Naslov
Evolución sedimentaria de una nava de la Sierra de Hoyo de Manzanares, Sierra de Guadarrama (Madrid, España). Implicaciones paleoclimáticas
(Sedimentary evolution in a depression of the Sierra de Hoyo de Manzanares, Sierra de Guadarrama (Madrid, Spain). Paleoclimatic implications)

Autori
David, Domínguez-Villar

Izvornik
Boletín de la Real Sociedad Española de Historia Natural. Sección geológica (0583-7510) 99 (2004), 1-4; 119-129

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Procesos periglaciares ; Grèzes litées ; Periodo frío ; Paleoclimático ; Sierra de Guadarrama ; España
(Periglacial process ; Grèzes litées ; Cold period ; Paleoclimatic ; Sierra de Guadarrama ; Spain)

Sažetak
A stratigraphic deposit in the Sierra de Hoyo de Manzanares has been discovered in a small depression of tectonic origing at 1250 metres of elevation. A succession of sediments was exceptionally preserved in a mostly erosive area. Two sections 1, 9 and 1, 2 metres deep were available in the lower and middle part of the depression, where the depth of the deposit is larger. It is possible to identify nine depositional units that shows alterning morphological dynamics. Coluvial materials have been described related with the gravitational dynamics. At present day, this kind of materials are deposited in most of the slopes of the depression. The fluvial dynamics were registered with systems of deficient drainage plains and alluvial cones. Currently, the fluvial dynamic in the depression is mostly erosive, excepts on the lower part where a small deficient drainage plain exists. Periglacial dynamics are present with different intensities. The presence of solifluction and thufurs or earth hummocks is related to a cold climate, although the fluvial depositional systems are preserved. Other periglacial dynamics are more intenses, like those related with the registered grèzes litées that imply a fluvionival dynamic and then a more severe cold climate. The periglacial dynamics at present are far from this elevations and the periglacial record must represent cooler climates in the past. In the sections has been possible to identify three cold periods related to periglacial dynamics alterning with temperate periods developing fluvial and gravitational dynamics. The sections began with a cold and very humid period that shows a progressive cooling. The following units represent a rapid transition to a temperate and less humid period. Progressively a new cold period is imposed, representing the coldest temperatures registered in the deposits of the depression. After this, again the climate changes to temperate conditions. Alast cold event is registered, in a shorter and less intense cooling period. A last switch to temperate climate is registered until the actual depositional dynamics. No dates are available yet, but the correlation with the best studied record in the region, the glacier of Peñalara, shows that the record might be originated since the last glacial period, according to the similarities of the cold periods recorded.

Izvorni jezik
Spa

Znanstvena područja
Geologija

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