Hematite nanospheres of possible colloidal origin from a precambrian banded iron formation

Jung Ho Ahn, P R Buseck

Research output: Contribution to journalArticle

41 Scopus citations

Abstract

Exceptionally small spheres (nanospheres) of hematite (diameters between 120 and 200 nanometers) occur in the Marra Mamba Iron Formation of the Hamersley Basin, Australia. The nanospheres are clustered into small aggregates and may have formed by structural ordering and dehydration of colloidal iron hydroxide particles. Individual spheres consist of numerous thin, curved hematite platelets surrounding a central void that is approximately half the diamter of the sphere; this texture suggests that they formed by a volume reduction of the original colloidal particles by ∼12.5%. The occurrence of hematite nanospheres supports the hypothesis that some of the iron was deposited colloidally during the development of banded iron formations, approximately 2.5 billion years ago.

Original languageEnglish (US)
Pages (from-to)111-113
Number of pages3
JournalScience
Volume250
Issue number4977
DOIs
StatePublished - 1990

ASJC Scopus subject areas

  • General

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