The Girón Formation ( es, Formación Girón, Jg) is an extensive

geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

stretching across from the north in

Teorama Teorama is a Colombian municipality located in the department of North Santander North Santander (Spanish: Norte de Santander) () is a department of Northeastern Colombia. It is in the north of the country, bordering Venezuela. Its capital ...

Norte de Santander North Santander (Spanish: Norte de Santander) () is a department of Northeastern Colombia. It is in the north of the country, bordering Venezuela. Its capital is Cúcuta, one of the country's major cities. North Santander is bordered by Venez ...

, across the Mesa de Los Santos and

Chicamocha Canyon The Chicamocha Canyon ( , es, Cañón del Chicamocha) is a steep sided canyon carved by the Chicamocha River in Colombia. With a maximum depth of , an area of and a length of , the canyon is the second-largest worldwide. The canyon is situated ...

towards west of

Nobsa Nobsa is a town and municipality in Sugamuxi Province, part of Boyacá department. The urban centre is situated on the Altiplano Cundiboyacense at from the national capital Bogotá at an elevation of . Other parts of the municipality range in ...

, Boyacá in the northern part of the

Altiplano Cundiboyacense The Altiplano Cundiboyacense () is a high plateau located in the Eastern Cordillera of the Colombian Andes covering parts of the departments of Cundinamarca and Boyacá. The altiplano corresponds to the ancient territory of the Muisca. The Alti ...

in the south. The formation extends across the northern and central part of the

Eastern Ranges The Eastern Ranges is an Australian rules football team in the NAB League, the Victorian statewide under-18s competition. The club is a founding member of the competition (1992) and has produced several players for the Australian Football Leagu ...

of the

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

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 ...

. The formation forms the

basement A basement or cellar is one or more floors of a building that are completely or partly below the ground floor. It generally is used as a utility space for a building, where such items as the furnace, water heater, breaker panel or fuse box, ...

in the

Middle Magdalena Valley The Middle Magdalena Valley, Middle Magdalena Basin or Middle Magdalena Valley Basin ( es, Valle Medio del Magdalena, commonly abbreviated to VMM) is an intermontane basin, located in north-central Colombia between the Central and Eastern Ranges of ...

and is forming the Serranía de Los Cobardes. The Girón Formation consists of thickly bedded red

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) ...

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, p ...

s and conglomerates deposited in a terrestrial

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. Alluv ...

and

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...

to fluvio-

lacustrine A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...

environment Environment most often refers to: __NOTOC__ * Natural environment, all living and non-living things occurring naturally * Biophysical environment, the physical and biological factors along with their chemical interactions that affect an organism or ...

in an extensional basin setting. The formation dates to the

Late Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name ...

period and has a maximum thickness of at its type locality in the valley of the

Lebrija River Lebrija River is a river of northern Colombia. It originates in the Cordillera Oriental (Colombia), Eastern Ranges of the Colombian Andes in Piedecuesta and flows through the northern part of the department of Santander Department, Santander into ...

Definition

The formation was first defined by Hettner in 1892 and named after Girón, close to

Bucaramanga Bucaramanga () is the capital and largest city of the department of Santander, Colombia. Bucaramanga has the fifth-largest economy by GDP in Colombia, has the lowest unemployment rate and has the ninth-largest population in the country, with 68 ...

Santander Santander may refer to: Places * Santander, Spain, a port city and capital of the autonomous community of Cantabria, Spain * Santander Department, a department of Colombia * Santander State, former state of Colombia * Santander de Quilichao, a m ...

. The type locality was defined by Langenheim in 1954 in the valley of the

. The formation was studied by various authors in the 1940s, Oppenheim in 1940, Dickey in 1941 and Trumpy in 1943, who described the formation as a lateral equivalent of the

La Quinta Formation The La Quinta Formation is a Jurassic geologic formation which crops out in the Cordillera de Mérida and Serranía del Perijá of western Venezuela and northeastern Colombia. The formation is also present in the subsurface of the Cesar-Rancher ...

of northern Colombia and western

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

. Julivert (1958) assigned a thickness of , while Navas in 1963 observed a thickness of . Cediel in the same year defined the thickness at its type locality of and divided the formation in seven units.Pulido González, 1985, p.9 Research by Osorio and Velandia, published in 2015, concluded a maximum thickness of at the type locality.Osorio & Velandia, 2015, p.979 On the Cáchira Páramo in Norte de Santander, the thickness is .Fúquen et al., 2011, p.43

Description

The Girón Formation extends over a distance of about from

in Norte de Santander in the north to

in Boyacá in the south, stretching across three departments;

and Boyacá.

