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Research about Georgia

Source-linked reports with geographic coverage including Georgia.

625 records · Page 35Linked to original sources
USGS1949

Sheet structure, a major factor in the occurrence of ground water in the granites of Georgia

Increasing demand for supplies of ground water in the Piedmont of Georgia has necessarily focused attention on granitic rocks, which have a considerable areal extent in this part of the state. These rocks have the property generally known as sheet structure. Major parting planes resulting from sheeting are usually sub-parallel to the rock surface on hills and in valleys and consequently control the circulation of subsurface water. Imperfect shallow pseudosynclinal basins formed by sheet planes in valleys are the receptacles for much subsurface water that percolates along these planes from nearby upland slopes. Therefore, wells drilled in lowlands in sheeted terranes almost invariably produce greater quantities of water than those on the uplands.

Georgia↗
USGS1939

Sienna ("ocher") deposits of the Cartersville District, Georgia

Sienna ("ocher") deposits in the Cartersville district, Georgia, occur in the contact zone between dolomitic limestone and underlying quartzite of Lower Cambrian age. These rocks, together with interbedded schists, were folded and recrystallized probably near the close of Paleozoic time. Simple fissures and transverse and oblique faults, formed during the late stages of folding, admitted hydrothermal solutions, which deposited concentrated masses of hematite and pyrite, and other ore minerals, in the dolomites and calcareous schists. There is some evidence that large bodies of iron carbonate also were deposited. Subsequent weathering has removed the dolomite near the surface, and its residuum in many places rests upon the more resistant quartzite. Iron derived from the hematite and pyrite, and possibly from iron carbonate, was transferred by meteoric waters and deposited as hydrous oxides by partial replacement of (1) irregular, structureless bodies of the residuum, and (2) irregular areas in schists both at the base of the dolomite and beneath the uppermost quartzite bed. A relatively thin superficial portion of the uppermost quartzite bed also was replaced. Transfer of the iron has taken place over short distances only, and the present positions of the sienna deposits reflect essentially the positions of the deposits of source minerals.

Georgia↗
USGS1936

The Battle Branch gold mine, Auraria, Georgia

The Battle Branch mine, in north-central Georgia, is well known locally for its pockets of exceptionally rich gold ore. During the period from May 24, 1934, to May 20, 1935, 781.97 ounces of bullion, of an average fineness of about 850, was shipped to the mint. The deposit is of the lode type; it consists of many quartz stringers and lenses grouped in three zones in a schistose phase of the Carolina gneiss. Three stages of mineralization are recognized. An early high-temperature stage produced coarsely crystalline silicates, such as garnet, kyanite, tourmaline, biotite, and muscovite, which were probably formed by a recrystallization of the minerals in the country rock. During the intermediate stage ankerite, quartz, and pyrrhotite were formed. The last stage was marked by chlorite, galena, and gold. Throughout the period of mineralization minor amounts of movement in and across the lode occurred. The distribution of the ore shoots is dependent to a large extent upon the distribution of the cross fractures. The ore shoots are pod-shaped bodies, which pinch and swell abruptly. The gold in the rich shoots is contemporaneous with galena and is clearly of hypogene origin.

Georgia↗
USGS1919

Deposits of Claiborne and Jackson age in Georgia

In 1911 the Geological Survey of Georgia published as Bulletin 26 a "Preliminary report on the geology of the Coastal Plain of Georgia," by Otto Veatch and Lloyd William Stephenson, prepared in cooperation with the United States Geological Survey under the supervision of T. Wayland Vaughan, a geologist in charge of Coastal Plain investigations, who contributed the determinations of the invertebrate fossils of the Tertiary and Quaternary formations. Although this report constituted a decided advance in our knowledge of the geology of the Coastal Plain of Georgia, it was admittedly of reconnaissance character, and corrections and additions to it were to be expected. During the last few years field work has been prosecuted vigorously in the Coastal Plain of Georgia, and the additional information thus accumulated throws light upon certain problems of stratigraphy left unsolved by Veatch and Stephenson and alters considerably some of their correlations. The object of the present paper is to present the new evidence regarding the age and correlation of the Eocene formations of Georgia and to revise in accordance with present knowledge the descriptions of the deposits of Claiborne and Jackson age.

Georgia↗