摘要
对红色风化壳粒度分析的前处理方法,目前存在着很大差异,这在一定程度上影响了分析结果的可靠性。采用不同前处理方法对中国西南岩溶区红色风化壳样品进行了粒度测试,结果表明各方法对粒度数据有明显影响。对于富含三水铝石的样品,用盐酸溶液煮沸处理后,可以使游离铝氧化物的胶结作用解体,从而使颗粒充分分散,即方法B效果较好;而对于蒙脱石含量较高的红色风化壳,由于盐酸溶液处理后会破坏蒙脱石晶格及硅胶体的出溶,从而会对矿物产生胶结作用,用方法A较为适宜;其他粘土矿物对不同前处理方法没有明显的敏感性。当利用粘粒含量作为红色风化壳发育程度及红壤类型划分的指标时,不同前处理方法将影响到对成果的正确解释,因此选择合适的前处理方法是必需的。在碳酸盐岩上覆红色风化壳的成因研究方面,以粒度频率分布曲线作为指标时,前处理方法的不同不影响对物源指示的判读,但利用粘粒含量及粉砂/粘粒比等参数时,可能会对研究结果产生影响。
As to the pretreatment methods of grain size analysis for red weathering crusts, at present there is a great discrepancy, and it influences the reliability of analytic results to some extent. This paper adopted different pretreatment methods to measure the grain size of red weathering crust samples in karst areas, southwestern China, and the results showed that they have apparent effects on the grain size data. As to samples rich in gibbsite, boiling with dilute HCI solution may disaggregate cementation of disassociative Al-oxide and enable grain size to be dispersed well, i.e., method B is good. However, as for samples rich in smectite, owing to destroying crystal structure of smectite and silicon-colloid unmixing through acting with HCl solution, it resulted in cementation of mineral panicles, so method A is good. Other kinds of clay minerals have no obvious sensitivity for different pretreatment methods. When clay content is used as the index for weathering intensity of red weathering crusts and type devision of red soils, different pretreatment methods will influence the accurate explanation of the results. Therefore, to select an appropriate pretreatment method is very necessary. With regard to genesis research on red weathering crusts underlying carbonatite, when grain size frequency distribution curves are used as indices, different pretreatment methods have no influence on source indication; but when clay content and ratio of silt to clay are used, the difference will likely effect research results.
出处
《矿物学报》
CAS
CSCD
北大核心
2006年第1期1-7,共7页
Acta Mineralogica Sinica
基金
国家自然科学基金项目(批准号:90202003)
中国科学院地球化学研究所领域前沿A类项目
中国科学院"西部之光"项目
南华大学科研启动基金
关键词
红色风化壳
粒度分析
前处理方法
中国西南岩溶区
red weathering crust
grain size analysis
pretreatment method
karst area in southwestern China
