Incised Valleys Around Desert Lakes
Petroleum Honours Degree, 2011
University of Adelaide
There has been much research investigating incised valleys in marine environments, however, minimal research has been done investigating incised valleys formed in dryland environments. Incised valleys are of specific interest to the hydrocarbon industry because they may fill with sediments which can form hydrocarbon reservoirs. Potential incised valleys have been identified around Lake Eyre, Australia. This research project will investigate whether they are indeed incised valleys or not. If shown to be incised valleys, they may be the first incised valleys in a modern playa environment to be documented. This project provides quantitative data describing these valley features and discusses their use as reservoir analogues.
Geographic Information Systems (GIS) software and satellite images were used to map in detail the depositional elements of the proposed incised valleys. The mappable depositional elements were: first, second and third order channels, floodplains, and terminal splay complex in three valley systems (river catchments). The maps of the incised valleys were then used to measure the geometric dimensions of the valleys.
The depositional elements of three river systems were successfully mapped in detail during this research project. The geometries of these river systems and their depositional elements were calculated and summarized into useable tables and charts. This geometry data will provide useful information about the previously undescribed systems which will be useful as a reservoir analogue for hydrocarbon exploration and production
This project found that the proposed incised valleys are indeed incised valleys. This is due to two main reasons: Firstly, the proposed incised valleys have a shape characteristic of incised valleys; secondly, Lake Eyre is known to have had lake level changes, so it is plausible to assume that incision occurred during these lake level falls. Further investigation using elevation data to link the previous lake levels to the geological features of the proposed incised valleys is required for further certainty that they are truly incised valleys.