Ophitic Texture

Ophitic texture, a variant the Poikilitic texture, is one where random plagioclase laths are enclosed by pyroxene or olivine. If plagioclase is larger and encloses the ferromagnesian minerals, then the texture is subophitic and the laths typically impinge on one another to form sharp angles. Note that the change from intergranular through subophitic to ophitic textures in basaltic rocks results from slower cooling and slower nucleation rates.

This textural sequence is typically found at the margins toward the center in diabasic or doleritic rocks (basaltic dikes) or from the chilled surface to depth of basaltic flows. If the cooling rate is very fast, the interstitial material between plagioclase laths may be quenched to glass to form an intersertal texture.

Bibliography



• Ron H. Vernon (2004): A pratical guide to rock microstructure. Cambridge editore
• Rocchi S. (1993): Meccanismi di cristallizzazione e strutture delle rocce ignee. SEU Pisa.
• David Shelley (1983): Igneous and metamorphic rocks under the microscope. Campman & Hall editori.


Photo
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Augite Crystals with plagioclase inclusions. Patagonia. XPL image , 10x (Field of view = 2mm)
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Augite Crystals with plagioclase inclusions. Patagonia. XPL image , 10x (Field of view = 2mm)
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Augite Crystals with plagioclase inclusions. Patagonia. XPL image , 10x (Field of view = 2mm)
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Augite Crystals with plagioclase inclusions. Patagonia. XPL image , 10x (Field of view = 2mm)
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Augite Crystals with plagioclase inclusions. Patagonia. PPL image , 10x (Field of view = 2mm)
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Augite Crystals with plagioclase inclusions. Patagonia. XPL image , 10x (Field of view = 2mm)
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Augite Crystals with plagioclase inclusions. Patagonia. PPL image , 2x (Field of view = 7mm)
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Augite Crystals with plagioclase inclusions. Patagonia. XPL image , 2x (Field of view = 7mm)
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Augite Crystals with plagioclase inclusions. Patagonia. PPL image , 2x (Field of view = 7mm)
doleritecpxpecilitici(5).jpg

Augite Crystals with plagioclase inclusions. XPL image , 10x (Field of view = 2mm)
doleritecpxpecilitici(7).jpg

Augite Crystals with plagioclase inclusions. PPL image , 10x (Field of view = 2mm)
doleritecpxpecilitici(8).jpg

Augite Crystals with plagioclase inclusions. XPL image , 10x (Field of view = 2mm)
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Augite Crystals with plagioclase inclusions. XPL image , 2x (Field of view = 7mm)
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Augite Crystals with plagioclase inclusions. PPL image , 2x (Field of view = 7mm)
ofiticaaa(5).jpg

Augite Crystals with plagioclase inclusions. XPL image , 2x (Field of view = 7mm)
ofiticaaa(7).jpg

Augite Crystals with plagioclase inclusions. XPL image , 2x (Field of view = 7mm)
doleritecpxpecilitici(9).jpg

Augite Crystal with plagioclase inclusions. XPL image , 10x (Field of view = 2mm)
ofiticaaa(12).jpg

Augite Crystals with plagioclase inclusions. XPL image , 10x (Field of view = 2mm)
ofiticaaa(10).jpg

Augite Crystals with plagioclase inclusions. XPL image , 2x (Field of view = 7mm)
doleritecpxpecilitici1(4).jpg

Augite Crystals with plagioclase inclusions. XPL image , 2x (Field of view = 7mm)
doleritecpxpecilitici1(5).jpg

Augite Crystals with plagioclase inclusions. XPL image , 2x (Field of view = 7mm)
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Augite Crystals with plagioclase inclusions. XPL image , 2x (Field of view = 7mm)
ofitica0129(3).jpg

Augite Crystals with plagioclase inclusions. XPL image , 2x (Field of view = 7mm)
ofitica0129(4).jpg

Augite Crystals with plagioclase inclusions. XPL image , 2x (Field of view = 7mm)
ofitica0129(7).jpg

Augite Crystals with plagioclase inclusions. XPL image , 2x (Field of view = 7mm)
ofitica0129(9).jpg

Augite Crystals with plagioclase inclusions. XPL image , 2x (Field of view = 7mm)