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 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 ...

between the Central and Eastern Ranges of the

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 basin, covering an area of , is situated in the

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, ...

of Santander, Boyacá, Cundinamarca and Tolima. The basin is structurally bounded by the Palestina Fault to the west and the Bucaramanga Fault to the east. The Middle Magdalena Valley hosts the middle course of the

Magdalena River The Magdalena River (, ; less commonly ) is the main river of Colombia, flowing northward about through the western half of the country. It takes its name from the biblical figure Mary Magdalene. It is navigable through much of its lower reaches, ...

, the main river of Colombia, flowing from the Upper Magdalena Valley in the south to the Lower Magdalena Valley to the northwest. The basin is elongated with an approximate width of and extends to the north for approximately , where it terminates against the Santander Massif and Cesar Valley. To the south, it terminates against the Upper Magdalena Valley, which consists of the Girardot and Neiva Sub-basins where the Central and Eastern Ranges converge. The basin is an important producer of oil in Colombia, with main fields Yariguí-Cantagallo, Moriche, Casabe, La Cira-Infantas, Velásquez, Santos, Palagua, Teca, Payoa and Lisama. The first three fields were among the twenty most producing fields of Colombia in 2016.En 20 campos se produce el 66 % del petróleo del país
/ref> Until 2008, La Cira-Infantas and Casabe produced more than and respectively.Garcia González et al., 2009, p.185 Main producing

reservoirs A reservoir (; ) is an enlarged lake behind a dam, usually built to store fresh water, often doubling for hydroelectric power generation. Reservoirs are created by controlling a watercourse that drains an existing body of water, interrup ...

are the Colorado, Mugrosa, Esmeraldas and La Paz Formations. Secondary reservoirs are Lisama and La Luna.Garcia González et al., 2009, p.80

Etymology

The name of the basin is taken from the middle course of the

Basin development

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 143.1 Mya. ...

period,

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 ...

began to pull apart causing separation of North America from South America. This

rifting In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear Fault (geology), downfaulted depression, called a graben, or more commonly ...

produced a

subduction zone Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

where the

Nazca Plate The Nazca plate or Nasca plate, named after the Nazca region of southern Peru, is an oceanic list of tectonic plates, tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction, along the Peru– ...

was subducting to the east under the

South American Plate The South American plate is a major tectonic plate which includes the continent of South America as well as a sizable region of the Atlantic Ocean seabed extending eastward to the African plate, with which it forms the southern part of the Mid ...

. Part of this subducting plate was the Baudo-Island Arc separated from the South American continent by the marginal Colombian Sea. The formation of the extensional

back-arc The back-arc region is the area behind a volcanic arc. In island arc, island volcanic arcs, it consists of back-arc basins of oceanic crust with abyssal zone, abyssal depths, which may be separated by remnant arcs, similar to island arcs. In conti ...

basin associated with this

subduction Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

is the origin of the Middle Magdalena Basin in the late

. Throughout the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

, the basin experienced thermal

subsidence Subsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope mov ...

and five transgressive-regressive cycles as part of a marine megacycle. In the

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

, the rate of

increased causing the marginal Colombian Sea to close and the Baudo-Island Arc to collide with the South American continent. This caused accretion of the Western Ranges and uplift of the Central Ranges transforming the

basin into the pre-Andean

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 lithospher ...

. Around the time of the

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

, the

increased its

to the east while the

experienced a westward pull. This caused the

Andean orogeny The Andean orogeny () is an ongoing process of orogeny that began in the Early Jurassic and is responsible for the rise of the Andes mountains. The orogeny is driven by a reactivation of a long-lived subduction system along the western margin o ...

in the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

and uplift of the Eastern Ranges in the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58intermontane basin situated between the uplifted Central and Eastern Ranges.

