Microtectonics
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Picture 1a: Prograde fabric eclogite, Maksyutov Complex, Southern Urals, Russia
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Prograde, subduction-related fabric in a glaucophane-bearing eclogite from the high-P/low-T Maksyutov Complex (Southern Urals). A prograde foliation S1 (horizontal) defined by fine-grained glaucophane (right side of photomicrograph) has been overgrown by garnet (left half of photomicrograph) and omphacite (green crystals in the right part of picture). Both garnet and the omphacite contain straight internal inclusion trails oriented parallel to the external S1 foliation. The chemical zonation of the garnet and the fact that the number and size of inclusions in the garnet decrease from the center toward its rim demonstrate garnet growth during the prograde metamorphic evolution. Scale bar in upper right is 150 µm long.
Related Publications:
Hetzel et al. (1998). Subduction- and exhumation-related fabrics in the Paleozoic high-P/low-T Maksyutov Complex, Antingan area, Southern Urals, Russia. Geological Society of America Bulletin 110, 916-930.
Picture 1b: as Picture 1a but with crossed-polarized light
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Prograde, subduction-related fabric in a glaucophane-bearing eclogite from the high-P/low-T Maksyutov Complex (Southern Urals). A prograde foliation S1 (horizontal) defined by fine-grained glaucophane (right side of photomicrograph) has been overgrown by garnet (left half of photomicrograph) and omphacite (green crystals in the right part of picture). Both garnet and the omphacite contain straight internal inclusion trails oriented parallel to the external S1 foliation. The chemical zonation of the garnet and the fact that the number and size of inclusions in the garnet decrease from the center toward its rim demonstrate garnet growth during the prograde metamorphic evolution. Scale bar in upper right is 150 µm long.
Related Publications:
Hetzel et al. (1998). Subduction- and exhumation-related fabrics in the Paleozoic high-P/low-T Maksyutov Complex, Antingan area, Southern Urals, Russia. Geological Society of America Bulletin 110, 916-930.
Picture 2: Lawsonite mylonite, Maksyutov Complex, Southern Urals, Russia
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Retrograde mylonite with stable! lawsonite from the high-P/low-T Maksyutov Complex Complex (Southern Urals). The mylonitic foliation in the photomicrograph is horizontal. Light-grey crystals with high relief are lawsonite (several occur just below the center of the image). The few green grains are chlorite and the dark minerals are titanite (sphene). Lawsonite, chlorite and titanite are synkinematic with respect to the mylonitic defomation, which must have occurred in the stability field of lawsonite. Scale bar next to large chlorite crystal in lower left is 250 µm long.
Related Publications:
Hetzel et al. (1998). Subduction- and exhumation-related fabrics in the Paleozoic high-P/low-T Maksyutov Complex, Antingan area, Southern Urals, Russia. Geological Society of America Bulletin 110, 916-930.
Picture 3: Boudinage of mica, Menderes Massif, SW Turkey
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Thin section photograph (crossed-polarized light) of boudinaged muscovite porphyroblasts that grew in the contact aureole of a granodiorite intrusion (Menderes Massif, SW Turkey). Picture provides evidence for ongoing deformation after the intrusion of the granodiorite. Width of photograph is 5 mm.
Related Publications:
Glodny J., Hetzel, R. (in press). Precise U-Pb ages of syn-extensional Miocene intrusions in the central Menderes Massif, western Turkey. Geological Magazine.
Hetzel et al. (1995). Miocene NNE-directed extensional unroofing in the Menderes Massif, SW Turkey. Journal of the Geological Society of London 152, 639-654.
Picture 4: Crenulation cleavage, Menderes Massif, SW Turkey
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Thin section photograph (cross-polarized light) of crenulation cleavage in greenschist facies metasediments (Menderes Massif, SW Turkey). The vertical crenulation cleavage (S2) overprints an older fabric (S1). Both cleavages are defined by white mica. Width of photograph is 2.5 mm.
Picture 5: Bookshelf feldspar, Menderes Massif, SW Turkey
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Thin section photograph (plane-polarized light) of feldspar cut by microfaults (Menderes Massif, SW Turkey). Rectangular fragments of the original magmatic feldspar have been rotated in a bookshelf manner (i.e. as small-scale tilted "fault blocks"). Note growth of green chlorite along the microfaults indicating greenschist-facies conditions during deformation. Width of photograph is 5 mm.
Related Publications:
Hetzel et al. (1995). Miocene NNE-directed extensional unroofing in the Menderes Massif, SW Turkey. Journal of the Geological Society of London 152, 639-654.
Picture 6: Andalusite surrounded by graphite, Menderes Massif, SW Turkey
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Andalusite porphyroblast in the contact aureole of a Miocene granodiorite (Menderes Massif, SW Turkey). During growth of the porphyroblast abundant graphite has accumulated at the margin of the andalusite. The andalusite constrains the intrusion depth of the Miocene granodiorite to less than 10 km.
Related Publications:
Glodny J., Hetzel, R. (in press). Precise U-Pb ages of syn-extensional Miocene intrusions in the central Menderes Massif, western Turkey. Geological Magazine.
Picture 7a: Cataclasite, stage 1
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Thin section photograph (cross-polarized light) of a cataclastic rock illustrating an incipient stage of cataclasis (Menderes Massif, SW Turkey). The cataclasite is characterized by many intragranular fractures that displace individual mineral fragments. The cataclasite was derived from a Miocene granodiorite, which can be recognized from the oscillatory zoning (formed during magmatic crystallization) of large plagioclase fragments (e.g. lower right part of picture). Width of photograph is 2.5 mm.
Related Publications:
Hetzel et al. (1995). Miocene NNE-directed extensional unroofing in the Menderes Massif, SW Turkey. Journal of the Geological Society of London 152, 639-654.
Picture 7b: Cataclasite, stage 2
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Thin section photograph (cross-polarized light) of a cataclasite showing an advanced stage of cataclasis (Menderes Massif, SW Turkey). The individual mineral fragments occur in a dark matrix of fine-grained chlorite and crushed mineral fragments. The dark-blue minerals left of the center are chlorite minerals, which formed from magmatic biotite. Locally fragments of zoned plagioclase can still be recognized (e.g. at the bottom in the center of the image). The cataclasite has been derived from a Miocene granodiorite and formed along a spectacular detachment fault (Picture 7 of the photographs related to Faulting and Neotectonics). Width of photograph is 2.5 mm
Related Publications:
Hetzel et al. (1995). Miocene NNE-directed extensional unroofing in the Menderes Massif, SW Turkey. Journal of the Geological Society of London 152, 639-654.
