The Girón Formation (, 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 expo ...

stretching across from the north in

Teorama Teorama is a Colombian municipality located in the department of North Santander. Climate References *Government of Norte de Santander - Teorama Municipalities of the Norte de Santander Department {{NortedeSantander-geo-stub ...

Norte de Santander Norte de Santander (Spanish for Northern 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. Norte de Santander is bordere ...

, across the Mesa de Los Santos and

Chicamocha Canyon The Chicamocha Canyon ( , ) 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 in the departments of Bo ...

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. (Do not confuse with The Altiplano or the Altiplano Nariñense, both fur ...

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 that currently competes in the Talent League, the Victorian statewide under-18s competition. History Inaugural playing squad (1992) Honours *Premiers (2): 2002, 2013 *Runners-up (6): 199 ...

of the

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

. The formation forms the

basement A basement is any Storey, floor of a building that is not above the grade plane. Especially in residential buildings, it often is used as a utility space for a building, where such items as the Furnace (house heating), furnace, water heating, ...

in the

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

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

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

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. Although its permeabil ...

s and conglomerates deposited in a terrestrial

alluvial Alluvium (, ) 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. Alluvium is also sometimes called alluvial deposit. Alluvium is ...

and

fluvial A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it ru ...

to fluvio-

lacustrine A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...

environment in an extensional basin setting. The formation dates to the

Late Jurassic The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...

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 Department, Santander, Colombia. Bucaramanga has the fifth-largest economy by GDP in Colombia, has the lowest unemployment rate and is the ninth most populous city i ...

, Santander. 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, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

. 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 Department may refer to: * Departmentalization, division of a larger organization into parts with specific responsibility Government and military * Department (administrative division), a geographical and administrative division within a country, ...

;

, Santander and Boyacá.

Lithologies

The Girón Formation is characterized by a thick sequence of red

feldspathic Feldspar ( ; sometimes spelled felspar) is 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 ''plagiocla ...

and

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

ceaous

s and thinly bedded reddish

s, conglomerates with

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

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 and shale. Most of the particles of which the stone is composed are less than and are too small to ...

s. In the south, the formation includes fragments of

schist Schist ( ) is a medium-grained metamorphic rock generally derived from fine-grained sedimentary rock, like shale. It shows pronounced ''schistosity'' (named for the rock). This means that the rock is composed of mineral grains easily seen with a l ...

quartzite Quartzite is a hard, non- foliated metamorphic rock that 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 tecton ...

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 , although this is not entirely accurate as the ratio of oxide to hydroxide can vary qu ...

. 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 miner ...

, rhyodacitic 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 co ...

s.Garavito Cubillos, 2008, p.31 To the southeast of

Cáchira Cáchira is a Colombian municipality located in the Departments of Colombia, department of Norte de Santander. The urban centre is situated at an altitude of in the Cordillera Oriental (Colombia), Eastern Ranges of the Colombian Andes. Climate ...

, 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 circulation, hydrothermal fluids that originate from a voluminous magma chamber several kilometers below the deposit itself. Predating or associated with those flui ...

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 Mohs scale, hardness of 3.5 to 4 ...

and

bornite Bornite, also known as peacock ore, is a sulfide mineral with chemical composition that crystallizes in the orthorhombic system (pseudo-cubic). It is an important copper ore. Appearance Bornite has a brown to copper-red color on fresh surfa ...

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 pC, 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 t ...

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 time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

Permian The Permian ( ) is a geologic period and System (stratigraphy), 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 251.902 Mya. It is the s ...

Diamante Formation Diamante or diamanté may refer to: Jewellery * Rhinestone, a diamond simulant * Sequin, a small shiny disk-shaped ornament Places Argentina * Diamante, Entre Ríos, a ''municipio'' in Diamante Department * Diamante Caldera, a volcanic caldera p ...

in the area around

Toledo Toledo most commonly refers to: * Toledo, Spain, a city in Spain * Province of Toledo, Spain * Toledo, Ohio, a city in the United States Toledo may also refer to: Places Belize * Toledo District * Toledo Settlement Bolivia * Toledo, Or ...

.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. 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 (, 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 shales with at the upper ...

