A geophysical and geological study of part of the Kilkivan district, South East Queensland

The major part of this thesis is a description of a magnetic survey of part of the Kilklvan district in south east Queensland. The outcrop is poor, so that a regional magnetic survey was undertaken in an attempt to define the geological boundaries between the major rock types, and to locate Magnetic anomalies that could be investigated in more detail. A total of 1068 magnetic stations was occupied in the regional survey. The magnetic values were contoured with an interval of 200 gammas and are presented as an overlay drawn to the same scale as the geological map.ln general the Triassic and Palaeozoic rocks have a contrasting magnetite content, so that the boundaries between the two are reflected in the regional magnetic contour map. A number of well defined magnetic anomalies were located in the area, most of which could be correlated with outcropping rocks that have a high magnetite content.Several areas were selected for a more detailed study, and a further 1010 magnetic stations were located along traverses across the anomalies found in the regional survey. This close survey indicated that the detailed geology of the area is exceedingly complex, and in only one case was a quantitative interpretation of the magnetic anomalies attempted.A method was developed for the interpretation of Magnetic anomalies over a dipping contact. The mathematical formulation of the problem was derived from first principles, and the final solutions evaluated using the G.E. 225 computer. The output from the computer is in the form of tables that have general application and which should be of value to geologists for the solution of structural problems.A geological map was drawn using as control the surface exposures and the regional magnetic contour map. A great variety of Palaeozoic and Triassic rock types exists in the area. These have been described; of particular interest is the occurrence of a glaucophane rock containing pumpellyite.