 | | Journal (article/letter/editorial) | | 1992 ABSTRACT Peridotite xenoliths from the Olmani cinder cone, northern Tanzania, possess distinctive...to result from interaction of ultra-refractory peridotite residues with carbonatite melts. Chief among...apatite in refractory harzburgite and wehrlite xenoliths, respectively. (3) LREE enrichment and strong...strong Ti depletion relative to Eu in all but one peridotite. Ca/AI ratios of the clinopyroxene-bearing dunites...illustrate that many LREE-enriched spinel peridotite xenoliths may have been affected by addition of very |  | | Report (chapter) | | contemporaneous volcanism in southern Kenya and northern Tanzania, the differences taking place abruptly at a latitude...contemporary volcanism in south Kenya and north Tanzania Table 8.1 summarizes the volcanic stratigraphy...northern Tanzania, mainly from c. 8 Ma, i.e. the age of the oldest known activity in northern Tanzania at Essimingor...case of Essimingor, the oldest of the northern Tanzania volcanoes, are similar to the peralkaline volcanoes...basaltic rocks show some resemblances to those in Tanzania (Appendix 2, Dawson 2008) in terms of the dominance |  | | Journal (article/letter/editorial) | | from Pleistocene–recent volcanism in northern Tanzania J.B. Dawson ⁎ Grant Institute of Geosciences,...canoes in the Gregory Rift Valley of northern Tanzania (termed the Younger Extrusives) comprise one of...evidence for which is found in Tanzanian mantle xenoliths. An integrated model involves carbonated olivine–nephelinite...asthenosphere by melting of carbonate-bearing peridotite. Small amounts of the melt migrate rapidly and...volcanism in northern Tanzania The Late Tertiary–Recent volcanic province of northern Tanzania is the most recently |  | | Report (issue) | | 2011006982 Cover: (Top) Mount Meru (4566 m high), Tanzania, from the western side. Courtesy Philippe Nonnotte...Carbonatite lava at Oldoinyo Lengai volcano, northern Tanzania. Courtesy Alexander J. Teague. 10 9 8 7 6 5 4...Africa—New data from lower-crustal and mantle xenoliths from the Bayuda volcanic field, Sudan . . . ....low-velocity anomaly beneath Ethiopia, Kenya, and Tanzania: Constraints on the origin of the African superswell...Ian D. Bastow, Derek Keir, and Eve Daly 5. Peridotite xenoliths from Ethiopia: Inferences about mantle processes |  | | Journal (article/letter/editorial) | | clinopyroxene from peridotite xenoliths from the Quaternary Labait volcano, Tanzania, document the influence...Rift Plume Cratonic lithospheric mantle Tanzania Introduction Xenolithic peridotites carried in...in rift-related alkali basalts from Tanzania offer a unique opportunity to investigate the effects of...et al. 2000), radiogenic Os isotopes in mantle xenoliths precipitated by rift magmas (Chesley et al. 1999)...unusually light Li in clinopyroxenes from mantle xenoliths from fareast Russia and SW Japan (Nishio et al |  | | Journal (article/letter/editorial) | | Metasomatised and veined upper-mantle xenoliths from Pello Hill, Tanzania: evidence for anomalously-light mantle...Abstract. Peridotite xenoliths from the Pello tuff cone in the Rift Valley of northern Tanzania, bear witness...previously depleted peridotite. Chemical and mineralogical gradients are present in the peridotite wall rocks...rocks, and hydrous phases developed in the peridotite are generally lower in Ti and Fe, but higher in Mg and...metasomatism has reduced the density of affected peridotite by up to 4.5%, supporting earlier geophysical |  | | Journal (article/letter/editorial) | | previously been identified in global suites of mantle xenoliths or diamond inclusions. They occur in certain harzburgite...xenolith suite from the Lashaine tuff cone, northern Tanzania. The Lashaine ultra-depleted garnets are...refractory mantle is recorded in the Lashaine xenoliths by an almost continuous variation from ultra-depleted...more gradual. KEY WORDS: Archean; metasomatism; peridotite; pyrope garnet; Tanzanian Craton I N T RO D...infiltrating silicic fluids with a hostrock containing chromite, olivine and orthopyroxene (Bell et al., 2005; |  | | Journal (article/letter/editorial) | | reaction at low pressures transforms the bulk peridotite