Application of geographically weighted regression (GWR) and singularity analysis to identify stream sediment geochemical anomalies, case study, Takab Area, NW Iran

• Published in: Journal of geochemical exploration 2022-04, Vol.235, p.106953, Article 106953
• Main Authors: Nazarpour, Ahad, Rostami Paydar, Ghodratollah, Mehregan, Fatemeh, Hejazi, Seyed Jafar, Jafari, Mohammad Amin
• Format: Article
• Language: English
• Subjects: Geochemical exploration; Geographical weighted regression; Local Singularity model
• ISSN: 0375-6742; 1879-1689
• DOI: 10.1016/j.gexplo.2022.106953

In geologically and lithologically complex areas, distinguishing weak geochemical anomalies from background and defining a valid threshold value are central issues in mineral exploration. This study benefited from using geographically weighted regression (GWR), ordinary least square regression (OLSR), singularity analysis, and a combined model of GWR and singularity analysis to identify geochemical anomalies related to Pb–Zn mineralization in the Takab area (Iran). In the analyses, major oxides were considered independent geo-variables related to upstream of stream sediment samples and on-site rock types. The results of GWR revealed the non-stationary effect of independent geo-variables on Pb–Zn geochemical anomalies, on local R2 among geo-variables, and on measured values of trace elements, which suggested a meaningful improvement in trace element prediction in comparison with OLSR. The results of singularity model showed that geochemical anomalies were closely coincident with known carbonate-hosted Pb–Zn deposits and with carbonaceous geological units in the Takab area. Anomalies delineated by singularity model illustrated another potential for follow-up mineral exploration. The results of the combined model of GWR and singularity model—based on consideration of Type I and Type II errors—exhibited not only higher coincidence with known mineral deposits but also introduced new potential exploration targets in the Takab area; that is, the combined model led to a more profound recognition of weak anomalies in a geologically and lithologically complex area. •GWR revealed the effect of geo-variables on Pb–Zn geochemical anomalies.•Singularity analysis indicated that geochemical anomalies were closely coincident with Pb–Zn deposits.•Combined model of GWR and singularity analysis introduced new exploration targets in the Takab area.