Isotopic composition of meteoric water in Sicily

The isotopic composition of meteoric water in Sicily (Italy,) was investigated from May 2004 until Jun 2006; a rain gauge network (50 sites) was installed and sampled monthly. During this same period most of the circulating groundwater in the investigated area was sampled from more than 560 springs and wells related to the main aquifers. The mean weighted precipitation values were used to define the weighted local meteoric water line (WLMWL) for several sectors of Sicily. The use of GIS tools, coupled with isotopic vertical gradients, allowed us to design an isotopic contour map of precipitation in Sicily. The defined meteoric compositions fitted well with most of the groundwater samples for each sector. However, in some areas fractionation processes occurring during and after rainfall, slightly modified the isotopic composition of the groundwate