| 不同选择性提取方法锶钡比的海陆相沉积环境判别探讨 |
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| 引用本文： | 王爱华,叶思源,刘建坤,丁喜桂,李华玲,许乃岑.不同选择性提取方法锶钡比的海陆相沉积环境判别探讨[J].沉积学报,2020,38(6):1226-1238. |
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| 作者姓名： | 王爱华 叶思源 刘建坤 丁喜桂 李华玲 许乃岑 |
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| 作者单位： | 1.中国地质调查局南京地质调查中心，南京 210016 |
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| 基金项目： | 国家自然科学基金项目41572096国家地质调查项目1212010611402 |
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| 摘 要： | 锶钡比是常用的海陆相沉积环境判别手段之一，黄河三角洲钻孔沉积物的传统全量锶钡比介于0.45±0.5之间，无法判别其海陆相沉积环境。黄河三角洲钻孔样品的选择性提取结果表明，全样的总量钡和锶中的75%以上的钡和50%以上的锶赋存于与沉积时的海陆相地球化学环境无关的陆源碎屑矿物中，在判别海陆相沉积环境时是应该剔除的。不同选择性提取方法的分析结果表明，黄河三角洲沉积物中的锶除碎屑硅酸盐矿物态外，主要呈现可交换态和碳酸态，赋存形态比较单一；而钡除了碎屑硅酸盐矿物态外其赋存形态复杂。以提取可交换态为主的醋酸钠法和醋酸铵法、以提取可交换态和碳酸盐态为主的柠檬酸法和稀盐酸法及络合剂+稀盐酸法所提取的锶钡比，均能较好地区分黄河三角洲的海陆相沉积环境。来自黄土的黄河三角洲物源的高碳酸钙和醋酸不能提取重晶石中钡的双重特殊性，导致黄河三角洲沉积物稀醋酸法提取的结果具有高锶低钡的特征并造成锶钡比偏高，尽管其锶钡比都大于1.0，但其对沉积时盐度环境的响应灵敏度大于其他选择性提取方法。选择性提取方法是解决目前传统的全样总量锶钡比海陆相沉积环境判别效果不佳问题的唯一有效手段。
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| 关 键 词： | 选择性提取 锶钡比 陆源碎屑沉积物 海陆相沉积环境 沉积环境判别 黄河三角洲 |
| 收稿时间： | 2019-07-10 |
Discrimination between Marine and Terrestrial Sedimentary Environments by the Selectively Extracted Sr/Ba Ratio: A case of sediments in the Yellow River Delta |
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| Institution: | 1.Nanjing Center of China Geology Survey, CGS, Nanjing 210016, China2.Qingdao Institute of Marine Geology, CGS, Qingdao, Shandong 266071, China |
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| Abstract: | The ratio of Sr/Ba is a commonly used methods for the distinction between terrestrial and marine sedimentary environments. "The Sr/Ba Ratio is less than 1.0 for terrestrial sedimentary environments and more than 1.0 for marine sedimentary environments" widely exists in various related textbooks and books. However， the traditional total Sr/Ba ratio of borehole sediments in the Yellow River Delta is between 0.45 and 0.5， which cannot be distinguished between marine and terrestrial sedimentary environments. The result of selective extraction for borehole samples from the Yellow River Delta shows that more than 75% of the total barium and more than 50% of the total strontium in the whole sample occur in terrigenous clastic minerals unrelated to the marine and terrestrial geochemical environment at the time of deposition， which should be excluded when we distinguish between the marine and terrestrial sedimentary environments. The results of different selective extraction methods show that strontium in the sediments of the Yellow River Delta is mainly exchangeable and carbonate， except for clastic silicate minerals， and its occurrence mode form is relatively single， while barium is complex， except for the clastic silicate minerals. The ratio of Sr/Ba mainly extracted is exchangeable by the sodium acetate method and ammonium acetate method， and the ratio of Sr/Ba mainly extracted is exchangeable and bound to carbonates by the citric acid method， dilute hydrochloric acid method， and complexing agent + dilute hydrochloric acid method， which can better distinguish between the marine and terrestrial sedimentary environments of the Yellow River Delta， as the high calcium carbonate from the source of the Yellow River and acetic acid cannot extract barite. The results from dilute acetic acid extraction in sediments are characterized by high strontium and low barium content， which leads to a high Sr/Ba ratio. Although the Sr/Ba ratio is greater than 1.0， the sensitivity of the Sr/Ba ratio by dilute acetic acid extraction to the salinity environment during deposition is greater than that of other selective extraction methods. The selective extraction method is the only effective method to solve the problem that the discrimination effect is not good enough to distinguish between marine and terrestrial sedimentary environments using the ratio of Sr/Ba. |
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