| Texto completo | |
| Autor(es): Mostrar menos - |
Kfouri, Luciana Ortiz
[1]
;
Millo, Christian
[1]
;
de Lima, Amanda Estela
[2]
;
Silveira, Carla Semiramis
[2]
;
Sant'Anna, Lucy Gomes
[3]
;
Marino, Egidio
[4]
;
Gonzalez, Francisco J.
[4]
;
Sayeg, Isaac Jamil
[5]
;
Hein, James R.
[6]
;
Jovane, Luigi
[1]
;
Bernardini, Simone
[7]
;
Lusty, Paul A. J.
[8]
;
Murton, Bramley J.
[9]
Número total de Autores: 13
|
| Afiliação do(s) autor(es): | [1] Univ Sao Paulo, Inst Oceanog, Praca Oceanog 191, BR-05508900 Sao Paulo, SP - Brazil
[2] Univ Fed Fluminense, Inst Quim, Programa Pos Grad Geoquim, BR-24020141 Niteroi, RJ - Brazil
[3] Univ Sao Paulo, Inst Energia & Ambiente, BR-05508010 Sao Paulo, SP - Brazil
[4] Geol Survey Spain, Marine Geol Div, Madrid 28003 - Spain
[5] Univ Sao Paulo, Inst Geociencias, BR-05508080 Sao Paulo, SP - Brazil
[6] US Geol Survey, Santa Cruz, CA 95060 - USA
[7] Univ Roma Tre, Dipartimento Sci, I-00146 Rome - Italy
[8] British Geol Survey, Environm Sci Ctr, Nottingham NG12 5GG - England
[9] Natl Oceanog Ctr, Waterfront Campus, Southampton SO14 3ZH, Hants - England
Número total de Afiliações: 9
|
| Tipo de documento: | Artigo Científico |
| Fonte: | DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS; v. 175, SEP 2021. |
| Citações Web of Science: | 0 |
| Resumo | |
The growth of ferromanganese (FeMn) crusts on soft substrates is uncommon. FeMn crusts generally accrete on hard-rock surfaces, where sedimentation rates are low and the rocks free of sediment cover. Here we use X-ray Powder Diffraction, Fourier Transform-Infra Red spectroscopy, Raman spectroscopy, X-ray Computed Micro Tomography, Scanning Electron Microscopy and Particle Size Distribution analysis to investigate FeMn crusts associated with a porous, weakly consolidated, and bioturbated siltstone consisting mainly of authigenic palygorskite. FeMn crusts occur both on the surface of the siltstone and as FeMn lining and/or infilling of bioturbation burrows. Our results show that variations in the water redox conditions lead to a micrometric alternation of hydro genetic vernadite and diagenetic todorokite and asbolane. These variations affected the oxidation state of Mn, which increased during the diagenetic formation of todorokite. The mineralogy of the FeMn oxides lining bioturbation traces is similar to that of the crusts growing on the siltstone, suggesting that they are genetically related and probably contemporaneous. Bioturbation burrows lined by FeMn oxides are unfilled (the siltstone porosity is 5-10%) or filled by bioclastic carbonate sediment. The soft siltstone possibly resulted from the alteration of volcaniclastic-pyroclastic sediments, forming authigenic palygorskite. Bioturbation of the sediment by burrowing organisms lead to seawater percolation, followed by hydrogenetic or diagenetic precipitation of FeMn linings under oxic/suboxic conditions within the burrows. These findings emphasize the importance of weakly-consolidated substrates with bioturbation cavities for the formation of marine polymetallic deposits. (AU) | |
| Processo FAPESP: | 14/50820-7 - Marine ferromanganese deposits: a major resource of E-tech elements |
| Beneficiário: | Frederico Pereira Brandini |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |