中国地质大学（武汉）王璐研究团队近日取得一项新成果。他们分析了皮尔巴拉克拉通中太古宙Mulgandinnah剪切带是否世界上最古老的弧切转换断层。相关论文于2024年7月15日发表在《地质学》杂志上。

据介绍，弧切转换断层是汇聚边缘构造的重要组成部分。它们发育在斜向俯冲系统之上，切割并置换了弧的整个岩浆部分，在随后的造山拼贴中，上覆板块的部分构造重复。在苏门答腊、新西兰和菲律宾的现存例子清楚地显示了这一过程，而古生代Altaids和新太古代苏伯利尔和伊尔冈克拉通则报道了古代的例子。

研究数据显示，古-中太古代东部皮尔巴拉克拉通（最近被解释为岩浆弧的中上地壳水平），被一个3.0-2.93Ga的主要弧切断层Mulgandinnah切割并重复，该断层切割了一个先前600×100km长的中太古代弧系统的片段，将不同的岛弧段横向移动到它们现在并置的200×200km保存下来的片段中。

这一证据揭示了3.0Ga前的板块侧向运动，并表现出斜向俯冲、弧深作用、弧切割和重复作用，反映了现代型汇聚边缘的地壳发育在中太古代已全面展开。

附：英文原文

Title: Is the Mesoarchean Mulgandinnah shear zone, Pilbara Craton, the world’s oldest arc-slicing transform fault

Author: Abdelmottaleb Aldoud, Timothy Kusky, Lu Wang

Issue&Volume: 2024-07-15

Abstract: Arc-slicing transform faults represent an integral component of convergent margin tectonics. They are developed above oblique subduction systems, cutting through and displacing the entire magmatic section of arcs, leading to tectonic repetition of segments of the overriding plate in the ensuing orogenic collage. Extant examples clearly show this process in Sumatra, New Zealand, and the Philippines, while ancient examples are reported from the Paleozoic Altaids and Neoarchean Superior and Yilgarn cratons. Here, we report data that document that the Paleo-Mesoarchean Eastern Pilbara craton, recently interpreted to be a preserved mid-upper crustal level of a magmatic arc, is cut and repeated by a major 3.0-2.93 Ga arc-slicing fault, the Mulgandinnah, which sliced a previously 600×100 km segment of a Mesoarchean arc system, laterally moving different segments to their presently juxtaposed 200×200 km preserved fragment. This evidence demonstrates lateral plate motions by 3.0 Ga and shows oblique subduction, arc plutonism, arc-slicing, and repetition, reflecting that crustal growth in modern-style convergent margins was in full operation by the Mesoarchean.

DOI: 10.1130/G52360.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G52360.1/645599/Is-the-Mesoarchean-Mulgandinnah-shear-zone-PilbararedirectedFrom=fulltext