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成壤碳酸盐碳同位素常被用于古环境研究,而原生碳酸盐的干扰会使其碳同位素值发生改变.为了建立判定成壤钙结核中是否存在原生碳酸盐的实验方法,对黄土高原地区中新世黄土中23个成壤钙结核孔隙和基质部位进行了微形态鉴定和碳酸盐碳同位素测试.结果表明,同一个钙结核基质(B)与孔隙(A)碳酸盐碳同位素差值(δ13C(B–A))范围为?0.16‰~0.44‰,其中基质中含原生碳酸盐的钙结核的δ13C(B?A)值范围为0.27‰~0.44‰,大于测量误差(±0.2‰),而不含原生碳酸盐的钙结核的δ13C(B?A)值范围为?0.16‰~0.13‰,在测量误差之内.由此,得到利用碳同位素手段判断黄土钙结核中是否含有原生碳酸盐的简便方法,将δ13C(B?A)的值在测量误差之内作为判断钙结核中不含原生碳酸盐的碳同位素标准.
Carboniferous carbon isotopes are often used in paleoenvironment research, and the carbonates of primary carbonates will change their carbon isotope values.In order to establish an experimental method to determine the existence of primary carbonates in pyroligneous bed nodules, Microformatology and carbonate carbon isotope measurements were performed on the pores and matrix sites of 23 calcareous calcium nodules in Miocene loess in the Loess Plateau.The results show that the same calcareous matrix (B) and pore (A) carbonate The δ13C (B-A) value of carbon isotope (δ13C (B-A)) ranged from 0.16 ‰ to 0.44 ‰, and the δ13C (BΔA) value ranged from 0.27 ‰ to 0.44 ‰ in calcareous nodules with primary carbonate. (± 0.2 ‰), while the δ13C (B-A) value of calcium tuberculosis without native carbonate ranged from 0.16 ‰ to 0.13 ‰, which was within the measurement error.Thus, the carbon isotope method was used to determine the loess The simple method of whether or not there is primary carbonate in calcium tuberculosis is to use δ13C (B-A) within the measurement error as the standard to determine the carbon isotope of native calcium carbonate in calcium tuberculosis.