Strelley pegmatite, Strelley Station, Port Hedland Shire, Western Australia, Australiai

Regional Level Types
Strelley pegmatite	Pegmatite
Strelley Station	- not defined -
Port Hedland Shire	Shire
Western Australia	State
Australia	Country

64 kilometres south-east of Port Hedland. The track to the pegmatite is twelve kilometres south from the Great Northern Highway along the Marble Bar Road, and is on your right as you travel south. The track travels south-west for 6.5 kilometres, and the pegmatite can be seen as a low ridge to the south side of the track. A four wheel drive vehicle is essential.

Mining started for alluvial cassiterite here in 1916, recovering thirty-five tonnes in that year. The pegmatite was mined again from 1928 to 1938 for cassiterite and tantalite, organised by Lady Deborah Hackett-Moulden of Adelaide, who was also involved with the Wodgina mine further west. Mining continued in 1943 by the Commonwealth Government as part of its war-time effort. Five tonnes of beryl was also collected the following year. All mining had been to this point alluvial material.

After the Second World War, the location was returned to Lady Hackett-Moulden but a lack of funds saw it sold to Northwest Tantalum Ltd, but they also abandoned ownership of it in 1955, viewing the deposit as uneconomic.

J.A. Johnson and Sons Pty Ltd purchased the pegmatite in 1967, then sold it soon after to Avela Pty Ltd, who in turn leased it to Goldrim Mining in 1968. By 2000, Sons of Gwalia had gained control of the site.

The pegmatite is largely intact with two small badly collapsed pits, and the concrete foundations of a water tank, the only mining evidence. A D9 bulldozer has ripped the surface of the pegmatite, but this only makes it easier to fossick.

The pegmatite is 700 metres long,25 to 200 metres wide and 150 metres thick, trending north-east to south-west, dipping almost vertically.

The zones are several quartz core segments, microcline-quartz zone, albite-quartz-microcline zone, muscovite greisen unit, and an albite-muscovite greisen unit.

Arrow shaped sub-centimetre sized tantalite and cassiterite crystals are found in the irregular fine grained albite-muscovite masses. The larger masses of tantalite have been pseudomorphed by microlite. Large grey and white beryl masses are found in the quartz-microcline masses, but the writer did not observe any crystals. Spessartine is also associated with the greisen.

The lithium phosphate masses at the pegmatite are unclear. It has been suggested by the reference as 'altered phosphate nodules with rims of sicklerite and purpurite around a core of tan lithiophilite'. Hureaulite,dufrenite, or apatite has been suggested as the white veinlets through the sicklerite. Purple lepidolite has been reported from the pegmatite but tests concluded little lithium, and is viewed as a lithian muscovite.

The Strelley Pegmatite is located between two mining projects held (in 2016) by Lithium Poer International Ltd, being the Strelley Project to the North and the Tabba Tabba Project to the South.

Strelley Station comprises a group of pastoral leases - primarily cattle.

Geochronology

Mineralization age: Mesoarchean : 2924 ± 120 Ma to 2836 ± 26 Ma

Important note: This table is based only on rock and mineral ages recorded on mindat.org for this locality and is not necessarily a complete representation of the geochronology, but does give an indication of possible mineralization events relevant to this locality. As more age information is added this table may expand in the future. A break in the table simply indicates a lack of data entered here, not necessarily a break in the geologic sequence. Grey background entries are from different, related, localities.

Geologic Time				Rocks, Minerals and Events
Precambrian
	Archean
		Mesoarchean		ⓘ Cassiterite (youngest age) 2836 ± 26 Ma ⓘ Cassiterite (oldest age) 2924 ± 120 Ma

Other Regions, Features and Areas containing this locality

References