SPATIAL VARIABILITY OF FE, MN, AND BA OF SEDIMENTS WITHIN THE CHIHUAHUAN DESERT, MEXICO

Exploratory Data Analysis (EDA) was applied to sediment geochemical data in order to discriminate between background and anomalous concentrations and to identify possible sources of the anomalies. The data consisted of ca. 3,000 samples in arid areas within the state of Chihuahua, which were mostly collected and analyzed by the Servicio Geologico Mexicano (SGM). A robust data analysis developed by Tuckey (Box-plot diagram) was applied and as a result, limits between background, anomalous, and outlier concentrations for each of Fe, Mn, and Ba were determined. Once the anomalous concentrations were superimposed on a map containing layers of hydrology, geology, mining, and urban areas, their possible source was linked to either mining, naturally enriched outcrop, or an urban waste discharge. Associations between elements and between element and rock outcrops were also investigated.