The Nature of Ore Deposits, Volume 2 |
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Common terms and phrases
according acid actinolite altered antimony arsenopyrite auriferous barite beds Berg biotite blende bornite brown hematite cadmia calcite calcspar carbonate Carboniferous cavities cement cerussite chalcopyrite chlorite cinnabar clay slate cobalt conglomerates consist contain copper pyrite country rock crystalline schists crystals deposits depth Devonian diabase dikes diorite district dolomite eruptive Erzlagerstätten fault fissures formation formed Freiberg galena galenite gangue garnet geologic gneiss gold placers gold-bearing gossan grains grams granite gravels hematite hornblende impregnated Inst intercalated iron pyrite Jahrb layers lead limestone limonite lodes magnetite mainly manganese masses metallic metamorphic metasomatic meters mica schist mineral veins mines mountain occur ore-bearing orebodies outcrop oxide platinum porphyry Posepny Prak pyrrhotite quartz quartzite quicksilver rarely reef region rich river sand sandstone schists shale silicates silver solutions strata stringers sulphate sulphides theory thick tons tourmaline Trans traversed U. S. Geol Ueber upper valley Zeit zinc zinc-blende zone
Popular passages
Page 635 - Magaz., 1868, 26. Bd., p. 231. — JD Whitney. The Auriferous Gravels of the Sierra Nevada of California. Cambridge (Harvard College Mem.) 1879—1880. - J. Leconte. The Old River Beds of California.
Page 635 - HW Turner. Auriferous Gravels of the Sierra Nevada. Amer. Geol., 1885, p. 372. — AC Lawson. The PostPliocene Diastrophism of the Coast of Southern California.
Page 610 - Chessy deposits, that is, in a quartzose rock scattered in nuggets varying from the size of a pea to that of a walnut. All the ores carry, besides iron and silica, a small percentage of manganese and alumina, together with an amount of zinc varying from two to eight per cent.
Page 355 - In both fissures and impregnations the mlneralogic character of the deposit Is simple. Cinnabar is the predominant ore. • • • The quicksilver ores, therefore, In the most important part of the Idria mines, have impregnated extensive masses of completely disintegrated rock, and have more or less saturated either highly porous or specially bituminous beds which acted as filters. The real channels of supply are not revealed. As the dislocations of the region are of Tertiary (probably Eocene) age...
Page 619 - On the contrary, the gravels formed by the transporting and washing action of water are found only in the channels of brooks and rivers, in fresh water lakes or along the sea-coast. They lie for the most part within the present valleys or along the present shore, but are also often found in stretches of fluviatile sediments, sometimes intersecting the present direction of the valley on old river terraces, or in sheets covering plateaus (California, Ohlapian in Transylvania) and finally in old shore...
Page 617 - Placer gravels are deposits of loose, more or less rolled, material derived from the destruction of older deposits, lying on the earth's surface, or at least very close to it, and containing paying amounts of ore or precious stones. As the material composing placer gravels has been exposed to all the influences of the atmospheric air and of the water seeping through the upper strata of the soil, placers will be found to contain, in the main, only relatively insoluble, and, in general, refractory...
Page 410 - Geological features of the gold production of North America: Trans. Am. Inst. Min. Eng., vol.
Page 349 - In recent years nickel has been extensively mined at Frankenstein in Prussian Silesia ... At the present time the nickel deposits have been mined to a depth of 183 ft. ... In 1901, 9,500 tons of ore were extracted ,and 114.3 tons of nickel were produced. There was a considerable increase of production in 1902.
Page 522 - rivalry at the present day is keener than ever before in the history "of economic geology, have been presented and weighed one "against the other in the descriptions which we have given of " numerous stratified deposits of sulphide ores of the most diverse " composition and age. "The sedimentary theory assumes that strata consisting of "sulphide ores, sometimes of considerable thickness, have been "deposited on the bottom of the ocean or sometimes of a shallow "coastal sea, exactly like limestone...
Page 613 - The amber occurs in nodules, varying in size from that of a nut to that of a man's head, though the latter size is very rare.