title of the thesis - Department of Geology - Queen's University

the Seti River (Fig. 2.1b, 2.2b; Robinson et al., 2006). This geometry suggests that the TSS south
of the upper Karnali valley and north of the Seti River forms an approximately 35 km wide
synclinorium plunging to the northwest, and closing to the southeast (Fig. 2.1b). This may be due
to crustal-scale buckling of the GHS following south-directed extrusion, as documented in central
Nepal (Godin et al., 2006b) and northwest Bhutan (Antolín et al., 2012; Kellett and Grujic, 2012).
Alternatively, the current geometry may be associated in part with the formation of the Gurla
Mandhata core complex to the northwest (Fig. 2.1b, 2.2b; Murphy and Copeland, 2005).
Mineral elongation lineations and asymmetric fabric elements of the upper Karnali valley
reveal predominant ESE-WNW strike-slip dominated deformation (Murphy and Copeland, 2005).
This contrasts with the typical top-to-the-north STDS structural fabrics, and thus prompted the
interpretation of this shear zone as a component of the normal, right-slip, WNW-striking Gurla
Mandhata-Humla (GMH) fault system (Murphy and Copeland, 2005). This fault system trends
roughly parallel to the strike of the orogen, from the Gurla Mandhata core complex southeast to
the upper Karnali valley, where it forms the contact between the TSS and the GHS (Figs. 2.1,
2.2). Further eastward, the GMH branches south and southeast, along the GHS-TSS contact and
obliquely across the GHS, respectively (Figs. 2.1, 2.2). The GMH is interpreted to accommodate
arc-parallel extension and translation between 15 and 7 Ma (Murphy and Copeland, 2005).
2.4.2 This study
Detailed mapping of transects across and along the upper Karnali valley reveal six
distinct lithotectonic domains. They are, from south to north, (I) folded TSS, (II) transposed TSS,
(III) ultra-high-strain zone, (IV) high-strain quartzite and pelitic GHS, (V) high-strain gneissic
GHS, and (VI) migmatitic GHS (Fig. 2.3). Deformation associated with the GMH is moderate to
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