Orientador: Elson Paiva de Oliveira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-19T05:31:18Z (GMT). No. of bitstreams: 1 DonattiFilho_JosePaulo_D.pdf: 4183333 bytes, checksum: fdab4641a69f3e0cb09bddeb14a2dedf (MD5) Previous issue date: 2011 / Resumo: A presente tese concentrou-se na classificação do magmatismo kimberlítico do Campo Kimberlítico Brauna no nordeste do Craton do São Francisco, e sua relação com as rochas encaixantes, xenólitos (e.g. crustais e mantélicos), mineralizações diamantíferas e contexto tectônico regional associado ao Greenstone Belt do Rio Itapicuru e Bloco Serrinha. O escopo do estudo refere-se à utilização de técnicas analíticas convencionais como microscopia, microscopia eletrônica de varredura, microssonda eletrônica e difratometria de raios-X para a classificação da mineralogia e da química mineral dos kimberlitos e xenólitos associados. Somado a isto, utilizou-se técnicas analíticas mais avançadas aplicadas ao estudo de kimberlitos, como a obtenção de dados geoquímicos de alto poder interpretativo (e.g. HFSE e REE) por ICPMS e XRF, com a finalidade de se entender a petrogênese dessas rochas. Além de análises isotópicas de Sr-Nd em rocha total e perovskita da matriz kimberlítica, e U-Pb em grãos de zircão e perovskita por SHRIMP e TIMS respectivamente, para definir e determinar fontes geradoras do magmatismo do campo kimberlítico. Este volume foi organizado sob forma de dois artigos completos, onde a grande maioria dos resultados desta tese foram apresentados. O primeiro artigo intitulado ?Age and Origin of the Neoproterozoic Brauna Kimberlites: magma generation within the metasomatized base of the São Francisco craton, Brazil?, teve como principal objetivo a classificação petrogenética dos kimberlitos e xenólitos associados do Campo Kimberlítica Brauna, desde então superficialmente explorada por empresas de exploração de diamantes na década de 80 e 90. Neste artigo foram utilizadas técnicas convencionais de classificação de rocha bem como: descrições petrográficas, relações de campo, microscopia eletrônica de varredura, microssonda RAMAM, difratometria de Raio-X e geoquímica de elementos maiores e traços. O artigo contempla também a utilização de técnicas mais avançadas até então inexistentes na literatura sobre kimberlitos no Brasil, são elas: datação radiométrica U-Pb em fenocristais de perovskita por Termal Ionization Mass Spectrometry (TIMS), dados isotópicos de Sr-Nd em rocha total e isótopos de Nd em fenocristal de perovskita. Além disso, o artigo contribui de forma representativa para uma discussão freqüente entre a comunidade internacional de kimberlitólogos sobre tipos de magmas kimberlíticos heterogêneos. O segundo artigo intitulado ?Zircon xenocrysts U-Pb dating from the Neoproterozoic Brauna Kimberlite Field, São Francisco Craton, Brazil: geodynamic implications for kimberlitic intrusion?, foi contemplado com dados isotópicos precisos de U-Pb em xenocristais de zircão do kimberlito e fenocristais de zircão do granodiorite encaixante por Sensitive High Resolution Ion Microprobe (SHRIMP II). Este artigo teve como principal objetivo a identificação das diferentes idades registradas nos xenocristais de zircão trazidos à superfície da Terra pelo magmatismo kimberlítico com o intuito de se entender a constituição da litosfera sob o Bloco Serrinha, onde o campo kimberlítico Brauna encontra-se intrudido. Além disso, o estudo isotópico detalhado do granodiorito encaixante também se fez importante para o entendimento da mecânica de colocação e forma de contaminação crustal desse tipo de magmatismo tão peculiar, tornando este artigo o segundo no mundo com esse tipo de abordagem / Abstract: The present thesis deals with the classification of the Brauna Kimberlite Field magmatism, northeast São Francisco Craton, and its relationship with the host-rock, xenoliths (e.g. crustal and mantelic), diamondiferous mineralization and the regional tectonic context associated to the Rio Itapicuru greenstone belt and Serrinha Block. The scope of this study refers to conventional methodologies such as scanning electron microscope, electronic microprobe and X-ray difratometry for the mineralogy classification of the Brauna kimberlites and the related xenoliths. Additionally, we have used more robust analytical techniques applied to the kimberlite