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| 1164 SHORT COMMUNICATIONS Riebeckite from near Sultan Hamud, Machalcos District, Kenya FINE specimens...specimens of striated, bladed prismatic and acieular riebeckite, sometimes radiating or platy, from the western...then Senior Government Geologist in Kenya. The riebeckite crystals, which are up to 6 cm in length, appear...(asbestiform riebeckite) has also been found. In one specimen (B.M. 1944,107) the riebeckite and quartz...with some quartz and riebeckite. In 1946, a magnificent specimen of riebeckite prisms intergrown with |
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| Properties and Cell Parameters in the Glaucophane-Riebeckite Series* I. Y. B o ~ Lawrence Radiation Laboratory...a function of composition in the glaucophane-riebeckite and magnesioriebeckite-ferroglaucophane series...crossite (C), magnesioriebeckite (0), riebeckite (0), and riebeckite-arfvedsmfite (R and 0). Optical properties...members by extrapolation are: fl Glaueophane Riebeckite Magnesioriebeekite 1.594 1.702 1.655 y (r--~)...referred to the C 2/m space group are: Glaueophane Riebeckite Magnesioriebeckite a0(A) b0(A) c0(A) fl(o) |
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| rhyolites from the Macedo de Cavaleiros region (NE Portugal) By M. LuIsA RIBEIRO, Lisboa*) With 13 figures...geochemistry of Variscan peralkaline gneisses from NE Portugal, discovered in 1962, is presented. Major and trace...Serviqos Geol6gicos de Portugal, R. Academia Ci~ncias, 19, 1200 Lisboa, Portugal. which they are overlain...des gneiss varisques peralcalins du nord-est du Portugal, d~couverts en 1962. Les analyses des 616ments...and HLAWASTSCH(1906) in the Cevadais area (SE Portugal). Meanwhile, many other articles have been published |
 | | Journal (article/letter/editorial) |
| acmite-hedenbergite-diopside system recently proposed byAoki do exist under some igneous conditions. When natural...92;Fe2Oa,4.60--->12.75. tions of these pyroxenes do not add up to the bulk analysis is ascribed mainly...composition lies within the proposed immiscibility region do exist under some igneous conditions. OccunnBNcB ol...Ambasibitika, Madagascar(16), is a pseudomorph after riebeckite (Lacroix, 1922) and has a compositionsimilar...rocks or their pegmatites and are associatedwith riebeckite or arfvedsonite as describedbelow. They are believed |
 | | Journal (article/letter/editorial) |
| d r o s o zwischen Alter-doChäo und Monforte — in der Provinz Alemtejo (Portugal) — führen einen bläulichschwarzen...de riebeckite et le zirkon qui l'accompagne. Comm. da commissäo do servifo geologico de Portugal VI,...w a t s c h , Über den Amphibol von Cevadaes (Portugal). RosenbuschFestschrift, Stuttgart 1906, S. 68...sein 2 ). Die Doppelbrechung des Osannits von Alter Pedroso ist sehr schwach, wegen der starken Absorption...d Apatit von Alter P e d r o s o 2 ) . IV; Osannit, isoliert aus d e m Umptekit von Alter P e d r o s |
 | Ballèvre, M., Fourcade, S., Capdevila, R., Peucat, J.-J., Cocherie, A., Fanning, C. Mark (2012) Geochronology and geochemistry of Ordovician felsic volcanism in the Southern Armorican Massif (Variscan belt, France): Implications for the breakup of Gondwana. Gondwana Research, 21 (4) 1019-1036 doi:10.1016/j.gr.2011.07.030 | Journal (article/letter/editorial) |
| few quarries inland (Bréthomé, Vairé). These rocks do not display a foliation, are devoid of veins, and...Metasomatism and rock identification The metavolcanics do not have primary magmatic compositions in either...2009b; Abati et al., 2010) as well as in northern Portugal (Macedo de Cavaleiros: Ribeiro, 1987). Detailed...the Cellier Unit (Ballèvre et al., 2002), as they do in the Lower Allochthon of Galicia. The Lower Allochthon...Early Ordovician calc-alkaline metavolcanics in Portugal (including the difference between coarse-grained |
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| waren. Ferner hat LACROIX (Riebeckit-Syenit von Alter Pedroso und seine Umwandlung in Leptynit und Gneis,...557). 342 I. Aufsi~tze und Mitteilungen aus Portugal beschrieben, von dem bereits 1902 (ira Zentralbl...eine im groi~en wahrnehmbare Orientierung der Riebeckite hervorgebracht. Andererseits sind nach LA01~O1X...granoblastisehen Struktur vorhergehend (ffir die Vorkommen in Portugal und Madagaskar), ebenso FR. ADAMS vielleicht ffir...an Gabbromassen. 2. LACROIXs Beobachtungen in Portugal usw. sind wohl so zu deuten, dal] nach AufhSren |
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| position an a log u e ace 11 e deR co nglomerats do Suursaari-Hogland 2 ,3 , 4. car Ra (;omposition a...Süll~kHJlel i Finland. 21 vom paläozoischem Alter cler Schiefer- und Grünsteinformationen der Petsamontunturit...werden. Die tektonisch wichtige Frage nach elen Alter;.;vcrhältnissen ...an altitude of ab out 230 m, but real eRker ridges do not oeeur. At the bottom of the valley whieh Reparatc...ice. Another notable fact is that erosion valleys do not occur in the esker gravel field :,urrounding |
 | | Report (chapter) |
| arbitrary, because similar rocks of the same ages do occur farther N in New Mexico (Foord et al. 1983)...these rocks represent primitive magmas although a few do carry ultramafic xenoliths. Schieffer & Nelson (1981)...rocks (Figs 3(c) and 3(d)). Peralkaline varieties do occur in the metaluminous belt (Cepeda & Henry 1983;...crust u n d e r the Trans-Pecos province, and how do these limits differ from those of m a g m a sources...have generously shared their unpublished data but do not necessarily agree with the interpretations in |
