Geological Society of London
m49.14_si_003.jpg (1.93 MB)

Fig. S2. Sedimentary geochemistry used to infer the provenance of Permian–Triassic marine sandstones related to the SE Gondwana active continental margin, South Island, New Zealand

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posted on 2019-02-13, 15:32 authored by Alastair H.F. Robertson, Romesh Palamakumbura
Photomicrographs of sandstones. (a)–(f) From the Permian–Triassic succession exposed at Parapara Peak, Takaka Terrane, Western Province. (a) Large, rounded grain of microcrystalline quartz (translucent; central) set in smaller angular to sub-rounded quartz grains, together with some plagioclase; GPS WSG 84 E24 82605 N60 40305; viewed under plane polarized light (PPL); Parapara section, Flowers Formation; Western Province. (b) Foliated siltstone lithoclast (partially recrystallized) within detrital grains of mostly quartz and plagioclase (as in a). The brown mineral is neomorphic biotite; viewed under PPL; Flowers Formation; Parapara section. (c) Large, sub-angular grain of altered feldspar (orthoclase) within smaller mostly angular to sub-angular grains, including common polycrystalline (detrital metamorphic) quartz; viewed under crossed nicols; Flowers Formation; Parapara section. (d) Upper left: polycrystalline quartz grain; centre right: large uniform monocrystalline quartz grain, of probable plutonic rock origin; note the incipient cleavage development picked out by neomorphic biotite; viewed under crossed nicols; Flowers Formation; Parapara section. (e) Large detrital grain of monocrystalline quartz showing incipient recrystallization at the edges, together with recrystallization of finer-grained quartz and biotite; viewed under plane crossed nicols; Flowers Formation; Parapara section. (f) Rounded monocrystalline quartz which cracked prior to final deposition; note the incipient cleavage picked out by biotite; Walker Formation; Parapara section.