Geologic structures

Faulting in the Middle Magdalena Basin is primarily reverse and thrust faulting. Reverse faulting is high angle in the west and low angle in the eastern and central areas of the basin with normal faults also developing along the eastern margin. These thrust faults formed from thrusting from the eastern margin of the Central Ranges in the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

and the western margin of the Eastern Ranges in the

. The major thrust faults in the Middle Magdalena Basin include the Infantas Thrust, La Salina Thrust, and Cantagallo Thrust. The basin is structurally bounded by the Palestina Fault, a dextral strike-slip fault system, in the west and the Bucaramanga-Santa Marta Fault, a sinistral strike-slip system, in the east. The major surface structures of the Middle Magdalena Basin are asymmetric

syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimposed ...

s and basement cored

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 ...

s, which formed as a result of thrusting from the Eastern and Central Ranges. The thrusting initiated faulting in the Pre-Mesozoic basement. The faults then pushed through the Jurassic layers to the Cretaceous ductile stratigraphy. The faults then form horizontally at the ductile-brittle transition for before cutting through the upper brittle stratigraphy. The resulting structure is a

against 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 fault next to an inclined

. Key folds in the basin for

hydrocarbon exploration Hydrocarbon exploration (or oil and gas exploration) is the search by petroleum geologists and geophysicists for hydrocarbon deposits, particularly petroleum and natural gas, in the Earth's crust using petroleum geology. Exploration methods ...

include the Nuevo Mundo and Guaduas Synclines. As suggested by the formation of the folds, both of these synclines are bounded by thrust faulting and anticlines.

Stratigraphy

The stratigraphy of the Middle Magdalena Basin can be divided into three sequences separated by angular unconformities. The basement of these sequences is Pre-Mesozoic metaclastics and sediments which are now exposed on the surface of the Central Cordillera as a result of its deformation and uplift. This geologic basement is at most deep, with faulted sections shifted up to approximately in depth. The

unconformity An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval ...

that separates the basement from the first sequences indicates the approximate time

began.

First sequence

The first sequence was deposited in the

during the

which caused the initial formation of the basin. This

formation is called the Girón Formation which consists of siltstones and rhyolitic tuffs. During this period, the basin also experienced granitic plutonism along its western margins. The

angular unconformity, separating the first and second sequence, is representative of the post-rift boundary.

Second sequence

The middle sequence represents the formations deposited throughout the

and

Early Paleocene The Danian is the oldest age (geology), age or lowest stage (stratigraphy), stage of the Paleocene Epoch or series (stratigraphy), Series, of the Paleogene Period or system (stratigraphy), System, and of the Cenozoic Era or Erathem. The beginnin ...

. The oldest formations in this sequence are the Tambor and Los Santos Formations. The conglomerates and sandstones indicate a continental to fluvial

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 ...

. In the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

, sea level began to rise and formed a shallow marine environment with siltstone and shale deposits of the Cumbre Formation. Sea level continued to rise throughout the

Middle Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 77.1 million years, it is the ninth and longest geologi ...

when the Tablazo and Salto limestones and Simití shales were deposited. The La Luna Formation represents a maximum flooding surface with deep marine deposits of limestone, chert, and shale. Sea level then began to fall, returning the environment to shallow marine with deposition of the Umir Formation of shales and sandstones. Finally, the

saw the deposition of the Lisama Formation, consisting of deltaic mudstones and sandstones. This entire middle sequence indicates a marine megacycle consisting of five transgressive-regressive cycles. The angular unconformity between the second and third sequences is a result of erosion from the accretion of the Western Ranges.

Third sequence

The final sequence represents deposition from the Early Tertiary to present day. Within this sequence, there are three subsequences that are the result of deformation and uplift of the Central and Eastern Ranges. The first subsequence consists of the Chorro Group with the

La Paz La Paz, officially Nuestra Señora de La Paz (Aymara language, Aymara: Chuqi Yapu ), is the seat of government of the Bolivia, Plurinational State of Bolivia. With 755,732 residents as of 2024, La Paz is the List of Bolivian cities by populati ...

and Esmeraldas Formations and the Chuspas Group with the Mugrosa and Colorado Formations, all deposited during the

. These groups consist of fluvial sandstones, mudstones, siltstones, and shales, and are a result of erosion in the Central Ranges. The second subsequence is the

Real Group, consisting of fluvial sandstones and conglomerates. Similar to the Real Group, the final subsequence is the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Eastern Ranges uplift. The uppermost sedimentary rocks of the basin are

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

alluvial fan deposits, overlain by Holocene sediments of the Magdalena River.

