The Chief Commercial Granites of Massachusetts

Cover
U.S. Government Printing Office, 1908 - 228 Seiten
 

Was andere dazu sagen - Rezension schreiben

Es wurden keine Rezensionen gefunden.

Andere Ausgaben - Alle anzeigen

Häufige Begriffe und Wortgruppen

Beliebte Passagen

Seite 217 - A microscopic granular structure sometimes characterizing adjacent feldspar particles in granite in consequence of their having been crushed together during or subsequent to their crystallization. CUT-OFF. Quarrymen's term for the direction along which the granite must be channeled, because it will not split. Same as "hardway.
Seite 219 - ... powdered, gives a brownish rust color. MATRIX. The general mass of a rock which has isolated crystals; sometimes called groundmass. MILLIMETER. French decimal lineal measure, the thousandth part of a meter or the tenth part of a centimeter. It is equivalent to nearly 0.04 inches, the meter being 39J5 inches.
Seite 217 - GLOSSARY OF SCIENTIFIC AND QUARRY TERMS. ACCESSORY MINERALS in granite are original constituents of the rock, found only in small, often only in microscopic quantity. ACIDIC.
Seite 40 - The impact of the hammer breaks up the granules on the immediate surface so that the light falling upon it is reflected, instead of absorbed, and the resultant effect upon the eye is that of whiteness. The darker color of a polished surface is due merely to the fact that through careful grinding all these irregularities and reflecting surfaces are removed, the light penetrating the stone is absorbed, and the effect upon the eye is that of a more or less complete absence of light or darkness. Obviously...
Seite 36 - Vinalhaven, 20 feet below the surface in the face of the quarry, there is a bed of granite sand 18 inches thick between two sheets, which at that point dip about 10° into the hill. On the southeast side of the Longfellow quarry, near Hallowell, some of the sheets within a wide heading include granite sand beds that are about 10 inches thick.
Seite 164 - ... the greenish tinge. An estimate of the mineral percentages made by applying the Rosiwal method to a camera lucida drawing of a thin section enlarged 40 diameters yields these results with a mesh of 1 inch and a total linear length of 34 inches.
Seite 90 - ... the porphyritic feldspars on the rough face is marked. The quarry, opened in 1906, measures about 100 by 35 feet and 5 feet in depth. The sheets, from 1 to 3 feet thick, are horizontal or inclined 15° S. There is but one set of joints, which strikes N. 65° E. and is vertical, and is spaced 5 to 20 feet. The rift is reported as horizontal and the grain as vertical, with N. 20° W. course. Biotitic knots are up to 1.5 inches across. A "shake" structure extends down to 16 inches from the surface.
Seite 40 - Merrill a explains the cause of these contrasts very satisfactorily: The impact of the hammer breaks up the granules on the immediate surface, so that the light falling upon it is reflected, instead of absorbed, and the resultant effect upon the eye is that of whiteness. The darker color of a polished surface is due merely to the fact that, through careful grinding, all these irregularities and reflecting surfaces are removed...
Seite 30 - The spacing of the joints varies considerably, ranging from 1 foot to 500 feet, but usually from 10 to 50 feet. In some localities the jointing is very irregular. The granite is broken up into various polygons, which at the surface, where weathering has made inroads, resemble bowlders. Quarries opened in such places are called bowlder quarries. Another sort of irregularity in joints consists in their discontinuity or intermittence, their strike and dip for the short spaces in which they occur being...
Seite 27 - The observations made in Europe and in this country, taken in connection with the various inferences geologists have drawn from them, indicate that sheet or " onion " structure in granite rocks is due to the following possible causes: 1. To expansion caused by solar heat after the exposure of the granite by erosion. 2. To contraction in the cooling of the granite while it was still under its load of sedimentary beds, the sheets being therefore approximately parallel to the original contact surface...

Bibliografische Informationen