ABSTRACT

The peraluminous Foulwind and Windy Point Granites are important components of the Foulwind Suite – a diverse group of high field strength element-enriched Carboniferous granitoids in New Zealand’s Western Province. Four phases are identified in the Foulwind Granite (Seal Point, Siberia Bay, Tauranga Bay, Lighthouse). A new age of 324.0 ± 4.1 Ma has been obtained for the relatively undeformed Siberia Bay phase. The rocks are generally enriched in high-field strength elements and the Tauranga Bay and Lighthouse phases can be classified as ferroan A-type granites, whereas classification of the other phases is ambiguous. Sr isotope compositions were disturbed by the formation of the Paparoa Metamorphic Core Complex. Nd isotopes vary considerably and indicate involvement of multiple sources. The Nd isotope and A-type signatures can be explained by melting of mid-Paleozoic I-type granites with variable involvement of Greenland Group metasediments. The tectonic setting of the Foulwind Suite is unclear, but may be related to processes subsequent to the generation of voluminous mid-Paleozoic granitoids and amalgamation of the Buller and Takaka Terranes.

摘要

过铝质 Foulwind 和 Windy Point 花岗岩是 Foulwind Suite 的重要组成部分——新西兰西部省的一组富含高场强元素的石炭纪花岗岩。在逆风花岗岩中确定了四个阶段（海豹点、西伯利亚湾、陶朗加湾、灯塔）。对于相对未变形的西伯利亚湾阶段，已经获得了 324.0 ± 4.1 Ma 的新年龄。岩石通常富含高场强元素，陶朗加湾和灯塔相可归类为铁 A 型花岗岩，而其他相的分类不明确。Paparoa 变质核心杂岩的形成扰乱了 Sr 同位素组成。Nd 同位素变化很大，表明涉及多种来源。Nd 同位素和 A 型特征可以通过中古生代 I 型花岗岩的熔融以及格陵兰组变质沉积物的可变参与来解释。Foulwind Suite 的构造环境尚不清楚，但可能与大量中古生代花岗岩的生成以及 Buller 和 Takaka 地体的合并之后的过程有关。