Fig. S1. Geological development and regional significance of an oceanic magmatic arc and its sedimentary cover: Permian Brook Street Terrane, South Island, New Zealand

Major element oxide crossplots of volcaniclastic sandstones from the Brook Street Terrane.(<b>a</b>) CaO v. SiO<sub>2</sub> plot showing general inverse correlation; (<b>b</b>) MgO v. SiO<sub>2</sub> showing a general inverse correlation; (<b>c</b>) Fe<sub>2</sub>O<sub>3</sub> v. MgO showing a general positive correlation; (<b>d</b>) MnO v. MgO again showing a general positive correlation; (<b>e</b>) CaO v. MgO showing general positive correlation for Takitiumu Mountain and some Nelson area samples, but with some exceptions from the Nelson area; (<b>f</b>) K<sub>2</sub>O v. MgO showing a general inverse correlation.