Geological and geophysical data integration for delimitation of mineralized areas in a supergene manganese deposits

Geophysical methods are widely used in mineral exploration. This paper discusses the results of geological and geophysical studies in supergene manganese deposits of southern Brazil. Mineralized zones as described in geological surveys were characterized as of low resistivity (20 Omega.m) and high chargeability (30ms), pattern found also in oxides and sulfite mineral deposits. Pseudo-3D modeling of geophysical data allowed mapping at several depths. A relationship between high chargeability and low resistivity may define a pattern for high grade gonditic manganese ore. Large areas of high chargeability and high resistivity may result in accumulation of manganese and iron hydroxides, due to weathering of the gonditic ore, dissolution, percolation and precipitation.

A Preliminary Study of Montana Copper - Nickel Ore

Deposits of sulfides, containing nickel and copper with associated platineferous minerals occur in the Stillwater Igneous Complex. This is a group of unusual igneous rocks situated in Stillwater and Sweetgrass counties in Montana.

Some Chromite Deposits in Madison County, Montana

Chromite occurs in Madison County, Montana, in two areas, one three miles southwest of Silver Star, the other five miles southeast of Sheridan. The ore bodies are small, lenticular masses surrounded by metamorphosed sedimentary rocks of the pre-Cambrian Cherry Creek series. The ore was deposited from the hydrothermal solutions which serpentinized the surrounding metamorphic host rocks.

The Beneficiation of Montana Silver Star Chromite Ore

It is known that there are large deposits of chromium ore in Stillwater and Carbon Counties in South-Central Montana. The late James F. Kemp of Columbia University, stated in 1928, that these were the largest chromium deposits in the United States and probably in the world, although they were not considered of commercial grade as compared with foreign ores.

Chromite Deposits Near Red Lodge and Silver Star, Montana

The Red Lodge and Silver Star chromite deposits of Montana have stimulated much interest during periods of war. The Red Lodge deposit is 25 miles southwest of Red Lodge which is also the nearest railroad point. Several workings are scattered throughout the area, exposing lense-like ore bodies averaging 33% chrome oxide. Silver Star is a much smaller deposit 5 miles west of Silver Star, Montana, which is its nearest rail­road point. Lenses of chromite are exposed by pits and trench­es, which average approximately 36% chromic oxide.

A Mineral Dressing Study of the Benefication of Philipsburg Manganese Carbonate Ore

The beneficiation of rhodochrosite ore to the extent that it is suitable for nodulizing and subsequent use in the steel industry is intriguing. Such ores from certain mines is relatively easy to beneficiate, but the rhodo-chrosite ore from several deposits of the Philipsburg district has never been successfully up-graded by any of the several known beneficiating methods.

Contents of rare earth and other chemical elements in Fe-Mn micronodules, nodules, and bottom sediments from the Clarion-Clipperton ore province in the Pacific Ocean

Processes governing the formation of rare earth element (REE) composition are under consideration for ferromanganese deposits (nodules, separate parts of nodules, and micronodules of different size fractions) within the Clarion-Clipperton ore province in the Pacific Ocean. It is shown that ferromanganese oxyhydroxide deposits with different chemical compositions can be produced in sediments under similar sedimentation conditions. In areas with high bioproductivity size of micronodules has positive correlation with Mn content and Mn/Fe and P/Fe ratios and negative correlation with Fe, P, REE, and Ce anomaly. Behavior of REE in micronodules from sediments within bioproductive zones is related to increase of influence of diagenetic processes in sediments as a response to the growth of size of micronodules. Distinctions in chemical composition of micronodules and nodules are related to their interaction with associated sediments. Micronodules grow in sediments using hydrogenous ferromanganese oxyhydroxides. As they grow, micronodules are enriched in labile fraction of sediments reworked during diagenesis. Sources of material of ferromanganese nodules are governed by their formation at the water bottom interface. Their upper part is formed by direct settling of iron oxyhydroxides from bottom water, whereas the lower part is accumulated due to diagenetic processes in sediments. Differences of REE compositions in ferromanganese deposits are caused by the reduction of manganese during diagenesis and its separation from iron. Iron oxyhydroxides form a sorption complex due to sorption of phosphate-ion from bottom and pore waters. Sorption of phosphate-ion results in additional sorption of REE.

Chemical composition of hydrothermal deposits and vulcanites from the Menez Gwen vent field, Mid-Atlantic Ridge

Surface hydrothermal deposits of the shallow-water Menez Gwen vent field located in the rift zone of the Mid-Atlantic Ridge are mostly composed of nonmetalliferous minerals in contrast to sulfide deposits of deep-water fields. Here sulfide minerals occur only in dispersed form. High-temperature sulfide deposits strongly enriched in copper and zinc occur only immediately below the surface of the bottom. This is related to subsurface boiling and phase separation of initial high-temperature hydrothermal ore-bearing solution that ascends from the interior to the floor surface.

Chemical and mineral compositions of sedimentary deposits and magmatic rocks from DSDP Legs 41, 45, 48, and 49

This collective monography by a group of lithologists from the Geological Institute of the USSR Academy of Sciences summarizes materials of the Deep-Sea Drilling Project from the Atlantic Ocean. It gives results of processing materials on the sequences drilled during DSDP Legs 41, 45, 48 and 49. These studies were based on lithological-facial analysis combined with detailed mineralogical-petrographic description. Its chapters give a number of ideas on formation of the Earth sedimentary cover, which can be used for compilation of regional and global schemes of ocean paleogeography, reconstruction of history of some structures in the World Ocean, correlation between sedimentary processes on continents and in oceans, estimation of perspectives for oil and gas fields and ore formation.