Geological and Mining Potential of Ecuador

1. Geological and Mining Potential of Ecuador by: John E. Bolaños (P.Eng. Geologist, M.Sc., M.C.S.M., Q.P. Geo) March 2010
Gold Nugget of 300 g , from Rio Blanco, Azuay, Photo: RA Jemielita, 1992
Phreatic volcanic explosion, Pichincha volcano, 1999, Photo: Public Domain
Coarse placer gold, Napo River, 1999.
Photo: J. Bolaños

2. Ecuador Location Map Ecuador comprises 650 Km of the N portion of the Andes It is located to the N of the Huancabamba oroclinal deflection It is part of the Circum-Pacific Fire Belt

3. GEOLOGICAL AND MINING POTENTIAL OF ECUADOR
•The geological literature of Ecuador starts in 1892 when Teodoro Wolf published the study “Geography and Geology of Ecuador”.
•After Wolf, several authors published various geological papers describing geological and mineralogical targets in Ecuador (i.e. Holloway, 1932 among others).
•Later, during the 60´s to the 90´s, Ecuador signed international agreements for technical cooperation with several countries such as U.K., Japan, Belgium, Germany, etc.
•One of the most productive programs carried out in Ecuador was the “Environmental Control and Mining Development Project” (PRODEMINCA) carried out during 1997 and 1999 with the participation and financing of the World Bank and the Governments of U.K., Sweden and Ecuador.
BRIEF HISTORY OF THE GEOLOGY

4. Geological Map of the Republic of Ecuador, Scale: 1:1.000.000
British Geological Survey and CODIGEM , 1993

5. Tectono -Metallogenic Map of the Republic of Ecuador, Scale: 1:1.000.000
British Geological Survey and CODIGEM , 1993

6. Primary Auriferous Potential Map of Ecuador (Fungeomine – Capemine 2008)

7. Simplified geological map of the Andes of Ecuador, focusing on Tertiary arc magmatic units.
One main conclussions is: “The spatial- time distribution of the Cu porphyries and related epithermal mineralizations of the Peru metallogenic belts are very similar to those ones in Ecuador.
Inset adapted from Meschede & Barck- Hausen (2001); main map adapted from Litherland et.al. (1994), Steinmann (1977), Dunkley & Gaybor (1977), Mc Court et al. (1977), Pratt et al. (1997), Hughes et al. (1988), and Palacios et al. (2008).
(Ph.D. Thesis Geochronology, Gechemistry, and Isotopic Composition of Tertiary Porphyry Systems in Ecuador. Philip Shütte, 2010, University of Geneve)
GEOLOGICAL AND MINING POTENTIAL OF ECUADOR

8. GEOLOGICAL AND MINING POTENTIAL OF ECUADOR
From West to East Ecuador counts with 6 geo-structural domains:
1. The Fore Arc Basin of the Coast
2. Western Cordillera
3. Interandean Graven
4. Real or Central Cordillera
5. Eastern Subandean Zone
6. Back Arc Basin of Iquitos
(Figure after Litherland and Zamora 1991)
GEO-STRUCTURAL DOMAINS (Terranes)

9. GEOLOGICAL AND MINING POTENTIAL OF ECUADOR
•Is the lower and flat zone to the W.
•Cretaceous to Cenozoic basin underlain by aloctonous basaltic ocean crust (Ocean Piñon Terrane).
•Geo-mining potential:
Fe+Ti+PGMs sedimentary (Esmeraldas and Manabi)
Au+Fe+Cu placer deposits related to rivers on the W of the Western Cordillera.
Au+Sb+Hg+Ba Epi-Mesothermal deposits to the S of the Coast (El oro).
(Figure after Litherland and Zamora 1991)
1. The Fore Arc Basin of the Coast

