Analysis of karst geodiversity in the Garraf massif (Catalonia).

The Garraf Massif is a remarkable example of geodiversity in a karstic environment. It is located next to the Catalan coast, to the SW of Barcelona city, and is formed mainly by Cretaceous and Jurassic carbonate rocks in which karst develops. It contains many exokarstic morphologies (microforms and megaforms), as well as an extraordinary endokarst, represented by large caves and deep vertical shafts, which condition the drainage.

Within the framework of the "Geoanthropic Map of Catalonia" project carried out by the Institut Cartogràfic i Geològic de Catalunya (ICGC), a series of cartographies have been made and published at 1:25 000 scale, with a total extension of about 650 km2, which has allowed a detailed mapping of the different karstic morphologies present in the study area (karren, skinholes, palaeopolje, etc.).

The aim of this work is, on the one hand, to analyse the diversity of karst environment by describing the karstic landforms, and on the other hand, to offer an overview of some aspects linked to the karst massif, such as the relationship between the karstic morphology with the structure and lithology of carbonate rocks and with subterranean hydrology, or the physicochemical characterization of residual sediments from decalcification (terra rossa) that are found filling sinkholes and cracks in the rock.

It is an active karst with a very efficient and well-ranked drainage system, which coexists with a developed paleokarst, whose main witness is the Begues polje as well as several paleo-caves unearthed along the coastline.

The Garraf Massif is a protected natural area (Plan de Espacios de Interés Natural), so it benefits from a high degree of protection, and is included in the inventory of Places of Geological Interest in Spain (Geozone 348), being a natural laboratory of extraordinary richness with a great didactic, informative, and scientific value.