Petroleum resources

The primary reservoirs in the Middle Magdalena Basin are fluvial sandstones and conglomerates from the Churro and Chuspas Groups, which have 20 to 25%

porosity Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure ...

and 0.5 to 1 D permeability. The main source of

hydrocarbons 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; their odor is usually faint, and may b ...

is the La Luna limestone, with a

Total Organic Carbon Total organic carbon (TOC) is an analytical parameter representing the concentration of organic carbon in a sample. TOC determinations are made in a variety of application areas. For example, TOC may be used as a non-specific indicator of wa ...

(TOC) content of 3 to 4% and Type II marine

kerogen Kerogen is solid, insoluble organic matter in sedimentary rocks. It consists of a variety of organic materials, including dead plants, algae, and other microorganisms, that have been compressed and heated by geological processes. All the kero ...

, sealed by overlying

shales. There are three types of traps that house hydrocarbons in the Middle Magdalena Basin. The two structural traps are large anticlines in the center of the basin and smaller anticlines along the western margin. Both of these anticlinal traps produce from Tertiary sandstones within the Churro and Chuspas Groups. The third trap is stratigraphical with the La Luna limestone sealed by overlying shales.

Primary fields

The table above shows some of the largest producing fields. Included is their producing formation, the lithologies of the formations, and the structure of the fields containing the

. The Tune and Avechucos Formations are equivalent to the Chorro and Chuspas Groups. Both the Casabe and Yariguí-Cantagallo Fields are located on the

towards the western margin of the basin with the Yariguí-Cantagallo Field located approximately north of the Casabe Field. Approximately east of the Casabe Field is the oldest and largest La Cira-Infantas Field, situated towards the central to eastern margin of the basin. The Velásquez Field is located at the southern end of the basin near the Upper Magdalena Valley. Current exploration is focused in the southern area of the basin, where heavy amounts of faulting could house potential

. Aside from the La Luna limestone, other potential

source rock In petroleum geology, source rock is a sedimentary rock which has generated hydrocarbons or which has the potential to generate hydrocarbons. Source rocks are one of the necessary elements of a working petroleum system. They are organic-rich sedim ...

s include

sediments such as the Paja and Simití Formations, or the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

shales of the Umir Formation.

Gallery

File:Petroleum regions - south america map-es.svg, VMM, major in South America File:Colombia Pipelines map-fr.svg, Pipelines in Colombia File:Alto Magdalena Pipeline physical map-fr.svg, Alto Magdalena pipeline File:Caño Limón-Coveñas Pipeline physical map-fr.svg, Caño Limón-Coveñas pipeline File:Colombia Pipeline physical map-fr.svg, Colombia pipeline File:Ocensa Pipeline physical map-fr.svg, Ocensa pipeline File:Escudo de Barrancabermeja.svg, Barrancabermeja File:Escudo de la Diócesis de Barrancabermeja.svg, Barrancabermeja File:Coat of arms of Santander Department.svg, Santander File:Escudo de San Miguel-La Dorada.svg, La Dorada File:Escudo de Puerto Boyacá.svg, Puerto Boyacá File:Escudo de Puerto Triunfo.svg, Puerto Triunfo File:Escudo de Pulí.svg, Pulí

References

Bibliography

* *

Etymology

Basin development

Geologic structures

Stratigraphy

First sequence

Second sequence

Third sequence

Petroleum resources

Primary fields

Gallery

See also

References

Bibliography

Further reading

Basin classifications

Colombia general

Middle Magdalena Valley

Maps