X-ray diffraction studies of the pore-lining chloritic mineral from the Tuscaloosa Formation disclose a marked pattern of odd-order line broadening for the 001 to the 00,16 reflections. The odd-order peaks are approximately twice as broad as the even orders after correction for instrumental broadening effects. These results are consistent with a randomly interstratified 7-Å/14-Å structure, which is most likely serpentine/chlorite. Quantitative analysis of line broadening and model calculations indicate that the serpentine/chlorite contains 7% serpentine layers.
A simplified method is proposed for quantifying randomly interstratified serpentine/chlorite. Residual line broadening (βr) is obtained from the half-height widths of uncorrected diffraction profiles for the 004 and 005 “chlorite” reflections by means of the following: ![](//static-cambridge-org.ezproxyberklee.flo.org/binary/version/id/urn:cambridge.org:id:binary:20240227121931021-0522:S0009860400018310:S0009860400018310_IEq1.png)
Percent serpentine in the random interstratification is computed from the empirical expression![](//static-cambridge-org.ezproxyberklee.flo.org/binary/version/id/urn:cambridge.org:id:binary:20240227121931021-0522:S0009860400018310:S0009860400018310_IEq2.png)
which is valid from about 1 to 20 percent serpentine.