Technical Glossary:Aeromagnetic surveyA geophysical survey...

Technical Glossary:



Aeromagnetic survey

A geophysical survey method conducted from an
aircraft that measures the magnetic intensities of
the rock units below.
Ag
The chemical symbol for the metallic element silver.
aircore drilling
A method of rotary drilling whereby rock chips are
recovered by air flow returning inside the rods.
Al
The chemical symbol for the metallic element
aluminium.
Alluvium
Detrital sediment laid down by water, especially by
rivers or streams.
alteration
A change in mineralogical composition of a
rock commonly brought about by reactions with
hydrothermal fluids or weathering.
amphibolite
A metamorphic rock composed predominantly of
amphibole and plagioclase.
Andesite
A volcanic rock of intermediate colour
and composition
Anomaly
An area highlighted by a geochemical or geophysical
survey as possessing greater than background metal
values or physical characteristics.
Anticline
Rock strata folded in a convex upward manner.
Archaean
The oldest rocks of the Pre Cambrian Era, older
than about 2500 million years.
Arsenopyrite
A sulphide mineral of arsenic and iron.
Assay
A laboratory procedure for determining the
presence or quantity of a component.
Au
The chemical symbol for the metallic element gold.
Auger sampling
A drilling process using a spiral auger to drill and
sample generally unconsolidated sediments.
Ba
The chemical symbol for the element barium.
Basal
At the base of.
Basalt
An extrusive volcanic rock: dark coloured, finegrained,
composed mainly of feldspar and pyroxene.
Base metals
The more common and chemically active metals,
especially. copper, lead, zinc, and nickel.
Basement
The igneous and metamorphic crust of the earth,
underlying sedimentary deposits.
Bedrock
Solid rock underlying surficial deposits.
billion
1,000 million.
Biotite
A black platy mineral.
Carbonaceous
Containing carbon.
carbonate
A compound containing the radical CO3; commonly
calcium carbonate or calcium-magnesium
carbonate.
Chalcopyrite
The sulphide mineral of copper; CuFeS2.
Chert
Very fine-grained rock composed of silica.
Chlorite
A pale-green platy hydrous silicate mineral related
to mica.
Clastic
Consisting of fragments that have been moved from
their place of origin.
Conglomerate
A clastic sedimentary rock containing rounded
pebbles or boulders
Copper (Cu)
The metallic element (Its chemical symbol).
Cr
The chemical symbol for the metallic element
chromium.
Cumulate
An igneous rock formed by the accumulation of
crystals that crystallised within a magma and then
settled to the base of the magma.
Craton
Large, and usually ancient, stable mass of the
earth’s crust.
Deformation
A general term for the process of folding, faulting,
shearing, compression or extension of rocks as a
result of stress.
Diamond drilling
Method of obtaining cylindrical core of rock
by drilling with a diamond-set or diamondimpregnated
bit.
Disseminated
Mineralisation in which mineral grains (especially
sulphides) are dispersed throughout a host rock (as
against being concentrated in a massive band).
Dolarenite
Dolomite rock consisting of sand sized grains.
Dolerite
A medium grained mafic intrusive rock composed
mostly of pyroxene and plagioclase.
Dololutite
Dolomite rock consisting of clay sized particles.
Dolomite
The mineral CaMg(Co3)2, or the rock composed of
the mineral.
Dolostone
A rock composed of the mineral dolomite.
Dolorudite
A dolomitic rock composed of fragments larger than
sand sized.
Dyke
Thin, sheet-like intrusion of magmatic rock.
EM Electro-magnetic; a
geophysical exploration method.
Evaporite
A sedimentary rock formed by the evaporation of
saline water.
Fault
A fracture in rock along which there has been
relative displacement of the two sides either
vertically or horizontally
Fe
The chemical symbol for the metallic element iron.
Feldspars
A group of pale coloured silicate minerals that are a
common component of igneous rocks.
Felsic
Descriptive of light coloured rock containing an
abundance of feldspar (generally potassium rich)
and quartz.
Fold
A bend in strata or any planar structure.
g/t
Grams per tonne.
gabbro
A coarse grained intrusive rock, which is low in
silica and has relatively high levels or iron and
magnesium minerals.
