Fieldwork conducted in the summer of 1998 on Holsnoy Island, western Norway, resulted in the discovery of 47 new outcrop locations which bear eclogite facies pseudotachylytes. The pseudotachylytes exhibit features common to shallow crustal pseudotachylytes, including rip-out zones, paired shears, injection veins, and liquid immisibility textures. Documented field relations show that multiple generations of pseudotachylyte cross cut each other. Field relationships also suggest that the pseudotachylyte formed prior to the eclogite contained in fracture planes and shear zones. In all observed cases the eclogite cross cuts the pseudotachylyte, and in some cases the pseudotachylyte has been eclogitized. Pseudotachylytes and eclogite that are located within 3 m of one another do not appear to be structurally related. Two dominant sets of fractures are found in the eclogite veins. The first set is oriented orthogonally to the eclogite, and was likely formed by hydrofracturing. The second set of fractures is oriented oblique to the eclogite plane and probably formed as a result of shearing during the development of the eclogite. As the fluids were exhausted the rock began to behave in a brittle manner and this would likely be when microfractures were initiated. The fractures that are present throughout the eclogite planes do not appear related to a volume reduction associated with a metamorphic phase transition from granulite to eclogite. / Department of Geology
| Identifer | oai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/186733 |
| Date | January 2000 |
| Creators | Jones, Jonathan L. |
| Contributors | Boundy, Theresa M. |
| Source Sets | Ball State University |
| Detected Language | English |
| Format | ii, 125 leaves : ill., maps (some col.) ; 28 cm. + 1 map (92 x 122 cm.). |
| Source | Virtual Press |
| Coverage | e-no--- |
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