What are vein mineral deposits?

What are vein mineral deposits?

vein, in geology, ore body that is disseminated within definite boundaries in unwanted rock or minerals (gangue). The term, as used by geologists, is nearly synonymous with the term lode, as used by miners. There are two distinct types: fissure veins and ladder veins.

Where do deposits form?

Placer deposits form at Earth’s surface when weathering action exposes gold from other, older lode deposits. The gold is swept into, and settles in, streams, lakes, rivers or the sea floor. Many placer deposits are of recent geologic age, but some are billions of years old.

How are magmatic deposits formed?

deposits of minerals formed deep in the earth’s crust during the solidification and crystallization of basic or alkaline magma containing high concentrations of valuable minerals. These deposits vary in shape and occur in igneous rocks that are related to them in origin.

What are four ways that ore deposits can form?

Subsurface mining (under the earths surface), Surface mining (on top the earth’s surface), Placer mining (shallow water dredging) and Undersea mining (deep sea). Name the two ways ore can be formed by Contact Metamorphism.

How are sediments deposited?

Deposition is the laying down of sediment carried by wind, flowing water, the sea or ice. Sediment can be transported as pebbles, sand and mud, or as salts dissolved in water. Salts may later be deposited by organic activity (e.g. as sea shells) or by evaporation.

How are sedimentary ore deposits made?

Ore deposits form in sedimentary environments as a result of one of two generalised geological processes: either as a result of mineral precipitation from solution in surface waters, most commonly from sea water or lake waters; or as a result of physical accumulation of ore minerals during processes of sediment …

How ore deposits are created?

Deposits of minerals form when a medium that contains and transports mineral-making ore releases and deposits the ore. When magma or lava cools, the magma and ore carried within it crystallize to form tiny minerals in the newly-created igneous rock.

How are ore created?

Ore is extracted from the earth through mining and treated or refined, often via smelting, to extract the valuable metals or minerals. Ores must be processed to extract the elements of interest from the waste rock. Ore bodies are formed by a variety of geological processes generally referred to as ore genesis.

How are veins used in the deposition of minerals?

Veins are mineral deposits which form when a preexisting fracture or fissure within a host rock is filled with new mineral material. The deposition of minerals is typically performed by circulating aqueous solutions. Many ore deposits of economic importance occur in veins.

How are veins formed in a rock wall?

Most vein deposits are formed as new mineral species are precipitated onto rock walls which themselves remain unaltered. In such cases mineral deposits fill the original crack or fissure in the host rock but do not extend into the host rock itself.

How does a vein form in a hydrothermal deposit?

The simplest hydrothermal deposit to visualize is a vein, which forms when a hydrothermal solution flows through an open fissure and deposits its dissolved load. A great many veins occur close to bodies of intrusive igneous rocks because the igneous rocks serve as heat…

What makes the polished surface of a vein?

This sometimes causes a polished surface, slickensides. A druse or vug is an unfilled part of a vein; it is usually lined with crystals that project inward. Vein matter is the mineral mass filling the vein; it may or may not be valuable.