composition from that of a harzburgite or lherzolite...erupting carbonatite volcano, Oldoinyo Lengai in Tanzania, has an alkali-rich composition dominated by sodium...complex, Malawi [3]) and volcanic (e.g., Kerimasi, Tanzania [4]) settings, and although they do occur in isolation...number of studies of the properties of carbonated peridotite at high pressures. At pressures greater than...kbar, free CO 2 cannot exist in equilibrium with peridotite but reacts with silicates through a series of |  | | Report (chapter) | | have resulted from later regional mapping by the Tanzania Geological Survey, together with radiometric dating...half graben, and in the east, lavas from the Kilimanjaro massif filled the depression to the north of...Monduli and the Shira and Mawenzi centres of Kilimanjaro). Some of these basaltic volcanoes, Ngorongoro... 1972) but there is no equivalent in northern Tanzania of the earlier Kenyan flood phonolites, dated...at several centres, such as at the Kibo cone on Kilimanjaro, and at Tarosero, continued into the Pleistocene |  | | Journal (article/letter/editorial) | | investigation of carbonates in peridotite xenoliths from northeastern Tanzania Received: 30 July 1999 / Accepted:...carbonates in peridotite xenoliths from the East African Rift in northeastern Tanzania occur as intergranular...microprobe analyses of mantle-derived carbonates (in xenoliths, xenocrysts, and megacrysts) reveals compositional...melts. Because most carbonate inclusions in peridotite xenoliths are calcitic, these authors are of the opinion...opinion that most, if not all, carbonates in mantle xenoliths are cumulates. Likewise, Ionov (1998) has argued |  | | Journal (article/letter/editorial) | | Springer-Verlag 1986 Petrology of spinel harzburgite xenoliths from the Kishb Plateau, Saudi Arabia Lung-Chuan...48109, USA Abstract. Two spinel harzburgite xenoliths from a Pleisto- cene alkali basalt unit erupted...contain ultramafic xenoliths. Petrological studies have been made for the xenoliths from the Birk area...presents the petrology of spinel harzburgite xenoliths from the Kishb Plateau and discusses its bearing...locality is shown by the star 336 clinopyroxenite xenoliths. The two samples studied here are from the west |  | Koornneef, Janne M., Davies, Gareth R., Döpp, Sonja P., Vukmanovic, Zoja, Nikogosian, Igor K., Mason, Paul R.D. (2009) Nature and timing of multiple metasomatic events in the sub-cratonic lithosphere beneath Labait, Tanzania. Lithos, 112. 896-912 doi:10.1016/j.lithos.2009.04.039 | Journal (article/letter/editorial) | | in the sub-cratonic lithosphere beneath Labait, Tanzania Janne M. Koornneef a,⁎, Gareth R. Davies a, Sonja...April 2009 Available online 6 June 2009 Keywords: Tanzania Cratonic lithospheric mantle Xenolith Metasomatism...and Sm–Nd systematics of xenoliths from Labait volcano, north-central Tanzania, document multiple metasomatic...Generally, the rift-related metasomatism beneath Tanzania has caused formation of interstitial clinopyroxene...sub-continental lithospheric mantle (SCLM) beneath Tanzania has experienced multiple metasomatic events related |  | Lorand, Jean-Pierre, Delpech, Guillaume, Grégoire, Michel, Moine, Bertrand, O'Reilly, Suzanne Y, Cottin, Jean-Yves (2004) Platinum-group elements and the multistage metasomatic history of Kerguelen lithospheric mantle (South Indian Ocean) Chemical Geology, 208 (1) 195-215 doi:10.1016/j.chemgeo.2004.04.012 | Journal (article/letter/editorial) | | siderophile trace elements in Kerguelen mantle xenoliths monitor a multistage melt-depletion/ metasomatic...sulfides) metasomatism in some Sierra Nevada mantle xenoliths (South Western USA) which can be accounted for...elements in supercritical aqueous fluids. Mantle xenoliths from the Kerguelen Islands are ideal rocks for...and Se). 