Clay semi-quantitative analysis

Table I. Semi-quantitative Analysis of Red Clay (Done by Emission Spectroscopy)...

Samples of the red clay having uniform physical and chemical characteristics were provided by G. R. Heath of the University of Rhode Island. The samples were obtained from core LLUU-GPC-2, collected on October 11, 1976, at 30° 20.9 n, 157° 50.85 w, water depth 5821 meters, and are representative of the smectite-rich region of the red clays which occurs in the sediment at depths below about ten meters. In this region, the sediment appears to contain about five to six percent by weight leachable iron and manganese in the form of hydrous oxides. The remaining material appears to be dominated by iron-rich smectite and lesser, varying amounts of phillipsite (2). The results of a semi-quantitative (precision in data is within a factor of 2) elemental analysis... 

Mossbauer spectroscopy may be used for semi-quantitative or qualitative determination of Fe2 /Fe3 ratios Table II shows that a rather good correlation exists between Mossbauer and chemical analysis for Fe2 /Fe3 ratios in clay mineral samples, but these measurements must be obtained at lower temperatures (< 150 K) in order to maximize the recoil-free fractions of both valence states in the sample ... 

Samples for clay mineralogical analysis were prepared using standard gravitational-technique. Semi-quantitative estimates of the relative abundance of clay minerals in the <2 pm fraction were made using the method given by Moore Reynolds (1989). 

Interpretation The following qualitative and semi-quantitative evaluation is useful for routine clay mineral analysis and has been adopted and modified from many literature sources. Use Brown Brindley (1980) and Thorez (1975) to refine the analyses if more detail is required. 

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