Record of deformation by secondary magnetic remanences and magnetic anisotropy in the Nar/Phu valley (central Himalaya)

The Chako antiform: A folded segment of the Greater Himalayan sequence, Nar valley, Central Nepal Himalaya

“…8(D)). The south-verging structures at the northern contact in Kyang may be explained by overprinting of a late, south-verging outof-sequence thrust, similar to thrust faults documented nearby in the village of Phu (Schill et al, 2003;Searle and Godin, 2003). D 2 deformation within the Chame detachment have the same characteristics (transposition, mineral lineation and shear sense indicators) as the D 2L high strain zones within the Lower Level.…”

“…The Mutsog synform and Chako antiform are a non-cylindrical antiform-synform pair, recording this younger contraction. Secondary magnetic remanences of samples from the north limb of the Chako antiform also record a late clockwise rotation mimicking the rotation of the fold limb of these folds (Schill et al, 2003).…”

“…Crustalscale folding is considered to represent D 3 deformation, since it folds D 2 structures (i.e. the contact between levels) and locally rotates S 2U fabrics in the core of the Mutsog synform (Schill et al, 2003). D 2L and D 2U features are deformed by a locally developed brittle spaced S 4 cleavage.…”

“…The S 2U crenulation cleavage may have formed during emplacement of the Upper Level on the Lower Level during biotite-grade retrograde metamorphism in both levels. Alternatively, the S 2U crenulation cleavage may have formed during later, renewed south verging deformation (Schill et al, 2003;Searle and Godin, 2003).…”

Temperature and age constraints on the metamorphism of the Tethyan Himalaya in Central Nepal: A multidisciplinary approach

“…Therefore the 150% thickening associated to D2 could explain the observed temperature. Whatever, palaeomagnetic investigations performed in the Dolpo-Manang area (Appel et al, 1991;Crouzet et al, 2001aCrouzet et al, , 2003Schill et al, 2003) have evidenced a post-deformation remanence acquisition carried by pyrrhotite. This remanence is acquired during the cooling just below 320°C (Rochette, 1987;Dunlop et al, 2000).…”