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

Busbanzá Busbanzá () is a town and municipality in the Colombian Departments of Colombia, Department of Boyacá Department, Boyacá. Busbanzá is part of the Tundama Province, a subregion of Boyacá. Busbanzá is located at from Sogamoso. It borders Beté ...

to Corrales, the Girón Formation unconformably rests upon the

Floresta Formation The Floresta Formation (, 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 period; Late Emsian, Eif ...

.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 (geology), age of the Late Jurassic Epoch and the uppermost stage (stratigraphy), stage of the Upper Jurassic Series. It spans the time between 149.2 ±0.7 annum, Ma and 143.1 ±0.6 (mi ...

,Méndez Espinosa, 2017, p.33 based on

ostracod Ostracods, or ostracodes, are a Class (biology), class of the crustacean, Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 33,000 species (only 13,000 of which are extant taxon, extant) have been identified,Brandão, S.N.; Antoni ...

s and

palynomorph Palynology is the study of microorganisms and microscopic fragments of mega-organisms that are composed of acid-resistant organic material and occur in sediments, sedimentary rocks, and even some metasedimentary rocks. Palynomorphs are the mic ...

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

Llanos Basin The Llanos Basin () or Eastern Llanos Basin () is a major sedimentary basin of in northeastern Colombia. The wikt:onshore, onshore foreland basin, foreland on Mesozoic rift basin covers the departments of Colombia, departments of Arauca Departmen ...

and the

Arcabuco Formation The Arcabuco Formation (, 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 conglomerates with occasional ...

to the west of the

Boyacá Fault Boyacá is the name of a region in Colombia. It may refer to other connections to Colombia: * Battle of Boyacá * Boyacá Department (Gran Colombia) * Boyacá Department ** Boyacá, Boyacá, a municipality * Boyacá State, a former state * Puerto ...

.Méndez Espinosa, 2017, p.32 The formation was deposited in an

or fluvio-

terrestrial environment, with fast-flowing

braided river A braided river (also called braided channel or braided stream) consists of a network of river channel (geography), channels separated by small, often temporary, islands called ''braid bars'' or, in British English usage, ''aits'' or ''eyots''. ...

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 or river cliff) and deposits sediments on an inn ...

deposition to a

deltaic A river delta is a landform, archetypically triangular, created by the deposition of the sediments that are carried by the waters of a river, where the river merges with a body of slow-moving water or with a body of stagnant water. The creati ...

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 (continent), Siberia during the Carboniferous period ...

, 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 diffraction is a generic term for phenomena associated with changes in the direction of X-ray beams due to interactions with the electrons around atoms. It occurs due to elastic scattering, when there is no change in the energy of the waves. ...

, resulting in

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

illite Illite, also called hydromica or hydromuscovite, 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 sandw ...

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

provenance Provenance () 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 in a wide range of fields, including archaeology, p ...

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 (geology), fold that is an arch-like shape and has its oldest Bed (geology), beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex curve, c ...

at NNE-SSW and ESE-WNW. Pervasive

cleavage Cleavage may refer to: Science * Cleavage (crystal), the way in which a crystal or mineral tends to split * Cleavage (embryo), the division of cells in an early embryo * Cleavage (geology), foliation of rock perpendicular to stress, a result of ...

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. Accordingly, physicists and engineers usually define magnetization as the quanti ...

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 most populous city in the United States of America. 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 Smi ...

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

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

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

Suárez Suárez is a common Spanish surname of Germanic origin, of which Juárez (surname), Juárez is an alternative form. It is widely spread throughout Latin America as a consequence of colonization. In origin it is a Patronymic surname, patronymic me ...

,Plancha 86, 1981Plancha 97, 2009 and the regional Bucaramanga-Santa Marta Fault.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 Santander, 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

, 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. Course The Sogamoso River is a river in northern Colombia, w ...

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 city and municipality in the Santander Department in northeastern Colombia, South America. The city has a population of about 150,000. It is part of the metropolitan zone ...

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). C ...

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

References

Bibliography

* * * * * * * * * *

Maps

* * * * * * * * * * * {{citation , last1=Ulloa , first1=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) (; 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 in basic and applied geosciences ...

, 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 Rhyolite formations