Fig. S1. Construction of a Paleozoic–Mesozoic accretionary orogen along the active continental margin of SE Gondwana (South Island, New Zealand): summary and overview

Petrographic features of semi-schists from East Bald Hill (northern Southland). (a) Weakly cleaved volcaniclastic sandstone, with relict elongated clasts of feldspar-phyric extrusive rock in a pelitic matrix; sample N13.134, equivalent of the West Burn Semischist, Caples Terrane; upper northern slopes of East Bald Hill, northern Southland, S45 35790 E 168 16473, viewed under plane polarized light (PPL). (b) Subangular grain of monocrystalline (volcanic) quartz, with strain shadows in sheared volcanogenic matrix; sample N13.137, equivalent of the West Burn Semischist, Caples Terrane; upper northern slopes of East Bald Hill, northern Southland, S45 35523 E 168 16531, viewed under PPL. (c) Volcaniclastic microconglomerate; altered basaltic clast within sheared (relatively incompetent) volcaniclastic fine-grained sandstone/phyllite; sample N13.135, equivalent of the West Burn Semischist, Caples Terrane; upper northern slopes of East Bald Hill, Caples Terrane, S45 35790 E 168 16473, viewed under PPL. (d) Polyphase shearing and folding in partially recrystallized volcaniclastic sandstone/microconglomerate. Note truncation of inclined shear fabric by later-stage sub-horizontal shear fabric; sample N13.135, equivalent of the West Burn Semischist, Caples Terrane; NW upper slope of East Bald Hill, northern Southland; S45 35790 E 168 16473, viewed under PPL. (e) Weakly cleaved volcaniclastic sandstone cut by veins (chlorite-rich) that were later folded; sample N13.135, equivalent of the West Burn Semischist, Caples Terrane; upper northern slopes of East Bald Hill, northern Southland, S45 35790 E 168 16473, viewed under PPL. (f) As above, but showing asymmetrical (top-right) microfolds, viewed under PPL.