Paleoclimate record and paleohydrogeological analysis of travertine from the Niangziguan Karst springs, northern china

摘要

Travertine deposite around the Niangziguan karst springs was used as a new type of paleoclimate record in this study. Five stages of Climate change in northern china from 200 ± ka to 36± ka before the present (B.P.) were reconstructed using the 18_o and 13_c isotope record of the travertine. Tendency of the change was towards a more arid climate. Coupling the tempo- ral -spatial evolution of the springs with climate change, the hydrogeological evolution could be di- vided into four major periods since middle Pleistocene: (1) No spring period; (2) the initial period of spring outcropping as the predominant way of discharge; (3) The culmination period of spring de- velopment; and 94) The spring discharge attenuation period.