2. Petrogenesis of Kerguelen mantle xenoliths The Kerguelen islands (Kerguelen Archipelago;...have provided the greatest diversity of mantle xenoliths ever observed in a within-plate oceanic setting |  | | Journal (article/letter/editorial) | | Petrography and mineral chemistry of mantle xenoliths in a carbonate-rich melilititic tuff from Mt....petrographic and mineralogical data for 21 mantle xenoliths (12 lherzolites, 8 wehrlites and 1 composite)...Formation, Mt. Vulture volcano, southern Italy. The xenoliths are rounded, coarse- to porphyroclastic-textured...chrome-spinel (14 20% MgO, ~30 40% Cr2O3). Many xenoliths contain partial melt glasses and accessory sulphide...garnet (pyrope; Mg84). Secondary veins in several xenoliths contain carbonate with significant Sr levels (~0 |  | | Journal (article/letter/editorial) | | traditionally most difficult in the intermediate fo2 region around FMQ, where graphite is no longer stable...was m o n i t o r e d against an international chromite s t a n d a r d ( U S N M 117075; Jarosewich etal...perfect RO:R203 (1:1) spinel stoichiometry, b Chromite standard USNM 117075 from Jarosewich et al. (1980)...o f f o ~ is the F e 3 + / ~ F e in spinel (c.f. Hill and Roeder 1974). Within The main variables controlling...the Cr/(Cr + A1) ratio rises significantly (c.f. Hill a n d R o e d e r 1974). This is a c o n s e q u |  | | Journal (article/letter/editorial) | | The Origin of Highly Silicic Glass in Mantle Xenoliths from the Canary Islands E.-R. NEUMANN∗ AND E....harzburgite, lherzolite, dunite and wehrlite mantle xenoliths from the Canary Islands (La Palma, Hierro, Tenerife...are generally silica undersaturated. Glasses in xenoliths from La Palma and Tenerife are rich in K2O compared...to the main phases in the host xenoliths (Fo>90, Cr-diopside, chromite), whereas those in less silicic...relationship between the melts and their mantle host xenoliths. The silicic glasses are interpreted as the products |  | | Journal (article/letter/editorial) | | patterns of continental rift volcanism beneath Tanzania Emily J. Chin1 Received: 3 May 2018 / Accepted:...as recorded in deep crustal xenoliths from northern Tanzania. The xenoliths are interpreted as magmatic...the precursors to successful continental ruptures (Hill 1991). Such a large amount of magma intruded and...rift magmas. Such cumulates are available as xenoliths erupted in volcanoes and provide the only direct...Fe-rich dunite xenoliths from the East African Rift in northern Tanzania (Fig. 1). The xenoliths are interpreted |  | Xu, Y., Mercier, J.-C. C., Lin, Chuanyong, Shi, Lanbin, Menzies, M. A., Ross, J. V., Harte, B. (1996) K-rich glass-bearing wehrlite xenoliths from Yitong, Northeastern China: petrological and chemical evidence for mantle metasomatism. Contributions to Mineralogy and Petrology, 125 (4) 406-420 doi:10.1007/s004100050231 | Journal (article/letter/editorial) | | Lin ? Lanbin Shi K-rich glass-bearing wehrlite xenoliths from Yitong, Northeastern China: petrological...secondary clinopyroxene (cpx) 1 olivine (ol) + chromite + feldspar (fd). The composition of the mineral...EH9 3JW, UK Introduction Abstract Ultramafic xenoliths in Cenozoic alkali basalts from Yitong, northeast...Grove Glasses in high-temperature ultramafic xenoliths have generally been interpreted as decompression...glasses are rarely reported in xenoliths despite the fact that mantle xenoliths are brought up at similar |  | | Journal (article/letter/editorial) | | S0016-7037(99)00004-6 Re-Os systematics of mantle xenoliths from the East African Rift: Age, structure, and...have undertaken a systematic study of mantle xenoliths from the Labait volcano, which lies within the...Tanzanian craton. The Re-Os systematics of the Labait xenoliths show that ancient, refractory lithosphere is present... the mantle section consists of harzburgitic xenoliths with whole rock 187Os/188Os between 0.1081 and...overlapping the range measured for metasomatic xenoliths and the Labait host melilitite (0.13 to 0.14) |  | Wulff-Pedersen, E., Neumann, E. -R., Vannucci, R., Bottazzi, P., Ottolini, L. (1999) Silicic melts produced by reaction between peridotite and infiltrating basaltic melts: ion probe data on glasses and minerals in veined xenoliths from La Palma, Canary Islands. Contributions to Mineralogy and Petrology, 137 (1) 59-82 doi:10.1007/s004100050582 | Journal (article/letter/editorial) | | Ottolini Silicic melts produced by reaction between peridotite and in®ltrating basaltic melts: ion probe data...data on glasses and minerals in veined xenoliths from La Palma, Canary Islands