以新疆东天山黄山一镜儿泉镍铜成矿带为例,采用奇异性填图技术识别复杂背景下隐蔽的可能矿致异常。结果表明:使用原始镍元素数据形成的地球化学图在吐哈盆地具有较高的浓度值,构造岩浆岩带大部分为中等规模或较弱;而使用奇异性填图技术计算的奇异值在吐哈盆地奇异性较弱,而构造岩浆岩带的奇异性显著。经地质分析认为:吐哈盆地高的元素值可能是镁铁一超镁铁岩浆内侵作用的结果,由于岩浆的分异程度较差,不易成矿,表现出大部分地区较弱的奇异性;而构造岩浆岩带的镁铁一超镁铁岩体,虽然规模小,异常规模中等或较弱,但是分异程度高,容易成矿,奇异性显著。通过浓度一面积(C—A)方法对研究区的奇异值进行分析,圈定出异常,结果表明,异常与已知矿床吻合较好,这为在本区圈定靶区提供了地球化学依据。
Extracting concealed metallogenic information is a fundamental task in exploration geochemistry. The Huangshan-jing' erquan Ni-Cu metallogenic belt, in the eastern Tianshan, Xinjiang, is chosen as a study case to identify concealed local anomalies from complex geochemical background by singularity mapping technique. The results illustrate that the Ni concentration value in the geochemical map according to primary Ni contents is obviously different from that in the geochemical map by singularity mapping technique. In the former, the Ni concentration value is high in the Tuha basin and medium to low in the tectonic-magmatic belt. While in the later, there are adverse features.Due to geological analysis, high concentration value of the element Ni is resulted from intruding of mafic-ultramafic intrusions. These intrusions are of low-degree differentiation and unfavorable to form deposits in Tuha basin so that there occur large-area anomalies in the basin. However, in the tectonic- magmatic belt, though intrusions are small and with medium to low geochemical anomalies, they are differentiated well and favorable to form deposits. The concentration-aera (C - A) method is used to analyze singularity value and delineate anomalies. Because delineated anomalies fit well with known Ni- Cu deposits, they can provide geochemical evidence for delineating target regions.