کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4733563 1357036 2011 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Key-ring structure gradients and sheath folds in the Goantagab Domain of NW Namibia
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
پیش نمایش صفحه اول مقاله
Key-ring structure gradients and sheath folds in the Goantagab Domain of NW Namibia
چکیده انگلیسی

The concept of deformation phases is one of the corner stones of structural geology but, despite its simplicity, there are situations where the concept breaks down. In the Goantagab Domain of NW Namibia, structures in an area of complex deformation can be subdivided into at least four sets, attributed to four deformation phases on the basis of overprinting relations. Three of these sets of structures, however, formed during the same tectonic event under similar metamorphic circumstances but slightly different flow conditions. These sets of structures show gradational transitions in space that can be understood by a concept of “key-ring structure gradients”, where older DA structures are reoriented and overprinted by new structures DA+1 that have similar orientation, and seem to grade into DA structures outside the overprinted area. This kind of behaviour may be common in inhomogeneous non-coaxial flow. In the core of the Goantagab Domain, D2 structures are thus reoriented and overprinted by local D2b folds and foliations that have the same orientation and style as D2 structures outside the domain core.

Research highlights
► We study complex low-grade deformation in Neoproterozoic metaturbidites in Namibia.
► Deformation is Cambrian in age and is part of the Damara orogenesis.
► The presence of syntectonic granites led to deformation gradients and sheath folding.
► Some foliations are only locally developed and form key-ring structural gradients

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Structural Geology - Volume 33, Issue 3, March 2011, Pages 280–291
نویسندگان
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