granodiorite
A type of intrusive igneous rock composition

Hematite
An iron oxide mineral, the principal ore of iron

Igneous
Rock or mineral that solidified from molten or partly molten material

Ignimbrite
A silicic extrusive volcanic rock

Intrusive
A body of igneous rock that invades older rocks

IOCG
A type of mineral deposit containing iron oxide, copper and gold

Limonite
A brown hydrous iron oxide

Magmatic
An accumulation of igneous rock

Magnetics
Measurement of the earth’s magnetic field and the magnetic character of the rocks

Manto
Vein, seam or lode spread horizontally (from the Spanish for blanket)

Metallogenic
Pertaining to the origin of ore deposits

Mineralisation
Anomalous concentration of mineral matter in rock; viz along faults, or close to deep igneous bodies

Mt
Million tonnes

Orogen
A belt of deformed rocks

Polymetallic
Mineralization with more than one type of valuable mineral

Porphyry
Texture in an igneous rock, type of copper deposit associated with igneous intrusions

Pyritisation
Introduction of pyrite (iron sulphide) into a rock during alteration and mineralization

Silicification
Introduction of silica into a rock during alteration and mineralization

Sinistral
Fault movement where the block on the far side appears to have moved to the left

Skarn
Rocks composed of calc silicates and ore metals derived from an intrusive

Speccularite
A type of hematite with a metallic lustre

Stockwork
Rock mass interpenetrated by small veins of random orientation

Stratiform
Having form of layers, ore body in layer within sediments

Subduction
Process where one tectonic plate passes beneath another over-riding plate

Sulphidation
Introduction of sulphide minerals into a rock during alteration and mineralisation

Supergene
Enrichment of minerals due to weathering and descending water table

Talus
Accumulation of fallen material at the foot of a slope

Volcanic
Pertaining to volcanoes, process or rock derived from a volcano

Vuggy
Rocks with many cavities (vugs)

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