Felice Di Gregorio

Geological impact of some tailings dams in Sardinia, Italy

This article deals with the results of a survey carried out in Sardinia on both active and abandoned tailings dams, and we also discuss the geological impact of tailings dams of two mines: the Masua mine, a large syngenetic Pb-Zn deposit located in Cambrian limestones, and the Montevecchio mine, a Pb-Zn vein deposit near a Hercynian granite intrusion. The characteristics and metal content of material in the dams were analyzed. A high contamination of heavy metals (Pb, Zn, Cd, Cu) was found both in the soils and water of Rio Montevecchio, a stream draining the tailings dams and other mining operations in the area.The study indicates that a control plan to minimize heavy metal pollution must be drawn up for all mines of the area, whether active or abandoned.

Granite Landscapes of Sardinia: Long-Term Evolution of Scenic Landforms

Sardinia is characterized by spectacular granite landscapes with superimposed scenic landforms. In the eastern part of the island, the granite reliefs consist of mountain massifs and plateaux separated by metamorphic reliefs and limestone plateaux. Granite landscapes show peculiar landforms such as inselbergs, tors and tafoni and diverse erosion microforms. In the extraordinary landscape of Gallura region, wide flat areas with outcropping rocks, vast extensions of isolated rock blocks and inselberg-type dome-shaped reliefs show evidence of a long period of intense weathering. Scenic landforms characterize the spectacular landscape of Sarrabus region, where differential erosion processes have selected the numerous dikes which have conditioned the orientation of the reliefs and coastal landforms. Many archaeological remnants can be found in most granite regions of Sardinia emphasizing the deep bond between man and the physical environment.

The Coastal Dunes of Sardinia: Landscape Response to Climate and Sea Level Changes

The Sardinian coasts are characterized by spectacular aeolian landscapes. These are concentrated in areas where the morphology of the coast, the age-long wind action on the wide sandy beaches and the past availability of sand from the continental shelf—during the low sea level during Pleistocene glacial phases—permitted remarkable volumes of sands to accumulate and to dominate above other forms of the coastal landscape. In the western coast of the island, hit by strong northwestern winds, vast dune fields, adorned by the Mediterranean bush and white flowers of sea, show a spectacular variety of landforms such as small nebkhas, loose dunes, cobblestone floors and deflation furrows. Lithified fossil dunes (aeolianites) occur along most Sardinian coasts, providing important information on past climate and sea level changes. These attractive wind landscapes offer researchers and visitors many and various opportunities of study, recreation and tourism, in a context unique due to the high value of the present and past landscapes.