Tab. 1: U-Pb analyses of zircons from rock samples in MT. Newton and Cumpston Massif, East Antarctica

We present new U-Pb zircon (SHRIMP) data on rocks from Mt Newton and Cumpston Massif in the southern Prince Charles Mountains. Our data demonstrate that Mt Newton was affected by a newly proposed Palaeoproterozoic "Newton" Orogeny at c. 2100-2200 Ma. Sedimentation, felsic volcanism (c. 2200 Ma), metamorphism and folding, followed by granite intrusion (c. 2100 Ma), suggest development of a trough or aulacogene in the area during the early Palaeoproterozoic. An orthogneiss from Cumpston Massif yielded an age of c. 3180 Ma for granitic protolith emplacement, which is in good agreement with many U-Pb zircon ages from similar rocks in the southern Mawson Escarpment. A syn- to late-tectonic muscovite-bearing pegmatite from Cumpston Massif yielded a c. 2500 Ma date of emplacement, which indicates early Palaeoproterozoic activity in this block, probably in response to a tectono-magmatic episode in the Lambert Terrane bordering the Ruker Terrane in the northeast. The correlation of tectono-magmatic events in both the Ruker and Lambert terranes of the southern Prince Charles Mountains provides evidence for their common evolution during the Proterozoic.

本研究提供了采自查尔斯王子山脉南部牛顿山与坎普斯顿地块的岩石样品的铀-铅锆石（U-Pb zircon）SHRIMP定年数据。研究结果表明，牛顿山受到了新近提出的古元古代（Palaeoproterozoic）“牛顿”造山运动（Orogeny）的影响，该造山运动的时限约为2100~2200 Ma。区内先后经历了沉积作用、长英质火山活动（约2200 Ma）、变质作用与褶皱作用，随后发生花岗岩侵入（约2100 Ma），这指示该区域在古元古代早期发育了拗拉谷（aulacogene）或断陷槽地。采自坎普斯顿地块的一块正片麻岩（orthogneiss）的花岗岩原岩（granitic protolith）侵位年龄约为3180 Ma，该结果与莫森陡崖南部同类岩石的大量铀-铅锆石定年数据吻合良好。采自坎普斯顿地块的一块同构造至晚构造期含白云母伟晶岩（muscovite-bearing pegmatite）的侵位年龄约为2500 Ma，这表明该地块在古元古代早期存在构造活动，该活动可能与东北部毗邻鲁克尔地体（Ruker Terrane）的兰伯特地体（Lambert Terrane）所发生的构造-岩浆（tectono-magmatic）事件相对应。对查尔斯王子山脉南部鲁克尔地体与兰伯特地体的构造-岩浆事件进行对比，可为二者在元古代（Proterozoic）的共同演化历程提供有力佐证。