THE RELATIONSHIP BETWEEN GEOLOGY AND LANDFORMS ALONG A COASTAL MOUNTAIN FRONT, NORTHERN CALABRIA, ITALY

The geomorphology of the central Coastal Range, a north south trending horst along the west coast of northern Calabria, is governed largely by major faults, fault scarps and the distribution of principal rock t ypes, as well as by a variety of slope processes operative in a Medite rranean climate. Segments of the major rivers and streams have three p rincipal orientations parallel to major faults in the study area: nort hwest right-oblique slip faults (oldest); E-W oblique slip faults; NE left-oblique slip faults; and north-south right oblique normal faults (youngest), all of which cut pre-Tertiary metamorphic rocks, Mesozoic limestone, Miocene molasse and calcarenite. Small, underfit alluvial f ans, composed chiefly of locally derived debris flow detritus, are pre sent at the mouths of large, west-flowing canyons, some of which reach eastward to the crest of the mountain range. Not only do the north-so uth normal faults displace rocks and structures of all orientations, b ut they also make steep scarps in the small alluvial fans and in sedim ents of the coastal plain. Locally, some of the scarps are buried by r ecent debris flow deposits. Incipient young rivers utilized the weakne sses along the major faults and cracks as avenues of erosion. Smaller streams and gullies generally flowed westward downflank of the north-t rending horst and incised, thereby, deep, V-shaped canyons; some of th em have captured older, SW-flowing canyons. Locally, they were guided in other directions where they encountered faults or tectonic fracture s. The rocks present a varied resistance to erosion, depending upon th e degree of cementation by groundwater salts, upon the orientation of the foliation, and upon the rocks themselves. Thus, mica schist with a relatively flat foliation forms nearly vertical sea cliffs, but the s ea cliffs are more gentle where the foliation is steep or dips towards the sea. Therefore, downslope movements are facilitated by seaward sl ip on foliation, schistosity, bedding and fault surfaces, and are evin ced especially by large and deep pre-Holocene landslides (Sackung) in phyllite having areal dimensions up to 2 Km2. Other downslope processe s include surficial creep and soil slip, particularly of highly fractu red phyllite and schist, block sliding and rock falls.