Album 4 - High-Pressure Shock Metamorphism
"Science Related" not "Scientifically Related"
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Additional photos for section 4, covering impact structure criteria 5, high-pressure shock
metamorphism evidence.
Microscopic view of four of the mineral grains, ranging in sizes from 1 to 1 1/2 mm, from the group shown on the far right. With no ability to view thin
sections or etch the grains, I viewed the larger and more transparent grains using the 300x option.
Blocks ranges in size from 2 1/2 to 3 1/2 mm. Although the photos are macro mode photo shots, multiple sets of
intersecting lines or shock lamellae, the shock-induced micro twinning along with strong rhombohedral planar
deformation features (PDFs) can be seen without the aid of a magnifier. In photos 5 & 6, the blocks appearance is
much like quartz. Quartz conglomerate with shock-induced fractured quartz pebbles (photo 7). Small magnetic
breccia consisting of quartz and other minerals held together by impact melt substances (photo 8).
Close-ups of quartz blocks showing rhombohedral
features, multiples sets of planar deformation features
or shock lamellae and planar fractures (photos 1 - 9).
Micro-twinning in the smaller nondescript quart block
shown in photo 7 at top of page.
Photo 1
Photo 9
Photo 8
Photo 7
Photo 6
Photo 5
Photo 4
Photo 3
Photo 2
Photo 1
Photo 6
Photo 4
Photo 3
Photo 5
Photo 2
Photo 10
Quartz conglomerate with shock fractured milky and transparent quartz crystals. Bright points show within each crystals held together by a fine-grain
yellowish-white matrix (photos 1 - 3). Fractured quartz within magnetic impact breccia consisting of quartz and other minerals held together by
impact melt substance (photos 4 & 5).
Photo 8
Photo 1
Photo 5
Photo 4
Photo 3
Photo 2
Photo 5
Photo 4
Photo 3
Photo 2
Photo 1
Planar deformation features on quartz grain transform to glass (diaplectic glass or thetomorph of quartz - photo 1). Polymorphs and thetomorphs of
quartz (photos 2 - 5).
Shock-induced quartz crystals converted to glass.
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Transparent to semi-transparent crystals found at the point of impact or the exact center of one of the small impact structures. Due to the many faces
and different shapes and sizes of those faces, it is difficult to discern the shape of the crystals structure. The faces do have similarities in shape and
being unfinished in form to the layers seen on the glass-like carbon.
Photo 7