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植硅体(phytolith)是植物体细胞中非晶体二氧化硅脱水后的产物。非晶体二氧化硅的一个聚合基有活性,能够结合植物细胞中的有机碳。植物体死亡后,非晶体二氧化硅脱水,形成坚硬的硅质物,具有抗风化、抗腐蚀、耐酸的特点。植物原生的有机碳被封闭在植硅体内,与外界隔绝,被很好地保存了下来。利用植硅体进行~(14)C年代测定,可以得到植物体死亡的年龄。本研究采集浙江田螺山新石器时代遗址水稻田土壤样本,提取其中的植硅体,通过元素分析、红外光谱进行鉴定,并利用加速器质谱对植硅体样品进行~(14)C年代测定,以期得到水稻田的使用年代;对同层位炭化植物种子也利用加速器质谱进行了~(14)C年代测定。对比结果显示,植硅体年代数据与炭化植物种子的年代在3σ误差范围内一致,植硅体年代数据的中值比炭化植物种子的年代数据中值略有偏老。可以认为植硅体的年代基本上代表了水稻田被使用的年代,植硅体测年可以作为植物年代测定的有效手段。同时,本文尝试针对本研究植硅体年代数据偏老的部分原因做了一点讨论。
Phytoliths are products of dehydration of amorphous silica in plant somatic cells. Amorphous silica has a polymeric group that is able to bind to organic carbon in plant cells. After the death of plants, amorphous silica dehydration, the formation of hard siliceous material, with anti-weathering, corrosion resistance, acid-resistant characteristics. Plant native organic carbon is enclosed in phytoliths, isolated from the outside world, is well preserved. The use of phytoliths for ~ (14) C dating, plant age can be obtained. In this study, the soil samples collected from the Neolithic sites in Tianluoshan, Zhejiang Province were collected and the phytoliths were extracted from the paddy soils. The phytoliths were identified by elemental analysis and FTIR spectroscopy. The age of the paddy field was obtained, and ~ (14) C dating was also performed on the same layer of carbonized plant seeds by using accelerator mass spectrometry. The results of the comparison show that the phytolith chronological data is consistent with the carbonization plant seed chronology within the 3σ error range. The median phytolith chronological data is slightly older than the chronological data of carbonized plant seeds. It can be considered that the age of phytolith basically represents the era in which paddy fields are used. The dating of phytoliths can be used as an effective measure for the determination of plant age. At the same time, this article attempts to discuss some of the reasons for the aging of phytoliths in this study.