porphyroblast
Look at other dictionaries:
Porphyroblast — [ thumb|right|350px|An almandine garnet growing as a porphyroblast in a quartzitic gneiss. This particular garnet measures 3 cm. Location: Paraíba, Brazil.] A porphyroblast is a large mineral crystal in a metamorphic rock which has grown within… … Wikipedia
Porphyroblast — Weiße Andalusit Porphyroblasten in grauer Matrix aus Whitehills (Schottland) Als Porphyroblasten bezeichnet man in der Mineralogie und Petrologie Einschlüsse von größeren Kristallen einer Mineralart in einer feinkörnigeren Matrix aus anderen… … Deutsch Wikipedia
porphyroblast — por·phyro·blast … English syllables
porphyroblast — … Useful english dictionary
Rock microstructure — includes the texture of a rock and the small scale rock structures. The words texture and microstructure are interchangeable, with the latter preferred in modern geological literature. However, texture is still acceptable because it is a useful… … Wikipedia
Augen — are large, lenticular eye shaped mineral grains or mineral aggregates visible in some foliated metamorphic rocks. In cross section they have the shape of an eye. Feldspar, quartz, and garnet are common minerals which form augen.Augen form in… … Wikipedia
Undulose extinction — is a geological term referring to the type of extinction that occurs in certain minerals when examined in thin section under cross polarized light. As the microscope stage is rotated, individual mineral grains appear black when the polarization… … Wikipedia
Porphyroclast — A porphyroclast is a clast or mineral fragment in a metamorphic rock, surrounded by a groundmass of finer grained crystals. Porphyroclasts are fragments of the original rock before dynamic recrystallisation produced the groundmass. This means… … Wikipedia
Massif Central (geology) — The Massif Central forms together with the Armorican Massif (Brittany and Normandy) one of the two big basement massifs in France. Its geological evolution started in the late Neoproterozoic and continues to this day. It has been shaped mainly by … Wikipedia
Geologie des Zentralmassivs — Die Geologie des Zentralmassivs beginnt im Neoproterozoikum, und seine Entstehungsgeschichte hält bis auf den heutigen Tag an. Das Zentralmassiv (franz. Massif Central) ist mit dem Armorikanischen Massiv eines der beiden großen… … Deutsch Wikipedia
