A Summary of Progress in Petrography. in 1887-1896 |
From inside the book
Results 1-5 of 5
Page 23
... schistose rocks were originally laid down as sediments . In the special part of the volume the author describes the present fea- tures of the green schists of Michigan , and shows conclusively that these were once igneous rocks , often ...
... schistose rocks were originally laid down as sediments . In the special part of the volume the author describes the present fea- tures of the green schists of Michigan , and shows conclusively that these were once igneous rocks , often ...
Page 24
... schistose structure is finely worked out , both macro- scopically and microscopically , and the mineral change that accom- panies the development of the foliation is well shown . A large body of green schists is thus proven to have been ...
... schistose structure is finely worked out , both macro- scopically and microscopically , and the mineral change that accom- panies the development of the foliation is well shown . A large body of green schists is thus proven to have been ...
Page
... schistose pl ary . By th both classe derived fro are eviden and felds quartz and -Mess traps of V localities 1 Edited b Bull . U. Bull . Ge MINERALOGY AND PETROGRAPHY.1 Petrographical News . - The gabbros of 1891. ] 831 Mineralogy and ...
... schistose pl ary . By th both classe derived fro are eviden and felds quartz and -Mess traps of V localities 1 Edited b Bull . U. Bull . Ge MINERALOGY AND PETROGRAPHY.1 Petrographical News . - The gabbros of 1891. ] 831 Mineralogy and ...
Page
... schistose structure , the normal gabbro grades into a gabbro - diorite or a horn- blende - gneiss . Further , uralitization of the pyroxene gives rise to green schistose rocks , identical in nearly all of their characteristics with the ...
... schistose structure , the normal gabbro grades into a gabbro - diorite or a horn- blende - gneiss . Further , uralitization of the pyroxene gives rise to green schistose rocks , identical in nearly all of their characteristics with the ...
Page
... Schistose structure , Optical anomalies . 143 , 144 Parallel growths . 367 , 368 Origin of Effect of , upon constants of crystals 826 Polymerism 576 144 , 574 , 831 Polymorphism . 575 Transition bet . cryst . and clastic rocks 826 ...
... Schistose structure , Optical anomalies . 143 , 144 Parallel growths . 367 , 368 Origin of Effect of , upon constants of crystals 826 Polymerism 576 144 , 574 , 831 Polymorphism . 575 Transition bet . cryst . and clastic rocks 826 ...
Other editions - View all
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...