10. GEOLOGICAL AND MINING POTENTIAL OF ECUADOR
2. Western Cordillera
• Mountain chain parallel to the Andean bearing.
• Located between the fore-arc of the Coast and the graven or interandean central valley.
• Formed by an accretionary prism mainly of ocean crust composition, continental crust and accreted Late Mesozoic to Cenozoic ocean terrains (Piñon, Pallatanga, Macuchi).
• It is overlain by calc-alkaline Post-Eocene continental margin volcanic sequences.
• Geo-Mining Potential:
Au+Pt placer deposits (i.e. rivers in Toisan Cordillera).
Au+Ag+Cu+Fe VHMS as those in the Macuchi Unit.
Cu+/-Au+/-Mo porphyry deposits (Imbabura, Bolivar and Azuay).
Au+ Cu High Sulphidation Epithermal Deposits (Macuchi Unit). (Figure after Litherland and Zamora 1991)

11. GEOLOGICAL AND MINING POTENTIAL OF ECUADOR
3. Inter-Andean Graven
•It is a graven valley bounded by regional faults with Andean bearing.
•Formed by thick and large Oligocene to Miocene volcano-sedimentary sequences that cover the Chaucha, Amotape and Guamote terrains with great mining potential.
•Au+Ag+/-Cu+As+Sb+Hg Epithermal deposits (Azuay and Loja).
•Cu+Mo+/-Au+/-Zn+/-Bi Porphyry deposits to the S of Ecuador
•Au+Ag+Cu+Zn+Pb Epi-Mesothermal deposits to the S of Ecuador.
•Sn+W associated to S type Granitoids in the Amotape terrain.
•Cu+Ni+Co+/-Cr+PGM´s deposits associated to ultramafic rocks and ophiolite complexes mainly in the Amotape terrain.
•Fe+Cu+Zn+/-Pb+Au VHMS related to the Amotape terrain.
•Cu+-Zn+Pb+Ba desposits related to granitoids on the Guamote division.
(Figure after Litherland and Zamora 1991)

12. •Formed by several litho-tectonic divisions of Andean bearing and separated by regional faults.
The Guamote division of flysch sediments, bounded eastwards by the ophiolitic Peltetec fault.
The Alao division, a mid-Jurassic oceanic island arc terrane bounded eastwards by the Baños fault.
The Loja division, a Triassic S-type biotite granite batholith with flanking semi-pelitic lithologies.
The Salado division of plutonic and island arc lithologies.
The Zamora division of continental plutonic and volcanic rocks.
In general it comprises Pre-Cretaceous metamorphic rocks intruded by S and I type intrusions.
This rocks are covered by Cenozoic volcanic.
(Figure Litherland et. al. 1994)
4. Real Cordillera

13. •Assosiated to the Alao Division are:
Ag+Au+Sb+Pb+Zn Epithermal deposits.
Fe+Cu+Pb+Zn+Ag+Au VHMS
Cu+Au+/-Mo Porphyry deposits
PGMs+Au deposits associated to mafic and ultramafic intrusions.
•Associated to the Loja Division (a Triassic S type intrusive) are:
Sn+W in S type granitoids.
Cu+Ag+Pb+Zn+Sn+/-W breccias bodies.
Au+Ag+Cu+As+Zn+Pb+Sb epithermal deposits.
•Associated to the Salado Division (plutonic and island arc lithologies) are:
Au+Cu+Mo+Pb+Zn skarn klippes.
Cu+Au epi-mesothermal deposits related to porphyries.
(Figure Litherland et. al. 1994)
4. Real Cordillera

