The Granites of Maine

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U.S. Government Printing Office, 1907 - 202 Seiten
 

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Seite 190 - SAP. Quarrymen's term for ferruginous discoloration along sheet or joint surfaces. SCHIST. A rock made up of flattish particles arranged in rough parallelism, some or all of which have crystallized under pressure. SCHISTOSITY. The quality of being like a schist. SEAM. Quarrymen's term for joint. SECONDARY MINERALS. Minerals whose presence is due to the alteration of the ori?inal minerals. SEDIMENTARY. A term designating those rocks that consist of particles deposited under water. SEGREGATION. The...
Seite 32 - numerous joints, the planes of which correspond very nearly with the slope of the hill," but does not undertake to explain them. Vogt * states that the sheets in granites of southeastern Norway measure from 6 inches to 6 feet in thickness and dip from 8° to 33° on the sides of the mountains, toward the valleys, but that they are horizontal on top and approximately parallel to the surface. He shows that they are of preglacial...
Seite 44 - ... Aplite dikes are supposed to have originated in the same deepseated molten mass as the granite they traverse, but they represent a later stage of igneous activity. The fissures they fill were the result of various tensional strains or contractions, possibly consequent upon the cooling of the granite. In color these dikes vary from bluish gray to light and dark reddish. The texture of some aplites is so fine that the mineral particles can not be distinguished with the unaided eye ; that of others...
Seite 36 - The foreman at this quarry was in the habit of calling certain sheets, marked by the absence of discoloration, "strain sheets," to distinguish them from the others. At one place a northwest-southeast compressive strain had actually extended the strain sheet about 5 feet, and also caused a vertical fracture that extended over 15 feet diagonally from the north-south working face to a point on a vertical east-west channel 5 feet back of the face, closing up the channel to half its original width.
Seite 24 - Bartlett 6 found that a piece of granite coping 5 feet long, under the effect of a winter temperature of 0° F. and a summer temperature of 96° F., expanded 0.027792 inch, or 0.000004825 inch per inch for each degree. The Ordnance Department at the Watertown Arsenal c tested the granites referred to under the heading " Elasticity," and found that slabs of gaged lengths of 20 inches in passing from a cold-water bath at 32° F.
Seite 29 - In examining such a structure it is important to make sure that the grinding of the section lias not in any way modified the original fractures. Tarr adds that at Cape Ann the rift does not traverse the "knots" or the basic dikes that cross the granite. Whittle gives two sketches made from polished surfaces of a wellknown granite quarried by the Maine and New Hampshire Granite Company at Redstone...
Seite 208 - B 312. The interaction between minerals and water solutions, with special reference to geologic phenomena, by EC Sullivan.
Seite 188 - BOULDER QUARRY. One in which the joints are either so close or so irregular that no very large blocks of stone can be quarried. CHANNEL. A narrow artificial incision across a mass of rock, which, in the case of a granite sheet, is made either by a series of continuous drill holes or by blasting a series of holes arranged in zigzag order.
Seite 57 - The joint and sheet structure affords ingress to surface water, containing its usual percentage of carbonic acid, and the " rift " or " shake " structure facilitates the kaolinization of the feldspar on either side of the sheet parting by this water. As the feldspars pass into clay the rock crumbles into sand consisting of quartz, mica, and kaolin, and of feldspar in various stages of kaolinization. In some places within the range and depth of frost a large part of this work may have been done by...
Seite 187 - A preliminary report on a part of the granites and- gneisses of Georgia : Georgia Geol.

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