Abstract
We present a large-scale study of the petrophysical relationship of resistivities obtained from densely sampled
ground-based and airborne transient electromagnetic surveys and lithological information from boreholes. The
overriding aim of this study is to develop a framework for examining the resistivity-lithology relationship in a
statistical manner and apply this framework to gain a better description of the large-scale resistivity structures
of the subsurface.
In Denmark very large and extensive datasets are available through the national geophysical and borehole databases,
GERDA and JUPITER respectively. In a 10 by 10 km grid, these data are compiled into histograms of resistivity
versus lithology. To do this, the geophysical data are interpolated to the position of the boreholes, which
allows for a lithological categorization of the interpolated resistivity values, yielding different histograms for a
set of desired lithological categories. By applying the proposed algorithm to all available boreholes and airborne
and ground-based transient electromagnetic data we build nation-wide maps of the resistivity-lithology relationships
in Denmark.
The presented Resistivity Atlas reveals varying patterns in the large-scale resistivity-lithology relations, reflecting
geological details such as available source material for tills. The resistivity maps also reveal a clear ambiguity in
the resistivity values for different lithologies. The Resistivity Atlas is highly useful when geophysical data are to
be used for geological or hydrological modeling.
ground-based and airborne transient electromagnetic surveys and lithological information from boreholes. The
overriding aim of this study is to develop a framework for examining the resistivity-lithology relationship in a
statistical manner and apply this framework to gain a better description of the large-scale resistivity structures
of the subsurface.
In Denmark very large and extensive datasets are available through the national geophysical and borehole databases,
GERDA and JUPITER respectively. In a 10 by 10 km grid, these data are compiled into histograms of resistivity
versus lithology. To do this, the geophysical data are interpolated to the position of the boreholes, which
allows for a lithological categorization of the interpolated resistivity values, yielding different histograms for a
set of desired lithological categories. By applying the proposed algorithm to all available boreholes and airborne
and ground-based transient electromagnetic data we build nation-wide maps of the resistivity-lithology relationships
in Denmark.
The presented Resistivity Atlas reveals varying patterns in the large-scale resistivity-lithology relations, reflecting
geological details such as available source material for tills. The resistivity maps also reveal a clear ambiguity in
the resistivity values for different lithologies. The Resistivity Atlas is highly useful when geophysical data are to
be used for geological or hydrological modeling.
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Journal of Applied Geophysics |
| Vol/bind | 134 |
| Sider (fra-til) | 199-209 |
| Antal sider | 10 |
| ISSN | 0926-9851 |
| DOI | |
| Status | Udgivet - 1 nov. 2016 |