metamorphism

Grenville Orogeny

Weil et a. (1998)


Outcrop Photo – paragneiss & marble


Outcrop Data



Geothermobarometry


3 CaAl2Si2O8 =
Ca3Al2Si3O12 + 2 Al2SiO5 + SiO2

GASP - garnet - aluminumsilicate - silica - plagioclase


Metamorphic Facies

+/- 100 MPa

+/- 50oC


Porphyroclast

Porphyroblast

Sillimanite
Replaces
Andalusite

Chlorite
replaces
Garnet

Sillimanite
Replaces
Kyanite

Reaction Rim

Cross-polar
view

Reaction lamella



Garnet Rim Conditions

500 MPa

550oC

 dP 
    P
 dt 
dD
 dP 
   
dt
 dt 


 dP 
    P
 dt 
1
 dP  dt
P

 ln P  t  C


 ln P  t  C

ln P  ln Po  t
Po  Pe

t


Po  Pe

t



t



t

D*  Po  P  Pe  P  P e  1



t



D  Do  D*  Do  P e  1




t



D  Do  P e  1
y  mx  b





D Do P t

 e 1
S
S S