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Ore deposits formed by lateral secretion are formed by metamorphic reactions during shearing, which liberate mineral constituents such as quartz, sulfides, gold, carbonates, and oxides from deforming rocks, and focus these constituents into zones of reduced pressure or dilation such as faults. This may occur without much hydrothermal fluid flow ...
In geology, a lens or lentil is a body of ore or rock that is thick in the middle and thin at the edges, resembling a convex lens in cross-section. [1] To thin out in all directions is to "lens out", also known as "lensing". The adjectives "lenticular" and "lentiform" are used to describe lens-like formations.
In ore deposit geology, hypogene processes occur deep below the Earth's surface, and tend to form deposits of primary minerals, as opposed to supergene processes that occur at or near the surface, and tend to form secondary minerals. [1] At great depth the pressure is high, and water can remain liquid at temperatures well above 100 °C.
Ore bodies of orogenic gold deposits are generally defined by ≤ 3–5% sulfide minerals, most commonly arsenopyrite in metasedimentary host rocks and pyrite/pyrrhotite in meta-igneous rocks, and ≤ 5–15% carbonate minerals, such as ankerite, dolomite and calcite. [16]
Since these ore deposits frequently form massive sulfide lenses, they are also named sediment-hosted massive sulfide (SHMS) deposits, [1] [4] as opposed to volcanic-hosted massive sulfide (VHMS) deposits. The sedimentary appearance of the thin laminations led to early interpretations that the deposits formed exclusively or mainly by exhalative ...
An ore shoot is a hypogenic mass that is deposited in veins within a planar channel or lode, found in a shear or fault zone, fissure or lithologic boundary. [1] The ore shoot is the area of concentration which contains a primary ore along the veins present in the rock, and consists of the most valuable part of the deposit.
When the ore forms a blanketlike body along the bedding plane of the rock, it is commonly called a manto ore deposit. Other ore geometries are chimneys and veins. [ 4 ] Polymetallic replacements/mantos are often stratiform wall-rock replacement orebodies distal to porphyry copper deposits, [ 5 ] or porphyry molybdenum deposits. [ 6 ]
Supergene enrichment occurs at the base of the oxidized portion of an ore deposit. Metals that have been leached from the oxidized ore are carried downward by percolating groundwater, and react with hypogene sulfides at the supergene-hypogene boundary. The reaction produces secondary sulfides with metal contents higher than those of the primary ...