Volcanism

Solution consists of a physical weathering process that takes place when the water dissolves the minerals and seeps downwards or percolates up to the surface. This geologic occurrence is what has caused there to be a lot of rich outcrops of minerals that have been discovered. This is also known as leaching by mining geologists because a lot of rich outcrops have been produced by some of the carrying rock being leached out while the minerals that were valuable stayed close to the surface.

The weathering process and method has been taking place for millions of years now and still continues to occur to this very day. Besides the quick removal of soils that are loosened by water or air, it is rarely noticed as only small changes in the topography and is produced in numerous common life spans of man. 

The speed in which the weathering occurs is controlled by the composition as well as physical conditions of rocks that are getting assailed, the conditions of the climate and the topography of the area they are placed in.

Vulcanism, which is the second of the greatest earth forming movements, does not concern mining geology as much as other forces of nature do. Vulcanism is just another word for volcanos. A volcano is a gap, or rupture, in the surface or crust of the earth, which permits hot, molten rock, ash and gases to flee from deep underneath the surface. Volcanic activity that has to do with the extrusion of rock is likely to produce mountains or features that are similar to mountains over a phase of time.

Volcanoes are in general located where tectonic plates pull apart or are coming together. A mid-oceanic ridge, such as the Mid Atlantic Ridge, has examples of volcanoes created by convergent tectonic plates that have pulled apart; the Pacific Ring of Fire has illustrations of volcanoes that have been brought about by these convergent tectonic plates coming together. On the other hand, volcanoes are generally not formed where two tectonic plates slide past one another. Volcanoes can also shape where there is a stretching of the crust of the earth and where the crust grows thin, like in the African Rift Valley, the European Rhine Graben with its Eifel volcanoes, the Wells Gray-Clearwater Volcanic Field as well as the Rio Grande Rift in North America.

As a final point, “mantle plumes”, or the well known, (or should we say infamous when it comes to prospecting) “hotspots”, can originate volcanoes; these hotspots can take place far from plate boundaries, like in the Hawaiian Islands.