Seismic shothole drillers' log-derived thematic GIS, Northwest Territories and northern Yukon: bedrock outcrop and subcrop, geohazards, and muskeg thickness

Abstract

This publication provides a collection of geoscience and biological information interpreted from seismic shothole drillers' log records. The shothole records provide point lithostratigraphic observations of muskeg and earth materials from surface to 10-20 m depth. Data are presented as GIS, allowing spatial patterns and distributions to be assessed.Bedrock situated at the top of drillers' log records is mapped as outcrop, while that situated below unconsolidated drift is mapped as subcrop. Identification of bedrock type and situation will aid bedrock mapping and drift exploration, particularly in areas of thick drift cover. It will also assist bedrock-generated landslide hazard assessments, and benefit granular aggregate exploration, as competent bedrock such as limestone could be quarried. Geohazards pertain to those records interpreted to represent hazards to infrastructure development, such as roads and pipelines, as well as future geophysical seismic exploration. The geohazards identified include the presence of ice or water at depth, and occurrences of flowing holes (water), flowing sand, and gas. Muskeg thicknesses and/or the presence of muskeg (thickness undefined) was interpreted from drillers' log records and plotted as thickness-proportional symbols. The available data permits broad trends in muskeg thickness and distribution to be discerned throughout the study area, and highlights areas where thick and extensive muskeg could pose a significant concern to future infrastructure development.