## 2 Study Area  
The Rock Group of Tajo de las Figuras is located within the municipal boundaries of Benalup (Cadiz province, southwestern Spain) (Figure 1A), in the extreme southeast of the Sierra Momia, at an altitude which ranges between 110 and 170 m above sea level. These sierras, which have little relief, are formed of siliceous sandstone belonging to the Aljibe Formation (lower Miocene) that grades downwards into reddish clays which range in age from Oligocene to Aquitanian. The Aljibe Fm., a 1500 to 2000 m thick succession, consists of meter thick planar-tabular or cross-stratified beds of medium to coarse-grained, pale orange to yellowish brown sandstones. The quartzose sandstones of Aljibe Fm. are strongly tectonized, the basic directions of the diaclase network being E-W. Its structure is in the form of piled up thrust sheets which provides important relief in the form of sierras with an average altitude of 400 to 500 m. It also has an abundance of structures due to tectonic instability, such as landslides and sand dykes [20]. The Rock Group of Tajo de las Figuras includes a total of seven natural rock shelters, mainly facing the south, termed Cueva del Tajo de las Figuras, Cueva del Arco, Cueva Cimera, Cueva Negra, Cueva Alta, Cueva del Tesoro, and Cueva de los Pilones. These host a set of engravings which can be attributed to the upper Palaeolithic and post-Palaoleolithic (Neolithic-Chalcolithic-Bronze Age) [21]. These paintings are of zoomorphic and anthropomorphic motives and signs [22] and form their own artistic style within the so-called \"schematic\" style, which can be differentiated from the rest of the artistic rock works in the Iberian Peninsula [23; 24]. The Rock Group of Penas de Cabrera is located within the municipal boundary of Casabermeja, in the interior of the Malaga province (southern Spain) (Figure 1A). Most rock shelters are sited on the northern flank of a thick succession of sandstones which ends in a small hill (570-620 m above sea level) which is located on the southern side of the Lower Miocene Colmenar Depression. The sandstones are arranged in meter-thick beds which generally are folded with dips that slightly exceed 30\({}^{\circ}\). However, at some points, such as where rock shelters with paintings are found, sandstones appear as blocks with chaotic distribution, being arranged vertically and even seem to be inverted with some frequency. The degree of tectonic fracturing of sandstones is very high, showing a dense network of faults and diaclases with preferential N260\({}^{\circ}\)E and N orientation. Given their affinity with the Germanic facies and the lack of fauna in the study area, the Permo-Triassic age has been assigned to these sandstone beds [25]; thus placing them in the Andalusian domain precisely in contact with the flysch of the Colmenar Unit. The Rock Group of Penas de Cabrera is formed of a total of 23 well-known rock shelters of smaller dimensions facing N, NW, NW, and W. It contains a series of post-Palaolelithic paintings (Chalcolithic) which can also be assigned to the \"schematic\" style, with an abundance of anthropomorphic and idiomorphic representations, idols, rectiforms, and arboriforms [26]. Both Rock Groups (Tajo de las Figuras and Perhas de Cabrera) show a high degree of deterioration, both of natural and anthropic origin, which has promoted various actions aimed at their protection by the relevant authorities, including their temporary closure to tourism [27; 28]. As the climatic conditions have a determining role in the development of rock weathering processes [29], the main climatic parameters of the study areas were collected for the period 1995-2014 from data supplied by the Antequera meteorological station (Z = 408, 370146 N, 044454 W) for Penas de Cabrera and the Grazalema station (Z = 913, 364538 N,  
Figure 1: (**A**) Location map. Small crosses indicate locations of rock shelters with prehistoric paintings and engravings.