Tectonic cycles of the New England Orogen, eastern Australia: A Review

The New England Orogen (NEO), the youngest of the orogens of the Tasmanides of eastern Australia, is defined by two main cycles of compression–extension. The compression component involves thrust tectonics and advance of the arc towards the continental plate, while extension is characterised by rifting, basin formation, thermal relaxation and retreat of the arc towards the oceanic plate. A compilation of 623 records of U–Pb zircon geochronology rock ages from Geoscience Australia, the geological surveys of Queensland and New South Wales and other published research throughout the orogen, has helped to clarify its complex tectonic history. This contribution focuses on the entire NEO and is aimed at those who are unfamiliar with the details of the orogen and who could benefit from a summary of current knowledge. It aims to fill a gap in recent literature between broad-scale overviews of the orogen incorporated as part of wider research on the Tasmanides and detailed studies usually specific to either the northern or southern parts of the orogen. Within the two main cycles of compression–extension, six accepted and distinct tectonic phases are defined and reviewed. Maps of geological processes active during each phase reveal the centres of activity during each tectonic phase, and the range in U–Pb zircon ages highlights the degree of diachronicity along the length of the NEO. In addition, remnants of the early Permian offshore arc formed during extensive slab rollback, are identified by the available geochronology. Estimates of the beginning of the Hunter-Bowen phase of compression, generally thought to commence around 265 Ma are complicated by the presence of extensional-type magmatism in eastern Queensland that occurred between 270 and 260 Ma.新英格兰造山带（New England Orogen, NEO）是澳大利亚东部塔斯曼造山系（Tasmanides）中最年轻的造山带，以两期主要的挤压-伸展旋回为典型特征。其中挤压阶段以逆冲构造作用与岩浆弧向大陆板块的推进为核心表现，而伸展阶段则以裂谷作用、盆地形成、热松弛过程及岩浆弧向大洋板块的后撤为典型特征。本次研究整合了来自澳大利亚地球科学局（Geoscience Australia）、昆士兰州地质调查局、新南威尔士州地质调查局，以及该造山带范围内已发表的其他研究成果的623条U-Pb锆石年代学（U–Pb zircon geochronology）岩石年龄数据，为厘清其复杂的构造演化历史提供了重要支撑。本研究聚焦整个新英格兰造山带，面向不熟悉该造山带细节、且可从现有研究总结中获益的读者，旨在弥补当前学术文献中的研究空白：现有相关成果要么是作为塔斯曼造山系整体研究一部分的宏观概述，要么是仅针对该造山带南北局部区域的详细个案研究。在两期主要的挤压-伸展旋回框架下，本文明确并评述了6个已被学界认可的独立构造阶段。各构造阶段的地质作用分布图揭示了对应时期的活动中心，而U-Pb锆石年龄的分布范围则凸显了新英格兰造山带沿线的构造穿时性程度。此外，现有年代学数据还识别出了在广泛板片回撤作用中形成的早二叠世近海岩浆弧残余。通常认为亨特-博文挤压期（Hunter-Bowen phase）始于约265 Ma，但昆士兰州东部在270~260 Ma期间发育的伸展型岩浆作用，使得该阶段起始时间的估算变得更为复杂。