Mariana Resources Ltd Sierra Blanca IP survey results
MARIANA RESOURCES LIMITED
AIM and PLUS code: MARL
7th November 2007
IP/Resistivity surveys delineate a large system of prospective
silicified structures at Sierra Blanca, Santa Cruz Province,
Argentina
Mariana Resources Limited (Mariana) has received interpreted results
for four grids of gradient array IP and Resistivity surveys
(totalling 55 line kilometres) completed at the Sierra Blanca
Project, Santa Cruz, Argentina. The report from Quantec Geoscience
(geophysical contractors and consultants) states "The gradient IP and
resistivity surveys appear to have detected and delineated a large
system of prospective silicified structures. The density of
interpreted veins appears to be very high, significantly greater than
usually encountered on these types of projects in Patagonia.
On October 15th. 2007, Mariana announced that bonanza grade gold and
silver mineralisation had been discovered at the Veta Chala Vein
located in the NE part of the concession after the IP survey was
completed (see Figure 1). Assays of rock chips taken across vein
outcrops yielded up to 17.8 g/t (grams/tonne) gold and 518 g/t (17
ounces/tonne) silver. Results of follow up diamond saw channel
sampling at Veta Chala are awaited.
In general, IP chargeability effects are often observed in
low-sulphidation epithermal systems as a result of the presence of
sulphides (usually pyrite) in the rock. High electrical resistivity
in such systems is typically caused by silica filling pore spaces and
voids. Chargeability and resistivity together, can be effective in
detecting epithermal veins, particularly in the Patagonian
environment.
In excess of 40 resistive lineaments have been identified at Sierra
Blanca, with an aggregate strike length of 24 kilometres, many of
which have coincident chargeability lineaments. (A synthesis of
lineaments overlain on resistivity images is shown in Figure 2). Some
of these resistivity lineaments correlate with outcropping quartz
vein zones, confirming the interpretation in these areas. A pattern
of brittle fracture and displacement is exhibited by the interpreted
lineaments, which is considered to be very significant, as key
exploration targets may be structural intersections at which
silicification has taken place.
Significantly, resistivity trends in the southernmost part (Vetarron)
are coincident with strongly northeast trending silicified and
brecciated wall rocks which outcrop over an area up to 200 metres in
width and 2 kilometres in length. The IP survey interpretation
indicates the Vetarron vein system extends further east for up to 800
metres under thin cover of recent volcanic ash. Previous limited rock
chip sampling of the main outcrop obtained up to 1.6g/t gold.
Commenting today, Managing Director, John Sutcliffe said: These
geophysical results indicate that we could well be dealing with a
large but poorly exposed mineralized system at Sierra Blanca. This,
together with the recent high-grade vein discovery is most
encouraging. Only a small part of the area has so far been explored
by Mariana. On-going detailed geological mapping, soil/rock chip
geochemistry and trenching will assist in prioritisation of these
targets for drilling.
ON BEHALF OF THE BOARD
John Sutcliffe
Managing Director
For more information:
Mariana Resources Limited
John Horsburgh (Chairman)
+61 2 9437 4588
John Sutcliffe (MD)
+5932 298 6464
RFC Corporate Finance Limited (Nomad)
Rob Adamson
+61 2 9250 0041
Will Souter
+61 2 9250 0036
Conduit PR Limited
(Public Relations)
Laurence Read
+44 20 7429 6605
+44 797 9955 923
Ed Portman
+44 20 7429 6667
+44 773 3363 501
Haywood Securities (UK) Limited
(Broker)
Daniel Brooks
+4420 7031 8000
Or visit website at www.marianaresources.com
ADDITIONAL INFORMATION
The exploration programme is being directed by the Argentina
Exploration Manager, Dr Gustavo A. Rodriguez under supervision of
Managing Director Mr John Sutcliffe. The geophysical surveys and
interpretation were carried out by geophysical consultants Quantec
Geoscience. Samples were prepared by ALS Chemex in Mendoza,
Argentina, using standard industry practice. Analytical work was
carried out at the ALS Chemex laboratory in Santiago de Chile, using
conventional fire assay technique for gold and silver. Exploration
information in this announcement has been compiled by John Sutcliffe
who is a Fellow of the Geological Society of London, a Chartered
Engineer and a Member of the Institute of Mining and Metallurgy. Mr
Sutcliffe has sufficient experience relevant to the style of
mineralisation and types of gold deposit under consideration and to
the activity that he is undertaking to qualify as a Competent Person
as defined in the JORC Code.
---END OF MESSAGE---