Page 142 - Petrology of Sedimentary Rocks
P. 142
MINERALOGY: THE PHYLLARENITE
L.R. MET. H.R. MET. IGN. .rL
(Slate, (Metaqtz, 4
MINERALOGY
CONTROLLED
BY
SOURCE
AREA
Arrows indicate whether constituent is increased or decreased
by prolonged abrasion.
-44 GRAVEL O$ SAND 44 SILT
MINERALOGY
CONTROLLED
BY
GRAIN
SIZE
Mica occurrence control led by hydraul ic factors. Soft MRF’s and
composite quartz break up into clays and single quartz grains and
become unrecognizable. Single quartz grains at first increase by
breakup of composite metaquartz, then diminish; very little quartz
occurs finer than 6$ - 70. It retains undulose extinction to
Retaqtz - - $aoo single qtz grains
@
C’f
MRF’s - - , -\L, -7 / ’ clay paste
/I./-
Abrasional Changes
136