study, such as ICPMS and XRF and also isotopic analysis of whole rock and perovskite Sr-Nd isotope, and also zircon U-Pb geochronology, using TIMS and SHRIMP respectively, to understand the kimberlitic source and magma generation process. This volume was organized under paper form where the results, discussions and conclusions are reported. The first manuscript entitle -Age and Origin of the Neoproterozoic Brauna Kimberlites: magma generation within the metasomatized base of the São Francisco craton, Brazil, had the main subject the Brauna kimberlites and xenoliths petrogenetic classifications, since then superficially explored by the exploration Companies during the 80's and 90's decades. In this article we have utilized conventional techniques for rock classification such as petrographic descriptions, field relationships i.e. SEM, RAMAM and X-Ray difratometry for major and trace elements geochemistry. Also we have analysed the samples by most advanced techniques inexistent in the Brazilian literature so far, for example: trace elements using ICPMS, U-Pb perovskite dating and whole rock Sr-Nd and perovskite Nd isotope by TIMS. Furthermore, this manuscript has contributed for the international kimberlite community discussion about the heterogeneous kimberlitic magma types. The second manuscript entitled -Zircon xenocrysts U-Pb dating from the Neoproterozoic Brauna Kimberlite Field, São Francisco Craton, Brazil: geodynamic implications for kimberlitic intrusion, was awarded with U-Pb isotopic data in zircon xenocrysts in Brauna kimberlites and its host rock Nordestina granodiorite batholith using the SHRIMP. This article had the principal objective, to place constraints on the lithosphere beneath the Archean Serrinha Block. Furthermore, the detailed isotopic study on the host-rock was important to improve our understanding about the form and dynamic of the kimberlitic intrusion. It is important to note that this paper is the second published paper with this subject in the world / Doutorado / Geologia e Recursos Naturais / Doutor em Ciências

The mineralogy and petrology of two kimberlites, a peripheral monticellite kimberlite, and its core of phlogopite kimberlite, from the West Auxiliary Pipe at Dutoitspan Mine are described. The mineralogy of the two kimberlites differs mainly in the presence of phlogopite macrocrysts, greater abundance of angular crustal inclusions, more heavy minerals and higher diamond grade in the phlogopite type. Microprobe analyses of olivine, phlogopite, monticellite, oxide minerals and garnet are presented. Silicate compositions are comparable in both kimberlites and zoning of olivine grains is typically towards a rim of Fo₈₉₋₉₀ʻ irrespective of whether cores are more Fe-rich or more Mg-rich. This is caused by re-equilibration after fluidised emplacement in the earth's crust of macrocryst-bearing kimberlite magma. Olivine aggregates were derived from sheared mantle lherzolite and single-crystal macrocrysts were formed at higher mantle levels from a kimberlitic crystal-mush magma. This was emplaced in the crust by rapid gas streaming. The post-fluidisation phenocrysts of olivine and phlogopite which formed then are in general more Fe-rich than macrocrysts. Re-equilibration of ilmenite results in the formation of complex perovskite and titanomagnetite mantles. Phlogopite macrocrysts are preserved in the monticellite contact rock where rapid quenching prevented their resorption and allowed separation of an immiscible carbonate melt, giving the abundant groundmass calcite. Atoll-textured spinels are found in the contact rock. Major and minor trace-element analyses of whole rock samples are presented and discussed, bringing into account the problem of contamination by crustal inclusions. Whole rock chemistry supports derivation of the kimberlites as partial melts of mantle material in the presence of a lithophile-element-enriched fluid. The monticellite contact rock is highly enriched in REE, Nb, and Sr due to rapid freezing of this perovskite-enriched phase. The monticellite type is more enriched in lithophile elements than the phlogopite type, which supports derivation of the monticellite type by a small degree of partial melting, further melting reducing the relative concentrations of lithophile elements to give the phlogopite kimberlite chemistry.