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| magma has taken place so that crystallites (which do not react to polarised light), in the form of tiny...basic lavas, cooling at approximately the same rate, do not normally show it because of their lower viscosity...are very fine grained to glassy. Some petrologists do not attach much importance to this three-fold division...variety in the peralkaline granites, commonly riebeckite or arfvedsonite; while ferrohastingsite may...norm (p. 14). The common varieties have riebeckite, riebeckite and aegirine, aegirine, or arfvedsonite |
 | | Book |
| kimberlites continue to defy precise classification, but we do now have improved characterizations rather than the...publishers. To produce this edition all I have had to do is to generate PDF (Portable Document Format) files...printer – a much simpler task! The software used to do this included Adobe PageMaker®, for editing the entire...classifications is appropriate for the rock in question. To do this in a consistent manner, so that different petrologists...measured in those examples where it seems necessary to do so. 2.2.1 PYROCLASTS Pyroclasts are defined as fragments |
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| mineraux circulant dans les galeries de mines. On se do it de considerer ces produits comme douteux en tant...decroissement se repe te sur toutes les parties d u noyau do nt telle est la ressemblance q ue l'on pe ut s ubstituer...d'Anloa, Cameroun. - Riebeckite, en cristaux de plus d'une tonne, d' Alter Pedroso, Portugal. - Corindon, cristal...2 ANKERITE Ca(Fe,Mg,Mn) (CO 3 ) 2 Rhomboedrique Do/omit e ( Trarerselle, Piemonl , 1ta lie). x 1,2....marnes, gres saliferes avec stontianite, calcite, do lomite, fluorine ; beaucoup plus rarement dans les |
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| of the pegmatite are several centimetres long and do not show preferred orientation. The rock contains...NW-SE contain a good deal of steenstrupine. The veins do not cut the lujavrite, but in a few of the diagonal...steenstrupine (fig. 30). The grains of steenstrupine do not disturb the lamination of the lujavrite. This...also a few large platy crystals of microcline which do not showevidence of deformation but are subject to...veins of finegrained albite in grains which otherwise do not show traces of deformation. In parts of the rocks |
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| of the pegmatite are several centimetres long and do not show preferred orientation. The rock contains...SE contain a good deal of steenstrupine. The veins do not cut the lujavrite, but in a few of the diagonal...steenstrupine (fig. 30). The grains of steenstrupine do not disturb the lamination of the lujavrite. This...also a few large platy crystals of microcline which do not show evidence of deformation but are subject...veins of finegrained albite in grains which otherwise do not show traces of deformation. In parts of the rocks |
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| Surface weathering is not the only process that may alter both magmatic and sedimentary rocks. They may also...fractions, show the same ratios to one another as do the oxide molecules or elementary atoms present in...in the tetrahedron fm-—c—2al—alk’, and when they do so are close to the plane fm-—c—2alk. Distinctions...lithosphere, in which O predominates. There, however, they do not participate to any great extent in the typical...according to the type of structure. Certain kz values do, however, tend to predominate. Si, for in- stance |
 | | Report (volume) |
| Obviously, samples showing recognizable metasomatism can do so only on a local scale, and because volcanically...isotopes e x c e p t t h a t t h e i n c l u s i o n s do r e c o r d s o m e h i g h e r 87Sr/S6Sr ratios...composition of alkaline rocks: new data from southern Portugal and East Africa. Contrib. Mineral. Petrol. 56...Di-Ne join in this system diopside and nepheline do not coexist as liquidus phases but are separated...(as NaA!SiO4 and NaA1Si3Os) would not appreciably alter their conclusions. The expansion of the primary |
 | | Report (issue) |
| the Petite SoleCordoba fault (western Spain and Portugal). This comparison suggests that this fault acted... 3. This belt separates two different structural do¬ mains: the southwesternmost domain is characterized...peralkalic igneous rocks (A, Arronches; AP, Alter Pedroso; E, Elvas; V, Vigo); 2, blastomylonitic belt...Hercynian sensu stricto folds be¬ cause the former do not have axial plane cleavage. The fold axes usually...places; for example, the Valongo anticline of east Portugal. The general distribution of the “en echelon” |
 | | Book (volume) |
| Modern History; But in an encythe various volumes do not cover the same field or touch the same materials...renderings, obscured by complicated accents, which do service in purely learned circles and have a scientific...parts must be remembered by any reader who desires to do justice to the treatment of any large subject. Cross-references...Encyclopedia is not called upon any direct part. It has to do with knowledge, rather than opinion, and to It cannot...whether in Europe or America, it is impossible to do adequate justice here. The interest shown in the |
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| essential changes. The editors cannot undertake to do more than correct obvious minor errors. References...essential changes. The editors cannot undertake to do more than correct obvious minor errors. References...in thunderstorms some of the heaviest disturbances do not come from the lightning itself, but the nature...essential changes. The editors cannot undertake to do more than correct obvious minor errors. References...relation to other organisms past and present. To do all this is no small task, and to say that, isnot |
Alter Pedroso, Alter do Chão, Alter do Chão, Portalegre, Portugal