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 (), ** * Aragonese and Occitan: ''Peninsula Iberica'' ** ** * french: Péninsule Ibérique * mwl, Península Eibérica * eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, def ...

, from

Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of th ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = '' Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , ...

. 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 1499.87 km2. History Earliest settlement There has been human settlement in the area for more than 40,000 y ...

(Portugal) to Sevilla (Spain). The

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the econom ...

activity in this region goes back thousands of years. The Iberian Pyrite Belt has had more than 2000 million tons of ore 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 geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, wh ...

Period, connected to active and hydrothermal 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 deposit, mainly copper-zinc which are associated with and created by volcanic-associated hydrothermal events 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 Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic Luster (mineralogy), lust ...

, and also chalcopyrite,

sphalerite Sphalerite (sometimes spelled sphaelerite) 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, Mississippi-V ...

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 cr ...

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 located where modern Portugal (south of the Douro river) and a portion of western Spain (the present Extremadura and the province of Salamanca) lie. It was named after the Lusitani or Lu ...

, a

Roman province The Roman provinces (Latin: ''provincia'', pl. ''provinciae'') 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 rule ...

for several centuries, was an abundant source of mineral ore which included

gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile ...

silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

copper Copper is a chemical element with the symbol Cu (from la, cuprum) 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 pink ...

, tin,

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, ...

, and

iron Iron () is a chemical element with symbol Fe (from la, ferrum) 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, right in ...

. Given its mineral riches, the area played a significant role in the expansion of Roman metallurgy. 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 () 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 Socialist Party. The municipal holiday is Ju ...

20 km to the north and the port city of

Mértola Mértola () is a 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 Portugal. Meanwhile, it is the second-lowest popula ...

40 km to the east, is situated on the Guadiana river. The Sao Domingos Mine and Ríotinto 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 late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire ...

there was a decline in the mining industry, 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 (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formul ...

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 ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular fo ...

). 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 river" (''Tejo''). Alentejo includes the regions of Alto Alentejo and Baixo Alent ...

References

{{reflist

External links

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