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56-517: The Spanish Silver Train was an improvised trail used to transport silver from Potosí , Peru across the isthmus of Panama in order to ship it to Spain via the Spanish treasure fleet . The silver was usually unloaded in Panama City , then put in mule trains and taken first to Nombre de Dios , and then, following the demise of that city in the late sixteenth century, to Portobello . The Silver Train

112-603: A karst terrain , a collapse breccia may form due to collapse of rock into a sinkhole or in cave development. Collapse breccias also form by dissolution of underlying evaporite beds. Fault or tectonic breccia results from the grinding action of two fault blocks as they slide past each other. Subsequent cementation of these broken fragments may occur by means of the introduction of mineral matter in groundwater . Igneous clastic rocks can be divided into two classes: Volcanic pyroclastic rocks are formed by explosive eruption of lava and any rocks which are entrained within

168-491: A phreatic eruption . The released pressure allowed the formation of the Caracoles tuff ring on top of the breccia. The magma then extruded outward from a dike to form a volcanic dome over the tuff . The dacite dome is 1,700 m (5,600 ft) by 1,200 m (3,900 ft) at the surface and narrows down to the 100 m (330 ft) wide dike at depth. Hydrothermal circulation and fracturing soon followed, altering

224-442: A candle tied to their foreheads. Many of them died or were seriously injured due to falls, accidents, and the harsh conditions of the mine life. Illness was another danger: at such a high altitude, pneumonia was always a concern, especially given the extreme and rapid changes of temperature experienced by workers climbing from the heat of the deep shafts to the freezing elements of the surface at 16,000 feet, and mercury poisoning took

280-521: A greater extent. According to his research, though as few as 4500 mitayos were actively laboring in the mines at any given time, this was due to the mita ordinaria system, in which the up to 13,500 men conscripted per year were divided into three parts, each working one out of every three weeks. In addition, many of the remaining mingas and wage workers were either mita ordinaria workers on their off weeks or former mitayos who remained in Potosí. Within

336-573: A known impact crater, and/or an association with other products of impact cratering such as shatter cones , impact glass, shocked minerals , and chemical and isotopic evidence of contamination with extraterrestrial material (e.g., iridium and osmium anomalies). An example of an impact breccia is the Neugrund breccia , which was formed in the Neugrund impact . Hydrothermal breccias usually form at shallow crustal levels (<1 km) between 150 and 350 °C, when seismic or volcanic activity causes

392-465: A little over a century earlier. This only increased the burden on the remaining natives, and at some point in the 1600s, up to half of the eligible male population might find themselves working at Potosí. Nevertheless, the number of mitayos dropped to about 4,000 by 1689, prompting the Viceroy Duke of Palata to raise the number again through a new census and inclusion of new populations not subject to

448-734: A meter in size and which form layers in the caldera floor. Some clasts of caldera megabreccias can be over a kilometer in length. Within the volcanic conduits of explosive volcanoes the volcanic breccia environment merges into the intrusive breccia environment. There the upwelling lava tends to solidify during quiescent intervals only to be shattered by ensuing eruptions. This produces an alloclastic volcanic breccia. Clastic rocks are also commonly found in shallow subvolcanic intrusions such as porphyry stocks, granites and kimberlite pipes, where they are transitional with volcanic breccias. Intrusive rocks can become brecciated in appearance by multiple stages of intrusion, especially if fresh magma

504-473: A mining center in early Spanish colonial history, Potosí still sits at one of the largest silver deposit systems in the world. Located in the Bolivian Tin Belt, Cerro Rico de Potosí is the world's largest silver deposit and has been mined since the sixteenth century, producing up to 60,000 tonnes by 1996. Estimates are that much silver still remains in the mines. Potosí became the second largest city, and

560-467: A reddish-brown gossan cap of iron-oxides and quartz, with grayish-blue altered dacite and many mine dumps below. Basement rocks consist of Ordovician clastic sediments consisting of phyllite with some sandstone interbedding . At about 13.8 Ma , the dome was extruded . During the explosive process, the Venus breccia formed when the ascending dacite magma reacted with groundwater to produce

616-510: A result of the extreme precipitation deficit during the winter months, with the resulting aridity leading to an increased diurnal temperature variation. Potosí is home to football teams Real and Nacional , which play their matches at the 32,000-capacity multi-purpose stadium Estadio Víctor Agustín Ugarte , one of the highest stadiums in the world. The city is served by Aeropuerto Capitán Nicolas Rojas , with commercial airline flights by Boliviana de Aviación , Bolivia's flag air carrier. There

