地球化学基因的构建与检验

Construction and Test of Geochemical Genes:Case Studies in China

地球化学基因是近年来提出的新技术。在分析地球化学基因构建方法的基础上提出了一种新的岩性地球化学基因LG01,并将早先提出的岩性地球化学基因命名为LG02,同时提出了两种稀土元素地球化学基因REEG01和REEG02。选择分别发育在广东连阳花岗岩体、广东佛冈花岗岩体、海南海口玄武岩、北京房山花岗闪长岩体上的4条风化剖面对岩性地球化学基因和稀土元素地球化学基因进行检验,结果发现岩石风化产物中的岩性基因和稀土元素基因均具有一定的稳定性,表现为稳定的遗传性和继承性;LG01岩性基因相对于LG02岩性基因具有更好的稳定性,REEG01稀土元素基因较REEG02稀土元素基因更稳定。建议将样品相对于中国酸性岩(由中国酸性岩元素丰度值代表的虚拟样品)的基因相似度称为酸性相似度,依据样品在LG01岩性基因方面的酸性相似度可将铝硅酸盐地质样品划分为类酸性成分、类基性成分和类中性成分3类(或类中酸性成分和类中基性成分两类)。从4个风化剖面样品及其表层土壤样品验证了LG01岩性基因的酸性相似度在物源示踪方面具有潜在应用价值。基于全国区域地球化学调查数据库和目标样品在不同地球化学基因中的相似度空间分析有可能实现对目标样品的溯源定位。

Geochemical gene is a new technique presented recently. According to the construction steps of a geochemical gene, a new lithogene called LG01 was presented and the early presented lithogene was named as LG02. Meanwhile, two rare earth element(REE) geochemical genes were also presented labeled as REEG01 and REEG02. These geochemical genes were tested on four weathering profiles which are LY18 D06 profile developed over the Lianyang granite intrusion located in Guangdong Province, TT profile formed on the Fogang granite intrusion also in Guangdong Province, HK06 profile formed on the Neogene basalt in Hainan Province, and ZKD2 profile developed over a granodiorite intrusion in Beijing, China. The results indicate that lithogenes and REE genes are stable or have subtle differences in the weathered products. Furthermore, LG01 gene is more stable than LG02 gene and REEG01 gene is more stable than REEG02 gene in these weathering profiles. The sample’s gene similarity relative to the acidic rock in China(a virtual sample with the elemental abundance of acidic rocks in China) is called acidic similarity. According to the acidic similarities of LG01 gene, samples can be classified into three groups as acidic-like composition, intermediate-like composition, and basic-like composition(or two groups as intermediate-acidic-like composition and intermediate-basic-like composition). The acidic similarity of LG01 gene can be used as a tool to recognize the provenance of soils or weathered products tested on samples from the four weathered profiles. Based on the regional geochemical survey database and the geochemical gene techniques,(forensic) geological samples may be traced or located.