Cenozoic noncoaxial transtension along the western shoulder of the Ross Sea, Antarctica, and the emplacement of McMurdo dyke arrays |
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Authors: | F Rossetti F Storti & F Salvini |
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Institution: | Dipartimento di Scienze Geologiche, Università'Roma Tre', Largo S. L. Murialdo 1, 00146 Rome, Italy,;Dipartimento di Scienze Geologiche, Università'Roma Tre', Largo S. L. Murialdo 1, 00146 Rome, Italy,;Dipartimento di Scienze Geologiche, Università'Roma Tre', Largo S. L. Murialdo 1, 00146 Rome, Italy |
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Abstract: | Field data on Cenozoic faults and the McMurdo dyke arrays in the Reeves Glacier–Mawson Glacier area, Victoria Land, Antarctica, allow us to support noncoaxial transtensional tectonics along the N–S-trending western shoulder of the Ross Sea. Dyke injection within a crustal-scale right-lateral strike-slip shear zone is testified by magma filled, tension gash-like arrangements within some master fault zones, and by the left-stepping arrangements of dykes in the intrafault zones. The noncoaxiality of deformation is shown by the re-activation of many dyke walls as right-lateral strike-slip faults. This suggests an increase in the strike-slip component over time along the western shoulder of the Ross Sea. Our data support the relevance of transtensional to strike-slip tectonics for triggering melting and controlling the geometry and modes of magma emplacement. |
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