he estimation of post-emplacement kimberlite erosion in South Africa through the study of upper-crustal xenoliths is relatively unexplored; however the presence of these xenoliths has been recognized for well over 100 years. Post-emplacement erosion levels of a small number of South African kimberlite pipes have been inferred through the study of the degree of country-rock diagenesis, the depth of sill formation, the depth of the initiation of the diatreme and fission track studies. Through these studies, several estimates were proposed for the Group I Kimberley kimberlites. Although the 1400 m estimate of erosion remains widely accepted today, this estimate relies on the presence of Karoo-like basalt xenoliths in the Group I Kimberley kimberlites, as their presence proves that basalt existed in the Kimberley area when the kimberlites were emplaced. Basaltic xenoliths were described during the early stages of mining in Kimberley, though only one of these descriptions suggests that the ‘basaltic’ boulders correlate with the Karoo basalts. Because of the discrepancy between these early documentations of upper-crustal xenoliths and because the occurrence of Karoo-like basalt xenoliths in the Group I Kimberley kimberlites is under question, a re-investigation of the erosion levels and the upper crustal xenolith suites in South African, Cretaceous-aged kimberlites, including Melton Wold, Voorspoed, Roberts Victor, West End, Record Stone Quarry, Finsch, Markt, Frank Smith, Pampoenpoort, Uintjiesberg, Koffiefontein / Ebenheuyser, Monastery, Kimberley (Big Hole), Kamfersdam , Jagersfontein, Kaal Vallei, De Beers, Bultfontein, Lushof, Britstown Cluster, Hebron and Lovedale, was conducted. This study presents the analytical results for upper-crustal sandstone and basalt xenoliths collected from dumps, excavation pits and borehole core at the above-mentioned kimberlites, and demonstrates that they correlate with stratigraphic units of the Karoo Supergroup on the basis of mineral and geochemical compositions. These upper-crustal xenoliths are incorporated into kimberlites and down-rafted to levels below their stratigraphic position during kimberlite emplacement, consequently recording the broad stratigraphy into which each kimberlite is emplaced. Therefore, the Cretaceous lateral extent of the Karoo Supergroup is inferred and post-emplacement erosion estimated by reconstructing the stratigraphy based on upper-crustal xenolith suites for each kimberlite and calculating the total thickness of the now-eroded units. The distribution of sandstone xenoliths indicates that during the Cretaceous the lateral extent of the Dwyka, Ecca and Beaufort Groups encompassed all of the examined kimberlites, while the ‘Stormberg’ Group was constrained to an area outlined by the Voorspoed and Monastery kimberlites. Similarly, basalt xenoliths occur in all of the Group II and transitional (143 – 100 Ma) kimberlites but only in the Group I (90 – 74 Ma) kimberlites that lie within close proximity to the western outcrop margin of the outcrop area of the Drakensberg Group basalts (Lesotho Remnant), namely Monastery, Jagersfontein and Kaal Vallei. This trend implies an eastward-retreat of the inland erosion front of the Karoo basalts between 140 and 90 Ma and subsequent erosion of the underlying sedimentary units. It also suggests that a thicker succession of Karoo strata was present at the time of Group II and transitional kimberlite emplacement and that there has been more post-emplacement erosion in these kimberlites than the younger Group I kimberlites, except for Monastery, Jagersfontein and Kaal Vallei. Estimates are unique to each kimberlite as they are dependent on both stratigraphic location, elevation and present country rock, and range from approximately 1000 – 2500 m for the older kimberlites and less than 700 m to 1400 m for the younger kimberlites. Furthermore, the upper-crustal xenoliths found at the Group I Kimberley kimberlites and the coinciding trend of basalt erosion demonstrate that Karoo basalts were eroded from the Kimberley area by the time the Group I Kimberley kimberlites erupted (~85 Ma). Therefore, basalts are omitted from the Group I Kimberley kimberlites post-emplacement erosion estimate, and the upper Beaufort Group is considered the upper limit of the stratigraphy that was present at the time of the eruption of the Group I Kimberley pipes. Therefore, the erosion estimates decrease from a previous estimate of 1400 m down to 400 to 1100 m, where 850 m is considered a dependable intermediate estimate.

