Palaeoclimate reconstructions on various timescales using stalagmites from Meghalaya, NE India, and applying U/Th dating, stable isotopes and element studies

洞穴沉积物提供了非常有用的古气候记录，可以准确地定年。在印度次大陆，迄今为止只有少数这样的记录。我们建议研究印度东北部的石笋，这是这些努力中的一个区域差距。在一项地面实况研究中，将应用一系列广泛的技术来了解该地区洞穴沉积物中与季风有关的气候信号是如何记录的。洞穴沉积物的年龄测定将在加州理工学院与J.阿德金斯合作进行。与稳定同位素（δ 18 O和δ 13 C、δ 34 S）平行，将采用激光烧蚀微量元素和灰度分析。试点调查将进行石笋，探索其潜力的扩展范围以外的树木年轮年代学的放射性碳校准规模，利用U/Th的日期加上14 C和10 Be的研究。我们计划研究碳酸盐相关的有机氮和硝酸盐。将根据气象数据对代用品结果进行校准。由此产生的校准，然后将被应用于开发记录的多个气候敏感参数的洞穴沉积物从相同的洞穴系统。总体目标是在不同的时间尺度上为该地区提供高质量的古气候重建，并根据气候强迫来解释这些重建。

Speleothems provide very useful palaeoclimate records which can be accurately dated. On the Indian sub-continent only few such well-dated records are available to date. We propose to study stalagmites from NE India, a regional gap in these efforts. In a ground-truthing study, a broad array of techniques will be applied to understand how monsoon-related climate signals are recorded in speleothems from this region. Age determinations of speleothems will be carried out at CalTech in cooperation with J. Adkins. Parallel to stable isotope (δ18O and δ13C, δ34S), laser ablation trace element and grey-scale analysis will be applied. Pilot investigations will be conducted on stalagmites to explore their potential for extending the radiocarbon calibration scale beyond the range of tree ring chronology by using U/Th dates coupled with 14C and 10Be studies. We plan to study carbonate-associated organic N and nitrate. Proxy results will be calibrated against meteorological data. The resulting calibrations will then be applied in the development of records of multiple climate-sensitive parameters in speleothems from the same cave system. The overall goal is to produce high quality paleoclimatic reconstructions for the region on a variety of timescales, and to interpret those reconstructions in terms of climate forcing.