14. GEOLOGICAL AND MINING POTENTIAL OF ECUADOR
•Summary of the Pre-Cretaceous geology of the Cordillera Real and sub-Andean zone (Jemielita and Bolaños, 1993)
DIVISION
(west to east)
GUAMOTE
P E L T E T E C F A U L T
ALAO
B A Ñ O S F A U L T
LOJA
L L A N G A N A T E S FA U L T
SALADO
C O S A N G A – M E N D E Z F A U L T
ZAMORA
SUBDIVISIONS /
LITHOLOGIES
Dark and pale orthoquartzites with slate/shale bands
Peltetec: dismembered
Ophiolite
Maguazo:
Turbidites.
Alao-Paute:
Andesitic green-stones, tuffs and sediments.
Tres Lagunas: biotite (garnet) granite and orthogneiss
Sabanilla: Ortho-and paragneiss, associated with semipelitic phyllites, schists and paragneisses.
Azafran: calc- alkaline batholith chain (diorite/granodiorite)
Upano: andesitic greenstones, tuffs black phyllites, graywackes and minor marbles.
Abitagua: calc-alkaline batholith chain.
Misahualli: andesites, dacites, basalts, and agglomerates.
Isimanchi: marbles and volcano-sedimentary rocks.
TECTONO METAMORPHIC STATE
Very low grade rocks overthrust W
Low grade rocks, steep fabrics, upright folds
Low to medium grade rocks thrust E with imbrications.
Low grade rocks thrust E with imbrications. High level skarnfield and serpentinite klippes
Essentially undeformed and unmetamorphosed
AGE
Upper Jurasic ?
Upper Jurasic (Callovian- Oxfordian)
? Triassic plutons in
?Palaeozoic sediments
Jurassic, with possible pre-Jurassic elements
Isimanchi: Triassic Igneous rocks: Jurassic
INTERPRETA- TION
Continetal sediments /
Clastic wedge
Ocean Floor, forearc and volcanic arc or marginal basin
S-type granites in
continentally – derived sediments
I-type plutons in volcano- sedimentary sequence
Continental I-type plutonic-volcanic arc

15. GEOLOGICAL AND MINING POTENTIAL OF ECUADOR
Possible collision model to account for the disposition of the individual lithotectonic divisions (Aspden and Litherland, 1991)

17. GEOLOGICAL AND MINING POTENTIAL OF ECUADOR
5. Eastern Subandean Zone
•It comprises the Eastern slopes of the Andes Cordillera.
•It is formed by forearc belt of the basement covered by volcano-sedimentary sequences.
•It is intruded by large “I” type batholiths.
•To the N of this zone there is the Cordillera del Cutucu, an uplifted zone that host important prospects of Au+Cu+other.
•To the S there is the El Condor Cordillera which counts with tremendous mineral discoveries of Au+Cu+U+others.

18. GEOLOGICAL AND MINING POTENTIAL OF ECUADOR
6. Back Arc Basin of Iquitos
•It comprises the Oriente or Amazonian basin mainly form by sedimentary and volcano-sedimentary sequences.
•It hosts the most important oil field of Ecuador.
•Associated to it there are important Au+Fe placer deposits.
•Si deposits are associated to some sedimentary formations.

19. Summary of the Mining Potential related to the geo-structural domains (BGS 1994 and Prodeminca 2000).

20. ORE DISTRICTS IN ECUADOR
•With PRODEMINCA (2000) five ore districts were described:
1. Azuay Distric (Cordillera Occidental and Cordillera Real),
2. La Plata District (Cordillera Occidental),
3. Imbaoeste (Cordillera Occidental),
4. Alao Paute District (Cordillera Real).
5.Zamora District (Cordillera del Condor).
(Figure Fungeomine, 2008)
3
5
4
1
2

21. Porphyry copper sub-belts of the northern Andes (Modified from Sillitoe, Prodeminca, 2000)
Porphyry Cu+Mo+/-Au deposits are occurring within the Azuay District (i.e. Chaucha, Gaby&Papa Grande, Fierro Urcu, others), Imbaoeste District (i.e. Junin) and Zamora Districts (i.e. San Carlos, Cumay, Tumi, El Hito&Santa Barbara, Mirador). Porphyry type mineralization and intrusion related epi-mesothermal mineralization are known to occur within the litotectonic terranes of the Andean Cordillera of Ecuador. Each district has been subdivided into mineralized belts and orefields. For example: The Azuay District (Collay Shincata Belt, Molleturo ore field and Ponce Enriquez Orefield), the Zamora District (Nambija Belt, San Juan Bosco orefield and Pachicutza orefield).

