Figure 1:
Graphic reproduction of the Presidente Vargas Diamond. Original dimensions 56.2x50x24.4 mm (Machado & Figuerôa 1999Machado I.F., & Figuerôa S.F.M. 1999. 500 years of mining in Brazil: A brief review. Ciência e Cultura, Journal of the Brazilian Association for Advancement of Science, 51(3/4):287-301.).
Figure 2:
Diamond, kimberlite and related rocks distribution within the Sanfranciscana plate and São Francisco Craton (Pereira 2007Pereira R.S. 2007. Cráton do São Francisco Kimberlitos e Diamantes. Tese de Doutorado, Universidade de Brasília, Brasília, Brasil, 200p.).
Figure 3:
Distribution of kimberlite-related rock in the southern portion of the São Francisco Craton and Paleoproterozoic Mineiro Mobile Belt (modified from Pereira 2007Pereira R.S. 2007. Cráton do São Francisco Kimberlitos e Diamantes. Tese de Doutorado, Universidade de Brasília, Brasília, Brasil, 200p.).
Figure 4:
Kimberlites in the headwaters of the São Bento, Abaeté and Indaiá rivers. Contour lines represent post-Gondwana or before Mata da Corda Formation deposition paleo relief (Pereira 2007Pereira R.S. 2007. Cráton do São Francisco Kimberlitos e Diamantes. Tese de Doutorado, Universidade de Brasília, Brasília, Brasil, 200p.).
Figure 5:
Pressure and temperature calculation of 517 garnet grains from the X-270, Regis, Vargem and Santa Rosa 04 kimberlites (modified after Read et al. 2003Read G., Grutter H., Winter S., Luckman N., Gaunt F. 2003. Stratigraphic relations kimberlite emplacement and lithospheric thermal evolution, Quiricó Basin, Minas Gerais State, Brazil. 8th International Kimberlite Conference Extended Abstract, Toronto, Canada.). Graphite and diamond fields are shown.
Figure 6:
Alluvium sampling in digging areas and along São Francisco River tributaries and from the Canastra 01 (CAN 01) kimberlite, primary and single diamond source (modified from Pereira 2007Pereira R.S. 2007. Cráton do São Francisco Kimberlitos e Diamantes. Tese de Doutorado, Universidade de Brasília, Brasília, Brasil, 200p.).
Figure 7:
Cr2O3 x CaO diagram of garnet recovered from the Canastra 01 kimberlite (Pereira 2007Pereira R.S. 2007. Cráton do São Francisco Kimberlitos e Diamantes. Tese de Doutorado, Universidade de Brasília, Brasília, Brasil, 200p.).
Figure 8:
TRS-04, TRS-101, 102, 104 diamond-bearing kimberlites and the São Miguel River digging (Pereira 2007Pereira R.S. 2007. Cráton do São Francisco Kimberlitos e Diamantes. Tese de Doutorado, Universidade de Brasília, Brasília, Brasil, 200p.).
Figure 9:
Diamond-bearing conglomerate overlying Botucatu sandstone in the old Água Suja digging, Romaria. Note down-thrown block to the left along a normal fault; such structures are commonly observed in the Alto Paranaíba high (Coelho et al. 2010Coelho F.M., Svisero D.P., Filho W.F. 2010. Geologia e Mineralogia da Mina de Diamante de Romaria, Minas Gerais. 5o Simpósio Brasileiro de Geologia do Diamante. Tibagi, Paraná, Brasil, p.50.).
Figure 10:
Exploitation of diamond-bearing conglomerate near Romaria. Evaluation of conglomerate and epiclastic kimberlite by GAR Mineração.
Figure 11:
Analyses of heavy mineral concentrates recovered from conglomerates and digging areas in Romaria: (A) garnet, (B) spinel (Pereira 2007Pereira R.S. 2007. Cráton do São Francisco Kimberlitos e Diamantes. Tese de Doutorado, Universidade de Brasília, Brasília, Brasil, 200p.). Higher Cr2O3 concentrations in garnet correspond to equilibrium conditions in greater depths within the lithosphere mantle and consequently higher pressures.
Figure 12:
Detail of basal conglomerate of the basal Capacete Formation in the Canastrel digging. Note the lack of pebble sorting from top to base.
Figura 13:
Diamond provenance study in occurrence areas in the São Francisco Craton (Pereira 2007Pereira R.S. 2007. Cráton do São Francisco Kimberlitos e Diamantes. Tese de Doutorado, Universidade de Brasília, Brasília, Brasil, 200p.).
Figure 14:
Kimberlite outcrop at the beginning of the more than 10 km long, grossly north-south silicified belt along the Santo Antônio do Bonito River right bank.
Figure 15:
Fragments and blocks of silicified kimberlite at Vendome Mines processing plant.
Figura 16:
(A) Large dodecahedral diamonds recovered in the Santo Antônio do Bonito, Santo Inácio and Douradinho rivers in the Coromandel area; (B) digital terrain model of the Chapadão area; (C) positioning of normal fault in relation to the start of the Santo Antônio do Bonito, Santo Inácio and Douradinho rivers diggings and localization of the Buriti plateau within the downthrown block to the west of the fault. Note absence of diggings on the east side of the Chapadão.
Figure 17:
Long period magnetotelluric sounding available in a 180 km long WSW-ENE profile across the magmatism associated to the Alto Paranaíba structural high (Bologna et al. 2006Bologna M.S., Padilha A. L., Vitorello I., Fontes S. L. 2006. Tectonic insight into a pericratonic subcrustal lithosphere affected by anorogenic Cretaceous magmatism in central Brazil inferred from long-period Magnetotelluric. Earth and Planetary Science Letters, 241:603-616.); (A) geological map of the region and location of the profile; (B) Três Ranchos-Coromandel garnet windows and localities of distinct diamond population with characteristics of unique young, proximal and primary diamond source (Pereira 2007Pereira R.S. 2007. Cráton do São Francisco Kimberlitos e Diamantes. Tese de Doutorado, Universidade de Brasília, Brasília, Brasil, 200p.); (C) occurrence of thick lithosphere (depths larger than 150 km) bellow the garnet window of high interest and localities of unique young primary proximal diamond source in the terrain surface (modified from Bologna et al. 2006Bologna M.S., Padilha A. L., Vitorello I., Fontes S. L. 2006. Tectonic insight into a pericratonic subcrustal lithosphere affected by anorogenic Cretaceous magmatism in central Brazil inferred from long-period Magnetotelluric. Earth and Planetary Science Letters, 241:603-616.).
Figure 18:
Diamond-bearing alluvial deposit within AMEEX Mineração area, belonging to Mr. Milton Soares França. Note pebble sorting from top to base next to the bedrock.
Figure 19:
Erratic pebble distribution in the basal Capacete Formation conglomerate.
Figure 20:
Hypothetical normal fault developed during the Alto Paranaíba structural high uplift. Probably developed along thrust fault planes related to the Brasiliano Orogeny, normal faults are possible secondary controls for intrusions emplacement, at the time when Cretaceous-Tertiary sediments were deposited over downthrown blocks (modified from Pereira 2007Pereira R.S. 2007. Cráton do São Francisco Kimberlitos e Diamantes. Tese de Doutorado, Universidade de Brasília, Brasília, Brasil, 200p.).