Month: June 2017

The areas of Ubirr and Nourlangie Rock I visited in May 2017 are dominated by the fluvial Kombolgie Formation sandstones and conglomerates. This sequence of sediments was deposited approximately 1.7 billion years ago by a braided river system flooding across a wide flat plain that had formed after a long period (~100 My) of erosion of even older rocks. The conglomerates seen at Nourlangie are the basal units of the Formation and the size of the quartzite pebbles indicates deposition by a high-energy river system. As the energy of the system decreased over time and with the increasing thickness of material deposited, the sediment able to be carried by the river became finer resulting in the upper units grading to sands.  Flash-floods would have occurred from time to time depositing thick layers of coarser sand, and cross-bedding is evident in places where river banks may have been over-topped.  Ripple marks…

I visited the Ranger Uranium Mine on Saturday 27th May as Energy Resources Australia (ERA) were holding a public Open Day.  Anti-uranium mining sentiment remains strong in the Territory to this day but the mini-buses for tours to the mine were full. The Australian Federal Government legislated for the development of the Ranger Mine in 1976 and, interestingly, the first stage of the Kakadu National Park (KNP) was declared in 1979.  So perhaps without the mine, there would be no KNP – a political compromise, perhaps? Traditional owners of the land on which the mine operates have been paid substantial mining royalties over the years. The town of Jabiru was originally built to accommodate the mine’s workforce in 1982 but also now acts as the service centre for tourism within KNP.  A 2007 study[1] estimated $15 million per year in tourism revenue was being contributed directly to the Top End…