In this article we have presented our initial findings on a lithic industry – the geological setting, the mining technology used, and the type of raw materials mined.
Following an initial study of the materials, we carried out a statistical analysis that allowed us to relate the typology of the archaeological materials to lithology and possible zonal distribution patterns. We have paid particular attention to mineralogical and petrological studies of the miners' grooved hammers.
We found that the stone tools were almost entirely made from dolerite. This type of igneous rock occurs in small isolated outcrops in the vicinity of the Sierra de Gibalbín, to the north of El Jadramil, and in another small outcrop to the south; these were possible source areas of the rock used to make the grooved hammers.
The nearest outcrops of these doleritic rocks to El Jadramil are in Gibalbín's zone (Mojon Blanco) or close to El Cuervo (Cortijo de la Sierra), approximately 11 kilometres to the north-west, or the outcrop of Casablanca approximately 4 kilometres to the south. In general these are rocks of ophitic to subophitic texture and sometimes porphoritic, with calcite, plagioclase, pyroxene, biotite and quartz as the principal minerals, and sphene, ilmenite, pyrite and other opaques may occur as secondary minerals (Divar et al. 1988). A surface find of a grooved hammer made from a quartzite cobble has also been reported.
In the zone where the mining shafts occur, we have found that the geology of the deposit is mainly Tertiary bio-calcarenites, which are of generally similar lithology but with a higher carbonate cementation of the rock.
Mining underground seems to have been focused in particular on slightly inclined strata where the rock was well cemented and compact. Sub-horizontal mining galleries followed these levels (Figs 4 and 5). Levels with nodules of more compact material were also targeted in galleries at the front of the quarry. These were seen in 2003 and 2006 (Figs 4 and 5d), but have now been destroyed by quarrying (2008).
Until now, many archaeologists who have participated in the surveys of the vertical shafts and horizontal galleries have interpreted them as wells for obtaining water (in Lazarich et al. 2003, chapter 5, 78-87 and 8; 444-5). Our evidence does not support this view for the following reasons:
Figure 8a: Fragment of a cereal mill, made of cemented biocalcarenite, found on the surface of the well site (scale = 6cm)
Figure 8b: binocular microscope view of the cereal mill (scale bar = 1mm)
Figure 8c: binocular microscope view of the raw material produced by this mining activity, a cemented biocalcarenite (scale bar = 2mm)
Figure 8d: Microscopic view of a thin-section, doubly polarized light, of the same rock (scale bar = 1mm).
From this study it is concluded that the site is unique in Andalusia, and ranks in scientific and archaeological importance to other classic European prehistoric mining sites.
There is urgent need for protective measures to be taken by the Council of Culture of the regional government of Andalucia, who should declare this as a site of Cultural Interest, in need of protection from further destruction by quarrying. We repeat our call of action made in 2003, supported by the SEDPGYM, which still remains ignored by the Council of Culture of the regional government of Andalucia. The geological and archaeological value of this site is unique in Spain as an excellent example of the prehistoric mining of non-metallic or flint substances.
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Last updated: Wed Jun 10 2009