STABLE-ISOTOPE COMPOSITION OF THE CARBONATE CONCRETION IN LOESS AND CLIMATE-CHANGE

Carbonate concretions are commonly found in the loess in China. Oxygen and carbon isotopic compositions of carbonate concretions collected f rom 14 different paleosols (S-1-S-14) in the Lishi Formation of Luochu an loess section, China were analysed. The isotopic compositions of co ncretion in loess are useful tools in paleoclimatic study. Usually the more developed the paleosol is, the less negative the delta(18)O valu es and the more negative the delta(13)C values are. The oxygen isotopi c composition of these paleosols varies within a range of about 1.3 pa rts per thousand. The carbon isotopic composition, however, shows larg er variations from one paleosol to the other, within a range of 5.3 pa rts per thousand. An attempt was made to semi-quantitatively estimate the paleosol formation temperature and precipitation based on the carb on and oxygen isotopic data obtained. Copyright (C) 1996 INQUA/Elsevie r Science Ltd