M.Sc. (Geology) / This treatise presents the first comprehensive investigation in petrography and geochemistry of a mantle-derived eclogite xenolith suite from the Balmoral kimberlite. Eclogites form a minor component of the Earth’s mantle however they play a vital role in our understanding of geodynamic processes, i.e. the subduction of oceanic crust (Jacob, 2004) and the crystallization of diamond within the sub-cratonic lithosphere. A large portion of eclogites from the Balmoral kimberlite pipe is comprised of bimineralic (garnet and clinopyroxene) rocks with the rest being corundum-bearing. Mica with average modal abundances ≤10 vol% is observed as an accessory phase in bimineralic xenoliths. Modal abundances of corundum in corundum-bearing samples range between 1 and 6 vol%. Textures are ambiguous in Balmoral eclogites and thus chemical criteria of McCandless and Gurney (1989) places all Balmoral eclogites into Group II. As typically observed in garnets from eclogites (Hills and Haggerty, 1989; Jacob, 2004), garnets from Balmoral eclogites are chromium- and manganese-poor. They have a general trend from pyrope-rich towards grossular-rich compositions, with some almandine. Garnets from the bimineralic eclogites have disparate suites of low- and high-MgO samples. High-MgO bimineralic garnets are pyropic in composition with averages at Pyr63Gros22Alm15, whereas garnets from the low-MgO suite are widespread from relatively less pyropic towards grossular-rich compositions with average compositions of Pyr49Gros40Alm11. Garnets from the corundum-bearing eclogites are homogeneous and characterised by the highest grossular component (averaging at Gros47Pyr28Alm25). The clinopyroxenes for Balmoral eclogites are omphacitic in composition. Jadeite content is highly variable (ranging between 8 and 58 wt%) in these clinopyroxenes. The clinopyroxenes in bimineralic eclogites are characterised by a wide variation from diopside-rich towards jadeite-rich compositions. Clinopyroxenes in corundum-bearing eclogites have the highest jadeite levels.

Diamonds are commonly present in an ore called kimberlite. Kimberlites vary extensively in mineralogy and therefore can complicate the processing and the extraction of diamonds. Weathering of kimberlite was investigated in this study and refers to the rapid physical breakdown of the kimberlite material. Kimberlite weathering by organic molecule adsorption was investigated utilising organic solutions; ethanol, formamide, n-hexane, oxalic acid, urea, pentanoic acid and acetic acid, was investigated. The extent of weathering was measured by XRD, TGA and FTIR analysis as well as by evaluating changes in the particle size distribution. The idea to predict the susceptibility of weathering of kimberlite based on TGA analysis was discredited as it was found that there was no correlation between the smectite content and the % weight loss from TGA analysis. In XRD analysis studies to relate the d-spacing to the extent of weathering, it was found that the technique was not sensitive enough to enable direct prediction of weathering behaviour. Organic solutions at 0.5 M generally did not significantly alter the d-spacing. In the case of utilising pure organic solutions, it was observed that switching from diluted to pure organic solutions did not increase the d-spacings but rather lowers the space. Cation pretreatment prior to organic weathering resulted in d-spacings up to 2 water layers (12.6 Å being equal to 1 water layer, 15.6 Å equal to 2 layers and 18.6 Å equal to 3 layer). The general trend was that the divalent cations Mg2+ and Ca2+ increased the d-spacings whereas monovalent cations Na+ and K+ decreased the spacing. In the case of pre-organic treatment prior to organic weathering, it was observed that the resulting d-spacing increased to 2 and 3 water layers. TGA analysis confirmed that the kimberlite structure did absorb organic reagents during weathering. It was observed that the amount of organic reagents adsorbed decrease in the following order: oxalic acid > urea > pentanoic acid > formamide > ethanol > n-hexane > acetic acid, with oxalic acid having been adsorbed the greatest. In addition, it was also shown that the extent of inorganic cation adsorption was more than that of organic solutions. The analysis also showed that organic pretreatments yielded promising results and the order followed was dimethyldioctadecylammonium chloride > cetylpyridium chloride > dodecylamine > pyridine in encouraging subsequent organic adsorption. FTIR analysis results indicated the mechanism by which organic molucules attached onto the mineral surface. It was observed that there was a disturbance of the bond between water in the interlayer and the silicate structure by a stronger H-bond gained through organic molecule attachment. Oxalic acid was observed to cause a structural change due to proton attack of the silicate structure. It was found that kimberlite weathering, in essence, occurred in the first 24 hours of contact with the solution. Oxalic acid was found to be the most effective weathering agent compared to the rest of the tested organic solutions. The effect of the tested solutions, at 0.5 M concentration, on kimberlite weathering followed the series Cu2+ > oxalic acid > ethanol > acetic acid > formamide > n-hexane > distilled water. This study therefore showed that the accelerated weathering of kimberlite utilising organic solutions was not as efficient