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The geology of Bolivia comprises a variety of different lithologies as well as
tectonic Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents ...
and sedimentary environments. On a synoptic scale, geological units coincide with topographical units. The country is divided into a mountainous western area affected by the
subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, ...
processes in the Pacific and an eastern lowlands of stable platforms and
shields A shield is a piece of personal armour held in the hand, which may or may not be strapped to the wrist or forearm. Shields are used to intercept specific attacks, whether from close-ranged weaponry or projectiles such as arrows, by means of a ...
. The Bolivian
Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...
is divided into three main ranges; these are from west to east: the Cordillera Occidental that makes up the border to
Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...
and host several active
volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates ...
es and geothermal areas,
Cordillera Central Central Cordillera refers to the New Guinea Highlands. Cordillera Central, meaning ''central range'' in Spanish, may refer to the following mountain ranges: * Cordillera Central, Andes (disambiguation), several mountain ranges in South America ** ...
(in some contexts also called Cordillera Oriental) once extensively mined for
silver Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...
and tin and the relatively low Cordillera Oriental that rather than being a range by its own is the eastern continuation of the Central Cordillera as a
fold and thrust belt A fold and thrust belt (FTB) is a series of mountainous foothills adjacent to an orogenic belt, which forms due to contractional tectonics. Fold and thrust belts commonly form in the forelands adjacent to major orogens as deformation propagates ...
. Between the Occidental and Central Cordillera the approximately 3,750-meter-high
Altiplano The Altiplano (Spanish for "high plain"), Collao ( Quechua and Aymara: Qullaw, meaning "place of the Qulla") or Andean Plateau, in west-central South America, is the most extensive high plateau on Earth outside Tibet. The plateau is located a ...
high plateau extends. This basin hosts several freshwater lakes, including
Lake Titicaca Lake Titicaca (; es, Lago Titicaca ; qu, Titiqaqa Qucha) is a large freshwater lake in the Andes mountains on the border of Bolivia and Peru. It is often called the highest navigable lake in the world. By volume of water and by surface area ...
as well as salt-covered
dry lake A dry lake bed, also known as a playa, is a basin or depression that formerly contained a standing surface water body, which disappears when evaporation processes exceeds recharge. If the floor of a dry lake is covered by deposits of alkaline c ...
s that bring testimony of past climate changes and lake cycles. The eastern lowlands and sub-Andean zone in Santa Cruz, Chuquisaca, and
Tarija Department Tarija () is a department in Bolivia. It is located in south-eastern Bolivia bordering with Argentina to the south and Paraguay to the east. According to the 2012 census, it has a population of 482,196 inhabitants. It has an area of . The city ...
s was once an old
Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...
sedimentary basin Sedimentary basins are region-scale depressions of the Earth's crust where subsidence has occurred and a thick sequence of sediments have accumulated to form a large three-dimensional body of sedimentary rock. They form when long-term subsidence ...
that hosts valuable hydrocarbon reserves. Further east close to the border with Brazil lies the Guaporé Shield, made up of stable
Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of th ...
crystalline rock.


Andes

The Andes of Bolivia began to rise about 200 million years ago (mya) during the
Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
. The western margin of what is now South America had been the place of several other
orogenies Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted t ...
before the Andes rose. It has been hypothesized that the central Andes gained its great height 26 to 14 mya as result of a compressive
failure Failure is the state or condition of not meeting a desirable or intended objective, and may be viewed as the opposite of success. The criteria for failure depends on context, and may be relative to a particular observer or belief system. One ...
of the
lithosphere A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of up to thousands of years ...
beneath Bolivia and neighboring areas. The great heights of the Altiplano, Codillera Occidental and Cordillera Oriental are isostatically compensated by an up to 70 km deep crust. Climate has responded to the formation of this important topographic barrier. It is not clear, however, if the rise of the Andes simply caused the extreme aridity of
Atacama Desert The Atacama Desert ( es, Desierto de Atacama) is a desert plateau in South America covering a 1,600 km (990 mi) strip of land on the Pacific coast, west of the Andes Mountains. The Atacama Desert is the driest nonpolar desert in the ...
and adjacent parts of Bolivia or if a preexisting
desert climate The desert climate or arid climate (in the Köppen climate classification ''BWh'' and ''BWk''), is a dry climate sub-type in which there is a severe excess of evaporation over precipitation. The typically bald, rocky, or sandy surfaces in desert ...
and associated low erosion rates allowed the mountains to build up to their current heights.Garcia-Castellanos, D., 2007
The role of climate in high plateau formation. Insights from numerical experiments
Earth Planet. Sci. Lett. 257, 372–390, doi:10.1016/j.epsl.2007.02.039
A hypothesis holds that scarce sediment supply to the Atacama Trench caused by arid climate induced high
shear stress Shear stress, often denoted by (Greek: tau), is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. '' Normal stress'', on ...
es in the
subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, ...
process that enhanced the Andean mountain building.


