Ecometals Announces Assay Results for Hole RZDDH10-06 and Drilling Update, Rio Zarza Gold Project, Ecuador
TORONTO, ONTARIO -- (Marketwire) -- 08/16/10 -- Ecometals Limited (TSX VENTURE: EC)(BERLIN: GDQ)(FRANKFURT: GDQ) -
Ecometals Limited announces receipt of analytical results from drill hole RZDDH10-06 and preliminary results from RZDDH10-07 on the Rio Zarza gold project in Ecuador. Geochemical results from hole RZDDH10-06 indicate anomalous Au, Ag, As and base metals in the Suarez Fm. Five composite samples are above the anomalous threshold, including 0.96ppm Au/2m and 2.62ppm Au/2m, and these are attributed to mineralized clasts of granodiorite and QF porphyry in the Suarez Fm conglomerate which are transported from source by sedimentary processes. Silicification and sulphide alteration indicate this hole is located in the distal hydrothermal alteration halo.
Hole RZDDH10-07 was drilled in section from hole RZDDH10-03A with the objective of determining the width of the strong hydrothermal alteration at the sub-Suarez unconformity. Hole RZDDH10-07 encountered the characteristic distal hydrothermal alteration halo.
Although no economic grade gold of an epithermal source has been intersected to date in the northeast part of the basin, the geological evidence for mineralization is strong and encourages further and persistent exploration.
The conceptual exploration model for mineralization is supported by and is refined with new drilling information. Important new factors believed to be controlling mineralization are considered to be:
-- Drill hole RZDDH10-03A intersected the best indication of hydrothermal
mineralization thus far. Massive quartz and clay alteration enclosed in
an alteration halo comprising silicification, sulphides and haematite is
characteristic of a mesothermal event, later overprinted by zoned veins
characteristic of epithermal style mineralization.
-- The lack of economic grade gold mineralization in this intersection is
attributed to close proximity to the causative deep (quartz-feldspar
porphyry) intrusive, where mineralizing fluids would be too hot for
precipitation of gold and associated metals, and the porous nature of
the Suarez Fm which is more conducive to disseminated style
mineralization.
-- The Misahualli Fm volcanics exhibit brittle deformation displaying
fractures which focus hydrothermal fluids forming high grade vein type
mineralization
-- The Suarez Fm sediments act as a thermal sink for hydrothermal fluids,
and the meteoric and connate basin water react with the ascending
hydrothermal fluids to deposit mineralization.
-- A thicker sequence of Misahualli and Suarez Fms towards the centre of
the basin therefore offers more vertical room and a more conducive
environment for epithermal mineral deposition
-- Mineralized clasts of granodiorite and QF porphyry in the Suarez Fm
conglomerate support the genetic model of a deep-seated intrusive as the
source of mineralization
Additional exploration targets are being developed both in the southern part of the Suarez-Misahualli basin and to the west in the area underlain by the Zamora Batholith.
Highlights of RZDDH10-06
-- ALS Chemex analytical results from diamond drill hole RZDDH10-06
indicate geochemically sub-economic anomalous zones with intersections
of gold, silver and base metals.
-- Five composite samples over 2m have anomalous Au over 50ppm threshold,
including 0.96ppm Au/2m and 2.62ppm Au/2m, all hosted by Suarez Fm
sediments. Anomalous Au is attributed to pyrite and chalcopyrite
mineralized granodiorite and QF porphyry clasts in the conglomerate,
which supports the geological model of a deep intrusive source of
mineralization.
