Tectono-magmatic controls of post-subduction gold mineralisation during late Caledonian soft continental collision in the Southern Uplands-Down-Longford Terrane, Britain and Ireland: A review

摘要

The Southern Uplands-Down-Longford Terrane (SUDLT) within the British Caledonides hosts several economically significant gold occurrences, including a 45 km long gold trend in central Ireland that includes the proven deposit at Clontibret. However, the region is relatively underexplored for gold and the well-constrained geology and tectonic history of the terrane provide a firm geological framework for investigating the roles of tectonic, magmatic and metamorphic processes in gold mineralisation during the transition from subduction of oceanic lithosphere to soft (thin-skinned) continental collision. The SUDLT is an Ordovician-Silurian fore-arc accretionary complex that evolved into a foreland basin fold-and-thrust-belt during continental collision in earliest Devonian times. Comparable terranes in Phanerozoic orogenic belts globally host significant orogenic gold deposits. However, the SUDLT exhibits a very low metamorphic grade and mineralisation exhibits similarities with orogenic, intrusion related and post-subduction porphyry gold systems.