Identifying kimberlite indicator mineral dispersal trains in the Pelly Bay region, Nunavut, Canada using GIS interpolation

摘要

Identification of kimberlite indicator mineral dispersal trains in glaciated terrain provides important clues in determining provenance. Complex ice flow history can distribute kimberlite indicator minerals such that dispersal trains are disguised within clusters of till samples containing abundant kimberlite indicator minerals. This study uses GIS with inverse distance weighted interpolation to identify and isolate dispersal trains within areas where large clusters of till samples with abundant kimberlite indicator minerals exhibit no apparent distribution patterns. The method was tested in the Pelly Bay region of Nunavut, Canada, where many areas contain clusters of till samples with abundant kimberlite indicator minerals, the method delineated dispersal trains within these areas. The study identified trains ranging from 1.5-7 km in length, with the heads of some trains ranging in width between 225 m and 3 km. Mg-ilmenite is the most abundant kimberlite indicator mineral in the Pelly Bay area, however, several trains with distinct relative abundances of kimberlite indicator mineral species were identified that suggest the presence of kimberlites with different intrusive phases. Our study suggests that several of the identified dispersal trains likely originated from kimberlite dykes and/or sills occupying NW-SE oriented structures in the bedrock.