近日，瑞典斯德哥尔摩大学Iain Pitcairn团队报道了太古宙变质沉积带中的金流动性：对造山型金矿床的影响。相关论文于2025年11月10日发表在《地质学》杂志上。

加拿大南部超级省由大型变质沉积带组成，例如与富金绿岩带相邻的庞蒂亚克和魁北克次级省。庞蒂亚克沉积岩曾被提议是南部阿比提比富金绿岩带的金来源。然而，与贫金绿岩带相邻沉积岩的对比研究仍属空白。

研究组分析了三个剖面采集的变质沉积岩及少量火山岩样本，这些剖面位于庞蒂亚克和魁北克变质沉积带内，且邻近金禀赋差异显著的绿岩带。研究组结合了变质沉积岩中硫化物的原位金数据与全岩超低检测限金数据。结果显示：在富金和中等禀赋剖面中，金浓度随变质等变线递减；而在贫金禀赋剖面中，金迁移作用有限。金从变质沉积岩中释放与黄铁矿-磁黄铁矿转变反应相关。该反应在贫金禀赋剖面中未完全进行，解释了观测到的有限金迁移现象。数据揭示了变质沉积带中金迁移与邻近绿岩带金禀赋之间的空间关联性。

附：英文原文

Title: Gold mobility in Archean metasedimentary belts: Implications for orogenic gold deposits

Author: Diogo Ribeiro, Bertrand Rottier, Antoine Godet, Georges Beaudoin, Clifford G.C. Patten, Carl Guilmette, Adrian G. Rehm, Isaac S. Malta, Jochen Kolb, Douglas K. Tinkham, Iain Pitcairn

Issue&Volume: 2025-11-10

Abstract: The southern Superior Province (Canada) comprises large metasedimentary belts, such as the Pontiac and Quetico subprovinces, adjacent to Au-endowed greenstone belts. The Pontiac sedimentary rocks have been proposed as a source of Au for the highly endowed southern Abitibi greenstone belt. However, a comparison with sedimentary rocks adjacent to poorly endowed greenstone belts is lacking. Here we examine a suite of metasedimentary and minor volcanic rocks collected from three transects in the Pontiac and Quetico metasedimentary belts adjacent to greenstone belts with variable Au endowments. We combine in situ Au data of sulfides in metasedimentary rocks with whole-rock ultra-low-detection Au data. Gold concentrations decrease across metamorphic isograds in the well- and moderately endowed transects, while limited Au mobility is observed in the poorly endowed transect. The release of Au from metasedimentary rocks is linked to the pyrite-pyrrhotite transition. This reaction is incomplete in the poorly endowed transect, explaining the limited Au mobility observed. Our data reveal a spatial correlation between Au mobility in metasedimentary belts and Au endowment in the adjacent greenstone belts.

DOI: 10.1130/G53574.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G53574.1/666487/Gold-mobility-in-Archean-metasedimentary-beltsredirectedFrom=fulltext