Tephrite

Tephrite (and their subvolcanic equivalent) form by far the largest volume of magmatic rocks in the Kaiserstuhl. Only in the western part of the complex, volcanic structures are exposed, where individual centers, parasitic to the main Kaiserstuhl volcano, are recognized. The outcrop of Blankenhornsberg shows a series of lava flow with intercalated tephritic breccias. In the Blankenhornsberg tephrite, augite and magnetite phenocrysts and leucite micro-phenocrysts are set in brown glassy matrix.

Bibliography

• Ulianov, A., Müntener, O., Ulmer, P., & Pettke, T. (2007). Entrained macrocryst minerals as a key to the source region of olivine nephelinites: Humberg, Kaiserstuhl, Germany. Journal of Petrology, 48(6), 1079-1118.
• Walter, B. F., Marks, M. A. W., & Markl, G. (2016). The Kaiserstuhl natural laboratory-an introduction and first results. Abstract Malawi Expert Council.
• Weisenberger, T. B., Spürgin, S., & Lahaye, Y. (2014). Hydrothermal alteration and zeolitization of the Fohberg phonolite, Kaiserstuhl Volcanic Complex, Germany. International Journal of Earth Sciences, 103(8), 2273-2300.
• Weisenberger, T., & Spuergin, S. (2009). Zeolites in alkaline rocks of the Kaiserstuhl Volcanic Complex, SW Germanyâ€“new microprobe investigation and the relationship of zeolite mineralogy to the host rock. Geologica Belgica

Photo
Augite, magnetite phenocrysts and leucite micro-phenocrysts (rounded colorless crystals) set in brown glassy matrix. Tephrite from Blankenhornsberg. PPL image, 2x (Field of view = 7mm)	Augite (high birefringence), magnetite phenocrysts and leucite micro-phenocrysts set in brown glassy matrix. Tephrite from Blankenhornsberg. XPL image, 2x (Field of view = 7mm)	Augite, magnetite phenocrysts and leucite micro-phenocrysts (rounded colorless crystals) set in brown glassy matrix. Tephrite from Blankenhornsberg. PPL image, 2x (Field of view = 7mm)
Augite (high birefringence), magnetite phenocrysts and leucite micro-phenocrysts set in brown glassy matrix. Tephrite from Blankenhornsberg. XPL image, 2x (Field of view = 7mm)	Augite, magnetite phenocrysts and leucite micro-phenocrysts (rounded colorless crystals) set in brown glassy matrix. Tephrite from Blankenhornsberg. PPL image, 2x (Field of view = 7mm)	Augite (high birefringence), magnetite phenocrysts and leucite micro-phenocrysts set in brown glassy matrix. Tephrite from Blankenhornsberg. XPL image, 2x (Field of view = 7mm)