Sedimentología y diagénesis de las secuencias lacustres someras en el área del yacimiento neolítico de Casa Montero (Vicálvaro, Madrid)

Abstract

The sedimentary succession at Casa Montero flint archaeological site belongs to the green-clays unit of the Intermediate Unit of the Madrid Basin. A succession of silt-clay (mainly Mg-smectites), dolomite and silica rocks has been studied to know the sedimentary environment and diagene- tic processes around the site. The succession consists of silt-clay and carbonate sequences that represent a lacustrine environment with subaerial exposure events. The exposition events led to the development of a enlarged pseudomicrokarst in the topmost carbonate level. Vertisols were reworked at the top of the sequence. The diagenetic processes include early dolomitization of palustrine carbonates, partial transformation of the Mg-smectites and silicification of carbonates and clays in a groundwater environment. The presence of the archaeological site is due to the presence of opaline cherts with "aging" to quartz, that are uncommon in the silt-clay sequences of the Madrid Basin. The "aging" give these flints optimum properties for the Neolithic industry.