Abstract Two north–south-trending belts of high-temperature–low-pressure (HTLP) sub-regional metamorphism have been identified in the New England Orogen of eastern Australia. Metamorphic complexes in the ∼1300 km long Early-Permian Inland belt have ages ca 300–290 Ma, and those of the ∼400 km long Mid-Permian Coastal belt ca 275–270 Ma. These periods correspond to the beginning and end of an extended (early–mid Permian) phase of subduction rollback and crustal thinning in eastern Australia. This paper describes and incorporates recent work on the Wongwibinda Metamorphic Complex in the southern New England Orogen as a basis for comparison with thirteen other HTLP sub-regional occurrences within the orogen. These are described in as much detail as is currently available. Some outcrops of HTLP rocks in difficult terrain have been subject to limited study and only conditional comparisons can be made. However, a significant number of characteristics shared between the complexes including: their location at the higher-temperature end of broad areas of very low-grade to greenschist facies metamorphic rocks, indicative of tilted crustal blocks; their association with major shear zones; the presence of migmatite at the high-temperature end of a steep metamorphic field gradient; the presence of two-mica granite formed by the melting of the local sedimentary pile; and temporal association with S-type granites; imply a common extension-related mechanism of formation for these HTLP belts. The connection with major faults and shear zones suggests the belts trace major crustal-scale extensional structures that migrated eastwards from ca 300 to 270 Ma. KEY POINTS Two previously undocumented belts of HTLP subregional metamorphism are identified within the NEO. Available dating indicates that metamorphism occurred along the belts at the beginning and end of a major early–mid Permian extensional phase in eastern Gondwana/Australia. The characteristics of the HTLP complexes including their association with shear zones indicates they may delineate major loci of extension.

中文翻译：

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澳大利亚东部新英格兰造山带的两条HTLP次区域变质带：以Wongwibinda变质杂岩体为例的产状和特征

摘要 在澳大利亚东部的新英格兰造山带中发现了两条南北走向的高温低压（HTLP）次区域变质带。约 1300 公里长的早二叠世内陆带的变质杂岩年龄约为 300-290 Ma，约 400 公里长的中二叠世海岸带的变质杂岩年龄约为 275-270 Ma。这些时期对应于澳大利亚东部俯冲回滚和地壳变薄的延长（早-中二叠世）阶段的开始和结束。本文描述并结合了新英格兰造山带南部 Wongwibinda 变质复合体的最新工作，作为与造山带内其他 13 个 HTLP 次区域事件进行比较的基础。这些都被尽可能详细地描述为当前可用的。一些困难地形中的 HTLP 岩石露头受到的研究有限，只能进行有条件的比较。然而，这些复合体之间共有的许多特征包括：它们位于极低品位到绿片岩相变质岩的广阔区域的高温端，表明地壳块体倾斜；它们与主要剪切带的联系；在陡峭的变质场梯度的高温端存在混合岩；由当地沉积桩熔化形成的二云母花岗岩的存在；与 S 型花岗岩的时间关联；暗示了这些 HTLP 带的常见延伸相关形成机制。与主要断层和剪切带的联系表明，这些带追踪了从大约 300 到 270 Ma 向东迁移的主要地壳尺度伸展结构。关键点 在近地天体中发现了两个以前未记录的 HTLP 次区域变质带。现有的测年表明，在冈瓦纳/澳大利亚东部早-中二叠世主要伸展阶段的开始和结束时，沿带发生变质作用。HTLP 复合体的特征，包括它们与剪切带的关联，表明它们可能描绘了延伸的主要位点。现有的测年表明，在冈瓦纳/澳大利亚东部早-中二叠世主要伸展阶段的开始和结束时，沿带发生变质作用。HTLP 复合体的特征，包括它们与剪切带的关联，表明它们可能描绘了延伸的主要位点。现有的测年表明，在冈瓦纳/澳大利亚东部早-中二叠世主要伸展阶段的开始和结束时，沿带发生变质作用。HTLP 复合体的特征，包括它们与剪切带的关联，表明它们可能描绘了延伸的主要位点。