  Manual interpretation of data collected from drill holes for mineral or oil
and gas exploration is time-consuming and subjective. Identification of
geological boundaries and distinctive rock physical property domains is the
first step of interpretation. We introduce a multivariate technique, that can
identify geological boundaries from petrophysical or geochemical data. The
method is based on time-series techniques that have been adapted to be
applicable for detecting transitions in geological spatial data. This method
allows for the use of multiple variables in detecting different lithological
layers. Additionally, it reconstructs the phase space of a single drill-hole or
well to be applicable for further investigations across other holes or wells.
The computationally cheap method shows efficiency and accuracy in detecting
boundaries between lithological layers, which we demonstrate using examples
from mineral exploration boreholes and an offshore gas exploration well.
