(Table 1) Micro-inclusion counts and ion concentrations in the five GRIP ice-core sections

We provide the first direct evidence that a number of water-soluble compounds, in particular calcium sulfate (CaSO4 2H2O) and calcium carbonate (CaCO3), are present as solid, micron-sized inclusions within the Greenland GRIP ice core. The compounds are detected by two independent methods: micro-Raman spectroscopy of a solid ice sample, and energy-dispersive X-ray spectroscopy of individual inclusions remaining after sublimation. CaSO4 2H2O is found in abundance throughout the Holocene and the last glacial period, while CaCO3 exists mainly in the glacial period ice. We also present size and spatial distributions of the micro-inclusions. These results suggest that water-soluble aerosols in the GRIP ice core are dependable proxies for past atmospheric conditions.

本研究首次提供直接证据，证明格陵兰GRIP冰芯中存在以固态微米级包裹体形式赋存的多种水溶性化合物，其中尤以二水合硫酸钙（CaSO4·2H2O）与碳酸钙（CaCO3）为典型代表。上述化合物通过两种独立方法得以检出：其一为固态冰样品的显微拉曼光谱（micro-Raman spectroscopy）分析，其二为对冰样升华后残留的单个包裹体开展能量色散X射线光谱（energy-dispersive X-ray spectroscopy）检测。二水合硫酸钙在全新世及末次冰期的冰层中均广泛富集，而碳酸钙则主要分布于冰期冰层内。本研究同时给出了该类微米级包裹体的尺寸与空间分布特征。上述结果表明，格陵兰GRIP冰芯中的水溶性气溶胶可作为重建古大气环境的可靠代用指标（proxy）。