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Showing 1 to 20 of 23 for “"Carbonatite"”.
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The geochemistry and petrogenesis of the Saltpeterkop carbonatite complex near Sutherland, Northern Cape, South Africa
The Saltpeterkop Carbonatite Complex is a Late Cretaceous (≈76 Ma) volcanic and shallow intrusive magmatic feature located approximately 20 km southeast of Sutherland in the Northern Cape. It is unusual among southern African carbonatite complexes in that it has not been deeply eroded, and retains …
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Structural Interpretation of an Alkaline-Carbonatite Complex Using Gravity and Magnetic Methods at Magnet Cove, Arkansas
<p>The Magnet Cove alkaline-carbonatite complex in the Ouachita Mountains of south-central Arkansas could be a valuable resource for rare earth elements, though it has not yet been thoroughly studied using geophysical methods, and existing geophysical models simplify its diverse nature. Prior to …
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Megacryst suite from the Salpeterkop carbonatite complex, Sutherland, Northern Cape, South Africa: an in-depth geochemical study
Presented here are major and trace element, stable (oxygen and hydrogen) and radiogenic (Sr-Nd-Pb) isotope analyses for a Cr-poor megacryst suite from the Salpeterkop complex, South Africa. The clinopyroxene, amphibole, phlogopite and ilmenite megacrysts all appear to be cogenetic, and based on …
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The oxygen, carbon & hydrogen isotope geochemistry of the Phalaborwa Complex, South Africa
… Phalaborwa Complex is a pipe-like ultramafic to carbonatite intrusion formed from multiple magma pulses. This produced a main pipe of pyroxenite, carbonatite and foskorite (olivineapatite-magnetite-calcite) and many smaller syenite plugs around the pipe. The complex is the oldest known …
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Exploring Diversified Vineyard Ecological Soil Management Strategies: Impacts of cover cropping, Spanish River Carbonatite, and smooth pigweed (Amaranthus hybridus) interactions on an agroecosystem
… amendment application (using Spanish River Carbonatite – SRC), affect both biotic and abiotic variables such as soil nutrients, plant growth, and plant and soil invertebrate community composition over time. My study included control greenhouse trials and trials in an operational vineyard. In …
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Petrogenesis of the Mesoproterozoic anorthosite, syenite and carbonatite suites of NW Namibia and their contribution to the metasomatic formation of the Swartbooisdrif sodalite deposits
… by syenite dykes (1,380-1,340 Ma) and younger carbonatites (1,140-1,120 Ma) along ENE and SE trending faults. Older ferrocarbonatite intrusions, the ‘carbonatitic breccia’, frequently contain wallrock fragments, whereas subordinate ferrocarbonatite veins are almost xenolith-free. Metasomatic …
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Petrology and alteration in the core of the Bear Lodge Tertiary intrusive complex, Bear Lodge Mountains, Crook County, Wyoming
… Phonolite, pseudoleucite trachyte porphyry, and carbonatite dikes cut across the core. Precambrian granitic rocks and lower Paleozoic sedi mentary rocks flank the intrusion and occur as xenoliths.</p> <p>The latite is relatively unaltered and consists mostly of oligo clase, andesine, alkali …
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The Sukulu complex, Eastern Uganda and The origin of the African carbonatites
… examination of the structure of an African carbonatite. The most important result of this survey was the demonstration that the carbonatites were emplaced in a plastic condition, in the form of "collars", dykes and ring-dykes, into and around an earlier calcitic plug which occupied the …
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Geochemical and isotopic constraints on the source regions of phanerozoic carbonatites and associated alkaline rocks from the Zandkopsdrift complex of Namaqualand, South Africa, and the Marinkas Quellen, and Dicker Willem complexes in Namibia
This is a study of Phanerozoic carbonatites and related alkaline silicate rocks from Zandkopsdrift in Namaqualand, South Africa (55 Ma), and Marinkas Quellen (529 Ma), and Dicker Willem (49 Ma) in southern Namibia, all emplaced within the Proterozoic Namaqua Natal province. The aims of this thesis …
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The kimeerlite occurrences from the vicinity of Rayton, South of premier mine, and from East Lynne, East of Pretoria
… constitutes only a small proportion of the carbonatite of the East Lynne occurrence. It is exceptionally rich in biotite and carbonate and is most probably a residual phase of the carbonatite intrusion. Thus it is not related to the same kimberlite activity as the other occurrences.
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Carbonatites as a record of the carbon isotope composition of large igneous province outgassing
… of mantle versus crustal carbon reservoirs. Carbonatite magmatism associated with LIPs provides a unique window into the isotopic systematics of LIP carbon because the majority of carbon in carbonatites crystalizes rather than degassing. Here, we present new δ<sup>13</sup>C data for the Guli …
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Halogen-element (F, Cl, and Br) behaviour in apatites, scapolite, and sodalite : an experimental investigation with field applications
… fluorapatite-magnetite deposit (China), the Oka carbonatite complex (Quebec), and Chinese mantle xenoliths and 36 scapolite samples from the Tieshan Fe-Cu skarn deposit (China), the Nickel Plate gold deposit (British Columbia), and the Grenville pegmatite/skarn/vein deposits (Ontario and Quebec) …
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Metaalbewerkers van Phalaborwa (Afrikaans)
… around Loolekop which represents the central carbonatite pipe of the Palaborwa Igneous Complex, about fifty historical known sites were identified and divided into three groups according to the metalworking and occupational remains on these sites. Test excavations were conducted on eleven of …
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Petrogenesis of natrocarbonatite at Ol Doinyo Lengai, East Africa—evidence from Fe and U isotope variations
… Lengai (ODL), Tanzania, is the only active carbonatite volcano on earth. Cyclical activity that consists of quiescent natrocarbonatite lava flow, explosive silicate eruption and dormancy has been observed throughout the 20th century at ODL. From 2007 to 2008, ODL explosively erupted …
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Geochemistry, Thermochronometry, Petrogenesis, and Geometry of Igneous Dikes in Central Arkansas: Implications for Mississippi Embayment Evolution
… and high Sr and Nb contents (indicative of carbonatite metasomatism). This decoupling between isotope ratios and trace element contents could represent low degrees of partial melting of a depleted asthenospheric source. The remaining samples show similar trace element slopes on normalized …
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Igneous life cycles: geochemistry of magma from mantle to surface and back again
… with a REE-rich, economically important carbonatite. However, questions remain about the origins of magma here. We present geochemical data for 121 primitive alkaline igneous rocks to allow a more complete picture of these uncommon igneous compositions. Examining primitive magma …
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Micro-geochemistry of the mantle and its volcanic rocks
… mantle, most recently equilibrated with a carbonatite melt. The limited Sr isotope variation in the cpx from this study is typical of global off-craton cpx implying that the majority of cpx in off-craton settings may have a recent, metasomatic origin. • The second micro-sampling study …
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U-Th-Pb fractionation in selected carbonate and silicate systems
… presents three detailed case studies from a carbonatite intrusive complex, lower crustal granulite xenoliths, and young volcanic rocks which represent a range of processes that fractionate V, Th and Pb. <br></br><br></br> New major, trace element and Sr, Nd and Pb isotope results are …
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The petrogenesis and geochemistry of the Namaqualand olivine melilitite pipe cluster, western South Africa
… spanning an age range of 35-56 Ma. A related carbonatite complex containing olivine melilitite is also found within this cluster, with an emplacement age of ≈ 55 Ma. The Namaqualand cluster represents the southernmost component of the Late Cretaceous to Paleogene-age …
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