Reliability of stable carbon and oxygen isotope compositions of pedogenic needle fibre calcite as environmental indicators: examples from Western Europe.

Stable carbon and oxygen isotope analyses were conducted on pedogenic needle fibre calcite (NFC) from seven sites in areas with roughly similar temperate climates in Western Europe, including the Swiss Jura Mountains, eastern and southern France, northern Wales, and north-eastern Spain. The δ13C values (−12.5 to−6.8 ‰ Vienna Pee Dee Belemnite (VPDB)) record the predominant C3 vegetation cover at the sites. A good correlation was found between mean monthly climatic parameters (air temperature, number of frost days, humidity, and precipitation) and δ18O values (−7.8 to−3.4‰ VPDB) of all the NFC. Similar seasonal variations of δ18O values for monthly NFC samples from the Swiss sites and those of mean monthly δ18O values of local precipitation and meteorological data point out precipitation and preferential growth/or recrystallisation of the pedogenic needle calcite during dry seasons. These covariations indicate the potential of stable isotope compositions of preserved NFC in fossil soil horizons as a promising tool for palaeoenvironmental reconstructions. [ABSTRACT FROM AUTHOR]