Embed Size (px)
Citation preview
Fosfato Sedimentar: geologia, sistemas naturais e implicações globais
Geól. Leandro G. Silva, MSc.
Pesquisador em Geociências
Sistemas Naturais
• Interação de sistemas
• Regulação da superfície
• Biota
• Paleoambientes
• Fatores econômicos
Bioelemental Sediments
• Nutrientes
• Depósitos sedimentares
• Interação biogênica
–Chert (C)
– Formação Ferrífera (I)
– Fosforito (P)
(Pufahl, 2010)
Phosphorite
• P-rich rock > 18 wt. % P2O5, can be 40 wt.% P2O5
• sedimentary phosphorite is a marine chemical sediment commonly associated with upwelling
• sedimentary phosphorite provides more than 80% of the total world production of phosphate rock
• Links natural systems
• annual consumption of phosphate rock ~200 million tons per year
• increasingly important source of U (50-200 ppm)
• peak phosphorus predicted in the next 30-50 years
Phosphorite
(Pufahl & Groat, 2017)
Sources & Reserves
(Jasinsky, 2016)
Sources & Reserves
(Cordell et al., 2009)
Demanda
(Cordell, 2011)
Phosphorus & Life
Phosphorus Cycle
Sedimentary Phosphorite
• Upwelling
• Trade winds
Sedimentary Phosphorite
Sedimentary Phosphorite
• Upwelling
• Margem Continental
Sedimentary Phosphorite
Sedimentary Phosphorite
• Mar Epicontinental
Phosphorus
Phosphorus
• Microbial degradation:– Sulfide oxidizing
– Sulfate reducing
– Breaks down organic matter
– Concentrate P in their cells
– Releases phosphate to pore water
– Promotes phosphogeneis
Phosphogenesis
Pufahl & Groat (2017)
Upwelling Non-Upwelling• Controls:– P concentration
– F Diffusion
– Bacteria
– Redox gradient
– Authigenesis
Pufahl & Hiatt (2012)
Phosphogenesis Redfield ratio (106C:16N:1P)
Phosphogenesis
• Redox gradient
• Organic matter
• Pyrite
• Dolomite
Pufahl & Hiatt (2012)
Pufahl & Groat (2017)
FrancolitaGeochemistry
• Authigenic Minerals
– Eh indicators
• Phosphate: links C, O and S
• Glauconite: Rb/Sr
• Pyrite: S isotopes
– Carbonates
Oceans and Atmosphere
• Great Oxygenation Event (2.4-1.8Ga)– Increase atm pO2
– Chemical weathering
– End of S-MIF
• Neoproterozoic Oxygenation Event (630-580Ma)– Oxygenation of
atmosphere and oceans
– Evolution of eukaryotes
– Evolution of metazoan
Pufahl & Hiatt (2012)Narbonne (2010)
Oceans and Atmosphere
• Glaciation & Oxygenation Events
Pufahl & Hiatt (2012)
Oceans and Atmosphere
• Deglaciation
• Weathering
• P input in the oceans
Biosphere – MicroorganismsSiphonophycus Myxococcoides
Arctacellularia
Melanocyrillium
Leiosphaeridia
Leiosphaeridia
Denezine (2018)Denezine (2018)
Biosphere – Ediacara Fauna
Ediacaran Fauna
(Xiao & Laflamme, 2008)
Precambrian vs Phanerozoic
Caird et al. (2017)
Pufahl & Hiatt (2012)
Precambrian vs Phanerozoic
Drummond et al. (2015)
Pufahl & Hiatt (2012)
Precambrian vs Phanerozoic
Pufahl & Hiatt (2012)
BHZ
BSB
Accummulation
Pufahl & Groat (2017)
• Classification
– Pristine
– Granular
Accummulation
Lima (2007)PristineGranular
Accummulation
Pufahl & Groat (2017)
Accummulation
Pufahl & Groat (2017)
Conclusões
• Fosforitos sedimentares são commodities essenciais para a economia brasileira
• Potencial para fosforito sedimentar é grande no Brasil
• Sistema complexo de acumulação e formação de depósitos econômicos
• Valor científico ligado a eventos climáticos globais, com consequencias em todas as esferas
• Evolução da vida
