Spectral characteristics of chlorites and Mg-serpentines using high- resolution reflectance spectroscopy

The present laboratory study using high-resolution reflectance spectroscopy (0.25–2.7 μm) focuses on two primary phyllosilicate groups, serpentines and chlorites. The results show that it is possible to spectrally distinguish between isochemical end-members of the Mg-rich serpentine group (chrysotile, antigorite, and lizardite) and to recognize spectral variations in chlorites as a function of Fe/Mg ratio (∼8–38 wt % Fe). The position and relative strength of the 1.4-μm absorption feature in the trioctahedral chlorites appear to be correlated to the total iron content and/or the Mg/Si ratio and the loss on ignition values of the sample. Spectral differences in the 2.3-μm wavelength region can be attributed to differences in lattice environments and are characteristic for specific trioctahedral chlorites. The 1.4-μm feature in the isochemical Mg-rich serpentines (total iron content ∼1.5–7.0 wt%) show marked spectral differences, apparently due to structural differences.

[1]  I. Mackinnon.  Ordered mixed-layer structures in the Mighei carbonaceous chondrite matrix , 1982 .

[2]  G. Hunt.  Visible and near-infrared spectra of minerals and rocks : I silicate minerals , 1970 .

[3]  K. Oinuma,et al.  Si-O Absorption Band Near 1000 cm−1 and OH Absorption Bands of Chlorite , 1967 .

[4]  Jack J. Hsia,et al.  Reflection properties of pressed polytetrafluoroethylene powder , 1981 .

[5]  A. Zaikowski.  Infrared spectra of the Orgueil (C-1) chondrite and serpentine minerals , 1979 .

[6]  D. J. Barber.  Matrix phyllosilicates and associated minerals in C2M carbonaceous chondrites , 1981 .

[7]  J. Serratosa,et al.  Infra-red Investigation of the OH Bonds in Chlorites , 1964, Nature.

[8]  Haruo Shirozu.  Cation distribution, sheet thickness, and O-OH space in trioctahedral chlorites - an X-ray and infrared study. , 1980 .

[9]  J. Fahey,et al.  The serpentine-group minerals , 1962 .

[10]  M. N. Bass.  Montmorillonite and serpentine in Orgueil meteorite , 1971 .

[11]  W. Meinschein,et al.  AQUEOUS, LOW TEMPERATURE ENVIRONMENT OF THE ORGUEIL METEORITE PARENT BODY , 1963, Annals of the New York Academy of Sciences.

[12]  J. Kerridge.  Major element composition of phyllosilicates in the Orgueil carbonaceous meteorite , 1976 .

[13]  U. Fink,et al.  Remote spectroscopic identification of carbonaceous chondrite mineralogies: Applications to Ceres and Pallas , 1979 .

[14]  M. Michel-Lévy.  Étude Minéralogique De La Chondrite C III De Lancé , 1969 .

[15]  Peter R. Buseck,et al.  Matrix mineralogy of the Orgueil CI carbonaceous chondrite , 1988 .

[16]  E. Anders,et al.  Chemical Evolution of the Carbonaceous Chondrites , 1962 .

[17]  K. Bostrom,et al.  Surface conditions of the Orgueil meteorite parent body as indicated by mineral associations , 1965 .

[18]  M. Gaffey,et al.  Asteroid surface materials: Mineralogical characterizations from reflectance spectra , 1977 .

[19]  A. Brammall.  The Paragenesis of Cookeite and Hydromuscovite Associated with Gold at Ogofau, Carmarthenshire , 1937 .

[20]  R. Ashley,et al.  Spectra of altered rocks in the visible and near infrared , 1979 .

[21]  Haruo Shirozu,et al.  Variations in chemical composition and structural properties of antigorites. , 1985 .

[22]  D. Sherman.  The electronic structures of Fe3+ coordination sites in iron oxides: Applications to spectra, bonding, and magnetism , 1985 .

[23]  L. Fuchs,et al.  Mineralogy, mineral-chemistry, and composition of the Murchison (C2) meteorite , 1973 .

[24]  P. Buseck,et al.  New phyllosilicate types in a carbonaceous chondrite matrix , 1979, Nature.

[25]  J. Kerridge.  LOW‐TEMPERATURE MINERALS FROM THE FINE‐GRAINED MATRIX OF SOME CARBONACEOUS METEORITES , 1964 .