The age and sediments source of the Amadeus Basin Cryogenian-Ediacaran stratigraphy

Abstract

The Amadeus Basin is a big intracratonic elongate basin that is mainly exposed in the Northern Territory. Sedimentation in the basin began in the Neoproterozoic and ended in the Late Devonian/Early Carboniferous. The Amadeus Basin stratigraphy, age and source of sediments are not well constrained. This study attempts to better constrain the age and sediment sources for the Johnnys Creek formation, Areyonga Formation, Pioneer Sandstone, Pertatataka Formation and Arumbera Sandstone.

U-Pb detrital zircon analyses were conducted using the Laser Ablation Inductively Coupled Plasma Mass Spectrometry technique (LA-ICP-MS) along with Hf isotopic analysis. The U-Pb data constrained the depositional age of the Pertatataka Formation and Areyonga Formation with a maximum depositional age (derived from the youngest zircon grain) of 651 ±19 Ma and 683 ±20 Ma respectively. The main source of sediments for the Arumbera Sandstone, Pertatataka Formation and Areyonga Formation is the Musgrave Province, while it is the Arunta region for the Pioneer Sandstone. This interpretation is based on peaks of zircon ages plotted as a probability density function. The epsilon Hf data yielded positive and negative values across the ages of all formation. This is indicative of a mix of juvenile and recycled crust host magmas.