Airborne Magnetic
Survey: | a survey conducted from the air for the purpose of recording the natural magnetic characteristics of rocks on and below the surface of the earth. |
| Anomaly/Anomalous: | an area identified as having a significantly different signature (geochemical and/or geophysical) than the host region or other regions on average, which may be indicative of a zone of potential exploration interest. |
| Archaean: | term used to describe some of the oldest rocks of the Precambrian era, formed from 4.0 to 2.5 billion years ago. |
| Breccia: | a rock made up of angular fragments enclosed in a finer-grained matrix. |
| Carat: | a unit of weight for diamonds, equivalent to 0.2 of a gram or 200 milligrams. |
| Crater Zone: | as the kimberlite volcano erupts, the debris is deposited into the crater zone. The crater zone is composed of 2 types of kimberlite: 1) pyroclastic kimberlite - composed of tuffs deposited on the surface and within the pipe vents. 2) epiclastic kimberlite - composed of eroded pyroclastic kimberlite that has been redeposited either outside of or within the pipe vent. Sedimentary features such as bedding and sorting are common in the crater zone. There are often xenoliths of surfical cover rock, vegetation (e.g. wood) and terrestrial organisms (e.g. microfossils) that existed at the time of emplacement. Usually in the Slave Craton all of the tuff ring of epiclastic kimberlite and part or all of the pyroclastic kimberlite have been eroded off by glaciation. Diamonds are found in this zone. |
| Craton: | describes an area of the Earth's crust that has not been significantly affected or reshaped by tectonic processes over geologically long periods of time. An Archaean craton is a crustal fragment that has not been significantly affected by peripheral tectonic prosesses since ~2.5 Ga (billion years ago). Globally, most diamondiferous kimberlites are associated with Archaean cratons. |
| Diamond: | a crystallized variety of pure carbon. |
| Diamondiferous: | containing diamonds. |
| Diatreme Zone: | explosive events, originating at deeper levels in the root zone initiate the formation of the diatreme zone. As the kimberlite ascends towards the surface, variations in the kimberlite composition and the physical properties of the surrounding host-rock determine the size and shape of the diatreme zone. Most often, this is the thickest zone in a kimberlite pipe and underlies the crater zone. It is typically greater than 1 km in length, is steep-sided, and carrot-shaped. The diatreme zone usually has a fragmented appearance, containing variable amounts of fragments (xenoliths) of host rock, deeper mantle rocks, and kimberlite (autoliths). Diamonds are found in this zone. |
| Dyke: | a discordant tabular body of igneous rock that was injected into and cuts across the foliation or layering of the enclosing rocks. |
| Facet: | one of the polished surfaces on a cut diamond. |
| Fissure: | a fracture or crack in rock along which there is a distinct separation. It is often filled with mineral-bearing material. |
| GPR: | "G"round "P"enetrating "R"adar is a geophysical electromagnetic technique that can be used to define planar shallow dipping bodies/horizons such as depressions in lake bottoms and fracture systems commonly associated with kimberlite bodies. Radar frequency pulses transmitted into the ground are reflected by material of differing electrical properties providing depth sections that appear similar to seismic sections. |
| Gem Diamond: | a diamond used normally in a faceted form, as an ornamental object in jewelry. |
| Geochemical Survey: | the sampling of rocks, stream sediments and soils to locate abnormal concentrations of metallic elements or minerals. The samples are assayed by various methods to determine the quantities of elements or minerals therein. |
| Geophysical Survey: | the exploration of an area in which physical properties relating to geology are used. Geophysical methods include seismic, magnetic, electromagnetic and gravity. |
| Granite: | a light-coloured, coarse-grained, igneous rock, consisting of quartz, alkali feldspar, micas and other associated/accessory minerals. |
| Grade: | number of carats in a physical unit of ore, usually expressed in carats per tonne. |
Indicator Mineral
Train: | the eruption of the kimberlite ejects rock and ash onto the surface, forming a tuff ring around the volcanic vent. During glaciation, the ice sheet scours the earth's surface and moves the kimberlitic debris from within and around the source pipe in a direction parallel to the direction of ice travel. The entrained debris is deposited as the ice sheet melts, leaving a trail of minerals and rock fragments. Geologists carefully sample the surficial glacial deposits searching for indicator minerals. The location of these minerals map out what are known as indicator mineral trains which are then followed back to the kimberlite source. The common minerals that can occur in indicator mineral trains are pyrope garnet, chrome-rich diopside, picroilmenite, chromite, olivine and diamond. |
| Kimberlite: | a type of igneous rock, some of which contain diamonds. |
Kimberlitic Indicator
Minerals: | specific minerals originating from kimberlitic rocks. Common indicator minerals are pyrope, chrome-diopside, picroilmenite and chromite. |
| Macrodiamond/Microdiamond - Diamond Size Distribution: | In nature there is a continuum of diamond sizes that occur in any given diamond-bearing rock. A complete set of sieve data, using a standard progression of sieve sizes illustrates all diamond sizes present in a given sample reported to the public. Diamond size distribution results should be reported in a table that shows the number and the weight of diamonds that occur on each of the standard sieve sizes per sample. |
| Pipe: | a colloquial term for an intrusive body of magmatic rock that has the three-dimensional shape of a geophysical cone. Carrot or diatreme shaped body. |
| Resistivity Survey: | a survey in which an array of electrodes is moved along profiles to determine lateral variations in resistivity. |
| Root Zone: | prior to, and during kimberlite eruption, the root zone is formed by the crystallization of the magma beneath the diatreme zone. Kimberlite in the root zone, known as hypabyssal kimberlite, commonly exhibits crystalline igneous textures, contains varying amounts of xenoliths, as well as diamonds. |
| Seismic Survey: | a method of geophysical exploration in which vibrations are set up by firing small explosive charges in the ground. Precise measurements of the resulting waves are taken, from which the nature and extent of underlying strata are revealed. |
Seismic Reflection
Survey: | the structure of subsurface is mapped by making use of the times required for a seismic wave (or pulse), generated in the earth by a near surface explosion of dynamite, to return to the surface after reflection from the formations themselves. |
| Sill: | a concordant sheet of igneous rock. A sill may become a dyke or vice versa. |
| Slave Province: | a mapped Archaean craton of North America, exposed in the Northwest Territories and Nunavut in northern Canada. To date over 300 kimberlites have been found in the Slave Province, with 3 deposits proving economic: (1) Ekati Diamond Mine - already in production, as Canada's first diamond mine in 1998, (2) DIAVIK - producing since 2003, and (3) Snap Lake - currently undergoing regulatory review and scheduled for full production in
2007. |
| Sonic Drilling: | coring performed by drilling with high frequency vibrations transmitted down the drill casing to a cutting shoe. The casing and the shoe vibrate into and over the ground, to produce an undisturbed core of unconsolidated material. |
| Till: | that part of a glacial drift consisting of material deposited by and underneath the ice, with little or no transportation and sorting by water. It is generally unstratified, unconsolidated heterogeneous mixture of clay, sand, gravel and boulders. |
| Xenolith: | describes any component of the kimberlite (fragment or crystalline) which is not genetically related to the host kimberlite magma; those components which were incorporated into the kimberlite during its ascent and emplacement. Examples of xenoliths include mantle nodules, country rock fragments, surficial cover rocks and organic matter, and most importantly, diamond. |
