creek


calanque ( French: [kalɑk] , “inlet”; Corsican : calanca , calanche , Occitan : calanca , calancas pl ) is a narrow, steep-walled inlet that is developed in limestone , dolomite , or other carbonate strata and found along the Mediterranean coast. A calanque is a steep-sided valley formed within karstic regions or by fluvial erosion or the collapse of the roof of a cellar that has been further partially submerged by a rise in sea ​​level . [1] [2][3]

Characteristics

Location

The best known examples of this formation can be found in the Calanques Massif ( Massís dei calancas in Occitan, the local local language) in the Bouches-du-Rhône department of France . This range extends for 20 km in length and 4 km in Marseilles and Cassis , culminating in Marseilleveyre (432 m) and Mont Puget (565 m). Similar creeks can be found aussi on the French Riviera near Esterel and on the island of Corsica (see Creeks of Piana). The highest point along the creeks is Mount Puget (565 meters) and Marseilleveyre (432 meters). [4] Similarities are seen between calanques, and rias , the river mouths formed along the coast of Brittany in Northern France.

The limestone creeks of the Massif des Calanques lie within the recently created Calanques National Park (2012) and include the Calanque de Sormiou , the Calanque de Morgiou , the Calanque d’En-Vau , the Calanque of Port-Pin and the Calanque de Sugiton . There are additional creeks in the park, further east along the coast, incised into Cape Canaille . These creeks formed in very different rock strata, often in layers of pebble conglomerate .

Calanques are also present in the Italian Apennines , in locations such as the Accona Desert and the Calanchi Natural Preserve of Atri .

Geology

Modern day creeks along the Mediterranean Sea are steep-sided valleys that the Holocene ( Flandrian ) marine transgression partially submerged to form cliff-edged inlets. These valleys were either incised by rivers or when they collapsed when they were dry. [1] [2] [3]

Along the coast of the Mediterranean Sea, some of the valleys, which were flooded to form creeks, might date back to the Messinian salinity crisis between 5.96 and 5.32 million years ago. During this period of time, the Mediterranean Sea est devenu isolated from the Atlantic Ocean and Its sea level dropped at least 1,500 meters below the level of the Atlantic Ocean. [5] [6] As a result, not only did evaporites accumulate on the abyssal plains of the Mediterranean Sea, but also rivers flowing into their deepened valleys by 100s of meters. For example, the Rhone River cut a canyonas deep as 576 meters into Cretaceous carbonate strata near its confluence with its tributary the Ardeche . Fluvial erosion by smaller streams and rivers, which is important in this area. [7] Also at this time, steep-walled, dry karstic valleys were formed by the collapse of cellars that developed in limestone, dolomite, and other carbonate rocks in response to the reduced sea level of the Mediterranean Sea. [8] Later, during the Pleistocene , these valleys were further enlarged and modified by fluvial, karst, and other processes during interglacialdrops of sea level in the 100 meter range. During these periods of interglacial low sea level, additional steep-sided valleys, which were later flooded to create creeks, along the Mediterranean coastline were formed by fluvial and karst processes. [9] Today, they can be seen as deep, narrow valleys that are partly submerged by the sea and are made of limestone or granite. [4]

Ecosystem

The creeks have-have Particular ecosystem , as soil is non-existent almost there, and the limestone cliffs INSTEAD Contain Numerous cracks qui into the roots of plants are anchored. Nevertheless, the biota is diverse, with over 900 plant species, [10] including a number of endemics like the Marseille Tragacanth and Sabline de Marseille : members of the Papilionaceae family, which can only be found in the hills of Marseille . [11]

In places where cliffs are less vertical, the vegetation is a classical Mediterranean scrub , typically consisting of densely growing evergreen shrubs such as sage , juniper and myrtle . It is similar to heath in many aspects, but with taller shrubs, typically 2-4 m high as opposed to 0.2-1 m for heath.

Like anywhere on Mediterranean coast, Calanques’ climate is arid, with moisture during much of the year only from evaporation of the sea. This xericity associated with the salt spray conditions the subsistence of an adapted vegetation.

The creeks also shelter rabbits , foxes , large crows and Bonelli’s eagles , as well as many reptiles and wild boars .

