The Canarian archipelago comprises seven main volcanic islands and several islets that form a chain extending for c.
La isla de Lanzarote, situada en el extremo oriental de la alineación del punto caliente de las Canarias, ha tenido escasa actividad eruptiva de rejuvenecimiento en el Holoceno, posiblemente reducida a las erupciones de 1730 y IS24, hecho que concuerda con el avanzado estado post-erosivo de la isla. La datación de la erupción del Volcán Corona, aparentemente el evento volcánico anterior en Lanzarote a las erupciones históricas, ha dado una edad media ponderada 40Arp9Ar de 21 ± 6,5 ka. Esta edad concuerda con las observaciones geológicas, particularmente las circunstancias de formación del tubo volcánico de 7,6 km de longitud y hasta 25 m de diámetro que se formó en las primeras fases de la erupción. El último tramo de 1,6 km está sumergido, finalizando a una profundidad de > SO m. Nuestra interpretación es que el tubo volcánico activo no pudo alcanzar esa profundidad circulando por un medio subacuático, sino que fluyó por una plataforma costera al menos 1,6 km más extensa y al menos SO m más baja que la costa actual, circunstancia que sólo ha podido darse en coincidencia con un pronunciado descenso del nivel marino en un máximo glacial, con toda probabilidad el último, hace unos 20 ka. La subsiguiente transgresión inundó el tubo hasta el nivel actual. La edad de la erupción queda pues limitada por las edades radioisotópicas en 21 ± 6,5 ka y, concordantemente, por el máximo descenso del nivel marino, registrado entre unos IS y 21 ka. El estudio de la erupción del Corona establece hitos importantes en la historia volcánica de la isla de Lanzarote y aporta evidencia significativa de los cambios del nivel marino ocurridos en las Canarias en relación con las glaciaciones.
Evidence of the warmest Pleistocene climatic changes is preserved in the eastern Canary Islands. Although the existence of raised fossiliferous marine deposits in northern Gran Canaria has been known since the 19th century, their chronology and significance with regard to past sea levels and temperatures have remained uncertain. Here, we show three marine transgressions recorded by raised marine deposits. The highest (85 m above sea level (masl)) and oldest marine deposit is interbedded in basaltic lava flows and has been dated using both palaeomagnetic and radiometric methods. The age of these deposits, located on the northwest coast of Gran Canaria, near the town of Agaete, places the marine transgression in a first Pleistocene interglacial into the Plio-Pleistocene limit. The marine deposit at an intermediate altitude (35 masl) has been dated using the unspiked K-Ar method on a pillowed basaltic lava flow. The age of these deposits in Arucas places the transgression in the penultimate (European Mindel/Riss sense) interglacial. The deposits at 12 masl in Las Palmas are attributed to the last Pleistocene interglacial on the basis of their fossil content, which is similar to that of the Matagorda deposits in Lanzarote and Matas Blancas in Fuerteventura. Radiometric dating of a lava flow overlying similar deposits at El Cotillo in Fuerteventura has been carried out. The molluscan fauna associated with the deposits permits an estimation of the sea temperatures by reference to their present biogeographical distributions. The Plio-Pleistocene boundary coincides at Agaete (end of Olduvai event) with a high sea level between 1.8 and 1.75 Ma (oxygen isotopic stage (OIS) 63), the dated marine deposits at Arucas (0.42 Ma) place an interglacial in OIS 11.3 and finally we confirm that, in the Canaries, with only one high sea level with a Senegalese fauna (OIS 5.5), they are not an outpost for the Mediterranean Tyrrhenian (deposits with Strombus) oscillations.
The Canary Archipelago has long been a sensitive location to record climate changes of the past. Interbedded with its basalt lavas are marine deposits from the principal Pleistocene interglacials, as well as aeolian sands with intercalated palaeosols. The palaeosols contain African dust and innumerable relict egg pods of a temperate-region locust (cf. Dociostaurus maroccanus Thunberg 1815). New ecological and stratigraphical information reveals the geological history of locust plagues (or infestations) and their palaeoclimatic significance. Here, we show that the first arrival of the plagues to the Canary Islands from Africa took place near the end of the Pliocene, ca. 3 Ma, and reappeared with immense strength during the middle Late Pleistocene preceding MIS (marine isotope stage) 11 (ca. 420 ka), MIS 5.5 (ca. 125 ka) and probably during other warm interglacials of the late Middle Pleistocene and the Late Pleistocene. During the Early Holocene, locust plagues may have coincided with a brief cool period in the current interglacial. Climatically, locust plagues on the Canaries are a link in the chain of full-glacial arid-cold climate (calcareous dunes), early interglacial arid-sub-humid climate (African dust inputs and locust plagues), peak interglacial warm-humid climate (marine deposits with Senegalese fauna), transitional arid-temperate climate (pedogenic calcretes), and again full-glacial arid-cold climate (calcareous dunes) oscillations. During the principal interglacials of the Pleistocene, the Canary Islands recorded the migrations of warm Senegalese marine faunas to the north, crossing latitudes in the Euro-African Atlantic. However, this northward marine faunal migration was preceded in the terrestrial realm by interglacial infestations of locusts.
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