Soil gas geochemical exploration in covered terrains of northern Chile: data processing techniques and interpretation of contrast anomalies

摘要

The Campanani, Casualidad and Inca de Oro prospects, owned by Codelco-Chile, are extensive areas covered by post-mineralization deposits. To assist the detection of potential exploration targets, we carried out basic soil gas sampling campaigns by means of the Ore Hound GOCC (R) passive collectors, which were buried on a regular grid at a depth of 30-40 cm. After 90-120 days, samples were retrieved, sealed, and adsorbent material was submitted to an acid elution and analysed by ICP-MS for a set of 72 elements. In this study, databases have been analysed and modelled by statistical and geostatistical methodologies, mainly by factorial kriging analysis (FK). In all cases, a systematic analytical error was detected, discriminated and filtered, allowing the definition of contrast anomalies at different scales of spatial variation, and the interpretation of evidence of secondary dispersion processes by which present time surface contrast anomalies have been developed.