April Tech Talk - Recently Discovered Asteroid Impact Structures
Recently discovered asteroid impact structures in Archean greenstone belts near Kalgoorlie, Ora Banda and Coolgardie.
About this event
The Ora Banda and Meyers asteroid impact structures are located in the heart of gold and nickel exploration and mining centres, but have only been recently recognised as unusual structures formed by significant asteroid impacts by using high resolution geophysical survey methods and drilling information acquired during routine mineral exploration programmes by Evolution Mining and Focus Minerals.
Geophysical surveying has revealed distinctive circular features supporting asteroid impact origins, and explains the geometry of a simple crater about 150m deep and 800m across at the Meyers Crater in Coolgardie, which is filled with over 100m of peat material, and a complex crater geometry at Ora Banda due to its large size, where a +60m deep ring-shaped crater moat formed around a central uplift zone.
Review of diamond core and mapping from within these crater structures has confirmed their impact origins, which is primarily based on polymict and angular suevite breccia containing abundant glass droplets, shocked quartz, shatter cone textures, and pseudotachylite glass formed along reactivated faults.
Based on crater fill sediments containing abundant plant material and microfossils, preservation of glass droplets, the level of erosion and nature of regolith cover, the Ora Banda crater is likely Cretaceous and the Meyers crater is likely Pleistocene-Miocene.
Dr Jayson Meyers
Kalgoorlie Country Club
108 Egan Street
Kalgoorlie WA 6430
Thursday, 15 April 2021
6.15pm – 9.15pm (UTC+08:00)