疏松质石笋碳酸盐的精确微区取样

摘要

High resolution analysis of abrupt climate events is a hot research field. Stalagmites,one of the important archives of paleclimatic records,usually with a growth rate of tens or hundreds of microns per year,have the potential to provide high resolution paleoclimate proxies.Reliable micro-sampling is the key step for stalagmite high resolution analysis. In this paper,technique details for micro-sampling of stalagmite carbonate using a commercial New Wave Technology MicroMill are described.Sample sizes averaging 100 μg were obtained from a 40 μm wide milled path despite the porous nature of the sample and the imperfect laminar structure.Sub-annual sampling resolution was achieved producing sufficient material for trace element and stable isotopic analysis.Key aspects of sample mounting and the optimum MicroMill parameter settings were established.The sample collection technique was perfected and cross contamination of undesired sample material was avoided.%高分辨率极端气候事件是古气候研究中的一个热点.作为重要的古气候信息载体之一的石笋,以其每年几十到几百微米的生长速率,为提取高分辨率古气候代用指标提供了可能.而可靠的微区取样则是石笋高分辨率分析的重要前提.本文利用美国New Wave微区取样装置,对微区取样技术在石笋碳酸盐中的应用进行了探讨.在年层并非平直的疏松质石笋表面,于40μm取样步长内,成功获得了平均质量约为100 μg的石笋微区分析样品.所获得的年内分辨率样品可同时提供微量元素分析和稳定同位素分析.重点讨论了石笋微区取样过程中必须注意的样品固定和取样参数设置等关键问题,提供了有效收集石笋微区样品和避免样品交叉污染的方法.