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Journal Club do DFMT com Samuel Silva dos Santos

Data do Evento: 
20/06/2018 - 12:15 até 14:15
Journal Club do Departamento de Física dos Materiais e Mecânica
 
Nesta semana o pós-graduando Samuel Silva dos Santos, do Grupo Teórico de Materiais do DFMT, apresentará o artigo
 
CaSiO3 perovskite in diamond indicates the recycling of oceanic crust into the lower mantle
 
F. Nestola et al.
 
Nature volume555, pages237-241 (08 March 2018) | 
 
DOI:10.1038/nature25972
 
Laboratory experiments and seismology data have created a clear theoretical picture of the most abundant minerals that comprise the deeper parts of the Earth’s mantle. Discoveries of some of these minerals in ‘super-deep’ diamonds—formed between two hundred and about one thousand kilometres into the lower mantle—have confirmed part of this picture1,2,3,4,5. A notable exception is the high-pressure perovskite-structured polymorph of calcium silicate (CaSiO3). This mineral—expected to be the fourth most abundant in the Earth—has not previously been found in nature. Being the dominant host for calcium and, owing to its accommodating crystal structure, the major sink for heat-producing elements (potassium, uranium and thorium) in the transition zone and lower mantle, it is critical to establish its presence. Here we report the discovery of the perovskite-structured polymorph of CaSiO3 in a diamond from South African Cullinan kimberlite. The mineral is intergrown with about six per cent calcium titanate (CaTiO3). The titanium-rich composition of this inclusion indicates a bulk composition consistent with derivation from basaltic oceanic crust subducted to pressures equivalent to those present at the depths of the uppermost lower mantle. The relatively ‘heavy’ carbon isotopic composition of the surrounding diamond, together with the pristine high-pressure CaSiO3 structure, provides evidence for the recycling of oceanic crust and surficial carbon to lower-mantle depths.
 
Data: 20 de junho de 2018 (quarta-feira)
 
Horário: às 12h10min
 
Local: Sala de Seminários José Roberto Leite  - Edifício Alessandro Volta (bloco C)
 
FONTE DA NOTÍCIA:
 
Rosana Batista Gimenes Biz
Universidade de São Paulo
Instituto de Física
Secretaria do Departamento de Física dos
Materiais e Mecânica - DFMT
 
Edifício Alessandro Volta (bloco C - sala 201)
Rua do Matão, 1371, trav. R 187,
Cidade Universitária
05508-090 São Paulo, SP, Brasil
 
Tel (+55)(11)3091-6979
Fax (+55)(11)3091-6831
 
Data de Término: 
20/06/2018 - 12:15

Desenvolvido por IFUSP