Paleoclimate record and paleohydrogeological analysis of travertine from the Niangziguan Karst Springs, northern China

Travertine deposited around the Niangziguan karst springs was used as a new type of paleoclimate record in this study. Five stages of climate change i n northern China from 200 +/- ka to 36 +/- ka before the present (B. P.) we re reconstructed using the O-18 and C-13 isotope record of the travertine. Tendency of the change was towards a more and climate. Coupling the tempora l-spatial evolution of the springs with climate change, the hydrogeological evolution could be divided into four major periods since middle Pleistocen e: (1)No spring period; (2)The initial period of spring outcropping as the predominant way of discharge; (3)The culmination period of spring developme nt; and (4)The spring discharge attenuation period. The attenuation is part ly related to the decrease of recharge as a result of the dry climate after 90 +/- kaBP.