Holocene paleohydrology of playa lakes in northern and central Spain: a reconstruction based on the mineral composition of lacustrine sediments

• Published in: Quaternary international 2000-01, Vol.73, p.7-27
• Main Author: Schütt, Brigitta
• Format: Article
• Language: English
• ISSN: 1040-6182; 1873-4553
• DOI: 10.1016/S1040-6182(00)00062-8

The focus of this study is the reconstruction of Holocene limnic conditions of playa lakes in central Spain using inorganic components of their sediments. It is demonstrated that the mineralogical sediment characters provide valuable paleoenvironmental information: If dolomites originate from authigenic precipitation or early diagenetic dolomitization, the Mg–Ca-ratio of dolomites, derived from the position of dolomite's major X-ray diffraction line, turns out to be an indicator for the reconstruction of paleosalinity. In contrast, the concentrations of carbonates and sulphatic evaporites and their changing proportion to siliciclastic sediments point to changing depositional environments. The comparison of investigations from different playa lakes and drainage basin systems shows that the interpretation of mineralogical sediment features always has to consider the petrographic, hydrologic, and geomorphic features of the catchment. As for the lacustrine sediments investigated there are no data available yet, a preliminary chronological framework is derived by comparison with results from neighbouring areas. Based on this the hypothesis is put forward that during the so-called Little Ice Age subhumid environmental conditions occurred over the central part of the Iberian Peninsula, while today climatic conditions are dry-subhumid to subarid. Also for times older than the Subatlantic distinct changes of environmental conditions are noticed, but various hiatuses in the sediments make correlation difficult.