Projects - Australia
Tarrawarra Project (100%)
The project is situated in Cretaceous sediments of the Central
Carnarvon Basin. The
local geology is dominated by the Gearle Siltstone which is part of
the Winning Group. The
Gearle Siltstone consists of carbonaceous and pyritic siltstone and
claystone. Bentonitic
claystone, barite nodules and secondary gypsum characterize the
formation, which is rarely well exposed.
The silver and lead-zinc mineralisation is believed to have
formed above the Giralia Lineament in a favourable black siltstone
environment and is structurally controlled, being related to
lineaments associated with the Giralia Lineament.
The axis of the Marilla anticline corresponds to the Giralia
Lineament.
The Giralia Anticline-fault is part of a major lineament which
extends to the south and intersects the Northampton Block in the
region of Kalbarri. In
the Northampton Block, the Pre-Cambrian basement outcrops and
contains extensive, but small base metal deposits.
At one stage, the Northampton area was Western Australia's
largest lead-silver producer.
Within EL 08/1737 the depth of basement is believed to be
2000-4000 metres (relatively shallow) and may be the source of the
mineralisation at Tarrawarra.
It is considered that superficial sulphide mineralisation at
Tarrawarra may represent a large tonnage base metal deposit of a
type that has not been previously recognised in Australia.
The mineralisation environment may be hot artesian waters in
a relatively shallow environment. Systems of this type have been
discovered in Tadzhikistan, where large tonnages of silver, zinc,
lead, thallium, barium and strontium were deposited by <100oC
ground waters in a carbonaceous shale.
Geophysics and drill testing is warranted because:
Ú Geochemical
anomalies at surface (particularly for silver) are significant.
Ú The
scale of the anomaly is significant – regionally 35km long and up to
5km wide.
Ú Marcasite
is the main iron sulphide rather than pyrite – at indicator of low
temperature mineralisation.
Ú The
presence of a favoured horizon, in this case a carbonaceous, gypsum
rich siltstone.
Ú The
relatively high temperature of the groundwater in the local area.
Ú The
presence of a large lineament, forming a prominent NNE trending
structural corridor from (approximately) Onslow to Carnarvon.
In addition to silver and base metal potential, previous
reconnaissance drilling, particularly by CRAE has confirmed the
potential for near-surface phosphate mineralisation.
Proposed work includes surface sampling; gravity and EM surveys;
re-evaluation of ASTER data, and should appropriate targets be
resolved, undertake a program of RC drilling.