Page 148 - Petrology of Sedimentary Rocks
P. 148
MINERALOGY - THE QUARTZARENITE
IGN. SED. MET.
MINERALOGY
CONTROLLED
BY
SOURCE
AREA
Arrows indicate whether constituent is increased or diminished
on prolonged abrasion. Chert is usually but not always present
in a sedimentary source area.
-4+ GRAVEL 0+ SAND 4+ SILT 8+
MINERALOGY
CONTROLLED
BY
GRAI 14
SIZE
Chert and vein quartz are most ahundant in the gravel sizes because
they start out as large pieces. Vein quartz diminishes with size
because some of its diagnostic criteria become unrecognizable in the
fine-sand to silt range. Chert, being finer grained, is recognizable
to much finer sizes.
142