as the Cu2+ solution. Comparing Cu2+ and oxalic acid treatments, results showed that 67 % of the particles passed 12 mm screen size due to Cu2+ weathering as opposed to 48 % in oxalic acid. In investigating the effects of variables, it was found that time of exposure had a small effect in the weathering of kimberlite. Increasing the organic concentration from 0.025 M to 0.5 M saw an increase in the amount of particles passing the 12 mm screen size by~20 %. There was however no improved weathering when the solution temperature was increased from approximately 25 °C to 40 °C. In the study of kinetics involved during organic weathering utilising oxalic acid and comparing with Cu2+ medium, a high mineral dissolution was observed in the first 24 hours of contact with the weathering solution. However, different weathering mechanisms were observed between Cu2+ and oxalic acid. Inorganic solutions foster weathering by interlayer cation exchange which results in the reduction of the surface energy and this encourages further crack propagation. Oxalic acid weathering mechanism was by proton attack of the structural cations which was then limited thereafter by oxalate salts precipitation. Al3+ and Mg2+ were the dominant cations in solution during weathering (reaching 40 mmol/L) at higher oxalic acid concentration. This indicated that the dissolution of the clay‟s octahedral structure occurred, making oxalic acid a more effective agent than the rest of the tested organic solutions. An alternative method to transform non-swelling clay minerals to swelling in kimberlites was highlighted. It was observed that cation exchange treatment in conjunction with acid and oxidation treatments on kimberlites containing non-swelling minerals: mica or forsterite that are at least 30 % in quantity may result in the presence of swelling clays after these treatments. Kimberlite that contained serpentine minerals was more resistant to alteration under these conditions. / Dissertation (MEng)--University of Pretoria, 2013. / gm2014 / Materials Science and Metallurgical Engineering / UPonly

Vorgestellt wird ein Verfahren zum Betrieb von Hochverfügbaren Diensten. Das Verfahren basiert auf der OpenSource-Software kimberlite und wird im URZ zur Absicherung verschiedener Dienste eingesetzt.

The aim of this study was to arrive at a fundamental understanding of kimberlite weathering and of factors which affect the rate and extent of weathering. Weathering was evaluated by measuring the change in size distribution after immersing crushed kimberlite in solutions of various compositions. Reproducibility of the measurements was found to be good, with the cumulative mass passing a given size differing by 7% or less, as tested for various weathering conditions. Kimberlite mineralogy, specifically the swelling clay content, was found to play a central role: kimberlite ores containing no swelling clay were not prone to weathering under any of the conditions tested. The cation exchange capacity (CEC) correlates well with the swelling clay content and with the weathering behaviour. The cation exchange capacity may be used in conjunction with the swelling clay content, as a predictor of possible kimberlite behaviour; however, given the relative complexity and cost of measuring swelling clay content (by X-ray diffraction), the CEC is the preferred parameter for practical use. Cations in the weathering solution have a strong effect on kimberlite weathering; the strength of the effect followed the series Cu2+ > Li+ > Fe2+ > Ca2+ > Fe3+ > Mg2+, whereas K+ and NH4+ stabilised the kimberlite somewhat against weathering. This sequence was in reasonable correlation with the ionic potential (ratio of valency to ionic radius), but with exceptionally strong weathering effects of Cu2+, and (to a lesser extent) of Li+ and Fe2+. The strong effect of the latter group of cations may be related to their tendency to adsorb onto other crystal sites in addition to the interlayer – the associated change in surface energy can change the fracture behaviour of the kimberlite. Measurement of the layer spacing of the swelling clay (by X-ray diffraction) showed no correlation between the weathering effect of a cation and the associated thickness of the interlayer. For solutions of cupric ions, the identity of the anion (chloride or sulphate) has little effect on weathering. The size of the crushed kimberlite ore similarly has little effect on the relative extent of size degradation by weathering. The concentration of cupric ions affects weathering, as does the weathering time – although 85% of the weathering caused by 30 days' exposure was found to occur within the first 24 hours. Increasing the temperature to 40°C (in a magnesium chloride solution) also increased weathering strongly. The kinetics of exchange of cuprous and potassium ions was measured (for two different kimberlites); the apparent reaction order (with respect to the concentration of exchanging cations in solution) varied between 1 and 3.5, and exchange of potassium was more rapid. This work has practical implications for in-plant processing of kimberlite, possible alternative kimberlite processing routes which eliminate one or more crushing steps, and for the stability of mine tunnels which pass through kimberlite. / Thesis (PhD (Metallurgical Engineering))--University of Pretoria, 2006. / Materials Science and Metallurgical Engineering / PhD / unrestricted

No description available.