Summary Geology RZDDH10-06
-- Drill hole RZDDH10-06 was located at UTM777673E/9583463N (PSAD56/UTM17S)
elevation 1586m, azimuth 315 degrees and inclination -70 degrees
-- The hole intersected 123.9m Hollin Fm sediments, Fruta Andesite to
262.4m, and then Suarez Fm polymictic conglomerate to 587. From 587.4 to
598m Suarez sediments are interlayered with Misahualli Fm porphyritic
andesite, followed by 598 to 651.4m of massive Misahualli Fm andesite
-- The lower Suarez Fm contains abundant chert/chalcedony clasts which may
represent silica sinter, the submarine surface expression of
hydrothermal activity
-- The alteration comprises pervasive argillic (chlorite-epidote-carbonate)
overprinted by haloes of silicification and sulphides and carbonate
veins representing a hydrothermal system
-- Five composite samples over 2m have anomalous Au over 50ppm threshold,
including 0.96ppm Au/2m and 2.62ppm Au/2m, all hosted by Suarez Fm
sediments. Anomalous Au is attributed to pyrite and chalcopyrite
mineralized granodiorite and QF porphyry clasts in the conglomerate.
-- Mineralized granitoids are probably derived from deep-seated intrusions
which are the causative body for higher level epithermal mineralization.
This evidence supports the genetic geological model and local
mineralizing systems.
Summary Geology Hole RZDDH10-07
-- Drill hole RZDDH10-06 is located at 777422E/9582835N (PSAD56/UTM17S),
elevation 1586masl, azimuth 315 degrees and inclination -70 degrees
-- Intersected 0 to 94.75m of Hollin Fm sandstone, shale and carbonaceous
mudstone, 94.75m to 435.10m Fruta Andesite, pervasive propyliitic
alteration with zones of carbonate-alunite-silica veins
+/- chalcopyrite
-- From 435.10 to 501.8m Suarez Fm polymictic conglomerate, sandstone,
wacke and carbonaceous mudstone, conglomerate clasts dominantly
granodiorite and quartz feldspar porphyry and minor chert and volcanics.
Alteration zones include illite-smectite-chlorite and silicification
with disseminated and veinlet pyrite and chalcopyrite. The Suarez and
Misahualli volcanics are interfingered at the base of the sequence, and
a significant fault zone was encountered at 490 to 500m.
-- From 501.8m to 613.3m is variously silicified, carbonate veined,
propyllitic altered porphyritic andesite of the Misahualli Fm
-- Alteration assemblages indicate this is in the distal hydrothermal halo
The main characteristics comparing the Rio Zarza results to Fruta del Norte are shown below.
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Fruta
Rio del
Feature Characteristic Zarza Norte
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Exploration Surface geochemisty YES YES
Geophysical signature
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Host Rocks Unconformity between Misahualli
volcanics and Suarez sediments YES YES
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Structure Pull-apart extensional basin YES YES
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Alteration Distal propyllitic and central
argillic haloes surrounding
quartz vein core YES YES
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Veins Chalcedony, colloform zoned
quartz veins YES YES
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Brecciation Hydrothermal brecciation YES YES
evidence of boiling
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Economic Au - Ag, +/- Pb - Zn YES YES
Minerals associated with sulphides
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Economic Grade Exceeding 1g/t and NO YES
and dimension 500Koz resource
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Style of Low grade disseminated
mineralization envelope with YES YES
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high grade veins at core NO YES
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Incidental Clasts of mineralized YES YES
material in Suarez
Hollin Fm cover
Proximal late stage
porphyry
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Next Drill Hole RZDDH10-08 Location and Other Targets
The next drill hole is located approximately 150m northeast and along strike of Hole 03/03A, at 777652E/9583023N (PSAD56/UTM17S) elevation 1585m. This hole is planned to intersect the same strong hydrothermal mineralized zones in hole RZDDH10-03A to determine the strike continuation of the zone and vector to the central core of the system. The target is a strong IP chargeability anomaly in the Suarez-Misahualli complex indicative of sulphides in the mineralized alteration halo.
On completion of this hole, the Company will have drilled approximately 4700m in 8 holes to total depth.
Approximately half of the Suarez-Misahualli volcano-sedimentary basin is present south of the Rio Blanco, in the southeast corner of the property. This area is towards the centre of the basin, with depth to the sub-Suarez unconformity estimated in excess of 600m depth. This will require additional deep-looking geophysical surveys (Time Domain EM) and deeper drilling capacity. This area offers similar potential for epithermal gold mineralization analogous to Fruta del Norte which has yet to be tested.