Galena
The common sulphide mineral of lead.
Geochemistry
The study of the abundance of elements in rocks
and soil by chemical methods.
Geophysics
The study and measurement of the physical
properties of rocks and geological formations.
GEOTEM A proprietary electromagnetic geophysical
exploration method.
Gold
The metallic element (chemical symbol Au).
Grade
Expression of relative quality (e.g high grade) or of
numerical quality (e.g. 1.2% Ni).
Granite
Light coloured, coarse-grained, intrusive igneous
rock; comprises large sections of the Earth’s
continental crust.
Granitoid
A field term for a coarse grained felsic rock
resembling granite.
Greenschist facies
A group of weakly metamorphosed rocks.
Greenstone
A field term for metamorphosed mafic and
ultramafic igneous rocks.
Hinge
A line that separates a relatively unfolded portion
of a group of rocks from a folded portion.
Hornblende
A green silicate mineral of the amphibole group.
Hydrothermal
Hot water; a mineral or geological process involving
hot water-bearing fluids.
Igneous
Formed by solidification of hot mobile material
termed magma.
Inferred Resource
That part of a resource for which tonnage and
or grade can be estimated with only low levels
of confidence.
INPUT An airborne electromagnetic exploration system.
Intrusive
A mass of rock formed by magma cooling beneath
the earth’s surface.
IP Induced polarisation: an electromagnetic
geophysical survey exploration method.
Jaspilite
A chemical sedimentary rock composed of
alternating iron oxide and silica rich bands.
Lateritised
Rocks altered and enriched in iron by weathering.
Lead
The metallic element (chemical symbol Pb).
Limb
One half or side of a folded rock unit.
Lineament
A significant linear feature of the earth’s crust,
usually equating a major fault or shear structure.
Lithification
The process by which a sediment composed
of individual particles is converted into a
coherent rock.
Lithology
The characteristics of a rock; especially mineral
content,, structure, grainsize, and classification.
Lode
A tabular or vein like deposit of valuable mineral
between well defined walls.
Mafic
Descriptive of rocks composed dominantly of
magnesium and iron forming silicatesMagnetics
Referring to a magnetic geophysical exploration
survey, or to the magnetic properties of the rock
units so surveyed.
Magnetic
Induced Polarisation An electromagnetic
geophysical exploration method
Malachite
A green hydrated copper carbonate mineral: formed
by weathering of copper sulphide minerals.
Marcasite
An iron sulphide mineral.
Measured Resource
That part of a resource for which tonnage,
densities, shape, physical characteristics, grade,
and mineralogy can be estimated with a high level
of confidence.
Mesoproterozoic
The middle of the three Proterozoic eras; between
about 1,600 and 1,000 million years ago.
Mesozoic
An era of geological time; between about 250 and
65 million years ago.
Meta (prefix)
Indicating the rock has undergone metamorphism.
Metamorphosed
A rock that has been altered by physical and
chemical processes involving heat, pressure and
derived fluids e.g a metamorphosed sediment
can be described as a metasediment (Note: All the
Archaean rocks described in the report have been
metamorphosed to varying degrees. For simplicity
the prefix meta- has not always been used).
Mineralisation
The concentration of metals and their chemical
compounds within a body of rock.
Mn
The chemical symbol for the metallic element
manganese.
Mudstone A sedimentary rock formed by the
lithification of layers of mud.
Nickel (Ni)
The chemical symbol for the metallic element nickel.
Olivine
An olive coloured magnesium-iron silicate mineral;
formed in ultrabasic igneous rocks.
Outcrop
An exposure of bedrock at the surface.
Ore
Mineral-bearing rock that may be mined and
treated at a profit.
Oxidised
A rock that has been exposed to air and water
causing its minerals to change by the addition of
oxygen (and perhaps carbon and water).
P The chemical symbol for the element phosphorous.
Pegmatite
A coarse-grained igneous rock with exceptionally
large crystals, formed from a magma that contains
a high proportion of water.
Pentlandite
An iron-nickel sulphide mineral.
Percussion drilling
A form of drilling carried out by the hammering
action of a drill bit.
