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尝试利用二次离子质谱(SIMS)技术,采用国家一级标样(GBW04481)Oka方解石和美国威斯康星大学标样UWC-3方解石,对长江中游清江和尚洞洞穴碳酸盐沉积物HS4石笋的8.3ka BP时段(236.3~235.6 cm)进行了季节分辨率的?18O原位分析,探讨了利用季节分辨SIMS?18O所呈现出的年际旋回对石笋进行相对定年的可能性;并通过SIMS法与常规法?18O值的比较,分析了两者间偏差产生的可能原因.以Oka作外标,利用Cameca IMS 1280离子探针在3个工作日内对UWC-3进行了氧同位素分析,获得的测量结果(?18OVPDB=?17.85‰±0.22‰,1SD)与其推荐值(?18OVPDB=?17.83‰?0.08‰)在误差范围内一致,说明仪器稳定性良好、测试方法可靠.用SIMS法获得的HS4石笋?18O季节分辨率记录,则呈现出较为显著的年际旋回特征,其旋回总数与同段石笋Mg/Ca比及石笋反光微层图像中所呈现出的年层总数一致,有望为不具备清晰年纹层石笋的相对定年提供一个新的方法.与常规法?18O分析结果相比,HS4石笋SIMS法?18O值系统偏负0.90‰,且季节性差异增大,其主要原因可能是缘于样品中细微裂隙、孔洞和包裹体的存在,同时亦不排除石笋中有机质的存在对SIMS?18O值可能造成的影响,说明要获得与常规法?18O值相符的SIMS?18O值记录,石笋样品的致密度和纯净度均至关重要.
In this paper, we use the SIMS technique to study the calcite of the HS4 stalagmite of the Heshangdong cave in the middle reaches of the Yangtze River using the Oka calcite of National Grade I (GBW04481) and UWC-3 calcite of the University of Wisconsin, In the BP period (236.3-235.6 cm), the seasonal resolution of 18O is analyzed in situ, and the possibility of relative dating of the stalagmite by seasonal resolution SIMS 18O is discussed. France 18O values, analysis of the possible causes of bias between the two.Used Oka as an external standard, the use of Cameca IMS1280 ion probe UWC-3 oxygen isotope analysis within 3 working days, the measurement obtained The results (18OVPDB = 17.85 ‰ ± 0.22 ‰, 1SD) and its recommended value (18OVPDB = 17.83 ‰ 0.08 ‰) in the error range, indicating that the instrument stability is good, the test method is reliable. SIMS obtained HS4 Stalagmite? 18O seasonal resolution records, then showed more significant characteristics of the interannual cycle, the total number of cycles and its stalagmite Mg stomatal and stratospheric reflectance micro-layer image shows the total number of years in the layer is expected to not have Clear stratum stalagmite relative set Provides a new method.Compared with the conventional method, the SIMS method of HS4 stalagmite has a negative value of 0.90 ‰, with a seasonal difference increasing, which may be due to fine cracks, holes and The existence of inclusions and the possible influence of organic matter in the stalagmite on the SIMS value of 18O indicate that to obtain the SIMS value of 18O consistent with the conventional method, the stomatal density and the purity of stalagmite samples are both It is very important.