Mariana Resources Exploration Update Southern Argentina and Northern Chile

VANCOUVER, BRITISH COLUMBIA -- (Marketwire) -- 03/05/12 -- Mariana Ltd ('Mariana' or 'the Company') (TSX: MRY)(AIM: MARL)(PLUS: MARL), the AIM and TSX quoted exploration and development company focused on Argentina and Chile, is pleased to update progress at its precious metal Los Amigos Joint Venture in Southern Argentina and precious metals and Iron Oxide Copper Gold ('IOCG') exploration projects in Northern Chile.

Overview

--  Scout diamond drilling at Los Amigos Joint Venture (S. Argentina -
    Mariana 49%) intersected shallow gold mineralisation at the Bajo target
    with 10.2m @ 1.2 g/t Au & 7 g/t Ag from 9.2m

--  Mapping at Jiguata (Chile, Region I - Mariana option on 100%) indicates
    a shallowly eroded lithocap with potential for high sulphidation gold-
    silver at depth and possibly deeper porphyry type copper-gold-molybdenum

--  Corcovado area applied for (Chile, Region II - Mariana 100%) along the
    Palaeocene Gold Belt, prospective for low sulphidation gold deposits

--  Mariana elects to dilute to 23.5% of Tierra Noble SA (Cliffs 76.5%) with
    IOCG exploration on-going (Chile, Regions II & III)

To view the figures referred to in this report click on the following link:

http://www.marianaresources.com/pdf/release/Mariana_120305.pdf

Executive Chairman John Horsburgh said, 'The gold intersection at Bajo and new Amigos target in the Los Amigos JV are encouraging. While Mariana's main objective remains its core projects in Santa Cruz Province, Argentina, the Company's focused programme for epithermal precious metals in Northern Chile is highlighted by the Jiguata Project while maintaining exposure to 'company-maker' copper-gold exploration operated and funded by Cliffs.'

Los Amigos JV (Mariana 49%)

JV operator Hochschild Mining plc ('Hochschild') focused on the Bajo target area in 2H 2011 with scout diamond drilling, drill core alteration mapping and field/data reviews completed, following Induced Polarisation ('IP') lines (34 line km), magnetic surveys, mapping and rock chip sampling. The IP traversed NW and WNW magnetic lineaments and Amigos, Gator and Bajo vein systems (Figure 2). Bajo (Figure 3) consists of a 5 km x 2km target area with quartz veining, silicification and epithermal-style alteration, in the western JV area (Figure 1). Ignimbrites and tuffs host quartz veins up to 1m wide with coincident chargeability anomalies, magnetic lows and strongly elevated molybdenum, gold, silver and arsenic in rock chips. Problems caused by ground conditions and poor access after snowfalls substantially delayed completion of the drilling. Best intersections were in hole LFD11-19 (Figure 3) with 3m @ 0.96 g/t Au and 4 g/t Ag from 0m and 10.15m @ 1.2 g/t Au and 7.4 g/t Ag from 9.15m, including 1m @ 6.9 g/t Au and 10.5 g/t Ag from 14.1m.

Mineralisation consists of poorly exposed breccias with chalcedonic quartz hosted by altered ignimbrite. Despite a single step-back hole (LFD11-23) not intersecting gold mineralisation down dip, hole LFD11-19 has flagged Bajo as a potentially gold-bearing system. Possible strike and plunge extensions are open.

Recent rock chip sampling highlighted the Amigos structure as a new priority target with rock chips up to 5 g/t Au and 680 g/t Ag in an untested area along a NW trending vein-breccia zone parallel to the main Amigos structure (Figure 4). Only eight holes to date have tested the 7.5 km trend, including three earlier holes by the JV (1m @ 1 g/t Au in LFRC09-009) and in 2005, Minera Andes drilled five holes with extensive hydrothermal breccias intersected.

Exploration under consideration for 2012 includes mapping, IP, trenching and channel sampling to define drill targets.

Jiguata (Option on 100%)

Mariana has an option to acquire the 5,600Ha Jiguata property from Catalina Resources PLC ('Catalina'), a UK-registered mineral exploration company (see News Release 19th July 2011). Jiguata is 150km east-northeast of Iquique in Northern Chile (Figure 5) at an elevation of 4,700m.

The property encompasses a 20 square km volcanic-hosted 'steam-heated' alteration zone indicated from satellite mapping and reconnaissance. The area is mostly Miocene-Pliocene andesites and volcanic breccias. Potential host rocks are mostly covered by younger volcanics and colluvium except for valley floors. Rock chip sampling has identified target areas, A, B and C/D (Figure 6). Previous exploration appears to have been limited to two inclined Reverse Circulation holes and trenching by The National Copper Corporation of Chile.

