A Summary of Progress in Petrography. in 1887-1896 |
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Page 9
... andalusite . Micaceous and quartzitic schists from the neighborhood of Ax embrace zircon , apatite , sphene , magnetite , and numerous other materials , thought to be due to the action of the granulite on the schists . On the granulite ...
... andalusite . Micaceous and quartzitic schists from the neighborhood of Ax embrace zircon , apatite , sphene , magnetite , and numerous other materials , thought to be due to the action of the granulite on the schists . On the granulite ...
Page 14
... andalusite is a new product , and in limestone wollastonite and garnet result from the contact action . The eruptives , on the other hand , become coarse- grained and porphyritic near the contact , the diorite losing hornblende and ...
... andalusite is a new product , and in limestone wollastonite and garnet result from the contact action . The eruptives , on the other hand , become coarse- grained and porphyritic near the contact , the diorite losing hornblende and ...
Page 22
... andalusite , of which the biotite and andalusite are new products . Corundum , tour- maline , sillimanite , and zircon are also new products , but are present only in small quantity . A cordierite - biotite rock , consisting of these ...
... andalusite , of which the biotite and andalusite are new products . Corundum , tour- maline , sillimanite , and zircon are also new products , but are present only in small quantity . A cordierite - biotite rock , consisting of these ...
Page 23
... andalusite there is an abundant development of cordierite in them , where they approach the eruptive . As in the case of the diorite contact belt , there have also been recog- nized in the belt surrounding the tonalite two distinct ...
... andalusite there is an abundant development of cordierite in them , where they approach the eruptive . As in the case of the diorite contact belt , there have also been recog- nized in the belt surrounding the tonalite two distinct ...
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Common terms and phrases
acid Al,O alteration Amer AMERICAN NATURALIST analysis andalusite angle aragonite augite axial ratio basalts beryl biotite brucite Bull calcite calcium chlorite cleavage Colby University color colorless composition constituents containing cordierite corresponding crystalline crystals density described diabase double refraction dyke eruptive rocks Fe,O Fe₂O feldspar FeO MgO CaO FeO MnO forms formula Franc gabbro-diorites gabbros garnet Genth gneisses granite granulites ground-mass H₂O habit hexagonal hornblende humite hypersthene imbedded inclusions Jour Kryst leucite masses melanophlogite metacinnabarite mica mineral MINERALOGY AND PETROGRAPHY.¹ Mitth molecules muscovite Neues Jahrb nosean occur olivine optical original orthoclase ottrelite parallel Penfield Petrog PETROGRAPHY.¹ Petrographical phenacite plagioclase plane plates polymorphism prismatic produced pseudomorphs pyroxene quartz regarded rock individual Rosenbusch schistose schists serpentine silica sodium soluble specific gravity specimens spinel structure substance sulphur symmetry tabular temperature tonalite tourmaline twinned varieties W. S. Bayley Waterville yielded Zeits zircon zone
Popular passages
Page 19 - The plane of the optical axes is perpendicular to the plane of symmetry, and makes with c an angle of °7 in acute /9. A = b. 2H na = 104° 27'.
Page 14 - The larger part of the dust is thought to be a sediment from the air, and to have been obtained by it from a region of crystalline schists. The chondri, on the other hand, are thought to be of cosmic origin, since they are similar to the chondri obtained in deep-sea soundings. If the amount of the dust collected from the snow in Greenland represents the fall of one year, the total amount falling upon the entire surface of the earth in this time is 125 million kilograms, equivalent to a cube of thirty-one...
Page 14 - Wiilfing 21 for investigation, by whom it has been found to consist in greater part of feldspar, quartz, mica, and hornblende. There are present in it also garnet, zircon, magnetite, augite, and sillimanite, and with them is mixed a nitrogenous organic substance. The most interesting constituents of the dust...