A Summary of Progress in Petrography. in 1887-1896 |
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Page 18
... diabase upon the enclosing rock . - Traube ascribes the differ- ences in the values of the axial ratios of different sheelites to the amounts of molybdenum occurring in them . Analyses of many specimens reveal the fact that white and ...
... diabase upon the enclosing rock . - Traube ascribes the differ- ences in the values of the axial ratios of different sheelites to the amounts of molybdenum occurring in them . Analyses of many specimens reveal the fact that white and ...
Page 23
... diabases , diabase - porphyries , diorites , and gabbros among the basic types , and granites and quartz - porphyries among the acid types . The resulting Bull . No. 62 , U. S. Geol . Survey . phy of upo stru dur garn ara Con gend Scop ...
... diabases , diabase - porphyries , diorites , and gabbros among the basic types , and granites and quartz - porphyries among the acid types . The resulting Bull . No. 62 , U. S. Geol . Survey . phy of upo stru dur garn ara Con gend Scop ...
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... ° 48 extinction of crystallograp slightly from of the zinc is Si 46 . correspondi many analys Amer . Jou 5 Ib . , Dec. , Ib . , XL . , I diabase , and the other an olivine - hypersthene - 1891. ] 828 Mineralogy and Fetrography . 827.
... ° 48 extinction of crystallograp slightly from of the zinc is Si 46 . correspondi many analys Amer . Jou 5 Ib . , Dec. , Ib . , XL . , I diabase , and the other an olivine - hypersthene - 1891. ] 828 Mineralogy and Fetrography . 827.
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... diabase . The paper contains an excellent series of analyses of the rocks and their most important components . Barrois has given us a masterly discussion of the diabases and diabase - porphyrites of Silurian age , occurring as dykes ...
... diabase . The paper contains an excellent series of analyses of the rocks and their most important components . Barrois has given us a masterly discussion of the diabases and diabase - porphyrites of Silurian age , occurring as dykes ...
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... Diabase . Diabase - porphyrite . Eclogite Gneiss 571 .572 , 825 , 826 , 1003 1003 Diorite . .368 , 571 , 572 367 Eleolite - syenite 573 Epidiorite 826 Gabbro - diorite . 1002 Gabbro - granite 1002 Gabbro .. 368 , 572 , 826 , 1002 571 ...
... Diabase . Diabase - porphyrite . Eclogite Gneiss 571 .572 , 825 , 826 , 1003 1003 Diorite . .368 , 571 , 572 367 Eleolite - syenite 573 Epidiorite 826 Gabbro - diorite . 1002 Gabbro - granite 1002 Gabbro .. 368 , 572 , 826 , 1002 571 ...
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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...