Las Islas Canarias hace 21.000 años ¿cómo les afectó LA ÚLTIMA GLACIACIÓN?

This article describes how the Canary Islands were affected by the last glaciation approximately 21,000 years ago. During this period, Europe and North America experienced the Earth's lowest temperatures. Although no archaeological remains of such ancient settlers have been found in the Canary Islands, they have been found in the Iberian Peninsula and Eurasia. Furthermore, it has been demonstrated that during the last glaciation, there was a significant decrease in sea level, resulting in the formation of abrasion platforms that remained emerged during this period. These platforms have influenced the current configuration of the islands' relief. During the Last Glacial Maximum (LGM), there were several main features in Europe and Africa. In Europe, the global average temperature decreased by around 5°C, and there were two ice sheets in the northern hemisphere. The sea level was 120 meters lower than it is today, and the plant and animal communities were different from the current ones. In Africa, the Sahara expanded, and the vegetation was mainly desert-like. During this time, the Canary Islands had a different topography due to the decrease in sea level. The article presents a reconstruction of the island landscape of the Canary Islands 21,000 years ago, during the last glacial period. Using submarine topography and geological evidence, it is determined that five of the islands (La Gomera, Tenerife, Gran Canaria, Lanzarote, and Fuerteventura) had between 238 and 1392 km2 of emerged insular platform at that time. The average increase in emerged surface area on islands with extensive platforms was 62%, and overall, it was nearly 45% for all the islands combined. Additionally, a geological evidence is mentioned in Lanzarote, where a volcanic tube was formed during the sea level drop. Alluvial deposits are also observed in the ravines of the islands, indicating significant incision due to the sea level drop during the glaciations. The article discusses the differences in the development of insular platforms in the Canary Islands. Three groups of islands are mentioned according to their degree of erosive evolution, with the older islands having wider platforms. However, Tenerife is an exception since, despite being old, it does not have a wide platform due to its lack of stability over time. It is suggested that the current platforms are inherited from glacial periods and that the islands of Tenerife, La Gomera, and El Hierro may not have been affected by the major Quaternary glaciations. Additionally, the sediments found on the insular platforms are discussed. The article addresses changes in the coastal relief of the Canary Islands due to landslides and rockfalls, as well as alluvial deposits and the influence of sea level. It is mentioned that landslides modified the coastal relief and affected the development of insular platforms. Furthermore, it is noted that sea level has experienced changes over time, with periods of rise and fall. It is concluded that during the last glaciation, the original abrasion platforms were submerged to about -100 m below the current sea level. [Extracted from the article]