The Bafq-Saghand metallogenic belt is located in the central part of the Kerman–Kashmar tectonic zone and contains 39 individual occurrences of iron oxide-apatite ± REE mineralizations. These mineral concentrations, e.g., Chadormalu, Choghart, Sechahun, and Esfordi, comprise a total of ~ 1500 million tons of iron ore with an average grade of ~ 55% Fe. In terms of origin, time, and geodynamic setting, several modes of formation have been suggested for these ore deposits, including magmatic, hydrothermal, and banded iron formation scenarios. In the present study, the tectonic setting and metallogeny of iron oxide-apatites of the Bafq-Saghand belt are investigated utilizing trace element geochemistry, age dating, and oxygen isotope analyses. The geochemical characteristics of apatite and magnetite and the δ¹⁸O values of magnetite (from − 0.1 to + 2.2 ‰) indicate a dominantly magmatic-hydrothermal (δ¹⁸O > + 0.9 ‰) formation process, although primary magmatic mineralizations were locally leached and hydrothermally redeposited (e.g., samples with δ¹⁸O < + 0.9 ‰). The Cambrian volcano-sedimentary host rocks to the mineralization is intruded by calc-alkaline tonalite, trondhjemite, granodioritic, dioritic, and granitic rocks that formed in association with subduction of the Proto-Tethys Ocean under the Gondwana supercontinent in the Neoproterozoic to Early Cambrian (525–547 Ma). Additionally, a later geodynamic episode produced intrusions of alkaline syenite and monzosyenite bodies during a continental rifting event. We provide new geochronological constraints for these younger alkaline igneous rocks that document a temporal range from 421 to 447 Ma for their intrusion. In combination with the previously reported overlapping ages of the older calc-alkaline magma bodies (525–547 Ma) with the volcano-sedimentary host rock (528 Ma) and the iron oxide mineralization (510–539 Ma), we can now exclude continental rifting as a geodynamic processes that is linked to ore formation in the region. Our results corroborate that the Bafq iron ore mineralization formed during subduction of the Proto-Tethys Ocean under the Gondwana supercontinent in a near surface continental margin setting.

Bafq-Saghand成矿带位于Kerman-Kashmar构造带的中部，包含39个单独出现的氧化铁-磷灰石±REE矿化带。这些矿物质浓度，例如Chadormalu，Choghart，Sechahun和Esfordi，总共包含约15亿吨铁矿石，平均品位铁约55％。在成因，时间和地球动力学背景方面，已为这些矿床提出了几种形成模式，包括岩浆，热液和带状铁形成场景。在本研究中，利用微量元素地球化学，年龄测年和氧同位素分析研究了Bafq-Saghand带氧化铁-磷灰石的构造背景和成矿作用。磷灰石和磁铁矿和δ的地球化学特征¹⁸磁铁矿（从- 0.1〜+ 2.2‰）的O值指示显性岩浆热液（δ ¹⁸ O> + 0.9‰）的形成过程中，虽然初级岩浆矿化在本地沥滤和再沉积热液（例如，样品用δ ¹⁸O <+ 0.9‰）。寒武纪火山沉积的母岩被钙碱性斜长石，长晶陨石，花岗闪长岩，闪长岩和花岗质岩侵入，这些岩体是与新特古生代至早寒武世的冈瓦纳超大陆下的原始特提斯海俯冲形成的。 525–547 Ma）。另外，后来的地球动力学事件在大陆裂谷事件中产生了碱性正长岩和辉长岩体的侵入。我们为这些年轻的碱性火成岩提供了新的地质年代学约束，这些侵入记录的时间范围为421至447 Ma。结合先前报道的较老的钙碱性岩浆体（525-547 Ma）与火山沉积主岩（528 Ma）和氧化铁矿化（510-539 Ma）的重叠年龄，我们现在可以将大陆裂谷排除为与该地区成矿有关的地球动力学过程。我们的结果证实了Bafq铁矿石矿化是在冈瓦纳超大陆下的原始特提斯海洋俯冲期间在近地表大陆边缘环境中形成的。