Lithologies

The Girón Formation is characterized by a thick sequence of red

feldspathic Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldspa ...

and

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...

ceaous

s and thinly bedded reddish

s, conglomerates with

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...

and lithic clasts,

s with white spots and purple to dark red

claystone Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone, slate, and shale. Most of the particles of which the stone is composed are less than and are too sm ...

s. In the south, the formation includes fragments of

schist Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes o ...

quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tect ...

s, and red and green

limonite Limonite () is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO(OH)·H2O, although this is not entirely accurate as the ratio of oxide to hydroxid ...

. The middle part of the sequence contains alternating greyish green sandstones and red to purple siltstones in beds up to .Royero Gutiérrez, 2001, p.16 In the

(VMM), the Girón Formation has been drilled and proved to comprise

rhyolitic Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...

rhyodacitic Rhyodacite is a volcanic rock intermediate in composition between dacite and rhyolite. It is the extrusive equivalent of those plutonic rocks that are intermediate in composition between monzogranite and granodiorite. Rhyodacites form from rapid ...

flows and

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...

s.Garavito Cubillos, 2008, p.31 To the southeast of Cáchira, Norte de Santander,

andesitic Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...

porphyry 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 ...

deposits in mineralizations of

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 hardness of 3.5 to 4 on the Mo ...

and

bornite Bornite, also known as peacock ore, is a sulfide mineral with chemical composition Cu5 Fe S4 that crystallizes in the orthorhombic system (pseudo-cubic). Appearance Bornite has a brown to copper-red color on fresh surfaces that tarnishes to v ...

occur in the Girón Formation.Fúquen, 2011, p.105

Stratigraphy and depositional environment

The Girón Formation in large areas of its extent overlies the

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 the ...

Bucaramanga Gneiss,Royero Gutiérrez, 2001, p.13 in the northern area the Arboleda Granite,Fúquen, 2011, p.46 and the

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...

Diamante Formation in the area around Toledo,

.Royero Gutiérrez, 2001, p.15 In this part, the formation is overlain by the Río Negro and Tibú-Mercedes Formations. In the central area at the type locality in the Lebrija River valley, the formation unconformably overlies the Bocas Formation and is overlain by the

Tambor Formation Tambor can refer to: * Tambor, Costa Rica, a town in Costa Rica ** Tambor Airport, an airport that serves Tambor, Costa Rica * El Tambor River, river in Guatemala * Jeffrey Tambor (born 1944), American actor * Tambor (dance), Afro-Venezuelan music ...

. On the Mesa de Los Santos and the Bucaramanga Massif, the formation overlies the Jordán Formation with an angular unconformity dipping 10 to 15°.Ayala et al., 2005, p.50 In the central part it is overlain by the

Rosablanca Formation The Rosablanca Formation ( es, Formación Rosablanca, Kir) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes and the Middle Magdalena Basin. The formation consists of grey limestones, dolomites and s ...

. In the southernmost extent of the formation, along the road from

Busbanzá Busbanzá () is a town and municipality in the Colombian Department of Boyacá. Busbanzá is part of the Tundama Province, a subregion of Boyacá. Busbanzá is located at from Sogamoso. It borders Betéitiva in the north, in the east and south ...

to Corrales, the Girón Formation unconformably rests upon the

Floresta Formation The Floresta Formation ( es, Formación Floresta, Df) is a geological formation of the Altiplano Cundiboyacense in the Eastern Ranges of the Colombian Andes. The sequence of siltstones, shales, coquinas and sandstone beds dates to the Devonian per ...