Western Cordillera

The Western Cordillera is made up by a series of active and extinct volcanoes rising from the western edge of the Altiplano plateau. This range divides the Chilean watersheds of
Salar de Atacama Salar de Atacama is the largest salt flat in Chile. It is located south of San Pedro de Atacama, is surrounded by mountains, and has no drainage outlets. In the east it is enclosed by the main chain of the Andes, while to the west lies a seconda ...
and the Pacific from the
endorheic An endorheic basin (; also spelled endoreic basin or endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but drainage converges instead into lakes ...
Altiplano basin. The western volcanoes of Bolivia are part of the Central Volcanic Zone of the Andes, a major upper
Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configu ...
volcanic province. Volcanic eruptions in Bolivia are scarce, the latest one occurred in Irruputuncu in 1995. Volcanic hazards do not represent any threat to the major populated centres which are all in the eastern Altiplano or further east, far away from the volcanic centers. Although the Western Cordillera concentrates most active volcanoes (volcanoes active in the last 10000 years) many old large
stratovolcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and p ...
es rises up to 100 km away from the main line of the Western Cordillera.


Altiplano plateau

The Altiplano plateau or Meseta del Collasuyu to differentiate it from other Andean high
plateau In geology and physical geography, a plateau (; ; ), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides ...
x is a wide and long-lived intermontane sedimentary basin with no outlet; it is
endorheic An endorheic basin (; also spelled endoreic basin or endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but drainage converges instead into lakes ...
. The Altiplano is an infill of sedimentary material from both Cordillera Occidental and Cordillera Oriental. The origin of the Altiplano and its great height has long been major question among geologists. Today the Altiplano is believed to have been an early
foreland basin A foreland basin is a structural basin that develops adjacent and parallel to a mountain belt. Foreland basins form because the immense mass created by crustal thickening associated with the evolution of a mountain belt causes the lithosphere ...
of the "proto-Andes" that got uplifted by crustal shortening in the
Late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene Epoch made up of two stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million years ago) to 5.333 Ma. The ...
. The Bolivian Altiplano hosts the world's largest reserves of
lithium Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid ...
. These reserves are in the salt-saturated waters of
Salar de Uyuni Salar de Uyuni (or "Salar de Tunupa") is the world's largest salt flat, or playa, at over in area. It is in the Daniel Campos Province in Potosí in southwest Bolivia, near the crest of the Andes at an elevation of above sea level. The Sala ...
and Salar de Coipasa, neither of which are currently being commercially exploited for lithium. Salt is extracted from the saltars in minor amounts to be sold as
table salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...
after being added
iodine Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...
from
Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...
.


Eastern Cordillera

Cordillera Oriental is made up of a bended arc of plutons. The bend occurs at the latitude of
Cochabamba Cochabamba ( ay, Quchapampa; qu, Quchapampa) is a city and municipality in central Bolivia in a valley in the Andes mountain range. It is the capital of the Cochabamba Department and the fourth largest city in Bolivia, with a population of 6 ...
and corresponds to eastward projection of the Arica elbow, the bend of south Amicas coastline at the Peru-Chile border. North of the bend Cordillera Centrals
batholith A batholith () is a large mass of intrusive igneous rock (also called plutonic rock), larger than in area, that forms from cooled magma deep in Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock types, su ...
s are northwest-southeast oriented while south of it they are north-south oriented. These bodies of
granitic A granitoid is a generic term for a diverse category of coarse-grained igneous rocks that consist predominantly of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quart ...
to
granodioritic Granodiorite () is a coarse-grained ( phaneritic) intrusive igneous rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar. The term banatite is sometimes used informally for various rocks ranging from ...
composition were formed in two episodes: the Early
Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Creta ...
(199–180 Ma) and the
Neogene The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago (Mya) to the beginning of the present Quaternary Period Mya. ...
(19–8 Ma). The emplacement of these igneous bodies have been interpreted as an effect of two temporary decreases in subduction angles of the ancient
Farallon Plate The Farallon Plate was an ancient oceanic plate. It formed one of the three main plates of Panthalassa, alongside the Phoenix Plate and Izanagi Plate, which were connected by a triple junction. The Farallon Plate began subducting under the w ...
. This arc of magmatic material hosts Bolivia's widely known tin belt as well as the famous
silver Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...
mine of
Potosí Potosí, known as Villa Imperial de Potosí in the colonial period, is the capital city and a municipality of the Department of Potosí in Bolivia. It is one of the highest cities in the world at a nominal . For centuries, it was the location o ...
. These mineralizations are of the porphyry
mineralization Mineralization may refer to: * Mineralization (biology), when an inorganic substance precipitates in an organic matrix ** Biomineralization, a form of mineralization ** Mineralization of bone, an example of mineralization ** Mineralized tissues are ...
type that are typical for convergent plate margins. The Cordillera Real form the northern, highly uplifted and eroded, part of the Central Cordillera.


