Isthmus of Panama

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Isthmus of Panama

The Isthmus of Panama (historically also Isthmus of Darién ) is an isthmus (isthmus) in the Central American state of Panama , which is bounded in the north by the Caribbean Sea and in the south by the Pacific Ocean . It represents the land bridge between North America and South America and forms the southern border of Central America .

The isthmus in the original sense includes the eastern part of the country, today's provinces Darién and Panamá (the former Colombian parts of the country), in a somewhat broader sense Panamá Oeste , Colón and Coclé . It extends between the Gulf of Darién in the Caribbean and the Gulf of Panama in the Pacific. In the broadest sense, which is more widespread today, the whole area between Costa Rica and Colombia , i.e. all of Panama, can be seen as the isthmus, the western part of which is between Golfo de los Mosquitos and Golfo de Chiriqui .

  • A Map of the Isthmus of Darien & Bay of Panama ( Moll 1697)

  • Map of central america and the isthmus ( Burr 1902)

  • Modern concept

It was generally accepted in science that the water exchange between the two oceans decreased significantly for the first time more than 3 million years ago and finally came to a standstill with the complete closure of the land bridge 2.76 million years ago. The trigger for this geological process was the collision of two tectonic plates, in the course of which the Pacific plate gradually pushed under the Caribbean plate , which ultimately led to the formation of the Panama Arc and its merger with the South American plate . A study published in February 2019 refers to the analysis of geological data, according to which the isthmus was not created solely by tectonic shifts, but that several volcanic eruption phases since the early Miocene had probably played a key role in this process (including the elevation of oceanic soils).

A study from 2015 postulated that the isthmus could have formed around 15 to 13 million years ago in the Miocene . A study published in August 2016, which was based on a broad basis of geological, palaeontological and molecular biological findings, confirmed the previous assumptions. The final closure of the land bridge at the beginning of the Quaternary immediately led to the formation of the Gulf Stream , which from then on transported seawater from tropical latitudes to the north, increasing the humidity and thus the potential for precipitation in the Arctic . However, more recent research suggests that the increasing arctic glaciation is more likely to be associated with a significant decrease in global CO 2 concentration, which in particular made the summer months cooler.

After the establishment of a permanent land connection, a large exchange of terrestrial mammals took place between the two continents. Before that, only a few species - such as the Panamacebus monkey - had been able to cross the strait between the two continents.

Due to its suitable geographical features, plans had been in place since the 16th century to build a canal at the site of the isthmus, which would connect the Atlantic with the Pacific. However, this was only realized through the Panama Canal , built between 1906 and 1914 , which halves the sea route from the North American east coast to the west coast.

See also

Web link

Individual evidence

  1. ↑ a b Isthmus of Darien. Entry in: Collins English Dictionary (2012, Digital Edition);
    Compare historically also Francis Borland: The History of Darien 1700. onA 1779, p. 7 ( digitized, Google, complete view );
    Darien, or Terra Firma Proper. Entry in: Richard Brookes: Brookes's General Gazetteer Improved. Verlag Johnson and Warner, 1812 (above) ( digitized version, Google, full view in Google book search);
    The name Isthmus of Darien is then found with the construction of the Panama Canal but also on the eastward adjoining depression of the Atrato (which is why the demarcation between South America and Central America is given differently), and the term Isthmus of Panama expands towards the west (the term isthmus from Nicaragua on Lake Nicaragua is included); See The Nautical Magazine and Naval Chronicle for 1869. Cambridge Library Collection, onA, p. 265 (New edition Cambridge University Press, 2013, ISBN 9781108054874 ; limited preview in Google Book Search).
  2. ^ A b Aaron O'Dea, et al .: Formation of the Isthmus of Panama . In: Science Advances . 2, No. 8, August 2016. doi : 10.1126 / sciadv.1600883 .
  3. ↑ David M. Buchs, Derek Irving, Henry Coombs, Roberto Miranda, Jian Wang, Maurylis Coronado, Rodrigo Arrocha, Mauricio Lacerda, Creed Goff, Eladio Almengor, Enier Portugal, Pastora Franceschi, Eric Chichaco, Stewart D. Redwood: Volcanic contribution to emergence of Central Panama in the Early Miocene . In: Scientific Reports . February 8, 2019. doi : 10.1038 / s41598-018-37790-2 .
  4. ↑ C. Montes, A. Cardona, C. Jaramillo, A. Pardo, JC Silva, V. Valencia, C. Ayala, LC Pérez-Angel, LA Rodriguez-Parra, V. Ramirez, H. Niño: Middle Miocene closure of the Central American Seaway . (PDF) In: Science . 348, No. 6231, April 2015, pp. 226-229. doi : 10.1126 / science.aaa2815 .
  5. ↑ KT Lawrence, S. Sosdian, HE White, Y. Rosenthal: North Atlantic climate evolution through the Pliocene-Pleistocene climate transitions . (PDF) In: Earth and Planetary Science Letters . 300, No. 3-4, December 2010, pp. 329-342. doi : 10.1016 / j.epsl.2010.10.013 .
  6. ^ Matteo Willeit, Andrey Ganopolski, Reinhard Calov, Alexander Robinson, Mark Maslin: The role of CO 2 decline for the onset of Northern Hemisphere glaciation . (PDF) In: Quaternary Science Reviews . 119, July 2015, pp. 22–34. doi : 10.1016 / j.quascirev.2015.04.015 .

Coordinates: 9 °  N , 79 °  W