The Iberian Pyrite Belt is a vast geographical area with particular geological features that stretches along much of the south of the

Iberian Peninsula The Iberian Peninsula ( ), also known as Iberia, is a peninsula in south-western Europe. Mostly separated from the rest of the European landmass by the Pyrenees, it includes the territories of peninsular Spain and Continental Portugal, comprisin ...

, from

Portugal Portugal, officially the Portuguese Republic, is a country on the Iberian Peninsula in Southwestern Europe. Featuring Cabo da Roca, the westernmost point in continental Europe, Portugal borders Spain to its north and east, with which it share ...

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

. It is about 250 km long and 30–50 km wide, running northwest to southeast from

Alcácer do Sal Alcácer do Sal () is a municipality in Portugal, located in Setúbal District. The population in 2011 was 13,046, in an area of 1,499.87 km2. History Earliest settlement There has been human settlement in the area for more than 40,000 y ...

(Portugal) to

Sevilla Seville ( ; , ) is the capital and largest city of the Spanish autonomous community of Andalusia and the province of Seville. It is situated on the lower reaches of the River Guadalquivir, in the southwest of the Iberian Peninsula. Seville ...

(Spain). The

mining Mining is the Resource extraction, extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agriculture, agricultural processes, or feasib ...

activity in this region goes back thousands of years. The Iberian Pyrite Belt has had more than 2000 million tons of ore removed, and still has more than 400 million left to exploit. It is the largest concentration of massive sulfides in the world.

Formation

The Iberian Pyrite Belt was formed 350 million years ago in the

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

Period, connected to active and

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

volcanism that led to the formation of a volcanic-sedimentary complex. Volcanic activity in the region led to eight giant

volcanogenic massive sulfide ore deposit Volcanogenic massive sulfide ore deposits, also known as VMS ore deposits, are a type of metal sulfide Ore, ore deposit, mainly copper-zinc which are associated with and produced by volcanic-associated hydrothermal vents in submarine environments ...

s (VMS) associated with polymetallic massive flanks of volcanic cones in the form of

pyrite The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue ...

, and also

chalcopyrite Chalcopyrite ( ) is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS2 and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a Mohs scale, hardness of 3.5 to 4 ...

sphalerite Sphalerite is a sulfide mineral with the chemical formula . It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in Sedimentary exhalative deposits, sedimentary exhalative, Carbonate-hoste ...

galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It crysta ...

and

cassiterite Cassiterite is a tin oxide mineral, SnO2. It is generally opaque, but it is translucent in thin crystals. Its luster and multiple crystal faces produce a desirable gem. Cassiterite was the chief tin ore throughout ancient history and remains ...

. The deposits of the Iberian Pyrite Belt are notable examples of volcanic- and sediment-hosted massive sulfide (VSHMS) deposits, which hybrids between the VMS and SEDEX deposits. Over 250 deposits are known in the belt.

Mining

From the eighth century BC, there was mining in the area but it was the Romans who exploited the mines with greater intensity, thanks to its strategic position in the Mediterranean. This southern area of

Lusitania Lusitania (; ) was an ancient Iberian Roman province encompassing most of modern-day Portugal (south of the Douro River) and a large portion of western Spain (the present Extremadura and Province of Salamanca). Romans named the region after th ...

, a

Roman province The Roman provinces (, pl. ) were the administrative regions of Ancient Rome outside Roman Italy that were controlled by the Romans under the Roman Republic and later the Roman Empire. Each province was ruled by a Roman appointed as Roman g ...

for several centuries, was an abundant source of mineral

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically including metals, concentrated above background levels, and that is economically viable to mine and process. The grade of ore refers to the concentration ...

which included

gold Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...

silver Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...

copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...

tin Tin is a chemical element; it has symbol Sn () and atomic number 50. A silvery-colored metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the ...

lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

, and

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

. Given its mineral riches, the area played a significant role in the expansion of

Roman metallurgy Metals and metal working had been known to the people of modern Italy since the Bronze Age. By 53 BC, Rome had expanded to control an immense expanse of the Mediterranean. This included Italy and its islands, Spain, Macedonia, Africa, Asia ...

. During the Roman period, extensive mining and storage of valuable minerals required protective fortifications and mineral warehouses. This physiographic region contains many areas that contain large concentrations of ore and areas of extreme environmental conditions such as the Rio Tinto River.

Small structures

There are remains of more than 20 such small structures in the Portuguese Castro Verde territory. A mining transportation route that existed between the mines of

Aljustrel Aljustrel (), officially Town of Aljustrel (), is a town and a municipality in the Portuguese district of Beja. The population in 2011 was 9,257, in an area of 458.47 km2. The present mayor is Nelson Domingos Brito, elected by the Socialis ...

20 km to the north and the port city of

Mértola Mértola (), officially the Town of Mértola (), is a town and municipality in southeastern Portuguese Alentejo near the Spanish border. In 2011, the population was 7,274, in an area of approximately : it is the sixth-largest municipality in Portu ...

40 km to the east, is situated on the Guadiana river. The São Domingos Mine and Riotinto mines accounted for one of the bases of the economy in the area. While in the

Middle Ages In the history of Europe, the Middle Ages or medieval period lasted approximately from the 5th to the late 15th centuries, similarly to the post-classical period of global history. It began with the fall of the Western Roman Empire and ...

there was a decline in the

mining industry Mining is the extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a la ...

, in the Industrial Revolution it intensified again, especially from the late nineteenth century when dozens of mines operated, primarily producing pyrite. Removal of

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

remained significant until the 1950s because of its application in the chemical industry (production of

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

). At present, this mining area is in decline. The economic viability depends on the extraction of copper, zinc, lead and, in some cases, precious metals like gold and silver. The São Domingos Mine is now a deserted open-pit pyrite mine in

Alentejo Alentejo ( , , ) is a geographical, historical, and cultural region of south–central and southern Portugal. In Portuguese, its name means "beyond the Tagus" (). Alentejo includes the regions of Alto Alentejo Province, Alto Alentejo and Bai ...

References

{{reflist

External links

http://www.fajapiritica.es
Faja Pirítica (in Spanish) Economic geology Sulfur mining Metallogenetic provinces

Formation

Mining

Small structures

See also

References

External links