Stable isotopes of pedogenic carbonates from the Somma-Vesuvius area, southern Italy, over the past 18 kyr: palaeoclimatic implications

Zanchetta, G., Di Vito, M., Fallick, A.E. and Sulpizio, R. (2000) Stable isotopes of pedogenic carbonates from the Somma-Vesuvius area, southern Italy, over the past 18 kyr: palaeoclimatic implications. Journal of Quaternary Science, 15(8), pp. 813-824. (doi: 10.1002/1099-1417(200012)15:8<813::AID-JQS566>3.0.CO;2-Z)

Abstract

Stable isotopes were measured in the carbonate and organic matter of palaeosols in the Somma-Vesuvius area, southern Italy in order to test whether they are suitable proxy records for climatic and ecological changes in this area during the past 18000 yr. The ages of the soils span from ca. 18 to ca. 3 kyr BP. Surprisingly, the Last Glacial to Holocene climate transition was not accompanied by significant change in delta O-18 of pedogenic carbonate. This could be explained by changes in evaporation rate and in isotope fractionation between water and precipitated carbonate with temperature, which counterbalanced the expected change in isotope composition of meteoric water. Because of the rise in temperature and humidity and the progressive increase in tree cover during the Holocene, the Holocene soil carbonates closely reflect the isotopic composition of meteoric water. A cooling of about 2 degreesC after the Avellino eruption (3.8 ka) accounts for a sudden decrease of about 1 parts per thousand in delta O-18 of pedogenic carbonate recorded after this eruption. The delta C- 13 values of organic matter and pedogenic carbonate covary, indicating an effective isotope equilibrium between the organic matter, as the source of CO2, and the pedogenic carbonate. Carbon isotopes suggest prevailing C-3 vegetation and negligible mixing with volcanogenic or atmospheric CO2.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Fallick, Professor Anthony
• Authors: Zanchetta, G., Di Vito, M., Fallick, A.E., and Sulpizio, R.
• Subjects: Q Science > QE Geology
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Journal of Quaternary Science
• ISSN: 0267-8179