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Deep‐sea biogenic silica: new structural and analytical data from infrared analysis ‐ geological implications
Author(s) -
Fröhlich François
Publication year - 1989
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.1989.tb00368.x
Subject(s) - biogenic silica , infrared , geology , infrared spectroscopy , diagenesis , quartz , mineralogy , amorphous silica , sedimentation , amorphous solid , crystallography , chemistry , diatom , paleontology , chemical engineering , oceanography , organic chemistry , optics , sediment , physics , engineering
The main parameters of infrared spectra have been investigated for marine siliceous skeletons and for silica polymorphs. From infrared (IR)data, the mean values for the Si‐O bond length (1.62 Å) and for the Si‐O‐Si angle (about 142°6) are inferred for biogenic silica. A model is proposed for the molecular structure of biogenic, amorphous silica, which consists of a discontinuous, three‐dimensional framework of short chains of [SiO 4 ] tetrahedra, bounded with apical hydroxyls. According to the relationship between the structure of the silica polymorphs and their infrared spectra, it is shown that a quantitative analysis of biogenic silica seems to be possible in quartz‐rich sediments. Some geological implications of these data are emphasized, including the processes of siliceous skeleton sedimentation and diagenetic evolution.