J. L. 2010. Identification of arid phases during the last 50 cal. ka BP from the Fuentillejo maar-lacustrine record (Campo de Calatrava Volcanic Field, Spain).ABSTRACT: Geochemical (element analysis, molecular analysis of organic compounds), physical, palynological, mineralogical and sedimentary facies analysis were performed to characterise the sedimentary record in Fuentillejo maar-lake in the Central Spanish Volcanic Field of Campo de Calatrava, in order to reconstruct the palaeoenvironmental and palaeoclimatic processes which controlled vegetation patterns and deposition of different sedimentary facies. The upper 20 m of core FUENT-1 show variations in clastic input, water chemistry, vegetation and organic fraction sources in the lake throughout the Late Pleistocene and Holocene. The temporal framework provided by 14 C accelerator mass spectrometry dating allows assigning the sequence to the last 50 cal. ka BP. Arid phases identified in the FUENT-1 sequence are correlated to Heinrich events (HE) and to stadials of the Dansgaard/Oeschger (D/O) cycles. Siliciclastic facies with high magnetic susceptibility values, high Juniperus pollen content, a low Paq index (aquatic macrophysics proxy index), a decrease in the relative percentage of the n-C 27 and an increase in the n-C 31 alkanes are indicative of arid and colder climatic events related to HE 2, HE 1 and the Younger Dryas (YD). Similar short cold and arid phases during the Holocene were identified at 9.2-8.6, 7.5-7 and 5.5-5 cal. ka BP. In dolomite-mud facies, the pollen data show an increase in the herbs component, mainly -Chenopodiaceae, Artemisia and Ephedra -steppe taxa; a low Paq index, a decrease in the relative percentage of the n-C 27 alkane and an increase in the n-C 31 alkane are also observed. This facies was probably the result of lower lake levels and more saline-alkaline conditions, which can be interpreted as linked to arid-warm periods. These warm and arid phases were more frequent during Marine Isotope Stage (MIS) 3 and the interstadials of MIS 2. HE 4, HE 2, HE 1 and the YD in core FUENT-1 were immediately followed by increases of warm steppe pollen assemblages that document rapid warming similar to the D/O cycles but do not imply increasing humidity in the area. Fuentillejo hydrology is controlled by changes in the atmospheric and oceanic systems that operated on the North Atlantic region at millennial scale during the last 50 cal. ka BP.

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The evolution of complex volcanic structures usually includes the occurrence of flank collapse events. Monogenetic cones, however, are more stable edifices with minor rafting processes that remove part of the cone slopes. We present the eruptive history of Mazo volcano (Lanzarote, Canary Islands), including the first detailed description of a syn-eruptive debris avalanche affecting a volcanic monogenetic edifice. The study and characterization, through new geological and morphological data and the analysis of a great number of documentary data, have made it possible to reinterpret this volcano and assign it to the Timanfaya eruption (1730–1736). The eruptive style evolved from Hawaiian to Strombolian until a flank collapse occurred, destroying a great part of the edifice, and forming a debris avalanche exhibiting all the features that define collapsing volcanic structures. The existence of blocks from the substrate suggests a volcano-tectonic process associated with a fracture acting simultaneously with the eruption. The sudden decompression caused a blast that produced pyroclasts that covered most of the island. This study forces to change the current low-hazard perception usually linked to monogenetic eruptions and provides a new eruptive scenario to be considered in volcanic hazards analysis and mitigation strategies development.

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On 19 September 2021, a new monogenetic volcano (Tajogaite) erupted on the island of La Palma (Canary Islands, Spain). After 86 days of strombolian eruption, with emissions of volcanic material, a pyroclastic cone 200 m high and 800 m in diameter was formed. Successive lava flows descended the western slopes and reached the sea on 29 September. On descending the coastal cliffs and entering the sea, the lava flows formed two lava deltas of 75 and 5 ha, on the submarine island shelf, backed by fossilized coastal cliffs. This work presents an approach, using comparative and numerical methods, to estimate the geoheritage value and support the conservation of a new volcanic landscape in an island territory with high anthropic pressure on land uses. In a first phase, a cartographic inventory was made of all the volcanic formations similar to the new volcano in the geological domain of the Canary Islands. In a second phase, their representativeness (A), rarity (R), diversity (D), integrity (I) and observability (O) was quantitatively measured by means of dimensional estimators. The results obtained show that the new volcano presents a geological value of the first order in the context of the Canary Islands, which is one of the most prominent hot-spot archipelago worldwide. Its value is based above all on its high conservation state with respect to the similar volcanoes in the Canary Islands. The high mismatch found between the intrinsic geological value and the environmental protection of this area, justifies the development and application of urgent basic guidelines for its protection, as well as the promotion of geotourism as opposed to alternative land uses.