.Ulloa et al., 2003, p.45 The formation forms the economic

in the Middle Magdalena Valley. The age has been estimated to be

, ranging from Oxfordian to

Tithonian In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 152.1 ± 4 Ma and 145.0 ± 4 Ma (million years ago). It is preceded by the K ...

,Méndez Espinosa, 2017, p.33 based on

ostracod Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typic ...

s and

palynomorph Palynology is the "study of dust" (from grc-gre, παλύνω, palynō, "strew, sprinkle" and '' -logy'') or of "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposit ...

s. Stratigraphically, the formation is time equivalent with the Buena Vista Breccia of the proximal area of the

Llanos Basin The Llanos Basin ( es, Cuenca Llanos) or Eastern Llanos Basin ( es, Cuenca de los Llanos Orientales) is a major sedimentary basin of in northeastern Colombia. The wikt:onshore, onshore foreland basin, foreland on Mesozoic rift basin covers the dep ...

and the

Arcabuco Formation The Arcabuco Formation ( es, Formación Arcabuco, Jar, JKa) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The formation consists of thick beds of light-coloured quartzitic sandstones and conglom ...

to the west of the Boyacá Fault.Méndez Espinosa, 2017, p.32 The formation was deposited in an

or fluvio-

terrestrial

, with fast-flowing

braided river A braided river, or braided channel, consists of a network of river channels separated by small, often temporary, islands called braid bars or, in English usage, ''aits'' or ''eyots''. Braided streams tend to occur in rivers with high sediment l ...

s and in certain parts

meandering river 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 bank w ...

deposition to a

deltaic A river delta is a landform shaped like a triangle, created by deposition of sediment that is carried by a river and enters slower-moving or stagnant water. This occurs where a river enters an ocean, sea, estuary, lake, reservoir, or (more rare ...

environment. Towards the top of the stratigraphic unit, the deposition became shallow marine.Fúquen, 2011, p.45 The overall tectonic regime represented an extensional basin setting.Fúquen et al., 2011, p.15 The rifting of the Jurassic and Early Cretaceous, resulting from the break-up of

Pangea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million y ...

, caused large variations in thickness of the Girón Formation.Jiménez et al., 2016, p.318

Provenance

The grains composing the Girón Formation have been analyzed using

X-ray diffraction X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...

, resulting in

as principal component (73 to 97%), and clay minerals belonging to the kaolinite group (2 to 4%) and

illite Illite is a group of closely related non-expanding clay minerals. Illite is a secondary mineral precipitate, and an example of a phyllosilicate, or layered alumino-silicate. Its structure is a 2:1 sandwich of silica tetrahedron (T) – alumina ...

(3-19%). It has been suggested a main component of the

provenance Provenance (from the French ''provenir'', 'to come from/forth') is the chronology of the ownership, custody or location of a historical object. The term was originally mostly used in relation to works of art but is now used in similar senses i ...

for the sediments was the Devonian

.Méndez Espinosa, 2017, p.147

Tectonics

The Girón Formation probably deposited as a result of regional uplift of the Santander and Floresta Massifs in the Late Jurassic.Mojica & Kammer, 1995, p.170 The formation is folded in an anticline around the type locality producing the Los Cobardes Anticlinal that extends to Contratación.Osorio & Velandia, 2015, p.975Jiménez et al., 2016, p.314Plancha 151, 2009 Transpressive tectonic movements after deposition produced five sets of fractures; an asymmetrical group of NW-SE, NW-SE, and E-W fractures and a set symmetrical with the general

anticline In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the ...

at NNE-SSW and ESE-WNW. Pervasive cleavage exists in the formation at the Floresta Massif.Ayala et al., 2005, p.53

Magnetization In classical electromagnetism, magnetization is the vector field that expresses the density of permanent or induced magnetic dipole moments in a magnetic material. Movement within this field is described by direction and is either Axial or Di ...

analysis performed in 2005 by Ayala et al. showed clockwise rotation of the formation in the southern area around Paz de Río of 31 ± 18° and Nobsa of 40 ± 18° respectively.Ayala et al., 2005, p.62 The Girón Formation is put into contact with the Cretaceous

