Download the technical report here: PB-Technical-Report-2021.pdf
Pedra Branca is an untapped gem located amidst excellent infrastructure in northeastern Brazil. The maiden Inferred Mineral (4,042,000 t grading 1.38 g/t Au for 180,000 ounces of gold, was calculated utilizing only 42% of the total assay results. South Atlantic’s reverse circulation drilling only averaged 40 m in depth. Phase II Exploration will conduct a deeper drilling and explore more to the southern portions of Pedra Branca.
- South Atlantic holds a 100% interest in the Project.
- 25 active mineral exploration licenses covering nearly 40,000 ha. View map here.
- Excellent infrastructure in and around Project area including electrical power, paved roads, work force and mine facilities/supplies.
- Phase 1 Exploration Program with US$1 million budget included:
- 12,286 m of trenches were excavated which led to 9,349 trench assay results
- 122 RC (reverse circulation) drill holes which led to a total of 4,356 RC drill assay results
- All historical diamond drill core with original assay results above 0.35 g/t Au were validated through re-assay.
- Tenements under mining designation from Agencia Nacional de Mineração (ANM), the national mining agency in Brazil, include the Coelho-Queimadas, Mirador Norte and Mirador Sul targets. These 3 tenements had 2,600 m of trenching completed which resulted in 2,646 assay results and 81 RC drill holes that totaled 3,334 m of drilling and resulted in 2,474 assay results. These results include the Condado Target that is the southern extension of the Coelho-Queimadas Target area.
- New Discoveries: The Igrejinha and Bombeiro Targets were identified as new mineralized areas that previously had little to no exploration. Combined, these two tenements received 1,950 m of trenching and 1,216 m of RC drilling from 30 drill holes. A total of 3,429 assays were received from both the trenching and drilling on these two tenements.
- Igrejinha Target: 2 trench discoveries of new mineralization
The project areas with historical and current exploration results is below. Please click to enlarge image.
Marcelo Antonio Batelochi (P.Geo.), MAUSIMM (CP), the Company’s Sr Exploration Manager is the Qualified Person as defined by National Instrument 43-101 who supervised the work program and preparation of the technical data on this webpage.
The Pedra Branca Project is hosted within the Ceará Central Domain, in the northern portion of the Borborema Province and comprises both the Tróia-Pedra Branca (Cruzeta Comples) and the Ceará Central Complex. Mineralization at Pedra Branca is identified as a mesothermal shear zone-hosted gold deposit.
Geotectonically, these complexes can be explained by the reconstruction of the Pangea Supercontinent, where there is a correlation between the African Shield (Nigeria Shield) and the Central Ceará Domain. The main tectonic event was associated with the Brazilian Pan-African orogen of Western Gondwana, aged at the end of the Neo‐Proterozoic, correlated to the convergence as described by Fragoso-Cesar (2008):
- the Amazonian with the West Africa cratons;
- the Borborema with Nigeria/Cameroon Belts;
- São Luís with West Africa; and
- São Francisco – Congo
The Borborema Province has been described by several authors as having high metamorphic grade and high complex structural development, with the supracrustal sequences metamorphosed to gneiss and migmatites or in high temperature schists associating the paragenesis of garnet, kyanite and sillimanite.
An extensive compilation by Companhia de Pesquisa e Recursos Minerais do Brasil (CPRM), the Brazilian Geological Survey, created a regional geologic map of the Borborema Province below.
Regional Geology of Northern Borborema Province, in Northeastern Brazil. Detail of ARIM Project (3) (CPRM, 2015), DNC - Northwestern Ceará Domain; DCC – Central Ceará Domain; DOJ – Orós-Jaguaribe Domain; DPS – Rio Piranhas – Seridó Domain; DJC – São José do Campestre Domain. Dextral Shear zones are showed in the map, interpreted as Brazilian reactivation (750-530 Ma). The black lines polygon, number 3, is the Troia-Pedra Branca studied region.
The regional crustal evolution model is a signature of a microplate or a small block or nuclei of Archean/Paleoproterozoic age that was subjected to the metallogenetic processes for the gold and platinum mineralization, although this is associated with distinct geological contexts. Additionally, the Troia Pedra Branca complexes have been interpreted as being encompassed in at least two regional tectono-thermal events, Transamazonian from 2.2 to 1.8 Ga and Brazilian-Panafrican 850-650 Ma, and were superimposed over the Archean rocks and gold mineralization of the Algodões and/or Tróia Greenstone belt. Several granitoid types are seen in this region.