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672-465: A thunderous noise, whereas it does in Aymara . Thus, if Potosí encompasses the idea of a thunderous noise, the location would have an Aymaran root rather than a Quechuan. The actual sharp structure of the term is contrary to the nature of both Aymara and Quechua. Another explanation, given by several Quechua speakers, is that potoq is an onomatopoeic word that reproduces the sound of the hammer against

728-404: A void to open along a fault deep underground. The void draws in hot water, and as pressure in the cavity drops, the water violently boils. In addition, the sudden opening of a cavity causes rock at the sides of the fault to destabilise and implode inwards, and the broken rock gets caught up in a churning mixture of rock, steam and boiling water. Rock fragments collide with each other and the sides of

784-531: Is 4,824 m (15,827 ft) above sea level . Today, Potosí continues to be an important mining center, and is the largest urban center in the Department of Potosí. A growing city, Potosí is now famous for its well-preserved colonial architecture, and unusual geographic setting as one of the highest cities in the world. It features a rare cold highland climate, and is marked by its long dry period, and short but strong wet season. While famous for its dominance as

840-426: Is a breccia composed of very large rock fragments, sometimes kilometers across, which can be formed by landslides , impact events , or caldera collapse. Breccia is composed of coarse rock fragments held together by cement or a fine-grained matrix. Like conglomerate , breccia contains at least 30 percent of gravel -sized particles (particles over 2mm in size), but it is distinguished from conglomerate because

896-458: Is a breccia containing very large rock fragments, from at least a meter in size to greater than 400 meters. In some cases, the clasts are so large that the brecciated nature of the rock is not obvious. Megabreccias can be formed by landslides , impact events , or caldera collapse. Breccias are further classified by their mechanism of formation. Sedimentary breccia is breccia formed by sedimentary processes. For example, scree deposited at

952-485: Is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix . The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of different origins, as indicated by the named types including sedimentary breccia, fault or tectonic breccia, igneous breccia, impact breccia, and hydrothermal breccia. A megabreccia

1008-732: Is also a railroad, the Rio Mulatos-Potosí line . The city of San Luis Potosí in Mexico was named after Potosí in Bolivia. In the United States, the name Potosi was optimistically given to lead-mining towns of Potosi, Wisconsin , and Potosi, Missouri , and also to the silver-mining town of Potosi, Nevada . Breccia Breccia ( / ˈ b r ɛ tʃ i ə / BRETCH -ee-ə or / ˈ b r ɛ ʃ i ə / BRESH -ee-ə , Italian: [ˈbrettʃa] ; Italian for 'breach')

1064-489: Is intruded into partly consolidated or solidified magma. This may be seen in many granite intrusions where later aplite veins form a late-stage stockwork through earlier phases of the granite mass. When particularly intense, the rock may appear as a chaotic breccia. Clastic rocks in mafic and ultramafic intrusions have been found and form via several processes: Impact breccias are thought to be diagnostic of an impact event such as an asteroid or comet striking

1120-406: Is less common in the mesothermal regime, as the formational event is brief. If boiling occurs, methane and hydrogen sulfide may be lost to the steam phase, and ore may precipitate. Mesothermal deposits are often mined for gold. For thousands of years, the striking visual appearance of breccias has made them a popular sculptural and architectural material. Breccia was used for column bases in

1176-697: Is no authoritative etymology for the word Potosí . According to legend, in about 1462, Huayna Capac , the eleventh Sapa Inca of what by then was known as the Inca Empire "set out for Ccolque Porco and Andaccaua, the location of his mines from which were taken innumerable arrobas of silver" (an arroba is a Spanish unit of weight equivalent to approximately 25 lb (11 kg)). Before leaving there, he saw Potosí, and admiring its beauty and grandeur, he said (speaking to those of his Court): "This doubtless must have much silver in its heart"; whereby he subsequently ordered his vassals to go to Ccolque Porco ... and work

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1232-436: Is the origin of the dollar sign . The urban complex in the remote Andes was important enough to be designated a Villa Imperial in the hierarchy of Spanish urban settlements. Although in mountainous terrain, the core of Potosí was laid out in the standard Spanish grid pattern, where by 1610 some 3,000 Spaniards and 35,000 creoles, mostly male, were resident. Indigenous settlements outside the core were more haphazard. The villa

