Fractionation of sulfur and oxygen isotopes in sulfate by soil sorption
Fractionation of sulfur and oxygen isotopes in sulfate by soil sorption
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DOI：
10.1016/0016-7037(90)90016-e
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发表时间：
1990-10
影响因子：
5
通讯作者：
D. R. Stempvoort;E. Reardon;P. Fritz
中科院分区：
文献类型：
--
作者：
D. R. Stempvoort;E. Reardon;P. Fritz
野外和实验室数据均表明，在高地森林土壤中，硫酸盐的吸附过程中没有明显的同位素分馏。这些土壤中主要的硫酸盐吸附过程是吸附到矿物表面。在加拿大安大略多塞特的塑料湖流域，来自灰壤B层的硫酸盐馏分具有以下平均同位素（%）。组成：水溶性硫酸盐，δ 34 S = +6.4;δ 18 O = −5.3;碳酸氢盐交换硫酸盐两种方法，δ 34 S =+4.5和+3.4;δ 18 O =− 6.2和−5.6; B层土壤渗水溶解硫酸盐，δ 34 S =+4.8;δ 18 O = −5.4。这些数据表明，土壤吸附富集溶解的硫酸盐在34 S约1 ± 1%。18 O降低0 ± 1%。相对于吸附的硫酸盐。制备针铁矿，这是一种矿物代表的酸性灰壤中的土壤吸附位点，如在塑料湖硫酸盐的实验室吸附得到类似的结果。吸附和溶解的硫酸盐之间的平均分馏被发现是-0.3%。34 S和0.1%。for 18 O。早期文献混淆了术语吸附;在许多情况下，应该使用更通用的术语吸附或保留。湖泊和海洋沉积物硫酸盐中S和O同位素的明显分馏被归因于“吸附”或“保留”，但更可能是硫酸盐还原的结果。显然，在地球表面条件下，硫酸盐中唯一重要的同位素变化发生在微生物过程中。
Both field and laboratory data indicate that there is no significant isotope fractionation of sulfate during sorption in upland forest Podzols. The dominant sulfate sorption process in these soils is adsorption onto mineral surfaces. In the Plastic Lake watershed, Dorset, Ontario, Canada, fractions of sulfate from Podzol B-horizons have the following mean isotope (%.) compositions: water soluble sulfate,δ34S= +6.4;δ18O= −5.3; bicarbonate-exchanged sulfate by two methods,δ34S= + 4.5and+ 3.4;δ18O=−6.2and−5.6; dissolved sulfate in B-horizon soilwater seepage,δ34S= + 4.8;δ18O= −5.4. These data indicate that soil sorption enriches dissolved sulfate in34S by approximately 1 ± 1%. and in18O by 0 +- 1 %. relative to sorbed sulfate. Similar results were obtained by laboratory sorption of sulfate by prepared goethite, which is a mineral representative of soil sorption sites in acidic Podzols like the one at Plastic Lake. The mean fractionation between sorbed and dissolved sulfate was found to be − 0.3%. for34S and 0.1 %. for18O.Earlier literature has confused the term adsorption; in many cases the more general term sorption, or retention, should be used. Pronounced fractionation of S and O isotopes in sulfate by lake and ocean sediments has been attributed to “adsorption” or “retention” but is more likely the result of sulfate reduction. Apparently, at Earth-surface conditions the only substantial isotope shifts in sulfate occur during microbial processes.