Granophyre

Granophyres typically are intrusive rocks that crystallized at shallow depths, and many have compositions similar to those of granites. A common occurrence of granophyre is within layered igneous intrusions dominated by rocks with compositions like that of gabbro. In such occurrences, the granophyre may form as an end product of fractional crystallization of a parent mafic magma, or by melting of rocks into which the mafic magma was emplaced, or by a combination of the two processes. The texture can be similar to micrographic texture and to the coarser graphic intergrowths of quartz and alkali feldspar common in pegmatite. These textures document simultaneous crystallization of quartz and feldspar from a silicate melt at the eutectic point, perhaps in the presence of a water-rich phase.

granite(graphic)2019(1).jpg

Graphic Granite. From James St. John.

Graphic Granite. From Sand Atlas.

Bibliography

• Cox et al. (1979): The Interpretation of Igneous Rocks, George Allen and Unwin, London.
• Howie, R. A., Zussman, J., & Deer, W. (1992). An introduction to the rock-forming minerals (p. 696). Longman.
• Le Maitre, R. W., Streckeisen, A., Zanettin, B., Le Bas, M. J., Bonin, B., Bateman, P., & Lameyre, J. (2002). Igneous rocks. A classification and glossary of terms, 2. Cambridge University Press.
• Middlemost, E. A. (1986). Magmas and magmatic rocks: an introduction to igneous petrology.
• Shelley, D. (1993). Igneous and metamorphic rocks under the microscope: classification, textures, microstructures and mineral preferred-orientations.
• Vernon, R. H. & Clarke, G. L. (2008): Principles of Metamorphic Petrology. Cambridge University Press.

Photo
Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)
Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)
Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)
Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)
Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)
Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 2x (Field of view = 7mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)
Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)
Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)
Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)
Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)
Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)	Quartz and feldspar intergrowth in a granophyre. XPL image, 10x (Field of view = 2mm)