Page 81 - Petrology of Sedimentary Rocks

7-h e Q UartZ C ontinuum

Note : Two geologic realms where straight extinction occurs, at opposite
ends of the scale: crystallization from magma or solution, (2) recrys-
. .
talllzatton of a sol::’ . In between is the realm of undulose quartz. Undulosity
is a function of size as well as strain. Thus schists have so much straight
quartz because they are the finest-grained, having been formed from fine-
grained source rocks, e.g., shales and siltstones. This diagram is a fusion
of ideas of H..E. Blatt and the writer -- December 1963.

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