Recently completed geological mapping over a 7 square km area identified alteration patterns ranging from widespread advanced argillic, localised alunite-argillic to variable argillic-pyritic and features such as sheeted quartz veins and veinlets. The altered sector is interpreted to comprise a shallowly eroded intrusive or porphyry-related lithocap with potential for high sulphidation gold-silver deposits at intermediate level and possibly deeper porphyry type copper-gold-molybdenum mineralisation. More detailed alteration mapping, geochemistry, ground magnetics and particularly resistivity type surveys (CSAMT, IP/resistivity) to locate prospective resistive horizons at depth are under consideration, subject to landowner access agreements.

The Company has an option on a 100% interest in the Jiguata Project exercisable up to 1 December 2014, with scheduled payments totaling US$300,000 and a final option payment of US$1,200,000, payable on exercise. Catalina will retain a 2% Net Smelter Return royalty.

Corcovado (100%)

Corcovado comprises 4,800 Ha of exploration concessions in Region II, 90km east of Taltal. The project lies within the N-S trending 600km Palaeocene Belt, characterised by volcanic centres, collapse calderas, basaltic andesite to rhyolite volcanics and epithermal gold deposits such as El Penon, Cachinal and Guanaco. Corcovado is 35km south of Guanaco (Figure 7).

The project area was identified from Mariana's satellite image interpretation, as a favourable setting over the western margin of the collapsed Lidia Caldera. It hosts domes, alteration and low temperature quartz-chalcedony and opaline silica along a NNW structure (Figure 7).

The area is desert terrain (2,000m-2,400m elevation), with rock talus and caliche cover. The western third forms part of the Pampa Blanca Lidia. East of the project area are flat-lying pampas with remnants of historic nitrate mining operations. The area is dominated by a ring of low hills (caldera margin) made up of gently dipping hydrothermally altered Eocene volcanics on the inner slopes.

Within the caldera, scarce outcrops of quartz-chalcedony, opaline silica and volcanic breccia float are interpreted to be derived from hot springs, sinters and eruptive activity along a NNW trending structure.

Weak geochemical gold, silver and pathfinder anomalies are consistent with a high erosion level and together with indications of hot spring activity along structures, could indicate precious metal deposition at depth. Initial exploration will include ASTER interpretation, structural/alteration mapping and ground magnetics. Low sulphidation epithermal targets such as deeper resistive zones beneath quartz-chalcedony and opaline silica float would be tested by RC/Diamond drilling.

Tolita

Because of access problems to the Tolita property (SE of Copiapo) on the part of some landowners, it was decided not to proceed with the option agreement with the tenement holder.

SCM Tierra Noble (Mariana 23.5% Cliffs Natural Resources 76.5%)

SCM Tierra Noble ('Tierra Noble') is a joint venture company formed between Mariana and Cliffs Natural Resources Inc. ('Cliffs'), the operator, in 2010 to explore Mariana's Perro Chico and Buenaventura projects and any new properties along the Northern Chile IOCG Belt (see Figure 5). Mariana elected to dilute last quarter from its participating 30% to 23.5% in order to focus funds on its key projects in Santa Cruz, Argentina.

Perro Chico (Tierra Noble 100% option and own concessions)

Tierra Noble completed a 6-hole 2,675m diamond drilling programme in 2H 2011 to test geophysical anomalies (ZTEM and magnetic) mainly in the Belleza/Pancho/Mascara sector (Figure 8). Best intersections were in PC11DD04 and included 6m @ 0.26 % Cu, 0.2 g/t Au, 24.3 % Fe from 194m, 10m @ 0.22 % Cu, 0.2 g/t Au, 8.6% Fe from 338m, 8m @ 0.58 % Cu, 0.9 g/t Au and 20.8% Fe from 454m. Two holes, PC11DD05 (drilled in gravels for 302 m) and PC11DD06, were stopped for technical problems.

Buenaventura (Tierra Noble 51%)

A programme of eight core holes for 3,000m was completed at the end of last quarter at Buenaventura, mostly testing targets recommended by geological consultants Mira Geoscience. Targets were located in covered areas west and south of Cerro Brecha and east of Loma Negra (Figure 9). No significant Cu/Au/Fe mineralisation was detected, although in many of the holes chalcopyrite traces are present. The best intersection was in BV11DD06, at Amada, with 14m @ 0.5% Cu (oxide) from 112m.

At the end of 2011, SCM Tierra Noble had spent US$3M at Buenaventura, thereby giving it the right to exercise the option for 51% of the property.

