Cartografía geomorfológica de detalle de la comarca de Punta del Hidalgo

La plataforma volcánica de Punta del Hidalgo y el cono de piroclastos de Las Rozas tienen su origen en una reactivación cuaternaria de la actividad eruptiva en el macizo volcánico antiguo de Anaga. Este sector representa una anomalía a las características generales del macizo por su reducida pendiente; a pesar de ello, las costas siguen siendo acantiladas por sectores. Además, en las laderas y talwegs aparecen formaciones detríticas modeladas por el mar. La mayor parte de la línea de costa actual está representada por playas de cantos y plataformas de abrasión. A estas formas se suman beach-rocks, plataformas de abrasión colgadas y paleoacantilados lejos del cero marino actual que creemos tienen su origen en variaciones glacioeustáticas. El objetivo del presente trabajo es realizar la cartografía geomorfológica de las formas y formaciones superficiales cuaternarias de Punta del Hidalgo. Asimismo, se procede a partir del análisis geomorfológico y sedimentológico a explicar la génesis de estas.The Punta del Hidalgo volcanic platform and the cinder cone of Las Rozas have been formed by a reactivation of the Quaternary eruptive activity in the old volcanic Anaga massif. This sector represents an exception to the general characteristics of the massif because of its reduced slope; nonetheless, the coasts are still cliffs. Moreover detrital formations are localized at the hillsides and talwegs and most of the current shoreline is represented by pebble beaches and wave cuts platforms. To those formations we have to add wave-cuts platforms, cliffs and beach-rocks far from the current sea-level. The present parper is focuses on the geomorphological cartography of quaternary formations of Punta del Hidalgo. In order to describe the genesis of these forms we will use the morphological and granulometric characteristics

Foredune responses to the impact of aggregate extraction in an arid aeolian sedimentary system

Coastal dunes have long suffered the effects of human interventions that have altered the landscape and operation of these ecosystems. Aggregate extractions have been shown to modify the biogeomorphological processes in aeolian sedimentary systems. The impacts associated to aggregate extraction include the reduction of available sediment and changes to the topography and vegetation patterns, thereby altering the sedimentary dynamics and limiting the recovery capacity of the dunefield. The aim of this article is to analyse the environmental effects produced by historical aggregate extraction in the foredune area of an arid aeolian sedimentary system (El Medano, Tenerife, Spain) through a study of the airflow dynamics and spatial distribution of vegetation, sediment and topographic changes. The methodology was designed with two temporal scales: (i) a long-term approach which compares historical sources and current ones; (ii) a short-term approach through experimental data collection to characterize the present functioning. For the latter, a field study was carried out in June 2021, collecting wind speed and direction data at a height of 0.50 m, sediment data (sand sheet thickness, grain size and sorting), and vegetation data (cover and species richness) at 40 sample points. The main results show that when the anthropic stress ceased the foredune did not follow a natural environmental pattern, and that the way it functions at the present time is determined by the changes induced by the aggregate extraction. Changes include alterations to the topography, the creation of a lagoon, and the generation of an aeolian deflation area and flow acceleration zones with the associated sand transport. This research contributes to an understanding of the environmental consequences of aggregate extractions on the foredunes of arid aeolian sedimentary systems and can enable the relevant authorities to make better-informed decisions that help the management of these ecosystems

Coastal Dunes Geomorphosites to Develop the Geotourism in a Volcanic Subtropical Oceanic Island, Tenerife, Spain

Coastal areas are exposed to high levels of human occupation, which has led to their degradation. Coastal dunes have been greatly altered by different historical and current land uses, causing the loss of their natural and cultural values. On the coast of Tenerife there are volcanic and organogenic sand active and relict dunes with multiple land uses, the most prominent of which is tourism (also the main cause of their deterioration). The aim of this study is to demonstrate the relevance of geomorphosites associated to the aeolian depositional systems of Tenerife as volcanic geoheritage through the application of international methodologies used for these evaluations, and to propose geotourism uses that will contribute to their sustainability. In Tenerife there are thirteen aeolian system geomorphosites in which palaeodunes, active dunes and a combination of both have been identified, 53.9% of which are protected. The main historical and current uses are related to grazing, sand mining and tourism. These different land uses have produced the degradation of these landforms, which have induced the loss of some of their scientific and additional values. The average score for the scientific values (0.58) is higher than for the additional values (0.41) in most of the thirteen selected geomorphosites; the values lie in the middle of the range and there is no correlation between the scientific and additional values (R2 = 0.17). The geotourism proposal presented in this study is associate to the volcanic diversity of the coast of Tenerife and should be aimed at both the general public and specialists. The number of visitors should be restricted and sustainable according to the zoning laws for the regulations and use of the protected areas; and it should use the net of authorized paths which already exists in the geomorphosites. To this end, certain facilities will be required to help disseminate and promote the heritage of Tenerife’s dune geomorphosites through panels, websites, apps or QR codes