The figure below illustrates the R-G-B (K-Th-U) showing the structural high complexity of these Archean Granite-Greenstone belt terrains, so typical of this Archean structure, having been reworked by several geotectonic events.
Lithological Units at Pedra Branca
Cruzeta Complex – Gray Gneisses-TTG
The Cruzeta Complex is composed of various types of gneisses. The color ranges from white grayish to dark gray. This Complex resembles traces of supracrustal rocks, para-gneiss and TTG, inbricated and folded.
Troia Greenstone Belt (Archean)
- Supracrustal Metabasalts and Metaultramafic lithologic units are composed of fine-grained mafic schists and meta-basic rocks, interlayered or transitional to the biotite schists, fine amphibolite schists sometimes found with garnet, hornblende and tremolites. Subsequently, there are intercalations of rare amphibole gneiss and coarse-grained deformed quartz veins in the form of pods, rods or relict folds. The interpretation of this meta-basic/ultrabasic rocks are correlated to a metamorphose typical basal succession of the of the mafic volcanic and/or komatiitic rock, having basic/ultrabasic metavolcanics rocks (amphibolite’s and hornblendites or phlogopites) succeeded by sediments like greywackes, carbonaceous pelitic, chemical sediments (cherts, BIF´s and unclean Manganese lenses).
Geologic Profile NW-SE
- Supracrustal – Para-Gneisses (Greenstone Belt Derivaties)-considered to be the metamorphosed Troia Greenstone Belt, banded gneisses with paragenesis of muscovite, k-spar, biotite, garnet, kyanite and sillimanite.
- Supracrustal – Coarse Grained Metasediments (Greywackes, metavolcano-clastics, metatuffs-composed of a wide range of textures and composition of schists.
- Supracrustal – Biotite Schists (Metapelitic and Graphitic) – mapped in several portions of the Troia Greenstone Belt, with presence of quartz, garnet and kyanite, and indicates a pelitic unit derivative.
- Supracrustal – Chemical Metasedimentary (BIF, BMF and Metachert) – Banded Iron Formation (BIF) occurs as thin bodies containing magnetite and grunerite and is rich in recrystallized quartz (like sugar grains) and strong magnetism is observed. The Banded Manganese Formation (BMF) shows intercalation and is represented by gondites and queluzites. The Metachert is characterized as thin and elongated along strike and consists mainly of fine recrystalized quartz grains.
- Supracrustal – Acid and Intermediate Metavolcanic – rhyolites and andesites in small local intercalations
- Metagranitoid High K (Archean to Paleoproterozoic) – easily identified on the aerial gamma-spectrometry and in the field. This is correlated to the granitic phase, at the end of the evolution of the Greenstone Beld, maybe Paleoproterozoic in age. These rocks cut the Troia Greenstone belt supracrustal rocks in succession. Their relationship with the gold mineralization is uncertain.
- Quartzite-Pelite-Carbonate Plataformal (Q-P-C) (Paleo, Meso to Newproterozoic) – The Q-P-C is common at the Northwestern part of the Ceara Complex and is characterized by a sequence of schists, quartzites and carbonates (Indepencencia Unit)
- A-type Granitic Rocks (Neoproterozoic) – the youngest granites, coarse grained phaneritic textures, sometimes porphyritic, and rich in K-feldspar. It is a massive batholith, not deformed or foliated, in which contact metamorphism is seen.
- Dike Swarms (Ediacaran Magmatism) – the swarms have been interpreted as being correlated to Ediacaran age in Brazilian geology (635 to 540 Ma). They are characterized as being formed in several Rift basins, purely intracontinental sedimentation, with volcanism and some bimodal magmatism occurring with an alkaline trend.
Geologic Structures at Pedra Branca
The main structural features include a very well-developed foliation, fracture system and intersecting lineation, strongly associated with tight to isoclinal folding systems. The fracture system is defined by 5 families and their attitudes, ranked by frequency is:
- N45°W / 85° SE (45/85)
- N15°W / 85° SW (255/85)
- N60° E / 85° SE (150/85)
- N25° E / 85° NW (295/85)
- N85° E / 85° NW (355/85)
Gold mineralization at Pedra Branca is identified as a mesothermal shear zone-hosted deposit.
