The Mercury Minerals from Terlingua, Texas, Issue 405

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U.S. Government Printing Office, 1909 - Mercury - 174 pages
 

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Page 205 - It must be borne in mind, however, that absolute determination, by work on the surface, of the occurrence or nonoccurrence of oil in any one locality, is not possible. The best that can be done is to calculate the degree of probability on the basis of surface indications and structural conditions.
Page 57 - Johnson 29 discuss the origin of the cherts in the following words: The Monterey shale has been subjected to a varying degree of alteration, none of it pronounced enough, except in certain restricted localities, to greatly change the appearance of the formation. Silicification has taken place, however, especially in the lower and middle portion, but the process by which the silica was so intimately introduced into the shales is not fully understood. A suggestion is at hand in sees. 13 and 14, T....
Page 10 - ... Goldfield. Much of the quartz, including some good ore, has a fine granular texture and has in part been formed by the silicification of shattered or crushed rhyolite. Typical vein quartz, such as is characteristic of the gold veins of the Appalachians or Sierra Nevada or such as is found in the preTertiary schists of the Bullfrog district, does not occur in the mines near Rhyolite, with the exception of the Original Bullfrog. The quartz is prevailingly fine grained, often of a porcelain-like...
Page 19 - ... geologic discussion is begun. The region is one in which little detailed investigation has been made, and most of the natural features are unnamed, while to many others names are indefinitely applied. The following definitions of names that have been newly applied and of names whose application has been made more definite have been submitted to the United States Geographic Board and have been approved and made permanent by that body. Most of these names appear on the map (PI. I). Coalinga district....
Page 110 - Future development will add much to the knowledge of this field, and will show the inaccuracies of the contouring as here presented, but it is hoped that the benefits which may accrue to the operators from a knowledge of the general structure of the field will compensate in a measure for the errors in detail which are to be expected in a map based on incomplete data.
Page 191 - In group 1 there are 13 wells, 1 of these being 1,300 feet in depth, the remainder varying from 80 to 500 feet in depth. The 1,300-foot well yielded flowing water and much gas; the others yield a heavy oil by pumping. The 12 oil-producing wells are all situated within an area of about 400 feet in length and 30 feet in width. The 1,300-foot well was bored a short distance in a northeasterly direction from the most northerly of the oil-yielding wells. The 12 oil wells yield altogether about 15 barrels...
Page 9 - All accessible portions of them have been more or less altered by the oxidation of the sulphides, by the solution of some of the gangue constituents, and by later movements along the fissures. Most of the lodes instead of being simple veins are fissure zones containing numerous stringers of vein material and in most cases showing no definite walls. The principal stringers are parallel with the sides of the lode as a whole, but they are linked by numerous irregular cross veinlets, and similar small...
Page 204 - ... of the oil from its source in the organic shales. This force is believed to be supplied by the tendency of oil to migrate by diffusion through certain media, such as dry shales, and this cause may be (and doubtless is in certain instances) augmented by hydrostatic pressure wherever water has come in contact with the petroleum. (c) Associated porous beds occupying such a position relative to the source of the oil and to impervious barriers as to permit the petroleum to pass from the source into...
Page 110 - ... the strata from one well to another and from one part of the field to another. The difficulties of such correlations are doubtless familiar to anyone who has tried to work out the underground structure of any of the California fields.
Page 109 - An examination of the contours shows that the beds are pitching a little east of southeast ( or striking a little north of northeast), and that the dip is about 850 feet for half a mile, or about 32.5 feet per hundred feet at right angles to the strike. The south and east components of this dip may be calculated by measuring in these directions instead of directly down the dip of the beds, which is always at right angles to the direction taken by the contours. BASIS OF THE CONTOUR MAP. The section...

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