Manganese deposits in part of the Sierra Maestra, Cuba
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Bulletin↗
Geology topics
Charles Frederick Park
Publications and source records attributed to Charles Frederick Park.
Dolomite and jasperoid in the Metaline District, northeastern Washington
The replacement ore bodies of the Metaline zinc-lead district, in northeastern Washington are limited to the greatly disturbed fault block through which the Pend Oreille River flows and are associated with the major faults but are not in them. They are mostly near the top of the Metaline limestone, of Middle Cambrian age, and below black Ordovician slate. The ores are generally in jasperoid and are surrounded by a shell of crystalline dolomite. Outside of the dolomite is a shell of coarse-grained calcite that in places was deposited along solution channels long distances from known ore bodies. Jasperoid, crystalline dolomite, and, to a less extent, coarse-grained calcite are therefore favorable but not infallible signs of the presence of ore nearby. The Metaline limestone was dolomitized regionally before the ore was introduced, and this early dolomitization is independent of the ore.
Washington↗
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↗