Paleozoic alkaline and related igneous rocks of Australia GIS

Alkaline and related rocks are a relatively rare class of igneous rocks worldwide. Alkaline rocks encompass a wide range of rock types and are mineralogically and geochemically diverse. They are typically though to have been derived by generally small to very small degrees of partial melting of a wide range of mantle compositions. As such these rocks have the potential to convey considerable information on the evolution of the Earth’s mantle (asthenosphere and lithosphere), particularly the role of metasomatism which may have been important in their generation or to which such rocks may themselves have contributed. Such rocks, by their unique compositions and or enriched source protoliths, also have considerable metallogenic potential, e.g., diamonds, Th, U, Zr, Hf, Nb, Ta, REEs. It is evident that the geographic occurrences of many of these rock types are also important, and may relate to presence of old cratons, craton margins or major lithospheric breaks. Finally, many alkaline rocks also carry with them mantle xenoliths providing a snapshot of the lithospheric mantle composition at the time of their emplacement.Accordingly, although Alkaline and related rocks comprise only a volumetrically minor component of the geology of Australia, they are of considerable importance to studies of lithospheric composition, evolution and architecture and to helping constrain the temporal evolution of the lithosphere, as well as more directly to metallogenesis and mineralisation.This GIS product is part of an ongoing compilation of the distribution and geology of alkaline and related rocks throughout Australia. The accompanying report document alkaline and related rocks of Paleozoic age.

碱性岩及相关岩石是全球范围内相对稀少的一类火成岩。碱性岩涵盖了广泛的岩石类型，在矿物学与地球化学维度均表现出显著多样性。通常认为，这类岩石源自多种地幔组分经历低程度至极低程度的部分熔融作用。正因如此，此类岩石能够为地球地幔（软流圈与岩石圈）的演化提供大量关键信息，尤其是交代作用的相关角色——交代作用可能在其形成过程中发挥了重要作用，且这类岩石本身也可能对交代作用有所贡献。这类岩石凭借其独特的组分与富集的源区原岩，还具备可观的成矿潜力，可产出金刚石、钍（Th）、铀（U）、锆（Zr）、铪（Hf）、铌（Nb）、钽（Ta）以及稀土元素（REEs）。值得注意的是，多数此类岩石的地理产出位置同样具有重要研究价值，其分布可能与古老克拉通、克拉通边缘或重大岩石圈断裂的存在密切相关。此外，许多碱性岩还携带有地幔捕虏体，可直观展现其侵位时期的岩石圈地幔组分特征。因此，尽管碱性岩及相关岩石在澳大利亚地质体积占比极低，但它们对于岩石圈组分、演化与结构的研究，以及约束岩石圈的时间尺度演化均具有重要意义，同时也对成矿作用与矿产资源勘探有着直接的指导价值。本地理信息系统（GIS）产品是当前正在进行的澳大利亚全境碱性岩及相关岩石分布与地质特征汇编工作的一部分。随附报告对古生代时期的碱性岩及相关岩石进行了系统记述。