LOCATION AND ACCESS
The best outcrops of dolomitic limestones or magnesites are located on the road from Navalmoral de la Mata to Guadalupe, some 2 km to the north of Navalvillar de Ibor. It is not easy to stop a car there, although there is a small entrance to the right of the road (heading south) where is is possible to park; cross the road with great care in order to make your observations.
ATTRACTIONS OF THE VISIT
Many of the deposits that have been described can be observed here, such as:
1) Detrital deposits and their sedimentary structures (Figure 1).
2) The dolomites, their initial features (lamination, flat stones,…), their crystalline, brown, and grainy appearance owing to chemical meteorisation (Figure 1).
3) Magnesites, which are the main point of interest. On the outcrop on the road it can be seen how a mass of large brown crystals (mm) enter the fractures and the stratification planes of the dolomites (grey in colours) and gradually replace them. The large crystals are of magnesite and are replacing the smaller crystals of grey dolomite. At this point what is known as a front of replacement can clearly be seen, in this case a magnesitisation front (Figure 2).
It should also be noted that it is in these rocks that the Cueva de Castañar is formed; the fact that these rocks are very rich in magnesium is what conditions the great mineralogical and morphological variety of the speleothems of this cave.