What does porphyry mean in relation to copper?
Porphyry copper deposits are copper ore bodies that are formed from hydrothermal fluids that originate from a voluminous magma chamber several kilometers below the deposit itself. Predating or associated with those fluids are vertical dikes of porphyritic intrusive rocks from which this deposit type derives its name.
Where are porphyry copper deposits found?
Porphyry copper deposits form in continental magmatic arcs along convergent plate-margin boundaries or in island-arc environments. The deposits are associated with subduction-related volcanic centers, although in some examples, they are thought to be associated with postcollisional volcanism.
How much of Earth’s copper is found in porphyry copper deposits?
Porphyry mines produce more than 70% of global copper, nearly all of the molybdenum, and about 20% of the World’s gold—in addition, 80% of rhenium, nearly all tellurium, and significant silver and zinc are also produced as by-products (Sillitoe, 2010; John and Taylor, 2016).
What is the difference between porphyry copper and sediment hosted copper?
In porphyry copper deposits, copper ore minerals are disseminated in igneous intrusions. Sediment-hosted stratabound copper deposits, in which copper is concentrated in layers in sedimentary rocks, account for about 20 percent of the world’s identified copper resources.
What is porphyry used for?
Porphyry is prized for its great compressive strength and exceptional durability. For this reason it is now most commonly used as a paving stone.
How porphyry deposits are formed?
Porphyry deposits typically form in oceanic or continental arcs above subduction zones (Fig. 1). As the oceanic plate and overlying sediment subduct, increasing pressures expel water from the sediment, and hydrous minerals in the oceanic plate start to break down.
What is the use of porphyry?
Porphyry was extensively used in Byzantine imperial monuments, for example in Hagia Sophia and in the “Porphyra”, the official delivery room for use of pregnant Empresses in the Great Palace of Constantinople, giving rise to the phrase “born in the purple”.
What is the highest grade of copper?
According to FQM, copper cathode produced at Las Cruces reaches a maximum quality of 99.9% copper. The mine with the highest grade of copper in the world is Sudbury (also known as Victoria) in Canada, where the grade of ore is nearly 8%.
Where can I find porphyry?
Rhomb porphyry is found in continental rift areas, including the East African Rift (including Mount Kilimanjaro), Mount Erebus near the Ross Sea in Antarctica, the Oslo graben in Norway, and south-central British Columbia.
What does porphyry look like?
Its chief characteristic is a large difference in size between the tiny matrix crystals and the much larger phenocrysts. Porphyries may be aphanites or phanerites, that is, the groundmass may have microscopic crystals as in basalt, or crystals easily distinguishable with the eye, as in granite.
Is porphyry A rare stone?
Imperial Porphyry is arguably the rarest and most historically important stone in the world. It comes from only one source; a single mountain in Egypt that the Romans called Mons Porphyry.