The geology of Panama includes the complex tectonic interplay between the Pacific, Cocos and Nazca plates, the Caribbean Plate and the Panama Microplate.

Geologic history, stratigraphy, and tectonics

The Cocos and Nazca plates formed in the Miocene. The Panama microplate is made of oceanic crust basalt, similar to the basalt plateau at the bottom of the Caribbean Sea. The

isthmus of Panama The Isthmus of Panama ( es, Istmo de Panamá), also historically known as the Isthmus of Darien (), is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country ...

formed due to convergent tectonics of the eastern Pacific

subduction zone 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, the ...

, which created a magmatic arc extending from southern

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. The center of the isthmus, from Arenal Volcano in

Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

to El Valle volcano in Panama was uplifted during the subduction of the unusually thick Cocos Ridge oceanic crust, which also produced the four kilometer high

Talamanca Range The Cordillera de Talamanca is a mountain range that lies in the southeast half of Costa Rica and the far west of Panama. Much of the range and the area around it is included in La Amistad International Park, which also is shared between the two ...

. The western edge of the Caribbean Plate—the

Central American Volcanic Arc The Central American Volcanic Arc (often abbreviated to CAVA) is a chain of volcanoes which extends parallel to the Pacific coastline of the Central American Isthmus, from Mexico to Panama. This volcanic arc, which has a length of 1,100 kilometer ...

—also collided in 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. ...

and was compressed as 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-A ...

moved northward. The El Valle volcano is the easternmost

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 per ...

in Central America. Dacite and andesite flows from five to 10 million years ago are the oldest rocks, followed by a period of quiet 3.4 million years ago and newer dacite

dome A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...

s and pyroclastic flows between 900,000 and 200,000 years ago. The volcano was the result of crust subduction. The combination of these forces produced the Isthmus of Panama and resulted in different

sea surface The sea, connected as the world ocean or simply the ocean, is the body of salty water that covers approximately 71% of the Earth's surface. The word sea is also used to denote second-order sections of the sea, such as the Mediterranean Sea, ...

salinity Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...

between the Pacific and Atlantic since 4.2 million years ago. It also resulted in massive interchange of species between North and South America and brought global changes in climate and ocean circulation. The Bocas del Toro Archipelago on the western Caribbean coast records local

stratigraphy Stratigraphy is a branch of geology concerned with the study of rock (geology), rock layers (Stratum, strata) and layering (stratification). It is primarily used in the study of sedimentary rock, sedimentary and layered volcanic rocks. Stratigrap ...

through this period, with Pliocene to Pleistocene coral reef carbonates overlying Miocene basalt and

siliclastic Siliciclastic (or ''siliclastic'') rocks are clastic noncarbonate sedimentary rocks that are composed primarily of silicate minerals, such as quartz or clay minerals. Siliciclasic rock types include mudrock, sandstone, and conglomerate Conglomera ...

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 ...

. In the remote southeastern Darién Province, crystalline

basement rock In geology, basement and crystalline basement are crystalline rocks lying above the mantle and beneath all other rocks and sediments. They are sometimes exposed at the surface, but often they are buried under miles of rock and sediment. The baseme ...

of the San Blas Complex forms massifs in the northeast and southwest, dating to the Cretaceous, Paleocene and Eocene. These rocks and others in the north such as

rhyolite 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 ...

, dacite, basaltic andesite, granodiorite and quartz diorite indicate that the region was a separate magmatic arc until 20 million years ago. In the south, pre-collision basement rocks include radiolarian chert, pillow basalt and

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-graine ...

. Complex faulting and folding formed the Chucunaque- Tuira Basin includes three kilometers of sediments from the Miocene deposited during the collision with South America. Offshore of

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 ...

and western Panama, the Panama Basin formed between 27 and eight million years ago due to asymmetric seafloor spreading between the Nazca and Cocos plates. The Mapelo rift and the Yaquina

graben In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic contex ...

in the eastern basin are remnants of old and now inactive spreading centers. Between 22 and 20 million years ago,

hotspot Hotspot, Hot Spot or Hot spot may refer to: Places * Hot Spot, Kentucky, a community in the United States Arts, entertainment, and media Fictional entities * Hot Spot (comics), a name for the DC Comics character Isaiah Crockett * Hot Spot (Tra ...

volcanism generated the Carnegie, Cocos and Malpelo ridges.

References

{{North America topic, Geology of