1288-486: The Earth and are normally found at impact craters . Impact breccia, a type of impactite , forms during the process of impact cratering when large meteorites or comets impact with the Earth or other rocky planets or asteroids . Breccia of this type may be present on or beneath the floor of the crater, in the rim, or in the ejecta expelled beyond the crater. Impact breccia may be identified by its occurrence in or around

1344-528: The Incan vassals desisted in their purpose and returned to Porco and told the king what had happened; relating the occurrence in their own language, on coming to the word noise, they said "Potocsí" which means there was a great thunderous noise, and from that later was derived (corrupting a letter) the name of potosí. It is believed that Potosí is a Quechua word. However, in Quechua the root p'otoj does not refer to

1400-599: The Pacific coast, shipped north to Panama City , and carried by mule train across the isthmus of Panama to Nombre de Dios or Portobelo , whence it was taken to Spain on the Spanish treasure fleets . Some of the silver also made its way east to Buenos Aires , via the Rio de la Plata . Some of the silver was also transported to Acapulco, Mexico , where it was sent via the Manila Galleons to buy Asian products. Cerro de Potosí's peak

1456-544: The Potosí mint. For Europeans, Peru– Bolivia was located in the Viceroyalty of Peru and was known as " Upper Peru " before becoming independent as part of Bolivia . Potosí was a mythical land of riches, it is mentioned in Miguel de Cervantes ' famous novel, Don Quixote (second part, chap. LXXI) as a land of "extraordinary richness". One theory holds that the mint mark of Potosí (the letters "PTSI" superimposed on one another)

1512-404: The base of a cliff may become cemented to form a talus breccia without ever experiencing transport that might round the rock fragments. Thick sequences of sedimentary ( colluvial ) breccia are generally formed next to fault scarps in grabens . Sedimentary breccia may be formed by submarine debris flows . Turbidites occur as fine-grained peripheral deposits to sedimentary breccia flows. In

1568-686: The command of Juan José Castelli ), which led to an increased sense that Potosí required its own independent government. Later, the Second Auxiliary Army (under the command of Manuel Belgrano ) was forced to retreat, Belgrano made the decision to blow up the Casa de la Moneda . The natives undid the fuse, as many refused to evacuate and would have lost their lives. Two more expeditions from Buenos Aires would seize Potosí. Potosí continues to be an important administrative center, mining town, tourist attraction, and population center in modern Bolivia. There

1624-562: The conditions at Potosí. Spanish American mines were the world's most abundant sources of silver during this time period. Spanish America's ability to supply a great amount of silver and China's strong demand for this commodity which the Spanish supplied via Latin American trade with the Philippines using the Manila Galleons , resulted in a spectacular mining boom. The true champion of this boom in

1680-410: The dacite and depositing ore minerals and gangue in the veins. Founded in 1545 as a mining town, it soon produced fabulous wealth, and the population eventually exceeded 200,000 people. The city gave rise to a Spanish expression, still in use: valer un Potosí ("to be worth a Potosí"), meaning "to be of great value". The rich mountain, Cerro Rico , produced an estimated 60% of all silver mined in

1736-427: The eruptive column. This may include rocks plucked off the wall of the magma conduit, or physically picked up by the ensuing pyroclastic surge . Lavas, especially rhyolite and dacite flows, tend to form clastic volcanic rocks by a process known as autobrecciation . This occurs when the thick, nearly solid lava breaks up into blocks and these blocks are then reincorporated into the lava flow again and mixed in with

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1792-477: The female population were sex workers, which is a typical phenomenon in mining towns generally. In the early 17th century, Basques were well established in the city and made up for a substantial number of the inhabitants in Potosí. They gathered in a confederation opposed to another one, the Vicuñas , a melting pot of natives and non-Basque Spanish and Portuguese colonists, fighting for control over ore extraction from

1848-640: The foot of the Cerro de Potosí —sometimes referred to as the Cerro Rico ("rich mountain")—a mountain popularly conceived of as being "made of" silver ore that dominates the city. The Cerro Rico is the reason for Potosí's historical importance since it was the major supply of silver for the Spanish Empire until Guanajuato in Mexico surpassed it in the 18th century. The silver was taken by llama and mule train to

