Economic Geology, Band 6Economic Geology Publishing Company, 1911 |
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acid alteration amount amphibole analyses andesite anticlinal arsenopyrite assays associated average bands barite beds bornite calcite carbonate cent chalcocite chalcopyrite chemical chert chlorite coal contain copper country rock County crystals Cuyuna deposits depth described diabase dikes district dolomite drilling ECONOMIC GEOLOGY fault feet feldspar ferruginous chert field fissures fractures Galena geologists gold grains granite graphite hematite Homestake igneous rocks Inst intrusion iron formation irregular itabirite limestone lodes magma magnetite Maquoketa shale masses material metallic metamorphic microscope minerals mining occur oil and gas oil rock ore-bodies origin outcrop oxide plates porphyry portion precipitation present probably production pyrite pyrrhotite quartz quartzite region replacement samples sand sandstone schists secondary sedimentary sediments shale silica silver slate solution specimens structure sulphides sulphur surface tellurium thickness tion U. S. G. S. Bull U. S. Geol veins zone
Beliebte Passagen
Seite 374 - The oil and salt pockets of the Texas Coastal Plain are probably not indigenous to the strata in which they are found, but are the resultant products of columns of hot saline waters which have ascended, under hydrostatic pressure, at points along lines of structural weakness, through thousands of feet of shale, sand, and marine littoral sediments of the Coastal Plain section, through which oil and sand are disseminated in more or less minute quantities.
Seite 316 - For chemical and physical researches relating to the geology of the United States, including researches with a view of determining geological conditions favorable to the presence of deposits of potash salts, $40,000; For preparation of the illustrations of the Geological Survey, $18,280; For preparation of the report of the mineral resources of the United States...
Seite 347 - pitting," is caused chiefly by the solvent action of acids on the iron of the boiler. Free acids capable of dissolving iron occur in some natural waters, especially in the drainage from coal mines, which usually contains free sulphuric acid, and also in some factory wastes draining into streams. Many ground waters contain free hydrogen sulphide, a gas that readily attacks boilers; and...
Seite 364 - After visiting all the great gas wells that had been struck in western Pennsylvania and West Virginia, and carefully examining the geological surroundings of each, I found that every one of them was situated either directly on or near the crown of an anticlinal axis, while wells that had been bored in the synclines on either side furnished little or no gas, but in many cases large quantities of salt water. Further observation showed that the...
Seite 404 - The chalcocite is rather coarsely crystalline, and the etch figures show that the larger areas are made up of numerous interlocking grains, which stand out distinctly and have no definite crystallographic relation to each other. The cleavage, as brought out by the etching, is apparently in two directions at right angles to each other, one more prominent than the other, one possibly prismatic and the other basal. The crystallographic intergrowths are the most interesting and also the most conclusive...
Seite 374 - ... under hydrostatic pressure, at points along lines of structural weakness, through thousands of feet of shale, sand, and marine littoral sediments of the Coastal Plain section, through which oil and sand are disseminated in more or less minute quantities. The oil, with sulphur, may have been floated upward on these waters, and the salt and dolomite may have been crystallized from the saturated solution.
Seite 364 - Probably very few or none of the grand arches along mountain ranges will be found holding gas in large quantity, since in such cases the disturbance of the stratification has been so profound that all the natural gas generated in the past would long ago...
Seite 799 - Significance of drafts in steam-boiler practice, by WT Ray and Henry Kreisinger. 1909. 61 pp. BULLETIN 368. Washing and coking tests of coal at Denver, Colo., by AW Belden, GR Delamater, and JW Groves.
Seite 567 - The result was one fourteenth-hundredth of one per cent., or a little more than seven-millionths part of the rock, a quantity that may seem surprisingly small to those who, by dwelling on the relative value of the ores magnify their relative quantity, a quantity certainly small enough to answer certain inconsiderate objections to the theory of derivation of the ores from the enclosing rock, based on the want of ocular evidence of their metalliferous character."1 As has already been stated, the ore...
Seite 376 - ... appellation they may be characterized locally, seem to have this much in common — huge lenses of gypsum or limestone, or masses of rock salt, or both, located more or less centrally. The dip of the rocks about the periphery of such areas seems to be away from the central mass, often at a high angle. The longer we study these peculiar structures the more convinced are we that although they may be located along lines of weakness, faults, or fractured anticlines, they are not to any great extent...