Abstract When using the nuclear track technique for multi-element detection and spatial mapping, the presence of moderate to high concentrations of boron or lithium results in a large number of (n,α) reactions when using the high thermal neutron fluences required to map trace amounts of uranium. When chemically etched, tracks generated by a large number of alpha particles cannot be spatially resolved, and are manifested instead by large-scale depressions in the detector surface. High Li and B concentration samples have the most pronounced topographic development in both CR-39 and CN detectors. Samples with low concentrations of Li and B or high concentrations of Gd, Sm or Eu developed moderate depressions. These depressions can affect uranium quantitation, but simultaneously, they provide useful information about the sample. This paper is a preliminary study of observations of etched bulk depressions, variations in track revelation time, and the mapping of samples containing elements with high thermal neutron absorption cross sections such as gadolinium.