Research conducted by scientists has revealed the presence of what may be the world’s largest known impact structure in southern New South Wales. This discovery surpasses the previously considered largest impact structure, the Vredefort impact structure in South Africa. The Deniliquin structure measures up to an astounding 520 kilometers in diameter.
The history of Earth’s bombardment by asteroids has remained largely hidden due to erosion and burial by sediment or subduction. However, recent geophysical discoveries are providing valuable insights into the Earth’s early history by uncovering signatures of impact structures and ejecta materials.
Studies have shown that some large impacts have been associated with mass extinction events. The Alvarez hypothesis, for example, explains the extinction of non-avian dinosaurs as a result of a massive asteroid impact. The Australian continent has been targeted by numerous asteroid impacts, with 38 confirmed and 43 potential impact structures.
The existence of the Deniliquin structure was first suggested by Tony Yeates in the 1990s. It was only recently confirmed using updated geophysical data collected between 2015 and 2020. Magnetic patterns and readings have revealed a symmetrical rippling pattern, a central low magnetic zone, radial faults, and small magnetic anomalies, all of which are characteristic of large impact structures.
However, in order to obtain further evidence of the impact, drilling deep into the structure is necessary. This would help determine the exact age and nature of the Deniliquin structure. Researchers speculate that it occurred during the Late Ordovician mass extinction event, which wiped out approximately 85% of species. Alternatively, it is also possible that the structure is even older, with an early Cambrian origin.
Additional studies and drilling will be crucial in shedding more light on the Deniliquin structure and its implications for Earth’s history. The discovery of this massive impact structure in southern New South Wales highlights the ongoing efforts of scientists to unravel the mysteries of our planet’s past.