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Eucla Basin - Heavy Mineral Sands

South & Western Australia

 

 

 

 

 

 

 

 Aerial view over Cyclone HM Deposit - WA                        Ooldea Range section of Project - SA

 

Overview

The Eucla Basin is a large sedimentary basin located in the central part of the southern region of Australia. It extends over a vast area stretching from the southeast coast in Western Australia and from the southwest coast of South Australia northward through to the boundary of the Nullarbor Plain with the Great Victoria Desert.

The basin contains continental and marine Cainozoic sediments ranging in age from 140 million years to the near present time. These sediments cover an area is in excess of 400 000 km2, both onshore and offshore beneath the Great Australian Bight of the Southern Ocean.

 

Regional Geology

The Eucla Basin extends along, and underlies, the Great Australian Bight from Israelite Bay in the west to Fowler's Bay in South Australia to the east. The onshore areal extent in Western Australia is around 172 000 km2. The Basin onlaps the Albany-Fraser Orogen to the east which is made up of Proterozoic granites and layered basic intrusives intruding Archean metamorphics. To the north and northwest the sediments onlap the mostly Permian Officer Basin which is made up of marine and continental sediments with strong glacial influences.

There are Eocene Paleodrainage systems that enter the basin on the northwestern margin. These carry sediments from the southern West Australian Shield. The overall thickness of sediments is thought to be less than 750m although the northern areas may be thicker than this.

   

The marine and continental sediments of the Eucla Basin range from late Jurassic Cretaceous to Tertiary and Quaternary in age. The Eocene epoch is one of several periods of marine transgression of the basin (37 Ma). There has been at least one subsequent major transgression in the Miocene (10-15 Ma). The Eocene sediments are known as the Pallinup Siltstone to the south and the Hampton Sandstone and the Wilson Bluff Limestone to the north. Eucla Mining has discovered heavy minerals in beach and dune deposits of the Pallinup Siltstone in the Bremer Bay (up to 5.2%) and Balladonia Areas (0.8%). The Hampton Sandstone in the Plumridge Lakes area was targeted for heavy minerals by Elmina NL in the late 1980's early 1990's. They also targeted the fluvial to paralic Miocene sediments of the Plumridge Formation.


The Geological survey of WA 1:250 000 mapping programme in the area has produced the best source of regional geology from the area. D.C. Lowry mapped part of the area in 1965-1966 and a later phase completed the mapping in 1970-1972 with W.J.E van de Graff from GSWA and M.J.Jackson and P.J.Kennewell from the then BMR. The maps were produced from aerial photography with a few ground traverses taken also. The interpretations of units in the more remote areas could be suspect. Significant deposits of coastal sediments are interpreted in most areas near the edge of the Eucla Basin, mostly identified as the Plumridge Beds. Many of theses sediments are covered by aeolian sands.

 

Company Exploration  

Diatreme has established good relations with the traditional owners over its exploration tenements in both Western Australia (the Pila Nguru Spinifex People) and South Australia (the Maralinga Tjarutja People). Negotiations led to the signing of exploration access agreements over the traditional lands and to the involvement of local community members in assisting the Company's exploration efforts through cultural heritage surveys and the provision of contract services for the construction of access tracks.

Exploration to date resulted in the identification of an Inferred Heavy Mineral Resource at the Cyclone Deposit in Western Australia, as detailed in releases to the ASX over the period July 2007 to February 2008. Work is ongoing and further drilling is being conducted in the area during 2008 to establish the extent of mineralisation.

 

Photograph Gallery

Drilling underway at Cyclone Prospect, WA   


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