22. High sulphidation epithermal deposits (alunite-Kaolinite) have been encountered in the Azuay District (Gañarin Belt, i.e. Quimsacocha; and Collay-Shincata Belt, i.e. El Mozo , Asaray, Cerro Colorado and Loma Quipal projects). Some other occurrences of this type of mineralization have been described to the south in the Loja Province (i.e. La Encrucijada and Quinapalma projects) suggesting the extension of the Collay- Shingata belt to the south.
Low sulphidation epithermal deposits/systems (adularia-sericite) have been described also in the Azuay District (Molleturo orefield i.e. Beroen project; Gañarin Belt i.e. Gañarin project; and Collay-Shicata Belt i.e. La Encrucijada project).
(Figure Prodeminca 2000).
EPITHERMAL DEPOSITS

23. Volcanic hosted massive sulphides have been related to the La Plata District (i.e La Plata and Macuchi projects) located on the western slopes of the Cordillera Occidental. Another important district for VHMS deposits is the Alao- Paute District located In the Cordillera Real (i.e. Pilas, Cruzacta and Guarumales projects). This VHMS deposits are Sierran-Kuroko types. Macuchi is an exception because its characteristics of not being strataform. (Figure Prodeminca 2000).
VHMS DEPOSITS

24. MINING COMPANIES IN ECUADOR

25. COMPANIES OF THE CONMIN
Bananas: 24,000 tpa:
30% of world’s market
Source: UNCTAD
Oil: 538,000 bpd State oil company Petroecuador produces 170,000 bpd Source CIA
Gold: 91,000 oz in 2000 reported from artisinal miners, mainly Nambija
Source USGS
Corriente’s Mirador
430mt @ 0.6% Cu 0.2g/t Au
International Mineral’s Gaby 6.3m oz @ 0.63 g/t Au
Dynasty’s Zaruma 1.1 moz @14g/t Au
Iamgold’s Quimsacocha
3.3m oz @ 3.2 g/t Au
Undeveloped Properties
Aurelian’s FDN
13m oz Au @ 7.23 g/t Au