La Luna Formation LA most frequently refers to Los Angeles, the second largest city in the United States. La, LA, or L.A. may also refer to: Arts and entertainment Music * La (musical note), or A, the sixth note * "L.A.", a song by Elliott Smith on ''Figur ...

in Norte de Santander,Fúquen, 2011, p.77 and is present in the

hanging wall In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

of the Bituima-La Salina Fault and cross-cut by several faults, among which the

Suárez Suárez is a common Spanish surname, widely spread throughout Latin America as a consequence of colonization. In origin it is a patronymic meaning "son of Suero" or "son of Soeiro". It is derived from the Latin name Suerius, meaning "Sugarman". T ...

, Cáchira,Plancha 86, 1981Plancha 97, 2009 and the regional

Bucaramanga-Santa Marta Fault The Bucaramanga-Santa Marta Fault (BSMF, BSF) or Bucaramanga-Santa Marta Fault System ( es, (Sistema de) Falla(s) de Bucaramanga-Santa Marta) is a major oblique transpressional sinistral strike-slip fault (wrench fault) in the departments of Mag ...

.Jiménez et al., 2016, p.315Plancha 120, 2010

Outcrops

The Girón Formation is found, apart from its type locality in the Lebrija River valley in

, stretching from the north around

, Norte de Santander,Plancha 66, 2009 to the south west of

in Boyacá.Plancha 172, 1998 The formation crops out along the Colombia-Venezuela border in Toledo, Norte de Santander,Plancha 111, 1999 and the urban center of Hacarí is built on top of the Girón Formation.Plancha 76, 2009 The formation forms the Serranía de Los Cobardes in the western front of the Eastern Ranges and is found throughout the

,Plancha 135, 2009Plancha 136, 1984 and the

Sogamoso River Sogamoso River () is a river of northern Colombia. It flows into the Magdalena River and on to the Caribbean Sea. The Sogamoso Dam on the river near Bucaramanga was completed in 2014. See also * List of rivers of Colombia References Furth ...

cuts through the Girón Formation. The Girón Formation also crops out along the highway from

Piedecuesta Piedecuesta (, officially ''Villa de San Carlos del Pie de la Cuesta'') is a town and municipality in the Santander Department in northeastern Colombia, South America. It has a population of about 120,000. It is part of the metropolitan zone of B ...

where frequent landslides of the fractured rocks occur in the rainy season.Taponada Vía Bucaramanga-Bogotá
- 1984 - El TiempoDerrumbes en Piedecuesta en Santander tienen incomunicadas a dos veredas
- 2017 -

RCN Radio RCN Radio (''Radio Cadena Nacional'', "National Radio Network") is one of the main radio networks in Colombia. Founded in 1949 with the integration of ''Radio Pacífico'' (Cali), ''La Voz de Medellín' and ''Emisora Nueva Granada'' (Bogotá). Carl ...

Enormes derrumbes taponan cuatro ejes viales de Santander. Paso restringido a un carril
- 2018 - El Frente

References

Bibliography

* * * * * * * * * *

Maps

* * * * * * * * * * * {{cite LSA , last=Ulloa , first=Carlos E. , last2=Guerra , first2=Álvaro , last3=Escovar , first3=Ricardo , year=1998 , title=Plancha 172 - Paz de Río - 1:100,000 , url=https://drive.google.com/open?id=0BwFQPMJEi17QalZXUHRfM0I2eFk , publisher=

INGEOMINAS The Colombian Geological Survey (CGS) ( es, Servicio Geológico Colombiano; formerly known as INGEOMINAS) is a scientific agency of the Colombian government in charge of contributing to the socioeconomic development of the nation through research ...

, pages=1 , accessdate=2018-10-09 Geologic formations of Colombia Jurassic System of South America Late Jurassic South America Jurassic Colombia Oxfordian Stage Kimmeridgian Stage Tithonian Stage Sandstone formations Siltstone formations Shale formations Conglomerate formations Tuff formations Alluvial deposits Deltaic deposits Fluvial deposits Lacustrine deposits Formations Formations Formations Formations