Gold mineralization at the Coelho and Queimadas targets is characterized by subparallel intra‐foliated millimetric/centimetric strings of sulfides in amphibole schists with magnetite, pyrite and pyrrhotite, and are associated with thin deformed quartz‐veins.
Hydrothermal alteration was observed in several trenches, represented by sulfides, quartz, carbonate, and transformed by metamorphic processes in two sulfides (pyrite and pyrrhotite) magnetite, and amphiboles, diopside, garnet and other minerals.
All gold mineralization appears to be folded, and sometimes stretching to pinch and swell patterns. The structural pattern of control of this mineralization could cause duplication or triplication of layer thicknesses. On the other hand, the breaking of drag folds could also break and separate them.
- Coelho-Queimadas—Two parallel zones of mineralization are seen at the Coelho-Queimadas Target, each ~500-500m in length and ~6-8 m thick and extending to ~80 m in depth. Mineralization is open at depth and laterally. Gold mineralization is associated with sulphides and is seen by amphibole shale with magnetite. The predominate amphibole is hornblende.
- Mirador—Four zones of mineralization, from 100 m to 300 m in length along a corridor ~1200 m in length, striking 42° NE. Mineralization is found at surface and exends at least 80 m in depth from drill intercepts. Mineralization is open laterally and at depth and is associated with silicification zones of hydrothermal origin and also in veins.
Exploration at Pedra Branca has been highlighted in press releases on the Company’s website with dates ranging from 22nd of October, 2020 to present. These can be found on the Investors Tab on the website under NEWS.
Identified gold mineralization at the Pedra Branca Property is recognized by most of the geological community as mesothermal shear zone hosted gold deposit, associated to the Senador‐Pompeu shear zone. Mineralization generally occurs associated with quartz veinlets parallel to the foliation (Coelho and Queimadas targets) and sub‐metric to meter milky quartz veins at the Mirador and Igrejinha targets. Mineralization is often continuous to considerable depths in these systems.
Igrejinha is one of our main targets alongside Coelhos and Queimadas. The RC drilling at Igrejinha was designed to better understand the geology, structure and controls on the known mineralized zones and their extension along the trend zones in order to support further exploration programs, following the Orogenic Gold Mineralization Model that is often continuous in significant depths in these systems.
The gold mineralization at Igrejinha is characterized by subparallel intra-foliated millimetric/centimetric strings of sulfides in amphibolite shale with magnetite and fine quartz-feldspar rock, subordinately by hydrothermal silicification zones and pyrite >> pyrrhotite sulphides.
The Igrejinha target continues to be the main focus of the Phase 1 RC drilling program, with PB-RC-002 returning 1 m grading 5.9 g/t from 22 m depth, and PB-RC-003A intercepting 3 m at 1.13 g/t Au from 5m depth. Trenches at Igrejinha, PB-TR-009 and PB-TR-006 returned 6 m grading 7.19 g/t Au, and 29 m grading 0.73g/t Au (Including 3m at 3.22g/t Au), respectively.
Click to enlarge the Igrejinha map
Gold mineralization is Identified as mesothermal shear zone hosted gold deposit, associated to the Senador‐Pompeu shear zone. Mineralization generally occurs associated with quartz veinlets parallel to the foliation at the Coelho- Queimadas Target. Typical shear zone structural elements are not evident in the field and hydrothermal alteration occurs locally and in a few meters halo in the tremolite‐actinolite schists, chlorite schists and biotite‐gneiss that constitute the wall rocks. Strong silicification is present in all targets while eventual biotite, epidote, diopside and carbonate alteration occurs at the Coelho‐Queimadas targets
The gold mineralization at the Coelhos-Queimadas Project is characterized by the subparallel intra-foliated millimetric/centimetric strings of sulfides in amphibole shale with magnetite and fine quartz-feldspar rock, subordinately by hydrothermal silicification zones and pyrite >> pyrrhotite sulphides.
Click to enlarge the Coelhos-Queimadas map