26. DEPOSITTYPEMINERALIZATIONRESOURCESAuAgJUNINCu-Mo-Agqtz-py-cpy-bn-moly veins in potassic&transition982 Mt @0.9%Cu, N/A60Structurally controlled emplacement of quartzporphyryto phyllic alteration0.04 % Mo, 1.9 g/t Aggranodioritic and dioritic porphyriesTELIMBELACu-Mocpy- py, moly associated with mt in qz not availableN/AN/Aqtz-dioritic porphyry&dykesporphyrystockworks and brecciasCHAUCHACu-Mocpy-py bn &late cpy-moly in qtz stockworks &>120 Mt @0.5% Cu,N/AN/Atonalitic batholith, qtz porphyriesporphyrydisseminations in potassic - phyllic zones0.03 % MoQUINSACOCHAepith. High-sulf.py-en related to advanced argillic altyeration zone3.3 M Oz @3.2 g/t Au, 3.3N/Aandesite flows + intra caldera dacitic domesAu-Cu-Ag(adakitic); typical high-sulf. Alteration zoningGABY-PAPAAu-Cu porphyryassociated with breccias (py, mt matrix) in potassic6.3 M Oz @0.63 g/t Au6.3N/Ahbl/plag. Porphiries+tonalite intrusionGRANDEor Na-Ca alteration zones& 0.12 % CuCAÑICAPAepith. High sulf.sulfides oxidized; Au anomalies not understoodnot availableN/AN/Apre-mineralization dacites and post-min. AndesitesAutypical high sulf.-type alteration zoningCANGREJOSAu-Cu porphyryAu associated with disseminated cpy (moly)not availableN/AN/Aqtz-dioritic to granodioritic intrusions punctured by andesites + breccias; roots of eroded statovolcano? PORTOVELOporphyry &py-cpy-si-gn vein sets; disseimsted py-mt-cpy in1.1 M. Oz @14 g/t Au1.1N/Afault-bounded vein set originating from dioritic toZARUMAepithermal Aupotassic alteration zone of porphyrygranodioritic porphyy intrusionsEL MOZOepith. High-sulf.vuggy silica + argillic advanced alteration>180,000 Au Oz. 0.180N/Aporphiritic andesite lava, vulcano clastic breccias, Autuffs, hydrotherm. Brecccias, dacitic dykesLA PLATAvolcanog. massive sericite+silic. Halo, diss. Py, chl + epidot+qz0,913 Mt @8,01 g/t Au, 0.232.52lavas and andesitic tuffsulfide Au-Ag88.29 g/t Ag, 5.01% Cu, 0.78%Pbcarbonaceous and detritical sedimentsCu-Pb-Zn6.71% Zn(Macuchi Unit) CURIPLAYAAu-Cu porphyryAu-cpy-py-mt in qtz stockworks & disseminationsnot availableN/AN/Aqtz-dioritic to granodioritic intrusions punctured by in potassic - phyllic zonesandesites + breccias; structurally controlledSAN high - gradesphal.-py-pyrrhot.-galena-Aspy-cpy-boulang. +>55,000 T@20 Oz/t AgN/A1.1veins hosted in porphiritic andesitic lavasBARTOLOMEpolymetallic vein qz-rhodochr.-dolomit. Carbonat. In veins2.9%Zn, 1.15% ZPb +/- Auand volcanics of Saraguro FormationsystemMOLLETUROhigh - gradenative silver, electrum, pyrite, sphalerite, galena392 g/t Ag, 3.4 g/t Au, N/AN/AYounger granodiorite and quartz diorite intrudingpolymetallic veinpyrrhotite, arsenopyrite, tetrahedrite, chalcocite0,69%Cu, 2.3%Pb, 4.24% Znthe volcanic Macuchi Unit. Mineralizationsystemand covellitein E-W vein systemFRUTA DEL high gradechalcedonic to crystalline quartz, mangan.-carbonat.58.9 Mt@7.23 g/t Au, 11.8 g/t Ag13.722.34The gold-silver mineralization at FDN is associatedNORTEintermediate-calcite, adularia, barite, marcasite, total 13,689,500 Au Oz.with veins, stockworks and disseminations, mainlysulphidation- goldpyrite as well as subordinate sphalerite, galena,in moderately to intensely silicified Misahuallí epithermal depositcpy with trace tetrah. and other silver sulphosaltsAndesite. Silicification and gold-silvermineralization are well developed at and belowthe basal contact of the Suarez FormationMIRADORCu-Au porphyryearly Mo, early Cu+-Au and later copper gold stages438 Mt @ 0.61 % Cu, 0.19 g Au/t 2.6722.4well defined alteration zonong, quartz-sericite (Corriente Mo is associated with early qz veining, both copper-1.59g/t Ag,total measured and overprintig K alt. Covering a large part of the wallResources Inc)gold events are sulphide dominatedindicated resources categorizationrock and qtz diorite porphyry. RIO BLANCOlow sulfidationquartz veins with calcedonic massive silica, banded 2.1 Mt @ 9.5 g Au/t, 69 g/t Ag0.644.66lavas and volcaniclastic rocks of predominant epithermal veinsand colloform textures with Au- electrum -py-Aspy-total measured and indicated andesitic composition (Saraguro Formation) galena-pirargirite.resourcesTotal28.120113.02ECUADOR MAIN DEPOSITS -Geological settings. LITHOLOGYIN SITU M Oz

27. 3
FRUTA DEL NORTE DEPOSIT October, 2009
FDN - Location and Concessions

28. Intermediate sulphidation epithermal mineralisation: quartz-carbonate- sulphide stockwork veining & brecciation.
FDN Deposit Geology
Andesite
Conglomerate
Late Andesite
125m
350m
?
250 m @ 35.18 g/t Au and 27.1 g/t Ag

29. MIRADOR PROJECT, LOCATION MAP

30. Concessions
4 copper deposits with a total of 25 billions of pounds (cut-off of 0.4% Cu)
Similar Geology, simple mineralisation
South sector > Cu-Au, north zone > Cu.
Mineralisation identified by soil / sediments geochemichal survey.

31. OTHER MINERAL OCCURRENCES IN ECUADOR
PRODEMINCA, 2000

32. OTHER MINERAL OCCURRENCES IN ECUADOR

33. MINERAL DEPOSITS IN ECUADOR (NORTH ZONE)

34. MINERAL DEPOSITS IN ECUADOR (CENTRAL ZONE)

35. MINERAL DEPOSITS IN ECUADOR (SOUTH ZONE)

36. MAIN MINERAL DEPOSITS IN ECUADOR

38. THANKS !
bolanos.john@gmail.com