Petrology
The study of rocks.
Platinoid
A member of the platinum group of elements;
platinum, palladium, osmium, iridium, rhodium and
ruthenium.
Plunge
Inclination of a fold axis or other structure.
Pluton
A relatively large body of igneous rock formed
beneath the earths surface
Ppb
Part per billion.
Ppm
Parts per million.
Prospect
An area of a tenement which has demonstrated
potential to host an orebody.
Prospective
A general term for the perceived potential for the
discovery of an orebody based on the knowledge
of factors such as favourable geological setting,
structures, alteration, geochemical and/or
geophysical responses, and the occurrence of
mineralisation.
Proterozoic
The younger part of the Precambrian Era between
2,500 to 570 million years ago.
Pyrite
A mineral composed of iron sulphide.
Pyrrhotite
A magnetic iron sulphide mineral.
Quartz
A mineral composed of silicon dioxide.
Reconnaissance
A general examination or survey of a region with
reference to its main features, usually preliminary
to a more detaied survey.
Radiometric
A geophysical survey method that measures the
radioactive properties of rock units.
Resource
In-situ mineral occurrence for which there are
reasonable prospects for eventual economic
extraction. The location, quantity, grade, geological
characteristics, and continuity are known,
estimated, or interpreted from specific geological
evidence and knowledge.
Reverse circulation (RC )
A percussion drilling technique in which the
cuttings are recovered through the drill rods thus
minimising sample losses and contamination.
Rotary air blast drilling (RAB )
Rotary drilling technique in which sample is
returned to surface outside the rod string by
compressed air.
Sandstone
A sedimentary rock composed primarily of sand
sized grains.
Schist
A metamorphic rock with a platy or foliated texture.
Sediment
Rocks formed by the deposition of solids from water.
Sericite
A fine grained variety of muscovite (potassium
mica) (an alteration product).
Shale
An extremely fine-grained sedimentary rock
composed predominantly of clay minerals.
Shear
A fracture in rock similar to a fault.
Sideritic
Containing the iron carbonate mineral siderite.
Silica
The compound SiO2.
The component of the mineral quartz.
Siliceous
Containing the mineral silica.
SIROTEM A proprietary electromagnetic geophysical
exploration survey method.
Sphalerite
The common sulphide mineral of zinc.
Siltstone
A very fine-grained sedimentary rock composed
predominantly of silt-sized grains.
Sn
The chemical symbol for the metallic element tin.
Soil sampling
Systematic collection of samples of soil at a series
of locations in order to study the distribution of
geochemical values in the soil.
Stratiform
Occuring in layers.
Stratigraphy
Composition, sequence and correlation of stratified
rock in the earth’s crust.
Strike
The direction of the trace of a geological unit or
structure on a horizontal surface.
Structural
Pertaining to geological structure.
Sulphide
A mineral compound characterised by the linkage
of sulphur and a metal ion.
Supergene
A mineral enrichment formed relatively near to the
Earth’s surface by the movement of chemicals in
solution and their deposition near the top of the
water table.
Syncline
A set of rock units folded into a concave-up shape.
Tantalum
The metallic element.
TEM Transient electro-magnetics; a
geophysical
exploration survey method.
Tectonic
Relating to rock structures formed by deformation
by folds or faults of the Earth’s crust.
Thrust
A low angle (shallowly inclined) fault or shear on
which the rocks on the top have moved up and over
the rocks on the bottom.
Ti
The chemical symbol for the metallic element
titanium.
Tin
The metallic element, chemical symbol Sn.
Ultramafic
Descriptive of igneous rock containing virtually
no quartz or feldspar and composed essentially
of ferromagnesian silicates, mainly olivine
and pyroxene.
Uranium
The metallic element.
Vein
A thin sheet-like intrusion into a fissure or crack,
commonly bearing quartz.
Violarite
A nickel-iron sulphide mineral.
Volcanic
Descriptive of rocks originating from volcanic activity.
Volcanoclastic
Sediment formed from fragments of volcanic rocks.
Weathering
The group of processes that change the character
and composition of rocks by decay.
Zinc (Zn)
The metallic element; and its chemical symbol.
Zn
The chemical symbol for zinc.