1904-501: The impact of the Potosi mita on the Indians is that mita labor was only one form of work at the mines. A 1603 report stated that of 58,800 Indians working at Potosi, 5100 were mitayos , or fewer than one in ten. In addition to the mitayos there were 10,500 mingas (contractual workers) and 43,200 free wage earners." However, historian Peter Bakewell emphasizes the role of mita labor in Potosí to

1960-426: The indigenous population. These mitayos faced harsh conditions in the mines, where they were often given the least desirable jobs. While more skilled laborers extracted the ore, mitayos were tasked with carrying it back to the surface in baskets, leather bags, or cloth sacks. These loads often weighed between 100 and 300 lbs, and the workers had to carry them up rickety ladders in steep, narrow shafts lit only by

2016-421: The lives of many involved in the refining process. The Potosí mita caused dramatic demographic shifts in the local indigenous population as wives and children moved with workers to Potosí while thousands more fled their traditional villages, forfeiting their ayllu land rights in order to escape the labor draft. By the late 17th century, upper Peru had lost nearly 50% of its indigenous population compared to

2072-403: The mesothermal regime, at much greater depths, fluids under lithostatic pressure can be released during seismic activity associated with mountain building. The pressurised fluids ascend towards shallower crustal levels that are under lower hydrostatic pressure. On their journey, high-pressure fluids crack rock by hydrofracturing , forming an angular in situ breccia. Rounding of rock fragments

2128-583: The mines and its management. Eventually, tension among both factions came to a head, resulting in the eruption of overt armed conflict starting 1622 up to 1625. The Spanish Crown intervened, siding at one point with the Basques. Both factions reached a settlement sealed with a wedding between the son and daughter of the leaders in either side, the Basque Francisco Oyanume and the Vicuña general Castillo. One of

2184-461: The mines and remove from them all the rich metal. They did so, and having brought their tools of flint and reinforced wood, they climbed the hill; and after having probed for its veins, they were about to open those veins when they heard a frightening thunderous noise which shook the whole hill, and after this, they heard a voice which said: "Do not take the silver from this hill, because it is destined for other masters." Amazed at hearing this reasoning,

2240-399: The mines, a figure called el Tío acts as a deity of the land itself. El Tío serves as a figure of the mountain itself. Laborers within the mines offer coca leaves and alcohol to statues constructed within the mines of the deity to protect themselves from the dangerous conditions. Potosí was a multiracial society, with native Andeans, Spanish settlers, and black slaves. The largest sector of

2296-479: The mita ( forasteros ). The reform failed, and the Duke's successor set the official number to 4,108 mitayos (1,367 active each week). In reality, the number of mitayos was even lower due to the increasing practice of buying oneself out of the obligation. For the remaining mita workforce, however, conditions remained harsh. Mine and mill owners notoriously ignored official regulations on provisions and especially withheld

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2352-512: The money the Indians should receive as recompensation for their travel. Just the cost of traveling to Potosí and back could be more than a mitayo was paid in a year, and so many of them chose to remain in Potosí as wage workers when their mita was finished. Former mitayos living in Potosí were not only exempt from the draft, but usually earned considerably more due to the valuable skills they had gained in permanent services. According to historian Noble David Cook, "A key factor in understanding

2408-521: The most famous Basque residents in Potosí (1617–19) was Catalina de Erauso , a nun who escaped her convent and dressed as a man, becoming a driver of llamas and a soldier. During the Bolivian War of Independence (1809–1825), Potosí frequently passed between the control of Royalist and Patriot forces. Major leadership mistakes came when the First Auxiliary Army arrived from Buenos Aires (under

2464-676: The ore, and oral tradition has it that the town derived its name from this word. Potosí has a rare climate for a city of its size, due to its extreme elevation at over 4,000m. Semi-arid and with average temperatures in its warmest month sitting right at 10 °C, the city's climate straddles a subtropical highland climate , Cwc , within the Köppen climate classification , with subpolar oceanic characteristics and an alpine climate (E). Summers are cool and wet. with daily highs rarely rising above 20 °C. Winters have cooler days with much colder nights, averaging −4 °C. These low temperatures are

2520-428: The overpressure of pore fluid within sedimentary basins . Hydrothermal breccias are usually formed by hydrofracturing of rocks by highly pressured hydrothermal fluids. They are typical of the epithermal ore environment and are intimately associated with intrusive-related ore deposits such as skarns , greisens and porphyry -related mineralisation. Epithermal deposits are mined for copper, silver and gold. In

