科研之友
微信
新浪微博
Facebook
分享链接
摘要
Australia%26apos;s Large Igneous Provinces (LIPs) span almost the entire Earth%26apos;s geological history, ranging from Early Archean to Recent. LIPs in continental Australia are represented by continental flood basalts, fragments of oceanic plateaux, volcanic rifted margins, layered mafic-ultramafic intrusions, sill complexes, dyke swarms and silicic-dominated volcanic provinces. In the last decade or so, several geologists have started to focus on LIPs in Australia, mainly from the perspective of their mineral potential, particularly after the discovery of the Nebo-Babel Ni-Cu-PGE deposit in the West Musgrave Province, central Australia. Wingate et al. (2004a) further advanced the inventory of LIPs with the announcement of a new LIP (ca. 1070 Ma Warakurna, extending for nearly 1500 km along an E-W trend), based on U-Pb dating of baddeleyite from mafic sills and dykes. The list of LIPs increased by including other well-known igneous provinces, such as the Fortescue, Hart-Carson, Kalkarindji (formerly known as Antrim Plateau Volcanics) and various dyke swarms (e.g., Widgiemooltha, Marnda Moorn, Gairdner). The Bunbury Basalt, although only covering a small area in the Cape Naturaliste-Cape Leeuwin Peninsula, joined the list of LIPs, due to its age links with the huge Kerguelen Plateau in the Indian Ocean. As indicated by the world-class Nebo-Babel deposit (%26gt; 1 Mt contained metal) and further discoveries in the West Musgrave and in the Kimberley region, the LIPs in these regions have good mineral potential. In the case of orthomagmatic mineral systems, the selection of areas or specific intrusions requires focusing on trace- and major-element geochemical trends to filter out mafic-ultramafic intrusions that may not have undergone sulphur saturation from those that have experienced sulphur saturation from processes, such as crustal contamination. In addition, consideration must be given to hydrothermal mineral systems that may have been generated as a result of thermal energy inputs, related to the emplacement into the crust of mafic-ultramafic magmas, as exemplified by recent discoveries in the West Musgrave Province. In eastern Australia, the Early Cretaceous Whitsunday volcanic province, is the largest known silicic LIP and comparable to the Chon Aike silicic LIP in South America. The mineral potential associated with the Whitsunday province is as yet not fully assessed. Similarly, the mineral potential for the Bunbury, Tasman Dolerite and Kalkarindji volcano-plutonic provinces is poorly known and yet to be fully explored. We conclude our contribution by providing a short review of crustal and mantle dynamics associated with LIP emplacement.
- 出版日期2012-10