In addition to the Suarez-Misahualli basin, other targets on the western side of the project underlain by the Zamora Batholith are being investigated. Trenching on soil geochemical anomalies has located hydrothermal quartz veins indicative of mineralizing processes. On the western side of the project, the conceptual target is high grade polymetallic Au-Ag+Zn-Pb vein type mineralization analogous to the Chinapintza (on the Ecometals Condor gold and Dynasty Jerusalem projects), and the Bira Gold Mine in Portovelo-Zaruma. The Bira mine is currently the largest underground vein hydrothermal gold producer in Ecuador.
Sample Preparation, Analytical Protocol and Quality Control
Samples were taken from half core split with a diamond saw, and composited over 5m intervals in the Hollin Fm and 2m in the Suarez Fm. Composite samples were crushed to 70% passing 2mm and riffle split 250g subsample for pulverizing to 85% passing 75um for analysis.
Samples were prepared at the ALS Chemex sample preparation laboratory in Quito, and analysed at the ALS Chemex South American regional laboratory in Lima, Peru. Gold was assayed using the fire assay technique, and multi element analysis using ICP-MS.
Control samples are included in each batch of 100 samples, including 6 Certified Reference Material (CRM), 5 field duplicates prepared from quartered split core, and 4 blanks. CRM and blank material is internationally certified and supplied by Ore Research and Exploration (Pty) Limited (OREAS) in Australia.
Quality control results indicate there is no apparent analytical bias or systematic contamination of samples, and analyses are accurate compared to CRM stated performance criteria.
Qualified Person
SR McMullan, P.Geo, Vice President of Exploration for Ecometals Limited, is a qualified person according to National Instrument 43-101 definition and has prepared the technical information included in this press release. Drilling, logging, sampling and dispatch were under the direct supervision of the Qualified Person.
Chief Executive Officer Fran Scola said, 'Drilling in the northeast part of the volcano-sedimentary basin has not yet resulted in discovery of significant gold mineralization, although there is strong geological evidence of active hydrothermal processes. The potential of the southern part of the basin is prospective and remains untested. Additionally, new targets to the west are providing encouraging initial results for vein type mineralization.
The Rio Zarza project is by no means completely explored. Drilling results have confirmed the presence of hydrothermal mineralizing systems, and discovery is dependent on continued aggressive and focussed exploration.'
About Ecometals
Ecometals Limited is a TSX Venture Exchange listed mineral exploration and development company focused on mineral resources in Latin America. Ecometals has gold exploration projects in Ecuador and also significant manganese, iron and gold projects in Brazil at grass roots exploration and development planning stages.
Safe Harbor Statement: Statements contained in this release that are not historical facts are forward-looking statements which involve risk and uncertainties, which could cause actual results to differ materially from those expressed in forward-looking statements.
These include risks relating to changes in economic or environmental conditions and the company's ability to execute its business model and strategic plans. The company relies on litigation protection for forward-looking statements.
Alteration Haloes
Alteration facies in the Suarez-Misahualli basin on the east side of the Rio Zarza gold project are complex, as they overlap in time and space, are the result of weathering, diagenetic, volcanic and hydrothermal processes, and represent an evolving volcanic-hydrothermal system where both the host rocks and fluids are changing temperature and chemistry.
Distal hydrothermal alteration haloes comprise pervasive chlorite-epidote and haematite, intermediate alteration is typified by pervasive silicification and disseminated sulphides, and proximal alteration is hydrothermal brecciation, argillic (quartz-illite) alteration, quartz-carbonate veining and massive replacement quartz. The alteration assemblage is typical of a low sulphidation type epithermal system, although there are some characteristics of intermediate sulphidation type mineralization.
Chlorite-epidote-carbonate (propyllitic) alteration occurs as both pervasive replacement of porphyritic feldspar crystals and groundmass, and also as veins. The pervasive replacement event is widespread and represents the distal alteration halo. Vein chlorite-epidote-carbonate veins cut the pervasive event, and occur closer to the core of the system.
