Geomorphology

Panoramic view of the Gardenaccia plateau. Puez marls outcrop in the two visible pyramids on the top.Panoramic view of the Gardenaccia plateau. Puez marls outcrop in the two visible pyramids on the top.

From the geomorphological viewpoint, the Dolomites are a unit made up of various mountain systems which, although being physically discontinuous in places, show a typical landscape morphogenetic unity.

The geomorphological evolution of the Italian Dolomites is linked to tectonic, lithological, climatic and, in more recent times, anthropogenic causes. In fact, the Dolomite landscape is the result firstly of lithogenesis and orogenesis and subsequently of morphogenesis processes, which have modelled these mountains up to the present. The result is a fantastic display of rock towers, steeples, ledges, crests and pinnacles sometimes isolated and sometimes clustered together in festoons or mountain ranges which overlie mild, green slopes with pastures, forests and anthropogenic infrastructures which accentuate the contrasts. This is the landscape of a universally famous, often described and depicted mountain heritage. Indeed, the term “Dolomite landscape” is attributed to certain mountainsthat can to some extent conjure up the geomorphological spectacularity of the Italian Dolomites.

Plate APlate ACalcareous and dolomite escarpments, ridges of volcanic rock, hollows in clayey soils, folded, faulted and twisted layers, talus cones and scree slopes, plateaux and small lakes, colours and shapes, light and shadow: their history is ancient, complex and fascinating. Starting from the Upper Miocene, rocks emerged from the sea and meteoric water started to flow on the new reliefs and mountains of this part of the continent and waves used to break on its coasts. Changes of temperature and humidity caused the physical and chemical weathering of rocks whereas the force of gravity, water and wind moved and redistributed debris. Little by little rocks started to be eroded, especially the least resistant clayey or marly rock types or pyroclastic deposits. Depressions and valleys formed in correspondence with outcrops of these weak rocks or with important tectonic displacements and related cataclastic belts. On the contrary, more resistant rock types, such as calcareous, dolomite or igneous rocks underwent a different morphogenetic evolution and gave origin to the highest mountain tops of the region. This morphogenesis took place in different ways and with different rhythms, also in relation with diastrophism activities and climate changes.The morphological configuration of the relief in the Dolomite region presents a clear relationship with the geological factors: the valleys are prevalently situated along fractures, faults, synclines, surfaces of stratigraphic or heteropic contact between diverse rock formations; the narrow passages and confluence valleys are generally determined by lithological factors; the different slope gradients are conditioned by the variety of rock types and so on. All this belongs to that branch of Geomorphology known as Structural Geomorphology. The plate A shows its diverse aspects in a schematic way. Morphotectonics (or Morphotectodynamics) studies the relationships between the relief forms and tectonic movements, that are the geomorphological consequences of diastrophic displacements occurring from the beginning of geohistory to date. On the other hand, Morphoselection studies relief forms in connection with selective or differentiated erosion, that it, the passive role of geological structures. If we refer to tectonic arrangement, we deal with Morphotectostatics; if, on the other hand, we refer to lithological composition, we deal with Morpholithology.

Sunset on Odle / GeislerSunset on Odle / Geisler