2576-526: The population were native men, forced to labor underground mining the silver ore, but there were considerable opportunities for merchants and native traders, who became wealthy. Suppliers of food as well as holders of urban and rural real estate prospered in Potosí. Women, particularly widows, held property, since they were guaranteed a portion of their husband's estate under Spanish law. Small-scale female vendors dominated street markets and stalls, selling food, coca leaves, and chicha (maize beer). A portion of

2632-407: The remaining liquid magma. The resulting breccia is uniform in rock type and chemical composition. Caldera collapse leads to the formation of megabreccias, which are sometimes mistaken for outcrops of the caldera floor. These are instead blocks of precaldera rock, often coming from the unstable oversteepened rim of the caldera. They are distinguished from mesobreccias whose clasts are less than

2688-444: The rock fragments have sharp edges that have not been worn down. These indicate that the gravel was deposited very close to its source area, since otherwise the edges would have been rounded during transport. Most of the rounding of rock fragments takes place within the first few kilometers of transport, though complete rounding of pebbles of very hard rock may take up to 300 kilometers (190 mi) of river transport. A megabreccia

2744-419: The silver industry was indeed the Spanish crown. By allowing private-sector entrepreneurs to operate mines under license and placing high taxes on mining profits, the Spanish empire was able to extract the greatest benefits. An example of a tax that was levied includes the quinto , a 20% severance tax on gross value. From the raw materials extracted from the mines, coins called pieces of eight were fashioned at

2800-508: The site of the first mint, in the Americas. By 1891, low silver prices prompted the change to mining tin, which continued until 1985. At peak production in the sixteenth and seventeenth centuries, the ore contained up to 40% silver. The ore deposits reside in veins present in the dacite volcanic dome . The hill is "honeycombed" with underground workings, reaching from the summit to depths of 1,150 m (3,770 ft). The conical hill has

2856-581: The void, and the angular fragments become more rounded. Volatile gases are lost to the steam phase as boiling continues, in particular carbon dioxide . As a result, the chemistry of the fluids changes and ore minerals rapidly precipitate . Breccia-hosted ore deposits are quite common. The morphology of breccias associated with ore deposits varies from tabular sheeted veins and clastic dikes associated with overpressured sedimentary strata, to large-scale intrusive diatreme breccias ( breccia pipes ), or even some synsedimentary diatremes formed solely by

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2912-491: The world during the second half of the 16th century. Potosí miners at first mined the rich oxidized ores with native silver and silver chloride ( cerargyrite ) that could be fed directly into smelting furnaces. Especially successful were the small clay "flower pot" furnaces called guayras , which had been used by the Incas. By 1565, the miners had exhausted the direct-smelting ore, and silver production plummeted. Silver production

2968-458: Was a prime target for English, Dutch and French privateers in the sixteenth and seventeenth century. Francis Drake and Guillaume Le Testu , a French privateer, succeeded in capturing the train . The trail, called Camino de Cruces in the eastern part and more generally El Camino Real still exists in places and has paving, though a full hike across Panama can take several days. Shorter trips are possible. Potos%C3%AD Potosí lies at

3024-575: Was an ecclesiastical court for legal issues regarding the clergy. Indigenous laborers were required to work in Potosí's silver mines through the Spanish mita system of forced labor, based on an analogous mit'a system traditional to pre-Hispanic Andean society (though the mit'a directed labor for public works and collective agricultural projects). Laborers were drawn from the native population of an area that encompassed almost 200,000 square miles. Thirteen thousand men were conscripted each year, constituting about one out of every seven adult males in

3080-516: Was governed by a Spanish corregidor and town council. Some 40 notaries documented and recorded commercial transactions as well as last wills and testaments. Since Potosí was of such economic importance to the Spanish Empire , the crown bureaucracy was a significant presence. Large churches, lavishly decorated inside, were built, and friars from the Dominican, Franciscans, Augustinians, Mercederians, and Jesuits were present, but no convent for women. There

3136-449: Was revived by the introduction of the patio process , invented by Spanish merchant Bartolomé de Medina in 1554. The patio process used mercury amalgamation to extract silver from lower-grade ores, and those containing silver sulfide ( argentite ), as was typical of the unoxidized ores found deeper in the mountain. In 1609, another mercury amalgamation method, the pan amalgamation process was invented in Potosí, and proved better-adapted to

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