Methods for constructing 3D geological and geophysical models of flood basalt provinces

Abstract

In this thesis, realistic 3D geological models of flood basalt provinces are constructed. These models are based on outcrop observations and remote sensing data from the North Atlantic Igneous Province, collected by a variety of methods including terrestrial laser scanning. Geophysical data are added to the models to make them suitable for generating synthetic seismic data.

Flood basalt provinces contain a number of different volcanic facies, distinguished by their outcrop appearance and physical properties. These include tabular-classic and compound-braided lava flows, intrusions and hyaloclastites. 3D models are constructed for tabular-classic lava flows based on satellite data from Iceland and laser scanning data from a variety of locations. Models for compound-braided lava flows are based on terrestrial laser scanning data and field observations from the Faroe Islands and the Isle of Skye.

An additional finding of this work is that volcanic facies can be differentiated in wireline log data from boreholes. Facies show characteristic velocity distributions which can be linked to onshore observations and used to understand volcanic facies in offshore boreholes. Data from boreholes on the Faroe Islands are used to add seismic velocities to the 3D geological models above.

This thesis also develops methods and workflows for constructing 3D geological models of flood basalt lava flows. The collection of digital 3D data using terrestrial laser scanning is evaluated, and data processing workflows are developed.