São Nicolau, Cape Verde

São Nicolau (English: " Saint Nicholas " ) is one of the smaller ( 388 km ²) and the mountainous Cape Verde Islands in the north of the archipelago. It belongs to the Ilhas de Barlavento (German: " Leeward Islands ").

Geography

São Nicolau is located in the north of the archipelago between the islands of São Vicente and Sal on a common deep-sea base with the uninhabited islands of Santa Luzia, Branco and Raso and the island of São Vicente. This results in a relatively flat and fish- rich marine basin between these islands on the otherwise quite deep ( 5,300 m) Cape Verde Sea threshold.

The highest point is Monte Gordo ( 1,312 m), a younger more even volcanic cone with a round tip. The mountainous center of the island receives irregular rainfall, while the low coastal regions and flung peninsulas are desert -like dry. Only in Faja can be operated thanks to a fresh water tunnel to an appreciable extent irrigation agriculture.

The district town of Vila da Ribeira Brava is now obsolete in population and economic importance of the city, in the south harbor and fishing town Tarrafal de São Nicolau.

Geology

The geological structure São Nicolaus can be categorized as follows ( from young to old):

• Quaternary sediments
• Monte Gordo Formation
• Preguiça lineup
• Haupteruptiva
• Conglomerates and breccias
• Figueira de Coxe lineup
• Obermiozäne marine sediments
• Old Eruptivkomplex

The volcanic building São Nicolaus is 131 bis 126 million years BP on old oceanic crust from the Barremian. The basal Eruptivkomplex old, open mainly in the north of the island in the valley of Ribeira Brava, consists of highly weathered Hyaloklastiten ( Palagoniten ), which are penetrated very intensively from a vein swarm. The courses can take up to 90% of the volume fraction. In addition to the Hyaloklastiten also eroded Phonolithschlote occur. The old Eruptivkomplex is at least older than 6.2 million years, probably even older than 11.8 million years BP.

The Upper Miocene marine sediments overlie a significant erosional the old Eruptivkomplex. They consist of fossiliferous Kalkareniten. Your particular means of foraminifera age is a time period from 11.8 to 5.8 million years BP indicated ( Tortonian and Messinian ), possibly only with 6.2 to 5.8 million years BP ( Messinian ). At fossils sediments lead Cirripedia ( barnacles ), echinoderms, molluscs, Gastropden, scattered corals, foraminifera ( Rotaliiden ) and red algae.

The overlapping Figueira de Coxe Formation is composed of submarine lavas and their breccias, mainly pillow lava. In the valley of Ribeira Brava also Pyroklastite stand at that point to a significant, local eruptive center. In the hanging wall of Figueira de Coxe lineup again was a significant erosion and there were conglomerates and breccias deposited. It is then deposited marine sediments.

The following Haupteruptiva represent the shield stage São Nicolaus. They can generally be divided ( lava flows ) into a lower, submarines ( with pillow lavas, tuffs and Hyaloklastiten ) and an upper subaerisches stage. They are found all over the island and are volumetrically the major part of the bedrock. In the submarine stage of marine carbonates ( calcarenites ) fossil echinoderms, molluscs ( oysters), corals and red algae ( Rhodolithen ) are switched, contain. The deposits suggest a shelf region of medium energy level. New dates show the Haupteruptiva an age from 4.7 to 2.6 million years BP ( Zancleum and Piacenzium ).

After further erosion, the young, subaerial lava flows of Preguiça Formation over the Haupteruptiva laid. They were dated and have a Pleistocene age of 1,7 bis 1.15 million years BP. In the hanging wall of the formation many spatter and cinder cones that are still well preserved in part, and can only be distinguished from similar deposits of 100000-50000 year-old, upper pleistocene Monte Gordo lineup easily created.

During the Quaternary, there was the formation of extensive Abrasionsplattformen that can reach up to 60 meters above present sea level. On the platforms lead several alluvial fans, few can be found even smaller, pyroclastic cone of Monte Gordo Formation and up to three horizons of fossiliferous Kalkareniten.

Petrological is in the volcanic São Nicolaus to primitive, ultramafic to mafic alkaline rocks with relatively high magnesium content (MgO varies from 8 to 19 weight percent ), including Pikrobasalte, basanites and nephelinites. As differentiated phonolite rocks are to lead, which were funded primarily during the shield stage.

The encountered in the basalt rocks isotopic variations agree best with a mixing of four terminal components:

• Radiogenic end component, which represents the profound Cape Verde Mantleplume
• Unradiogene end component with MORB composition of the Mid-Atlantic Ridge
• Lower Cretaceous, the Cape Verde archipelago under overlying MORB component
• São Vicente -like carbonatite component.

This underlines the importance relatively shallow Magmenreservoire in Magmenentstehung below São Nicolau.

History

The island was discovered on St. Nicholas Day in 1460 by the Genoese Antonio da Noli captain, who was commissioned by Henry the Navigator for the Portuguese crown in possession. A stable colonization by secondary colonization of the southern islands, and new immigrants from Madeira and Portugal followed in the 18th century. Historically, the island played an important role through the seminary opened in 1866, the oldest in West Africa, which included a secular school. Among the former seminarians include the largest writers and artists of the archipelago in the 19th and 20th century, a pioneer of Cape Verdean identity and independence. The historic town of Vila da Ribeira Brava is grouped around the bishop's church Igreja Matriz de N. Senhora do Rosário, formerly the largest church in West Africa, as well as the birthplace of the poet José Lopes da Silva ( pseudonym: Gabriel Mariano, born May 18, 1928 † February 18, 2002 ). On the other side of the valley is the renovated as a museum Semiar High School.

Today, about 12,700 people live on the island, much less than before the devastating droughts and famines of the 1940s, when a large part of the population starved or emigrated to São Tomé and Príncipe.

• Pictures

One of the typical gravel road to São Nicolau

Seen coast of the island from the boat

Economy and Tourism

More than other islands survived São Nicolau, thanks to the donations made by family members in exile.

The main economic activities are fishing spot and emigration.

Tourism has great potential due to more beaches, beautiful hiking trails and a network of small streets. He still has not developed because the transport links improve by plane and ferry only in recent years. For hikers São Nicolau is popular thanks very nice and compared to Santo Antão less strenuous mountain and coastal walks.