The Ross(–Delamerian) Orogeny significantly impacted the formation of the tectonic structure of the Pacific Gondwana margin during the early Paleozoic era. Northern Victoria Land (NVL) in Antarctica preserves the aspect of the Ross Orogeny that led to the union of the Wilson (WT)–Bowers (BT)–Robertson Bay Terrane. The aspect of the Ross Orogeny in the NVL is characterized by subduction of oceanic domains toward the continental margin (continental arc) and the accretion of the associated marine–continental substances from 530–480 Ma. In the Mountaineer Range in NVL, the Ross Orogeny strain zone is identified at the WT/BT boundary regions. In these areas, fold and thrust shear zones are observed and aspects of them can be seen at Mt. Murchison, the Descent Unit and the Black Spider Greenschist zone. The Dessent Unit corresponds to a tectonic slice sheared between the WT and BT. The metamorphic evolution phase of the Dessent Unit is summarized in the peak pressure (M₁), peak temperature (M₂) and retrograde (M₃). The sensitive high-resolution ion microprobe (SHRIMP) zircon U–Pb ages of 514.6 ± 2.0 Ma and 499.2 ± 3.4 Ma obtained from the Dessent Unit amphibolite are comparable to the M₁ and M₂ stages, respectively. The Dessent Unit underwent intermediate pressure (P)/temperature (T)-type metamorphism characterized by 10.0–10.5 kbar/~600 °C (M₁) and ~7 kbar/~700 °C (M₂) followed by 4.0–4.5 kbar/~450 °C (M₃). Mafic to intermediate magmatism (497–501 Ma) within the WT/BT boundary region may have given rise to the M₂ stage of the Dessent Unit, and this magmatism is synchronous with the migmatization period of Mt. Murchison (498.3 ± 3.4 Ma). This indicates that a continuous process of fold-shearing–magmatic intrusion–partial melting, which is typically associated with a continental arc orogeny, occurred before and after c. 500 Ma in the Mountaineer Range. During the Ross Orogeny, the Dessent unit was initially subducted underneath the WT at depth (10.0–10.5 kbar, ~35 km) and then thrust into the shallow (~7 kbar, ~23 km), hot (≥700 °C) magmatic arc docking with the Mt. Murchison terrain, where migmatization prevailed.

中文翻译：

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南极维多利亚州北部维多利亚山脉登山者及其周围地区罗斯造山运动的时间和变质演化

在古生代早期，罗斯（-德拉米尔）造山运动显着影响了太平洋冈瓦纳边缘的构造构造。南极洲的北维多利亚土地（NVL）保留了罗斯造山带的特征，导致了威尔逊（WT）-鲍尔斯（BT）-罗伯逊湾地带的合并。NVL的罗斯造山带的特征是，海洋区域向大陆边缘俯冲（大陆弧），并且在530-480 Ma内增加了相关的海洋-大陆物质。在NVL的Mountaineer Range中，在WT / BT边界区域确定了罗斯造山带应变带。在这些区域中，观察到了褶皱和推力剪切带，并且在山上可以看到它们的各个方面。默奇森（Murchison），血统单位和黑蜘蛛格林希斯特（Black Spider Greenschist）区。Dessent单元对应于在WT和BT之间剪切的构造切片。Dessent单元的变质演化阶段总结为峰值压力（M₁），峰值温度（M ₂）和逆行温度（M ₃）。从敏感单元闪石获得的灵敏高分辨率离子微探针（SHRIMP）锆石U–Pb年龄分别为M ₁和M ₂阶段，分别为514.6±2.0 Ma和499.2±3.4 Ma 。Dessent单元经历了中压（P）/温度（T）型变质，特征为10.0–10.5 kbar /〜600°C（M ₁）和〜7 kbar /〜700 °C（M ₂），然后是4.0–4.5 kbar /〜450°C（M ₃）。WT / BT边界区内的镁铁质至中岩浆（497-501 Ma）可能引起了M ₂岩浆活动与山的迁移期同步。默奇森（498.3±3.4 Ma）。这表明在c之前和之后发生了连续的剪切-岩浆侵入-部分熔融的连续过程，这通常与大陆弧造山运动有关。登山者山脉中的500 Ma。在罗斯造山运动期间，Dessent单元最初在深空（10.0–10.5 kbar，〜35 km）下在WT之下俯冲，然后推入热（≥700°C）的浅层岩浆（〜7 kbar，〜23 km）。与山弧对接。默奇森（Murchison）地形，那里普遍有迁移。