| Summary: | Rocks of the Millen Schists were analysed during GANOVEX X (2009/10) to evaluate the nature of the contact between the Ross-age Bowers and Robertson Bay Terranes in northern Victoria Land. The majority of this work was carried out in proximity to the Millen Thrust System, a major structure that separates the whole Millen Shear Belt into two overlying tec tonic units. The Millen Shear Belt has been widely acknowledged to repre sent the tectonic contact between the two terranes. Lithological similarities between the rocks in the hanging wall and footwall of the Millen Thrust Sys tem and those located in the Bowers and Robertson Bay Terranes support this suggestion. The structural history of the Millen Schists can be divided into three stages: (i) formation of isoclinal folds and pervasive S1 foliation that largely parallels bedding S0; (ii) upright D2 folding along northwest-south east axes and (iii) localised D3 high-strain that was dominantly related to reverse transport along the Millen Thrust System. Interpretations based on field observations and the available geochronological data supports a model where: (i) sub-horizontal northeast-southwest directed pure shear shortened the juxtaposed (by the late Cambrian) Bowers and Robertson Bay terranes; (ii) strain localisation along the Millen Thrust System resulted in the devel opment of a complex finite strain pattern in the Millen Schists, which records evidence of dominant northeast directed reverse transport with minor lateral displacement.
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