ADDITIONAL INFORMATION

Exploration information in this announcement has been compiled by Vice-president, Exploration, Dr Gustavo Rodriguez (MAIG) and John Horsburgh who is a Fellow of the Australasian Institute of Mining and Metallurgy. It includes information supplied by Los Amigos Joint Venture operator Hochschild and SCM Tierra Noble operator Cliffs. Mr Horsburgh has sufficient experience relevant to the style of mineralization 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. Mr. Horsburgh is a Qualified Person within the meaning of National Instrument 43-101.

For further information please visit website at www.marianaresources.com.

About Mariana Resources

Mariana Resources Ltd is an AIM and TSX quoted exploration and development company with an extensive portfolio of gold, silver and copper projects in Argentina and Chile. In southern Argentina, in addition to the advanced Las Calandrias gold-silver project, the Company has the Sierra Blanca silver-gold project (100%); the Los Amigos joint venture (49%) with Hochschild Mining and staked a 215,000 Ha land package (100%) . All of these projects are located in the Deseado Massif epithermal gold-silver district in mining-friendly Santa Cruz province of southern Argentina, which hosts four mines and several advanced projects. In Chile, Mariana has a joint venture with US based international mining and natural resources company Cliffs Natural Resources Inc., to explore for iron oxide-copper-gold deposits ('IOCG') in a 92,000 km2 area ('SCM Mariana Area') in north-central Chile along the highly prospective Atacama Fault Zone. The SCM Mariana Area includes the 44km2 Buenaventura and 46km2 Perro Chico IOCG projects. Mariana is also evaluating a number of gold-silver and copper-gold opportunities independent of and outside the Cliffs JV area.

Safe Harbour

This press release presents 'forward-looking statements' within the meaning of Canadian securities legislation that involve inherent risks and uncertainties. Forward-looking statements include, but are not limited to, statements with respect to the future price of gold and other minerals and metals, the estimation of mineral resources, the capital expenditures, costs and timing of the resources, the realization of mineral reserve estimates, the capital expenditures, costs and timing of the development of new deposits, success of exploration activities, permitting time lines, currency exchange rate fluctuations, requirements for additional capital, government regulation of mining operations, environmental risks, unanticipated reclamation expenses, title disputes or claims and limitations on insurance coverage. Generally, these forward-looking statements can be identified by the use of forward looking terminology such as 'plans', 'expects' or 'does not expect', 'is expected', 'budget', 'scheduled', 'estimates', 'forecasts', 'intends', 'anticipates' or 'does not anticipate', or 'believes', or variations of such words and phrases or state that certain actions, events or results 'may', 'could', 'would', 'might' or 'will be taken', 'occur' or 'be achieved'.

Forward-looking statements are subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, performance or achievements of Mariana to be materially different from those expressed or implied by such forward looking statements, including but not limited to: risks related to international operations, actual results of current exploration activities; actual results of current or future reclamation activities; conclusions of economic evaluations; changes in project parameters as plans continue to be refined; future prices of gold and other minerals and metals; possible variations in ore reserves, grade or recovery rates; failure of equipment or processes to operate as anticipated; accidents, labour disputes and other risks of the mining industry; and delays in obtaining governmental approvals or financing or in the completion of development or construction activities. Although the management of Mariana believes that the expectations reflected in such forward-looking statements are based upon reasonable assumptions and have attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking statements, there may be other factors that cause results not to be as anticipated, estimated or intended. There can be no assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking statements. Mariana Resources does not undertake to update any forward-looking statements that are incorporated by reference herein, except in accordance with applicable securities laws.

NEITHER THE TSX NOR ITS REGULATION SERVICES PROVIDER (AS THAT TERM IS DEFINED IN THE POLICIES OF THE TSX EXCHANGE) ACCEPTS RESPONSIBILITY FOR THE ADEQUACY OR ACCURACY OF THIS NEWS RELEASE

Contacts:

In Australia:

Mariana Resources Ltd

John Horsburgh

Chairman

+61 2 94374588


Mariana Resources Ltd

Glen Parsons

CFO

+612 94374588
www.marianaresources.com


RFC Corporate Finance Limited (Nomad)

Rob Adamson

+61 2 9250 0041


RFC Corporate Finance Limited (Nomad)

Will Souter

+61 2 9250 0050


In U.K.:

Fox Davies Capital ( Co UK Broker)

Jonathan Evans

+44 20 3463 5000


St Brides Media and Finance Ltd (PR)

Felicity Edwards

+44 20 7236 1177


Ambrian Partners

Klara Kaczmarek

+44 20 7634 4725


In Canada:

Mariana Resources Ltd (Vancouver Office)

Kathryn Witter

+1 604 669 9336


Renmark Financial Communications (PR)

Arash Shahi

+1 514 939 3989