ABSTRACT

The Permian Mackellar Formation in the central Transantarctic Mountains is a fine-grained siliciclastic succession, which was deposited in a marine to brackish inland sea (Mackellar Sea) along the hinterland of the Gondwana margin. The Mackellar strata were deposited in an elongate, trough-shaped basin oriented subparallel to the present trend of the Transantarctic Mountains. At the head of the Robb Glacier, the Mackellar beds include, in the middle of the succession, a mass transport deposit, which exhibits folding and thrusting. Structural data (e.g. facing direction and axial planes of overturned folds, orientation and vergence of thrust faults) indicate axial transport down the elongate depositional basin. Unconformable relationships to strata overlying the mass transport deposit suggest reactivation and doming of the deposit following its initial emplacement. Subsequently there was partial collapse of the toe-ward part of the extant deposit along a listric fault, the result of loading by deltaic sandstones of the overlying Fairchild Formation.

摘要

横贯南极山脉中部二叠纪 Mackellar 组为细粒硅质碎屑岩层序，沿冈瓦纳边缘腹地沉积于海相至半咸水内海（Mackellar Sea）。Mackellar 地层沉积在一个细长的槽形盆地中，该盆地取向与目前跨南极山脉的走向亚平行。在罗伯冰川的顶部，Mackellar 层在序列的中间包括一个质量输送沉积物，该沉积物表现出折叠和推力。结构数据（例如翻转褶皱的朝向和轴向平面、逆冲断层的方向和辐辏）表明沿细长沉积盆地的轴向输送。与大众运输沉积物上覆地层的不整合关系表明沉积物在其初始就位后重新激活和隆起。随后，由于上覆 Fairchild 组的三角洲砂岩加载，现存矿床的趾部沿一个利斯特里克断层发生​​了部分坍塌。