The Tectonomagmatic Setting of Early to Middle Jurassic Bimodal Volcanism in the Transantarctic Mountains

横跨北极山脉的比尔德莫尔冰川地区拥有南极洲最完整的冈瓦纳序列(灯塔超群的维多利亚群)。该层序被与冈瓦那碎屑有关的费拉群拉斑玄武岩所覆盖。火山作用和泛滥玄武岩喷发反映了横贯北极山脉的构造环境的重大变化，从与活动板块边缘有关的前陆盆地到与冈瓦那裂解有关的大陆裂谷。该项目的目标是：1)建立详细的火山岩地层格架，以评价区域单元减薄和同沉积伸展正断层作用的重要性；2)研究该层序的古火山学，特别是部分岩浆作用形成的古火山学，以了解岩石形成的物理环境及其与推断的构造环境的关系；3)进一步确定火山岩的地球化学特征，以便更好地确定岩浆成分随时间的变化以及硅质和玄武岩之间可能的关系；4)初步评估硅质岩浆的可能源区。

The Beardmore Glacier region of the Transantarctic Mountains has the most complete Gondwana sequence (Victoria Group of the Beacon Supergroup) in Antarctica. This sequence is overlain by tholeiitic flood basalts of the Ferrar Group which are related to Gondwana fragmentation. The volcanism and flood basalt eruption reflect a major change in tectonic environment in the Transantarctic Mountains, from a foreland basin associated with an active plate margin to a continental rift related to Gondwana breakup. The objectives of this project are to: 1) establish a detailed stratigraphic framework for the volcanogenic rocks in order to assess the importance of regional thinning of units and of syndepositional extensional normal faulting; 2) investigate the paleovolcanology of this sequence, in particular that part of it formed by phreatomagmatic processes, in order to understand the physical environment in which the rocks were formed and the relations to the inferred tectonic setting; 3) further characterize the geochemistry of the volcanogenic rocks in order to better define time dependent changes in magma compositions and possible relations between the silicic and basaltic rocks; 4) attempt a preliminary assessment of possible source regions for the silicic magmas.