Received: 15 November 1998...1998 / Accepted: 17 May 1999 Abstract Mantle xenoliths hosted by the historic Volcan de San Antonio,...associated minerals in the vein system of veined xenoliths show a gradual transition in composition from...patterns are exhibited by glass in unveined peridotite xenoliths. Clinopyroxenes shift from LREE-enriched |  | | Journal (article/letter/editorial) | | Open-system Peridotite a b s t r a c t The crystal-rich alkaline basalt of the Füzes-tó scoria cone in the...The basalt also includes numerous spinel peridotite xenoliths. In one of them we studied several silicate...basalt and in the silicate melt veins of the peridotite xenolith show two compositionally distinct populations...represented by the silicate melt veins in the studied peridotite xenolith. It is notable that group2 spinels are...2001; Roeder, 1994), the depletion of the mantle peridotite source and the nature of partial melting processes |  | Luguet, A., Jaques, A.L., Pearson, D.G., Smith, C.B., Bulanova, G.P., Roffey, S.L., Rayner, M.J., Lorand, J.-P. (2009) An integrated petrological, geochemical and Re–Os isotope study of peridotite xenoliths from the Argyle lamproite, Western Australia and implications for cratonic diamond occurrences. Lithos, 112. 1096-1108 doi:10.1016/j.lithos.2009.05.022 | Journal (article/letter/editorial) | | geochemical and Re–Os isotope study of peridotite xenoliths from the Argyle lamproite, Western Australia...Available online 18 June 2009 Keywords: Peridotite xenoliths Lithosphere Diamond Craton Re–Os dating...petrology and Re–Os geochemistry of a suite of peridotite xenoliths, some carrying abundant diamonds, from the...Australia. The microdiamonds from the peridotitic xenoliths are similar in their properties to the minor population...Neoarchean–Paleoproterozoic cratonic provinces. The Argyle peridotite xenoliths were derived from within the diamond stability |  | | Journal (article/letter/editorial) | | occurring in Cr-diopside series and Al-augite series xenoliths; as megacrysts in a variety of igneous environments;...minor phases in tectonic slices of upper-mantle peridotite. New data are given for pargasite and associated...associated phases in a lherzolite from Tanzania and in kelyphite replacing garnet in a S. African kimberlite...and primary parental peridotite. Because of its widespread occurrence in xenoliths transported by kimberlites...now been found in peridotitic or pyroxenitic xenoliths, in megacryst suites of basic and ultrabasic volcanic |  | Talukdar, Debojit, Pandey, Ashutosh, Chalapathi Rao, N. V., Kumar, Alok, Pandit, Dinesh, Belyatsky, B., Lehmann, B. (2018) Petrology and geochemistry of the Mesoproterozoic Vattikod lamproites, Eastern Dharwar Craton, southern India: evidence for multiple enrichment of sub-continental lithospheric mantle and links with amalgamation and break-up of the Columbia supercontinent. Contributions to Mineralogy and Petrology, 173 (8) doi:10.1007/s00410-018-1493-y | Journal (article/letter/editorial) | | fluorine-rich phlogopite, amphibole, apatite, chromite, allanite, and calcite. The trace-element geochemistry...involved in the generation of its mantle source region. Contrasting thoughts on the origin of enriched...intimate mixture of metapelites and ultradepleted peridotite undergoes melting. Interestingly, hybridized...objective to understand the nature of the mantle source region and the relevance of the lamproitic magmatism in...mica–amphibole–rutile–ilmenite–diopside (MARID) suite of xenoliths (Dawson and Smith 1977) but with higher Na/K ratios |  | | Journal (article/letter/editorial) | | 143Nd/144Nd have lighter δ60/58Ni Ultramafic xenoliths show systematic but limited inter-mineral δ60/58Ni...reported for 22 peridotite xenoliths from the USA (Kilbourne Hole, New Mexico), Tanzania, and Cameroon...spanning nearly the entire range observed in peridotite worldwide. Dunites (n=2) are lighter in δ60/58Ni...as -0.38‰. The δ60/58Ni in the Kilbourne Hole xenoliths correlate negatively with bulk-rock Fe concentration...Klaver et al., 2020). The data for ultramafic xenoliths show a range in δ60/58Ni = +0.04‰ to +0.36‰ (Ratié |
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