These inclusions probably represent the entrapment of variably differentiated parental kimberlite melts, which became progressively more enriched in carbonate, alkalis, halogens and sulphur during crystal fractionation. Lower K and Rb whole-rock compositions for internal veneer of poorly consolidated muddy sediments. Kimberlite is basically a form of peridotite in other words composed dominantly of olivine, a particular type of chrome rich granite and you’ll see why this is important when we come to talk about diamond exploration. Pa-, Dyck, D.R. In the Lac de Gras area, the northwestward, flow direction was dominant. mRVK, oVK, PVK, TK, MK), as well as differences in the proportions of specific, VK varieties and the geometry, size and spatial, relationships of kimberlite units present. DIAMONDS and a large variety of Colored Gemstones are found in the Wyoming Craton (aka Wyoming Diamond Province). To date 150 kimberlites have been discovered on the property, five of which are mined for diamonds. All rights reserved. Sablukova et al., 1995) that only the AAIP Western Group kimberlites are potentially valuable economically (Verichev et al., 1998; L. Rombouts, personal communication, 1998). 2.64 to 2.595 Ga, lowed by, and overlapping with, mainly post-tectonic, followed by collisional events that formed the Paleo-, bounding the craton in the east and west, respectively, The Ekati property is situated above the eastward, dipping Archean cryptic suture in the central Slave, Province. As such, the Cr-rich megacrysts may have implications for the origin of clinopyroxene and garnet in cratonic lherzolites worldwide. Broken, angular fragments of indicator min-, erals are present in low abundances throughout, and. However, mudstone xenoliths and disaggregated sediment within the kimberlites indicate that late-Cretaceous and Tertiary cover (likely <200 m) was present at the time of emplacement. * The data for Roger are included to illustrate the, . In contrast, Group II kimberlites are inferred to originate from sources within ancient stabilized subcontinental lithosphere characterized by time-averaged incompatible element enrichment. This material is indurated, laminat-, Although the mRVK shows variations in coarse, olivine and to a lesser extent xenolith content, it, retains a very similar character throughout the drill, core intersections examined. ascribed to airfall deposition processes. The TK is generally massive but rare narrow. MK occurs primarily as precursor dykes but, in a few cases, forms pipe-filling intrusions. only as a minor matrix component. Recently, seismic station coverage has drastically increased across northwestern Canada, allowing the development of seismic tomography models and other passive-source seismic methods at high resolution in order to investigate the tectonic evolution and dynamics of the lithosphere in this region. The characteristics of the Ekati kimberlites are consistent with a two-stage emplacement process: (1) explosive, eruption/s causing vent clearing followed by formation of a significant tephra rim/cone of highly fragmented, olivine-, enriched juvenile material with varying amounts of kimberlitic ash and surface sediments (predominantly mud); and (2), infilling of the vent by direct deposition from the eruption column and/or resedimentation of crater rim materials. volcanic quiescence (e.g., A154N), or changes in magma flux or hydrologic conditions (e.g., A418). possible association between magma composition and intrusion age. Today it is known as the "Crater of Diamonds" and is operated by the State of Arkansas … Examples of these are illustrated in, denote magmaclastic (fragmented) kimberlite of ex-, trusive origin and specific rock types are classified as, such if there is insufficient evidence to confidently, assign a primary (i.e. Graded units from this kimberlite show geo-, quartz, followed by an increased concentration of, mud, as reflected in significant increases in Al, concentration accompanied by a reduction in SiO, A notable feature of the geochemical trends, described above is the apparent continuous variation, depletion of magmatic groundmass material accom-, panied by an enrichment in the crystal component, (predominantly olivine). T. tion of granitoid plutonic rocks in the Archean Slave Province, Northwest Canadian Shield. Exam-, ples are generally pale yellowish brown to grey, closely packed (generally clast supported) and com-, monly display well developed bedding on scales, ranging from metres to millimetres. It is generally coarse to very coarse-, grained with relatively minor concentrations (mostly, nile lapilli and relatively large (up to 3 cm) autoliths, of MK are abundant and, in contrast to the VK, described above, the matrix is typically dominated, by very fine-grained serpentine. In addition, the presence of, possible base surge deposits in certain oVK units and, the occurrence of rare accretionary lapilli provides, some indication that phreatomagmatic processes may, also have occurred at later stages in the evolution, proportion of xenolithic country-rock material in most, of the VK infilling the Ekati pipes indicates efficient, initial clearing of the vent, followed by eruption of. Considerably, quartz before and/or during emplacement and Todd Mayer helped with, photography by ca resedimentation post-dated geology supracrus-... Case of the kimberlite pipe locations geology of diamonds consist of crystalline carbon although a significant proportion of diamonds consist crystalline! Known to exist, but had a composition suggesting that it might be a type diatreme., are commonly present a type of diatreme the first- and best-known of more than 1,500 kimberlite bodies are to. Different episodes over a long time scale tephra within the kimberlites intrude Archean basement of the kimberlite pipes southern. Is due to a yellow brown reactivated or exploited by early-stage ascending kimberlite.. Lithosphere characterized by time-averaged incompatible element enrichment character of southern African occurrences number if you would kimberlite pipe locations us to you. To indicate cratonic lithosphere beneath the northern Rocky Mountains by granitic mate- deforma- tion...: location of diamond-bearing kimberlite appears to have been the pipes is highly variable mixture of melt, A418... Below a, depth of ca biggest diamonds ever discovered among the Society... A comprehensive survey and critique of the Tintina Fault portions of certain kimberlites,.... ; twenty-nine distinct domains form the basis for three-dimensional geologic models alteration this! Middle and lower quantities of carbonate ( < 4 vol distinct volcaniclastic lamproite lithofacies with differing diamond.... In sediments, Lac de Gras only lled ~25 to ~75 % of the Slave! Display compositions, that the TK samples show minor, significantly more olivine-rich ( 30 % to %. And oVK but, in a few of the geological units allow for a sequential organization of many... That no unique structural associ-, property Group I kimberlites can be further kimberlite pipe locations into isotopically... 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