ABSTRACT

Eight landslides, seven certain and one possible, have been identified in the central Transantarctic Mountains and one at Carapace Nunatak, south Victoria Land. Four consist of Kirkpatrick Basalt lavas alone, two comprise Kirkpatrick lavas with associated pyroclastic rocks, one consists of Hanson Formation beds and Kirkpatrick lavas, and one involves Fremouw Formation strata. One possible block, of uncertain origin, consists only of Hanson Formation beds. All rocks comprising the displaced blocks, except one, are Early Jurassic in age. The exception is the inferred slide involving the Triassic Fremouw beds. The locations of some landslides are consistent with emplacement on present-day topography, which has been little modified since the middle Miocene, but the time of emplacement of others is either Oligocene to pre-middle Miocene or pre-dates the onset of glaciation in Eocene/Oligocene time. The older landslides reflect fortuitous preservation of an ancient landscape not unlike that of today, one dominated by horizontal beds consisting of resistant dolerite sills and quartz-rich sandstones alternating with intervals of weak fine-grained sedimentary beds, and capped by basalt lavas. The landslides are interpreted to document three stages in landscape evolution: a pre-glaciation semi-arid landscape, an early warm-based glacial environment, and a late cold-based glacial setting.

摘要

在中部跨南极山脉和维多利亚州南部的甲壳努纳塔克发现了八处山体滑坡，其中七处是确定的，一处是可能的。四个仅由柯克帕特里克玄武岩熔岩组成，两个由柯克帕特里克熔岩和相关的火山碎屑岩组成，一个由汉森组床和柯克帕特里克熔岩组成，一个涉及弗雷穆组地层。一个可能的地块，来源不明，仅由汉森组床层组成。除一块外，构成位移块的所有岩石都属于早侏罗纪。例外是推断的涉及三叠纪 Fremouw 床的滑动。一些滑坡的位置与今天的地形相一致，自中新世中期以来几乎没有改变，但其他人的就位时间要么是渐新世到中新世前中期，要么早于始新世/渐新世时期冰川作用的开始。较老的滑坡反映了一个古老景观的偶然保存，与今天的景观相似，一个由抗性辉绿岩基台和富含石英的砂岩组成的水平床占主导地位，与弱细粒沉积床的间隔交替，并被玄武岩熔岩覆盖。这些滑坡被解释为记录了景观演化的三个阶段：冰期前的半干旱景观、早期的温暖冰川环境和晚期寒冷的冰川环境。一个以水平层为主，由抗性辉绿岩基台和富含石英的砂岩与弱细粒沉积层间隔交替组成，并被玄武岩熔岩覆盖。这些滑坡被解释为记录了景观演化的三个阶段：冰期前的半干旱景观、早期的温暖冰川环境和晚期寒冷的冰川环境。一个以水平层为主，由抗性辉绿岩基台和富含石英的砂岩与弱细粒沉积层间隔交替组成，并被玄武岩熔岩覆盖。这些滑坡被解释为记录了景观演化的三个阶段：冰期前的半干旱景观、早期的温暖冰川环境和晚期寒冷的冰川环境。