重庆梁天湾14号石笋沉积特征与同位素年龄

对采自重庆金佛山梁天湾洞穴的一根长290mm的14号石笋进行了高精度的定年和稳定同位素分析．在此基础上，对石笋的沉积结构、层面构造、沉积间断等特征标志进行了研究，阐述了重庆梁天湾涧石笋的沉积特征以及洞穴占滴水的动态变化．TIMS-U系测年结果表明：该石笋形成于31．9KaB．P．，结束于15．21Ka B．P．，属于末次冰期晚期的产物．石笋的沉积基本连续。没有明显的沉积间断，共分为4个旋回，沉积速率从老到新分别为65．22mm/Ka,8．37mm／Ka，97．09mm／Ka,24．39mm／Ka．

Isotopic Ages and Depositional Characteristics of LT. 14 Stalagmite from Liangtianwan Cave, Jinfu Mts, ChongQing

A 290 mm length stalagmite, the LT14 stalagmite, was collected from the Liangtianwan Cave, located in Kingfo Mrs, south of Chongqing. Through the high resolution of TIMS-U series dating and stable isotope analyses, the authors study the depositional structure, band construct and deposition-interruption of the stalagmite and then expound the depositional characteristics and discuss the variation of the paleo-dripping water of the LT14. The TIMS-U series dating data shows that the LT14 stalagmite formed at 31.9 Ka 13. P. to 15.21 Ka 13. P. , in the late period of the Last Glaciation. The LT14 stalagmite deposited continuously and there is no visible deposit-interruption. The deposition of the LT14 can be divided into four cycles and the depositional rate from the oldest to the youngest cycle is 65.22 mm/Ka, 8.37 mm/Ka, 97.09 mm/Ka and 24.39 mm/Ka respectively.