Summary:
The Goschen Central Project includes fine-grained sheet-style HMS mineralisation, interpreted to have been deposited in an off-shore environment. Fine grained, off-shore HM deposits in the Murray Basin are often referred to as WIM-style deposits.
WIM-style deposits have been long recognised as rich potential sources of zircon and titania products (rutile, ilmenite, leucoxene), however more recently have been acknowledged for their significant rare earth element content, held in the minerals monazite and xenotime.
Heavy mineral mineralisation at Goschen Central is of a fine-grained sheet geometry, interpreted to have been deposited in an off-shore environment. Fine grained, off-shore HM deposits in the Murray Basin are often referred to as WIM-style deposits.
The Goschen Central project is located in the Murray Basin of south-eastern Australia. The Murray Basin is a low-lying, saucer-shaped intra-cratonic depression containing thin, flat-lying Cainozoic sediments. It extends approximately 850 km from east to west and 750 km from north to south, covering an area of 300,000 km2 of south-western New South Wales, north-western Victoria and south-eastern South Australia.
A Tertiary succession of freshwater, marine, coastal, and continental sediments including HM were deposited in the basin. Much of the sedimentary sequence is the result of repeated marine incursions from the southwest, with the latest transgression-regression event resulting in deposition of the Late Miocene to Late Pliocene Loxton Sand (previously named the Loxton-Parilla Sand).
The Loxton Sand was deposited in shallow-marine, littoral, and fluvial conditions and comprises fine to coarse-grained, commonly moderately well-sorted sand with minor clay, silt, mica, and gravel and is the host sequence to all the known heavy mineral sand deposits in the Murray Basin. These deposits are of two principal types: the coarser-grained smaller “strand-style” occurrences and the finer-grained large WIM-style (e.g. Goschen Central).
The WIM-style deposits, named after the Wimmera area of the Murray Basin, consist of a solitary or composite broad, lobate sheet-like body of considerable aerial extent, highly sorted and associated with fine micaceous sand. These deposits are thought to represent accumulations formed below the active wave base in a near-shore environment, possibly representing the submarine equivalent of the strand-style deposits. The WIM-style deposits are considerably larger in tonnage and lower in grade than strand-style deposits.