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.

本研究整合了高勒克拉通（Gawler Craton）北部的年代学、同位素与稀土元素（REE）地球化学分析数据，旨在验证由地球物理数据集解译得到的主要边界（Baines等，2011）是否确实代表异地地壳块体之间的缝合带。
高勒克拉通北部至少部分区域的基底为新太古代（Neoarchaean）基底岩系（Reid等，2014），其同位素特征与高勒克拉通南部及北澳大利亚克拉通（North Australian Craton）的基底岩系相似。
高勒克拉通南北两部的新太古代基底岩系具有相关性（Reid等，2014），且未出现系统性的同位素与稀土元素分异，这表明上述边界所分隔的实为原地地壳块体：这些块体曾发生减薄（并可能彼此裂离），并在晚古元古代至中元古代（Mesoproterozoic）期间发生了重新拼合。
与此地质过程类似的现代实例为西南太平洋区域，其中的大陆带状地块（如豪勋爵海隆（Lord Howe Rise））已与澳大利亚板块发生分离。