Economic Geology, Band 4Economic Geology Publishing Company, 1909 |
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Häufige Begriffe und Wortgruppen
altered analyses andesite anticlinal banket beds biotite breccia calcite carbon cassiterite cent chalcopyrite character chemical chlorite clays coal field contain copper country rock County Cretaceous crystals dacite deposits depth described dikes diorite discussion district earlier andesite ECONOMIC GEOLOGY evidence fault feet feldspar fissure folding formation formed Geol geologists gneiss gold grains granite graphite hornblende igneous rocks intrusive iron later lignite limestone lode magma magnetite mass material metals metamorphism miles minerals mining Mizpah occur oil and gas origin orthoclase outcrop oxide pebbles petroleum pools porphyry present probably production pyrite pyroxene quartz quartzite reef region rhyolite River salt sand sandstones schist schistose seams sedimentary serpentine shales siliceous silver solutions South structure sulphides surface telluride tellurium temperature theory thickness tion Tonopah tourmaline tuffs U. S. G. S. Bull U. S. Geological Survey upper rhyolite veins writer zone
Beliebte Passagen
Seite 575 - This book gives a condensed account of the ore deposits at present known in South Africa. It is also intended as a guide to the prospector. Only an elementary knowledge of geology and some mining experience are necessary in order to understand this work. With these qualifications, it will materially assist one in his search for metalliferous mineral occurrences and, so far as simple ores are concerned, should enable one to form some idea...
Seite 149 - In porous rocks that are only partly filled with water the oil accumulates at the upper limit of the saturated area. This limit of saturation traces a level line around the sides of each structural basin, but the height of this line may vary greatly in adjacent basins and in different sands of the same basin. Partial saturation is the condition most generally found, in which case accumulations of oil may occur anywhere with reference to the geologic structure; it is...
Seite 677 - September 25, 1909. This volume gives descriptions and analyses of all the principal Iron Ore deposits of the State together with a history of the old charcoal furnace Industry. The main building stones of the State are described and elabo-, rate tests given of their strength and crushing limit, together with chemical analyses, petrographic determinations, etc.
Seite 148 - In most cases it is probable that a combination of these two conditions exist — that the porous rocks are completely saturated with water up to a certain level, but above that point they are dry. The movement of the hydrocarbons through the rocks will not be the same in the two cases, and therefore each condition must be considered separately. If small quantities of oil and gas enter a dry porous rock at different points the oil will flow down as long as gravity is sufficient to overcome the friction...
Seite 149 - ... likely, however, to occur upon terraces or levels, as these places are favorable to accumulation in both dry and saturated rocks. Under all conditions the most probable locations for the accumulation of gas are on the crests of anticlines. Small folds along the side of a syncline may hold a supply of gas, or the rocks may be so dense that gas can not travel to the anticline, but will remain in volume close to the oil.
Seite 512 - Movements in Porous Rocks. — The porous rocks into which the oil and gas enter may be dry, or they may be completely saturated with water. In most cases it is probable that a combination of these two conditions exists — that the porous rocks are completely saturated with water up to a certain level, but above that point they are dry. The movement of the hydrocarbons through the rocks will not be the same in the 'two cases, and therefore each condition must be considered separately. If small quantities...
Seite 416 - California, the northern batholith stretches from Washington up through British Columbia to Alaska. Another smaller mass now occupies the central part of Idaho. Innumerable intrusives of less volume broke through the crust in Southern California, Southern Arizona, Western Nevada, Oregon, and elsewhere. The age of the batholith of Western Montana is somewhat in doubt, it may belong to a later epoch. But throughout this revolution and the birth of the mountain ranges on the coast, the Cretaceous was...
Seite 512 - If small quantities of oil and gas enter a dry porous rock at different points the oil will flow down as long as gravity is sufficient to overcome the friction and the capillary attraction. The gas will diffuse with the air or water vapor contained in the pores of the rock. Oil and gas entering a porous rock that is completely saturated with water will be forced up to the top of the porous stratum by the difference in the specific gravity of the hydrocarbons and the water. Here the oil and gas will...
Seite 512 - Whether the petroleum comes from within or from below the shales, it must pass through them, and to do this it must pass through the very small pores existing in those relatively impervious beds. The nature and cause of this movement are not understood. Capillary action and great rock pressure may be suggested as causes which aid in forcing the petroleum out from the shales, but there are not sufficient data on this subject to justify any scientific explanation. It matters little what is the ultimate...
Seite 299 - authorized to carry on experiments and investigations pertaining to any and all questions and problems that admit of laboratory methods of study and the solution of which would tend to benefit the industrial interests of the State, or would be for the public good...