Composition:

Petrographic Description:  In this sample the sodic plagioclase and 
hornblende are subhedral, the quartz, biotite, and opaques are anhedral.  
Some of the basal sections of hornblende shown twinning while the biotite is 
partly chloritized.  Some of the plagioclase show sericitization in the cores, 
and occasionally normal zoning.  The quartz often show undulose extinction.
Apatite occurs as a minor accessory mineral, and much less zircon (in 
biotite) and epidote.  The modes are 53% plagioclase, 21% quartz, 15% 
biotite, 9% hornblende, 1.4% miscellaneous (apatite, epidote, sericite), and 
0.6% opaques.  Very weak spectral features indicate the presence of a trace 
of carbonate.

Microprobe Analysis:  The plagioclase composition ranged from An38 to 
An50 (andesine-labradorite).  The hornblende composition was relatively
homogeneous, with a composition equivalent to hastingsite.


Chemical Analysis:
SiO2  63.08
CaO  2.39
TiO2  0.67
Na2O  3.56
Al2O3  16.88
K2O  1.3
Fe2O3  1.41
H2O  1.06
FeO  4.08
P2O5  0.1
MnO  0.09
MgO  5.98
TOTAL  100.6  (CO2 not analyzed)
