K-rich mantle metasomatism control of localization and initiation of lithospheric strike-slip faulting
Vaughan, Alan P.M.; Scarrow, Jane H.. 2003 K-rich mantle metasomatism control of localization and initiation of lithospheric strike-slip faulting. Terra Nova, 15 (3). 163-169. 10.1046/j.1365-3121.2003.00485Before downloading, please read NORA policies.
Text (Final revised version)
A conceptual model is proposed where bulk transtension, or local transtension during bulk simple shear (resulting from mantle anisotropy- or lithosphere rheology contrasts), of heterogeneously enriched lithospheric mantle, trigger localised K-rich magmatism, which focusses strain and causes nucleation of lithosphere-scale transtensional or strike-slip shear zones. Transtension-triggered magmatism is most likely to be located at sites of maximum metasomatism of the lithospheric mantle. Magma-generated fractures propagate upwards, nucleating zones of lithospheric weakness, which focus shear in narrow transcurrent faults or at basin margins. In this way, magmatism controls fault timing and location. Although volcanism will be coeval with fault development and volcanoes will appear fault-controlled, counterintuitively, our model suggests that faults are, in a sense, volcano-controlled. We suggest that this new transtension–K-rich magmatism–transcurrent faulting association represents a hitherto unrecognised genetic relationship as significant as, for example, the ocean island magma series.
|Programmes:||BAS Programmes > Antarctic Science in the Global Context (2000-2005) > Antarctica in the Dynamic Global Plate System|
|Additional Keywords:||lamprophyre, structural geology, igneous petrogenesis|
|NORA Subject Terms:||Earth Sciences|
|Date made live:||25 Nov 2008 10:19|
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