A Summary of Progress in Petrography. in 1887-1896 |
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Page 9
... augite . The new minerals developed in the surrounding rock by the solution of the inclusion are spinel , hypersthene , and sometimes labra- dorite , sometimes forming holocrystalline aggregates , and at other times occurring as ...
... augite . The new minerals developed in the surrounding rock by the solution of the inclusion are spinel , hypersthene , and sometimes labra- dorite , sometimes forming holocrystalline aggregates , and at other times occurring as ...
Page 14
... augite , and sillimanite , and with them is mixed a nitrogenous organic substance . The most interesting con- stituents of the dust are little chondri of opaque , isotropic transpar- ent , and double refractive material . The larger ...
... augite , and sillimanite , and with them is mixed a nitrogenous organic substance . The most interesting con- stituents of the dust are little chondri of opaque , isotropic transpar- ent , and double refractive material . The larger ...
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... augite are often zonally developed . In the former the kernel shows evidence of having been corroded , while the external envelope never exhibits sign of such resorption . Analyses of one variety of the augite and of the hornblende ...
... augite are often zonally developed . In the former the kernel shows evidence of having been corroded , while the external envelope never exhibits sign of such resorption . Analyses of one variety of the augite and of the hornblende ...
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... , Waterville , Me . Bull . U. S. Geol . Sur . , No. 59 . Bull . Geol . Soc . Amer . , Vol . II . , p . 339 . 6770 portion of the augite is in idiomorphic crystals and in From the AMERICAN NATURALIST , November , 1891 .
... , Waterville , Me . Bull . U. S. Geol . Sur . , No. 59 . Bull . Geol . Soc . Amer . , Vol . II . , p . 339 . 6770 portion of the augite is in idiomorphic crystals and in From the AMERICAN NATURALIST , November , 1891 .
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... augite . The porphyrites are divided into andesitic varie- ties in which the feldspar - microlites are older than the augite , and into variolitic kinds with feldspar younger than augite . A large part of the rocks of the region studied ...
... augite . The porphyrites are divided into andesitic varie- ties in which the feldspar - microlites are older than the augite , and into variolitic kinds with feldspar younger than augite . A large part of the rocks of the region studied ...
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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...