Pervasive haematite alteration in the Suarez Fm appears to be partly diagenetic and stratiform. However, the same alteration is observed both in the Misahualli and Zamora Batholith in the vicinity of the basin, which suggests this is spatially restricted to the area of the basin. Haematite is indicative of oxidizing meteoric water, which suggests a widespread zone of meteoric water percolation. Haematite also occurs in zoned veins and as martite alteration after magnetite, which is clearly hydrothermal origin.
Silica alteration is manifested as massive quartz replacement and breccia matrix, pervasive cementation, chalcedony/chert clasts, and as quartz veins, all of which are hydrothermal-related. Pervasive silicification is a proximal alteration halo, and the chert clasts are derived from submarine effusion of silica-rich hydrothermal fluids in a submarine environment forming a local and delicate sediment which is easily eroded. The massive quartz breccia and replacement intersected in hole RZDDH10-03A is formed at the core of a mesothermal hydrothermal vent. Quartz veins are relatively lower temperature (epithermal) event, are typically zoned with carbonate, chlorite and haematite, and overprint the massive mesothermal quartz.
Sulphides occur as primary (biogenic) carbonaceous sediments in the Suarez Fm, dissemination and veinlets in the Suarez and Misahualli, and in clasts and xenoliths of granodiorite and quartz feldspar porphyry derived from the Zamora Batholith. Disseminated-veinlet sulphides and clasts and xenoliths in the Suarez and Misahualli Fms are hydrothermal-related, but represent different age mineralizing events.
The dominant sulphide species is pyrite, with lesser marcasite, chalcopyrite and arsenopyrite. Chalcopyrite is generally associated with carbonate veins deeper in the section, and may be related to proximity to the underlying porphyritic intrusive and Cu abundance in the volcanics.
Sulphides are both spatially and geochemically associated with anomalous gold. Inter-element correlations indicate gold is correlated with silver, arsenic and sulphur, which means gold and silver are associated with pyrite and pyrrhotite. Anomalous Au intersections in holes 01, 03A, 04 and 05 are all within the IP Chargeability body, which represents a sulphide alteration halo.
Carbonate (primarily calcite) occurs as local discontinuous stratigraphic horizons in the Suarez Fm, and as veins. Calcareous mudstone (marl) units in the Suarez have a distinctive fine grained black coloured appearance with ladder calcite veinlets. The absence of carbonaceous material or fossil remnants in the calcareous mudstone suggests this is a chemical precipitate, possibly deposited from waters enriched in CO2 from degassing of hydrothermal fluids into a submarine environment. Carbonate veinlets are typical at the top of the Misahualli Fm andesite, and are probably a primary volcanic texture. Secondary calcite veins crosscutting the stratigraphic layers are of hydrothermal origin, with the occurrence and density of veins increasing towards the core of the system caused by upflow of hydrothermal fluids rich in CO2.
Magnetite alteration has been seen at the base of the Suarez Fm directly overlying the massive hydrothermal quartz zone. Magnetite alteration has also been noted in outcrop of the Suarez Fm along the Rio Blanco, which is presumably at a higher stratigraphic level, although the stratigraphy of the Suarez is indistinct. Magnetite is typical of a higher temperature assemblage more commonly associated with porphyry style mineralization. Magnetite destructive alteration is more commonly seen in the core of the hydrothermal system, but only occurs in host rocks with primary magnetite abundance.
Understanding the alteration haloes is key to vectoring to the centre of the mineralizing system, where high grade Au-Ag and base metals are deposited. Only the disseminated-veinlet sulphides and pervasive silicification have distinctive geophysical responses in IP Chargeabbility and resistivity respectively. Magnetite alteration would also have a magnetic response, but this cannot be discriminated from the response of the Fruta and Misahualli volcanics, which have a characteristic strong magnetic response.
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Contacts:
Ecometals Limited - Investors
Fran Scola
Chief Executive Officer
scola@lfmpartners.com
Ecometals Limited - Investors
Daniel Major
Chief Operating Officer
djmajor@ecometalslimited.com
Ecometals Limited - Information
Enquiries
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www.ecometalslimited.com