In March and April 1959, a seismic party from the Bureau of Mineral Resources extended a seismic survey carried out in 1958 in the Latrobe Valley. A seismic reflection traverse was run across the Latrobe Syncline between Tyers and Traralgon South to determine the structure of the coal measures, the depth of basement and, if possible, the type of basement.
Results indicated that the Latrobe Syncline (the structural feature which coincides with the Latrobe River Valley) is a broad syncline in which the strata are more or less horizontally bedded. The maximum thickness of coal measures is about 2200 ft. The survey provided information on the structures of the limbs of the Latrobe syncline and on several minor structures superimposed on the main syncline. It did not, however, show for certain what type of basement rock underlies the coal measures.
The survey provided information on the structure of the formations beneath the coal measures; and although some of the seismic data is of poor quality, there is probably an unconformity in the stratigraphic section between 5000 and 9000 ft. Reflections recorded at times as great as 2700 millisec, show that the sediments in the Latrobe Valley are probably between 10,500 and 15,000 ft. deep.
