Crystalline hornfels of the inner hornfels zone (Andalusite-Cordierite hornfels)

The sample is a crystalline hornfels containing large andalusite porphyroblasts and cordierite poikiloblasts within a matrix dominated by biotite and feldspar. Andalusite porphyroblasts are up to 2 cm in size and contain chiastolite-like inclusions, albeit poorly developed. Cordierite poikiloblasts are up to 8 mm in size and exhibit twinning, including sector twins.

Crystalline hornfels of the inner hornfels zone.

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Panoramic view of crystalline hornfels of the inner hornfels zone (Andalusite-Cordierite hornfels) thin section. Image by Andy Tindle (Virtual Microscope). PPL image, field of view = 2.5cm.

Panoramic view of crystalline hornfels of the inner hornfels zone (Andalusite-Cordierite hornfels) thin section. Image by Andy Tindle (Virtual Microscope). XPL image, field of view = 2.5cm.

Bibliography

• David Shelley (1983): Igneous and metamorphic rocks under the microscope. Campman & Hall editori.
• Gray.E Bebout; Derek. C Cooper; A. Don Bradley; Seth J. Sadofsky (1999): Nitrogen-isotope record of fluid-rock interactions in the Skiddaw Aureole and granite, English Lake District. American Mineralogist, Volume 84, pages 1495–1505, 1999

Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 2x (Field of view = 7mm)	Andalusite crystal and rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)	Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 2x (Field of view = 7mm)
Andalusite crystal and rounded cordierite crystal (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)	Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 2x (Field of view = 7mm)	Andalusite crystal and rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)
Andalusite crystals in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 2x (Field of view = 7mm)	Andalusite crystals and rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)	Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 2x (Field of view = 7mm)
Andalusite crystals and rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)	Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 2x (Field of view = 7mm)	Andalusite crystals in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 2x (Field of view = 7mm)
Andalusite crystals in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 2x (Field of view = 7mm)	Andalusite crystals and rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)	Rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)
Rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)	Rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)	Andalusite crystals in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 10x (Field of view = 2mm)
Andalusite crystals in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 10x (Field of view = 2mm)	Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 10x (Field of view = 2mm)	Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 10x (Field of view = 2mm)
Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 10x (Field of view = 2mm)	Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 10x (Field of view = 2mm)	Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 10x (Field of view = 2mm)
Andalusite crystals in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 10x (Field of view = 2mm)	Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 10x (Field of view = 2mm)	Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 10x (Field of view = 2mm)
Andalusite crystals in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 10x (Field of view = 2mm)	Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 10x (Field of view = 2mm)	Andalusite crystal in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 10x (Field of view = 2mm)
Andalusite crystals and rounded cordierite crystals in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 1,25x (Field of view = 9mm)	Andalusite crystals and rounded cordierite crystals with sector twinning in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 1,25x (Field of view = 9mm)	Andalusite crystals and rounded cordierite crystals in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 1,25x (Field of view = 9mm)
Rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)	Andalusite crystal and rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)	Rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)
Rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)	Rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)	Rounded cordierite crystals (with sector twinning) in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. XPL image, 2x (Field of view = 7mm)
Andalusite crystals and rounded cordierite crystals in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 2x (Field of view = 7mm)	Andalusite crystals and rounded cordierite crystals in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 2x (Field of view = 7mm)	Andalusite crystals and rounded cordierite crystals in a matrix dominated by biotite. Roughtenghyll, Cumbria, England. PPL image, 2x (Field of view = 7mm)
Rounded cordierite crystals with sector twinning. Roughtenghyll, Cumbria, Inghilterra. Roughtenghyll, Cumbria, England. XPL image, 10x (Field of view = 2mm)