Lowlands and Sub-Andean zone

The Sub-Andean Zone and the Northern and Eastern Lowlands share a common ancient history but has since the Andean orogeny developed to two distinct zones. While both zones share essentially the same old
sedimentary Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...
platform Platform may refer to: Technology * Computing platform, a framework on which applications may be run * Platform game, a genre of video games * Car platform, a set of components shared by several vehicle models * Weapons platform, a system ...
strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...
the strata at the Sub-Andean Zone have been folded and thrusted into a
fold and thrust belt A fold and thrust belt (FTB) is a series of mountainous foothills adjacent to an orogenic belt, which forms due to contractional tectonics. Fold and thrust belts commonly form in the forelands adjacent to major orogens as deformation propagates ...
with structural traps where
hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
fluids have accumulated. The limit between the fold and thrust belt and the Eastern Lowlands is drawn by the Serranía del Aguaragüe a north-south range representing the Andean thrust front.


Fold and thrust belt

The relatively low Cordillera Oriental, located east of
Cordillera Central Central Cordillera refers to the New Guinea Highlands. Cordillera Central, meaning ''central range'' in Spanish, may refer to the following mountain ranges: * Cordillera Central, Andes (disambiguation), several mountain ranges in South America ** ...
, are part of a
fold and thrust belt A fold and thrust belt (FTB) is a series of mountainous foothills adjacent to an orogenic belt, which forms due to contractional tectonics. Fold and thrust belts commonly form in the forelands adjacent to major orogens as deformation propagates ...
and exposes
Silurian The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago (Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoi ...
and
Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. ...
age
strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...
some of which are
fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
-bearing. The fold and thrust makes up the framework of the hydrographic network of Pilcomayo and other rivers. Currently one of Bolivia's most
seismic Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other ...
zones is the
Cochabamba Fault Zone The Cochabamba Fault Zone or Cochabamba Shear Zone ( es, Zona de falla de Cochabamba) is an east-southeast trending zone of sinistral strike-slip faults near the city of Cochabamba in the Bolivian Andes. The movements along Cochabamba Fault Zone ...
located just below the city of
Cochabamba Cochabamba ( ay, Quchapampa; qu, Quchapampa) is a city and municipality in central Bolivia in a valley in the Andes mountain range. It is the capital of the Cochabamba Department and the fourth largest city in Bolivia, with a population of 6 ...
and its fertile valley. This fault zone is related to the
Arica Arica ( ; ) is a commune and a port city with a population of 222,619 in the Arica Province of northern Chile's Arica y Parinacota Region. It is Chile's northernmost city, being located only south of the border with Peru. The city is the cap ...
elbow and the bend in the Andes at this latitude.


Eastern Lowlands

The geology of the eastern lowlands is dominated by the ancient
Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...
sedimentary Chaco
Tarija Tarija or San Bernardo de la Frontera de Tarixa is a city in southern Bolivia. Founded in 1574, Tarija is the largest city and capital and municipality within the Tarija Department, with an airport ( Capitán Oriel Lea Plaza Airport, (TJA)) off ...
Basin that has considerable hydrocarbon reserves. During the Carboniferous, the Chaco-Tarija Basin was covered by thick
sequence In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is called ...
s that included
sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...
filled channels. In the 1970s these sandstone were interpreted as
tillite image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...
from the late Paleozoic glaciations, but new interpretations consider them to be of marine origin but still glacially influenced. The
depositional environment In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will b ...
for these channel systems has been likened to that on the floor of the present day
Labrador Sea The Labrador Sea (French: ''mer du Labrador'', Danish: ''Labradorhavet'') is an arm of the North Atlantic Ocean between the Labrador Peninsula and Greenland. The sea is flanked by continental shelves to the southwest, northwest, and northeast. I ...
, which was influenced by repeated
Pleistocene The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed ...
glaciations. The late
Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configu ...
deformation associated with the Andean orogeny forced hydrocarbons sourced in
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, w ...
shales to migrate to shallower
stratigraphical Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostrati ...
levels.


