ABSTRACT

Neoproterozoic and Cambrian tectonic and magmatic events in southeast Australia, Tasmania, New Zealand and the Transantarctic Mountains have been described as aspects of the Ross–Delamerian Orogeny. Summaries of the salient points suggest they are parts of the same active margin that developed along a paleo-Pacific rifted edge of the fragmented Rodinia supercontinent. Late Neoproterozoic to Cambrian subduction produced a major magmatic arc that cuts Neoproterozoic and early Cambrian rocks. The Ross–Delamerian Orogen includes two exotic blocks, the Beardmore and VanDieland microcontinents, which accreted in the early Cambrian and middle Cambrian respectively. Other possible exotic elements are the Bowers Terrane in northern Victoria Land and the Takaka Terrane in New Zealand, with both sharing a common middle to late Cambrian history. Compressive deformation occurred at poorly constrained intervals in the early Cambrian but is well constrained in the middle Cambrian. In Australia and Victoria Land of Antarctica, magma compositions changed in the late Cambrian reflecting a change to extension. Bi-modal volcanism and stratigraphy in the Pensacola Mountains of Antarctica are similarly interpreted. Subduction slowed and ceased towards the end of the Cambrian implying a change in relative motion along the Australian–Antarctica segment of the Gondwanan plate boundary.

摘要

澳大利亚东南部、塔斯马尼亚、新西兰和横贯南极山脉的新元古代和寒武纪构造和岩浆事件被描述为罗斯-德拉梅造山运动的各个方面。对这些突出点的总结表明，它们是沿着支离破碎的罗迪尼亚超大陆的古太平洋裂谷边缘发育的同一活动边缘的一部分。新元古代晚期到寒武纪的俯冲作用产生了一个主要的岩浆弧，切割了新元古代和早寒武纪的岩石。罗斯-德拉莫造山带包括两个外来地块：Beardmore 和 VanDieland 微大陆，分别在早寒武世和中寒武世增生。其他可能的奇异元素包括维多利亚州北部的鲍尔斯地体和新西兰的塔卡卡地体，两者都有共同的中晚期寒武纪历史。早寒武世压缩变形发生在约束较差的区间，但在中寒武世则受到良好约束。在澳大利亚和南极洲维多利亚地，寒武纪晚期岩浆成分的变化反映了扩张的变化。南极洲彭萨科拉山脉的双峰式火山活动和地层学也有类似的解释。俯冲作用在寒武纪末期减慢并停止，这意味着冈瓦南板块边界的澳大利亚-南极洲部分的相对运动发生了变化。南极洲彭萨科拉山脉的双峰式火山活动和地层学也有类似的解释。俯冲作用在寒武纪末期减慢并停止，这意味着冈瓦南板块边界的澳大利亚-南极洲部分的相对运动发生了变化。南极洲彭萨科拉山脉的双峰式火山活动和地层学也有类似的解释。俯冲作用在寒武纪末期减慢并停止，这意味着冈瓦南板块边界的澳大利亚-南极洲部分的相对运动发生了变化。