Abstract Cretaceous alkaline-ultramafic stocks in the northern Prince Charles Mountains (PCM) contain zircon xenocrysts entrained during magma ascent to the surface. These xenocrysts provide the only evidence for the age of the underlying crustal rocks in the area. The zircons display a range of ages from ca 2700 Ma to ca 300–260 Ma, with the most dominant ages of ca 900–800 Ma and ca 660–500 Ma. These data indicate that the presently exposed ca 1000–950 Ma metamorphic rocks in the northern PCM are underlain by other geological unit(s). The presence of ca 2700 Ma zircons indicates that a Neoarchaean component is present in the lower crust and that the presumed Proterozoic Rayner Province is not entirely composed of Proterozoic protoliths, but rather is a tectonic mixture of Neoarchaean and younger rocks. This finding questions a Cambrian (Kuunga-age) collisional suture running through the Ruker Province, which may thus be further south within the sub-ice terrain. Nevertheless, the presence of ca 900–800 Ma and ca 600–500 Ma zircons argue for more widespread post-1000 Ma metamorphic events than are observed at the surface. Ca 300–260 Ma zircons, which could not have been derived from any known crystalline rocks in this region, indicate within-crustal chambers parent to mafic dyke suites.

中文翻译：

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白垩纪碱性-超镁铁质岩石中的锆石异晶证明了北部查尔斯王子山脉（南极东部）大陆地壳的年龄

摘要 查尔斯王子山脉 (PCM) 北部的白垩纪碱性-超镁铁质储层含有岩浆上升到地表时夹带的锆石异晶。这些异种晶体为该地区下伏地壳岩石的年龄提供了唯一的证据。锆石的年龄范围从大约 2700 Ma 到大约 300-260 Ma，其中最主要的年龄为大约 900-800 Ma 和大约 660-500 Ma。这些数据表明，PCM 北部目前出露的约 1000-950 Ma 变质岩下伏有其他地质单元。大约 2700 Ma 锆石的存在表明下地壳中存在新太古代成分，并且推测的元古代雷纳省并非完全由元古代原岩组成，而是新太古代和较年轻岩石的构造混合物。这一发现对穿过 Ruker 省的寒武纪（Kuunga-age）碰撞缝合线提出了质疑，因此该省可能在亚冰地形内更靠南。尽管如此，大约 900-800 Ma 和大约 600-500 Ma 锆石的存在证明了比在地表观察到的更广泛的 1000 Ma 后变质事件。Ca 300–260 Ma 锆石不可能来自该地区任何已知的结晶岩，表明地壳内腔室是基性岩脉套件的母体。