Tourism

The creeks between Marseille and Cassis are popular among locals and locals alike, offering several vantage points (such as the Corniche des Crêtes and Cap Canaille ) allowing spectacular panoramas . A great number of hikers frequent the area, following numerous pre-marked trails. The cliffs are also used as training spots for rock climbers . However, this excessive use of microhabitat

Most of the creeks are also closed to the public during the summer (typically July through September) due to the risks of forest fire that often occur during the dry season.

The best time to visit is likely March through May, rain is rare. As no fresh water sources are available in the creeks, visitors are advised to carry large supplies of water, especially during the summer heat, to prevent dehydration .

Boat tours are also available starting from Marseille , Cassis or La Ciotat , which can provide for some spectacular sightseeing.

In April 2012, most of the creeks were declared National Parks due to their uniqueness. [12]

More information on the tourist office’s website: https://www.ot-cassis.com

The Cosquer Cave

Main article: Cosquer Cave

The Cosquer cave is an underwater grotto in the Calanque de Morgiou , 37 m underwater, that was once inhabited during Paleolithic , when the sea level was much lower than today. Its walls are covered with paintings and engravings dating back to between 27,000 and 19,000 BC and depict many terrestrial animals such as as bison , ibex , and horses as well as sealsand auks . [9] [13]

See also

  • Badlands

References

  1. ^ Jump up to:b Bird, ECF, 2008 Coastal Geomorphology: An Introduction , 2nd ed. John Wiley and Sons Ltd. West Sussex, England. ISBN  978-0-470-51729-1
  2. ^ Jump up to:b Goudie, A., 2004 Encyclopedia of Geomorphology. Routledge. London, England. ISBN  0-415-27298-X
  3. ^ Jump up to:b Monroe, WH, 1970 A Glossary of Karst Terminology. Water Supply Paper 1899-KUS Geological Survey. Reston, Virginia.
  4. ^ Jump up to:b “THE CREEKS, Provence” . 2012. Archived from the originalon 2012-01-12 . Retrieved 2012-10-10 .
  5. Jump up^ Krijgsman W., Hilgen FJ, Raffi I., Sierro FJ, Wilson DS, 1999,Chronology, causes and progression of the messinian salinity crisis. Nature. v. 400, no. 6745, pp. 652-655.
  6. Jump up^ Ryan WBF, 1976,Quantitative evalutation of the depth of the Western Mediterranean before and after the Last Miocene salinity crisis. Sedimentology. v. 23, no. 6, pp. 791-813.
  7. Jump up^ Mocochain, L., Audra P., Clauzon G., O. Bellier, J.-Y. Bigot, O. Parize, and Monteil P. 2009,The effect of river dynamics on the Messinian Salinity Crisis on karst landscape and caves: Example of the Lower Ardèche river (mid Rhône valley)Geomorphology, c. 106, no. 1-2, pp. 46-61.
  8. Jump up^ Audra, P., L. Mocochain, H. Camus, E. Gilli, G. Clauzon, and J.-Y. Bigot, 2004,The Effect of the Messinian Deep Stage on karst development around the Mediterranean Sea. Examples from Southern France. Geodinamica Acta. v. 17, no. 6, pp. 27-38.
  9. ^ Jump up to:a Collina-Girard B , J., 1996. Prehistory and coastal karst area: Cosquer Cave and the “Calanques” of Marseille. Karstologia. v. 27, pp. 27-40.
  10. Jump up^ http://www.visite-bateau-calanques-marseille-cassis.fr/data/php/getfile.php?nom=La-faune-et-la-flore-des-Calanques.pdf
  11. Jump up^ “Archived copy” . Archived from the original on 2012-08-06 . Retrieved 2013-04-06 .
  12. Jump up^ “The Calanques Near Cassis” . 2012 . Retrieved 2012-10-10 .
  13. Jump up^ Collina-Girard, J., 2004, Finiglacial transgression, archeology and texts (examples of the cave Cosquer and the myth of Atlantis)Human records of recent geological evolution in the Mediterranean Basin-historical and archaeological evidence. CIESMWorkshop Monographs. no. 24, pp. 63-70.

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