Town Mountain Granite

Town Mountain Granite
State Texas
Name Town Mountain Granite
Geologic age preCambrian (Proterozoic)
Lithologic constituents
Major
Igneous > Plutonic > Granitic > Granite (Pluton)
Comments Coarse-grained, pink, quartz-plagioclase-microcline rock, in part porphyritic with large microcline phenocrysts. Occurs in plutons up to 13 mi in size that tend to be concordant circular vertical cylinders with concentric textural variaions; boundaries range from sharp and regular to highly irregular with wide zones of mixed rock. Makes up Enchanted Rock granite mass, Gillespie and Llano Counties.
References

Barnes, V.E., Romberg, F., and Anderson, W.A., 1954, 19th International Geologic Congress, Algiers 1952, Comptes rendus, sec. 9, pt. 9, p. 152-153.

Bureau of Economic Geology, 1992, Geologic Map of Texas: University of Texas at Austin, Virgil E. Barnes, project supervisor, Hartmann, B.M. and Scranton, D.F., cartography, scale 1:500,000.

NGMDB product
Counties Blanco - Burnet - Gillespie - Llano - McCulloch - Mason