Abstract:
The Beishan region of Gansu Province forms a significant metallogenic belt for non-ferrous and precious metals within the Central Asian Orogenic Belt in northwestern China, and has long been a focal area for mineral exploration and research. Recently discovered through systematic geological surveys in this region, the Dongshuangjingzi iron deposit is a medium-sized hematite resource. This paper systematically describes the deposit's geological characteristics, defines its ore types and mineral assemblages, analyzes its genetic mechanism, and evaluates the area's prospecting potential. The aim is to provide a scientific basis and new insights for regional iron ore exploration. The study employed an integrated methodology, including geological mapping, high-precision magnetic surveys, engineering verification, systematic petrographic and ore microscopic observations, phase analysis, and regional stratigraphic and tectonic analysis. This approach was used to constrain the deposit's metallogenic epoch and tectonic setting. Results indicate that the ore bodies are primarily hosted within low-grade metamorphic sedimentary rocks, with their occurrence strictly controlled by the host stratigraphy. The dominant natural ore type is hematite-quartzite, accompanied by minerals such as limonite, siderite, and magnetite. The ore typically exhibits a banded structure, characteristic of sedimentary-metamorphic iron deposits. Based on petrographic, geochemical, and regional geological evidence, the Dongshuangjingzi deposit is interpreted as a Paleoproterozoic sedimentary-metamorphic iron formation, subsequently modified by regional metamorphism. The spatial distribution of ore bodies, combined with stratigraphic, structural, and magnetic anomaly data, suggests that the deep and lateral extensions of the iron-bearing formations hold significant prospecting potential. Synclinal structures hosting the banded iron formation are identified as key geological indicators for exploring similar deposits. Therefore, subsequent exploration should prioritize the core and flanks of these synformal structures. This discovery enhances the understanding of metallogenic types in the Beishan belt and provides a new direction for regional iron ore prospecting.