Palaeogeography of the South Australian Craton within Nuna

Integrated geochronology, isotopic and REE geochemical analysis from the northern Gawler Craton were used to test if major boundaries interpreted from geophysical datasets (Baines et al., 2011) truly represent sutures between allochthonous crustal blocks. The northern Gawler Craton appears to be underlain at least in part by Neoarchaean substrate (Reid et al., 2014) that is isotopically similar to basement rocks in southern Gawler Craton and the North Australian Craton. The correlation of Neoarchaean basement in both the southern and northern Gawler Craton (Reid et al., 2014) and lack of systematic isotopic and REE variations suggest that these boundaries separate autochthonous crustal blocks that have been attenuated (and possibly rifted from each other) and re-amalgamated in the Late Palaeoproterozoic to Mesoproterozoic. A modern analogue for this is the SW Pacific in which continental ribbons (e.g. Lord Howe Rise) have been separated from the Australian plate.

通过对北高勒克拉通（Gawler Craton）开展综合年代学、同位素及稀土元素（REE）地球化学分析，旨在验证从地球物理数据集（Baines等，2011）中解译出的主要边界是否真正代表异地地壳块体之间的缝合带。北高勒克拉通的下伏基底至少部分为新太古代（Neoarchaean）物质（Reid等，2014），其同位素特征与南高勒克拉通及北澳大利亚克拉通的基底岩石相似。南高勒与北高勒克拉通均存在新太古代基底的相关性（Reid等，2014），且缺乏系统性的同位素及稀土元素变化，这表明这些边界分隔的是原地地壳块体——它们在古元古代晚期至中元古代经历了减薄（可能彼此裂离）并重新拼合。这一过程的现代类比是西南太平洋（SW Pacific），其中大陆条带（如Lord Howe Rise）已从澳大利亚板块分离出去。