L036 Latrobe Valley seismic reflection survey, VIC, 1959

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.

1959年3月至4月，矿产资源局（Bureau of Mineral Resources）的一支地震勘探队对1958年在拉特罗布谷（Latrobe Valley）开展的地震勘探进行了延伸作业。本次勘探在泰尔斯（Tyers）与南特拉尔贡（Traralgon South）之间的拉特罗布向斜（Latrobe Syncline）区域部署了地震反射测线（seismic reflection traverse），旨在查明煤系地层（coal measures）的构造特征、基底（basement）深度，并尽可能确定基底类型。结果显示，与拉特罗布河谷重合的拉特罗布向斜为宽缓向斜构造，地层大致呈水平层状产出；煤系地层最大厚度约2200英尺。本次勘探获取了拉特罗布向斜两翼的构造信息，以及叠加于主向斜之上的多处小型构造数据，但未能明确确定煤系地层之下的基底岩石类型。此外，本次勘探还获取了煤系地层之下地层的构造信息；尽管部分地震数据质量欠佳，但在5000至9000英尺深度的地层剖面（stratigraphic section）中可能存在不整合面（unconformity）。记录到的最大反射时间达2700毫秒，表明拉特罗布谷内的沉积物厚度可能介于10500至15000英尺之间。