Northern Lowlands

The Northern Lowlands are and have long been a depositional milleau are mostly covered by Tertiary and Quaternary deposits. The bulk of these deposits are now
laterite Laterite is both a soil and a rock type rich in iron and aluminium and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content. They develop by ...
s. River
erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is di ...
and
sediment transport Sediment transport is the movement of solid particles (sediment), typically due to a combination of gravity acting on the sediment, and/or the movement of the fluid in which the sediment is entrained. Sediment transport occurs in natural system ...
have created a large number of
oxbow lake An oxbow lake is a U-shaped lake or pool that forms when a wide meander of a river is cut off, creating a free-standing body of water. In South Texas, oxbows left by the Rio Grande are called '' resacas''. In Australia, oxbow lakes are cal ...
s and added copious
meander A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank) and deposits sediments on an inner, convex ban ...
s to the rivers.


Guaporé Shield

In the north and east of Santa Cruz Department the crystalline and
Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of th ...
Guaporé Shield (also called Central Brazil Shield) makes up most of the
bedrock In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of be ...
but is mostly covered by
Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non- avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...
laterite Laterite is both a soil and a rock type rich in iron and aluminium and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content. They develop by ...
s and Quaternary
alluvial Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Al ...
basins. The shield expresses itself topographically as a large elevated
hinterland Hinterland is a German word meaning "the land behind" (a city, a port, or similar). Its use in English was first documented by the geographer George Chisholm in his ''Handbook of Commercial Geography'' (1888). Originally the term was associated ...
located north of
Serranías Chiquitanas The Serranías Chiquitanas are a group of low mountain ranges in the northeast of the Bolivian department of Santa Cruz. The ranges are located at the southern periphery of the discrete massif of the Guaporé shield. The Serranías Chiquitanas s ...
towards the Brazilian border. High-grade metamorphic rocks occur in the Bolivian part of the Guaporé Shield partly due to the 2000 million years old "Trans-Amazonian tectonothermal event" that affected parts of South America. Low-grade metamorphic rocks occur as well. The Guaporé Shield is believed to extend beneath the
Phanerozoic The Phanerozoic Eon is the current geologic eon in the geologic time scale, and the one during which abundant animal and plant life has existed. It covers 538.8 million years to the present, and it began with the Cambrian Period, when anima ...
Tarija-Chaco and Beni Basin sediments into the Andes. It has been suggested that weaknesses in the shield were responsible for the formation of the Arica Elbow. The East-West Río Mercedes Line in the Guaporé Shield hosts several
Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided ...
diabase Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-gra ...
intrusion In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...
s. As of 1985 the rocks of Guaporé Shield were considered to be poorly known. Near the Brazilian border the iron deposit of
El Mutún ''El Cerro Mutún'' (Spanish for "the Mountain Mutún") is an iron ore deposit. Located in the Germán Busch Province in the Santa Cruz Department of Bolivia, near Puerto Suárez, it extends across the border into Brazil, where it is called the '' ...
stands out as the world's largest
iron ore Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the ...
deposit. It is located in the Serranía de El Mutún, also called Cerro Mutún or Serranía de Jacadigo in Brazil. The shield also underlies Serrania Caparuch or Huanchaca which is the inspiration for the '' Lost World'' of
Conan Doyle Sir Arthur Ignatius Conan Doyle (22 May 1859 – 7 July 1930) was a British writer and physician. He created the character Sherlock Holmes in 1887 for '' A Study in Scarlet'', the first of four novels and fifty-six short stories about Ho ...
. Proyecto Precámbrico, an Anglo-Bolivian technical cooperation project, explored the area between 1976 and 1986. There are a series of published 1:250,000 scale maps of the area with accompanying bilingual reports, along with more detailed 1:100,000 maps of regions of economic interest. There is a published geochemical atlas. Most of this data is summarised in an "Overseas Memoir" of the
British Geological Survey The British Geological Survey (BGS) is a partly publicly funded body which aims to advance geoscientific knowledge of the United Kingdom landmass and its continental shelf by means of systematic surveying, monitoring and research. The BGS he ...
.''The Geology and Mineral Resources of the Bolivian Precambrian Shield''. M Litherland and others: Overseas Memoir 9, British Geological Survey, Her Majesty's Stationery Office, 1986.


See also

* List of volcanoes in Bolivia * Natural gas in Bolivia *
Potosí Potosí, known as Villa Imperial de Potosí in the colonial period, is the capital city and a municipality of the Department of Potosí in Bolivia. It is one of the highest cities in the world at a nominal . For centuries, it was the location o ...
* San Cristóbal mine (Bolivia) * Siglo XX mine


References


External links

* {{South America topic, Geology of