Earth Sciences 2: Introduction to Metamorphic Rocks

Metamorphic Microstructures

This is a set of photomicrographs illustrating metamorphic textures, arranged as a slide show. You can either follow the sequence through in order, or else scroll down the list below (which roughly follows the outline of lecture 3) and click on individual terms.

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Textural equilibration
Granoblastic texture Granoblastic-polygonal texture Decussate texture

Deformation and recrystallisation in low-grade rocks
Relic sedimentary texture Relic igneous textures Recovery, recrystallisation of quartz Kinking of mica

Preferred orientation and metamorphic fabrics
Shape orientation Schistosity Lineation

Textures reflecting nucleation and growth patterns
Porphyroblastic texture Hornfelsic texture Poikiloblastic texture
Inclusion patterns - andalusite Inclusion patterns - garnet Idioblastic (euhedral)

Disequilibrium textures - reactions and restricted mass transfer
Pseudomorphs Reaction rims 1 Reaction rims 2 Symplectites

Sequences of deformation and mineral growth
Rotated porphyroblast Rotational porphyroblast Helicitic porphyroblast

Emergency Exit to Course Materials

DJW - August 1997