Den övergripande tanken med projektet är att ta reda på vad som hände på Västra Gräddmanhällan,utanför Kalix kust, för 2 miljarder år sedan. Det görs genom att ta reda på vad det är för bergarter ochstrukturer som hittats på området och hur de korrelerar till varandra. De två huvudsakliga delarna somprojektet fokuserar på är de stromatolitiska strukturerna som finns i de sedimentära bergarterna på VästraGräddmanhällan och de magmatiska intrusionerna som går genom de sedimentära bergarterna. De skaidentifieras med hjälp av tre olika metoder som ska komplettera varandra. Alla tre metoder kräver attprover från platsen hämtas till Uppsala Universitet där de kan slipas ned till tunnslip. Det kommer finnastotalt åtta prover tagna från olika stromatolitiska strukturer, både från land och Västra Gräddmanhällanoch två stycken tunnslip från de magmatiska intrusioner som tidigare antagits vara antingen kimberliteller lamprofyr. Alla tunnslip kommer att studeras i ett optiskt mikroskop och då kommer vissa tunnslipväljas ut för att undersökas i SEM och sedan Elektronmikrosond. Det finns vissa egenskaper i de olikabergarterna som är avgörande för resultatet. I de stromatolitiska strukturerna är spår av paleobiologiviktigt. De saker som kommer att kunna ge en indikation på tidigare liv i en stromatolit är bland annatorganiskt kol och pyrit. Fynd av antingen opaka mineral, organiskt kol eller andra intressanta struktureri det optiska mikroskopet kommer därför påverka projektets gång. För de magmatiska intrusionerna blirdet istället mineralsammansättning och eventuella karbonater som blir viktiga för hur synen på Sverigesgeologiska historia kommer se ut i fortsättningen. / The overall idea of the project is to find out what happened on the Western Gräddmanhällan, off thecoast of Kalix, two billion years ago. This is done by finding out what rocks and structures that are foundin the area and how they correlate to each other. The two parts that this project focuses on is thestromatolitic structures found of the Western Gräddmanhällan and the igneous intrusions that passthrough the sedimentary rocks. They must be identified using three different methods that willcomplement each other. All three methods require samples from the site to be brought to Uppsalauniversity and then be ground down to thinsections. There will be a total of eight thin sections takenfrom different stromatolitic structures, both from the coast and the western Gräddmanhällan and twopieces of thin sections from the magmatic intrusions that are already assumed to be either kimberlite orlamprophyre. All thin sections will be studied in an optic microscope and then certain thin sections willbe selected to be examined in SEM and then Electron Microprobe. There are certain properties in thedifferent rock types that are decisive for the result. In the stromatolitic structures, traces of paleobiologyare important. The things that will be able to give an indication of past life in a stromatolite includeorganic coal and pyrite. Findings of either opaque mineral, organic carbon or other interesting structuresin the optical microscope will therefore affect the progress of the project. For the magmatic intrusions,it will instead be the mineral composition and possible carbonates that will be important for how theview of Sweden's geological history will look in the future.

Le craton Archéen canadien, en partie situé au Québec, possède plusieurs occurrences de roches mantelliques reliées aux kimberlites, dont les intrusions Le Tac et Lac Shortt situées dans la région de Chibougamau. Les phases minérales dominantes sont l'olivine, la phlogopite et la serpentine. Les minéraux matriciels sont la serpentine, l'apatite, la pérovskite, le diopside et la calcite. Deux générations d'olivine sont observées dans les deux intrusions. La phlogopite possède une composition variable suggérant une interaction chimique avec un magma de type kimberlitique. La composition des intrusions Le Tac et Lac Shortt est similaire aux kimberlites de faciès hypabyssal des Groupes I et II. Les diagrammes des profils des multi-éléments corrèlent avec ceux des kimberlites avec des anomalies négatives en Rb, Sr et K et positives en Nd et La. Le potentiel diamantifère des deux intrusions étudiées est faible, mais cette région peut tout de même être intéressante pour l'exploration diamantifère.