Fabric and stable isotopic composition of a Holocene stalagmite (CR1) from a cave in northern Sicily record changes in paleorainfall in the early Holocene. High δ13C stable isotope values in the calcite deposited from ca. 8500 to ca. 7500 yr ago are interpreted as reflecting periods of high rainfall. The wet phase was interrupted by two periods of multi-century duration characterized by relatively cool and dry winters centered at ca. 8200 and ca. 7500 yr ago, highlighted by low δ13C and δ18O values. A high variability of δ13C values is recorded from ca. 7500 to ca. 6500 yr ago and indicates that the transition from a pluvial early Holocene to the present-day climate conditions was punctuated by decadal-scale periods of relatively dry winters. In northern Sicily, the traditional elements of the Neolithic appear at ca. 7700 yr ago. It is possible that changes in rainfall influenced the passage from hunter-gathering to farming and sheep-herding economies.

UDC: 551.44 Ugo Sauro: Dolines and sinkholes: Aspects of evolution and problems of classification The doline is the most representative landform of the karst surface. The name derives from the word dolina, a Slav term indicating any depression in the topographical surface. For nearly a century, this name acquired widespread use and a well defined meaning in the international literature; as a result it is not possible to substitute it with another term such as "vrtača" or "kraška dolina", for example, as proposed by some authors (Gams, 1973, 1974). The use of sinkhole as a synonym for doline in the American literature has also created some ambiguity, because sinkhole is mostly applied in the sense of collapse doline or of cover doline. From the detailed studies of the dolines of different karst areas, it is possible to infer that the structure and the genesis of this form may be complex (Sauro, in press-a-and-b). The most correct way to define a doline is to add an adjective indicating a peculiar attribute. The most significant attributes are those linked to both the morphogenetical mechanism and the hydrological structure. On the basis of these attributes it is possible to distinguish several categories and types of dolines. Most importantly to understand a doline it is necessary to be able to reconstruct its history even if that may be complex, as some dolines formed by specific processes may later further evolve through different processes.

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