In the case of rice wheat cropping, vermiculite content decreased with depth,
illite content decreased from [L.sub.1] to [L.sub.3] and then increased for [L.sub.4] and [L.sub.5].
This confirmed that the material consists of felspar (disordered anorthoclase), alpha quartz, kaolinite and
illite. The
illite was a surprise, I have to admit.
7a) and very small amounts of
illite, illite-smectite, chlorite, and kaolinite.
On a trouve que l'effet adverse de l'argile d'
illite sur la recuperation de bitume etait relie a son acidite.
Paleozoic shales of the Till Plains contain more
illite and chlorite than kaolinite, whereas Pennsylvanian shales or underclays of the plateau contain a larger proportion of kaolinite (Volpi and Szabo 1988).
Illite (Figure 7-11) is a 2:1 type clay with moderate surface area (100-120 [m.sup.2]/g) and moderately high negative surface charge.
In order to find indicators of the critical temperature for the hydrothermal deposition of low quartz in the andesite of Las Vigas, chlorite and
illite were analyzed by microprobe, and the resulting values were fitted into the temperature curves of Cathelineau et al.
*
Illite has the same substitutions as vermiculite.
* (
illite)--analcime I--calcite I--(thomsonite)--natrolite (calcite II),
X-ray diffraction analysis of the residue shows quartz as the dominant residue component, with scarcely more than trace quantities of magnesium calcite (Ca, Mg)[CO.sub.3] and the clay mineral
illite ([KAl.sub.2]([OH.sub.2]).
Clay samples are dominated by either smectite or mixed-layer clays and contain lesser amounts of
illite and kaolinite.