The Montecristo district, northern Chile, is one of the few places worldwide where there is a direct relationship between magnetite-(apatite) (MtAp) mineralization and iron oxide-copper–gold (IOCG) mineralization. The MtAp mineralization includes Ti-poor magnetite, fluorapatite, and actinolite and is crosscut and partially replaced by a younger IOCG mineralization that includes a second generation of actinolite and magnetite with quartz, chalcopyrite, pyrite, and molybdenite. The MtAp stage at Montecristo is interpreted as the crystallized iron-rich melts that used the pre-existing structures of the Atacama Fault System as conduits. These rocks later acted as a trap for hydrothermal IOCG mineralization. Geochronology data at Montecristo indicate that the host diorite (U–Pb zircon 153.3 ± 1.8 Ma, 2-sigma), MtAp mineralization (⁴⁰Ar-³⁹Ar in actinolite, 154 ± 2 Ma and 153 ± 4 Ma, 2-sigma), and the IOCG event (Re-Os on molybdenite, 151.8 ± 0.6 Ma, 2-sigma) are coeval within error and took place in a time span of less than 3.4 Ma. The εHf_i and εNd_i values of the host diorite are + 8.0 to + 9.8 and + 4.3 to + 5.4, respectively. The whole-rock ⁸⁷Sr/⁸⁶Sr_i values of the IOCG mineralization (0.70425 to 0.70442) are in the lower end of those of the MtAp mineralization (0.70426–0.70629). In contrast, εNd_i values for the IOCG mineralization (+ 5.4 and + 5.7) fall between those of the MtAp rocks (+ 6.6 to + 7.2) and the host diorite, which suggests that the IOCG event was related to fluids having a more crustal Nd (εNd_i < + 5.7) composition than the MtAp mineralization. This likely reflects the mixing of Nd from the MtAp protolith and a deep magmatic-hydrothermal source, very likely an unexposed intrusion equivalent to the host diorite. Sulfur isotope compositions (δ³⁴S, + 0.3 to + 3.4‰) are consistent with a magmatic source.

智利北部的蒙特克里斯托地区是世界上少数几个磁铁矿（磷灰石）（MtAp）矿化与氧化铁-铜-金（IOCG）矿化之间存在直接关系的地方之一。MtAp 矿化包括贫钛磁铁矿、氟磷灰石和阳起石，并被横切并部分被较年轻的 IOCG 矿化所取代，其中包括第二代阳起石和磁铁矿以及石英、黄铜矿、黄铁矿和辉钼矿。蒙特克里斯托的 MtAp 阶段被解释为使用阿塔卡马断层系统预先存在的结构作为管道的结晶富铁熔体。这些岩石后来成为热液 IOCG 矿化的陷阱。Montecristo 的地质年代学数据表明，主体闪长岩（U-Pb 锆石 153.3 ± 1.8 Ma，2-sigma）、MtAp 矿化（阳起石中的⁴⁰ Ar- ³⁹ Ar，154 ± 2 Ma 和 153 ± 4 Ma，2-sigma）、和 IOCG 事件（辉钼矿上的 Re-Os，151.8 ± 0.6 Ma，2-sigma）在误差内同时发生，并且发生在小于 3.4 Ma 的时间跨度内。寄主闪长岩的εHf _i和εNd _i值分别为+8.0至+9.8和+4.3至+5.4。IOCG 矿化体全岩⁸⁷ Sr/ ⁸⁶ Sr _i值（0.70425~0.70442）处于 MtAp 矿化体全岩 87 Sr/ 86 Sr i 值（0.70426~0.70629）的较低端。相反，IOCG 矿化的 εNd _i值（+ 5.4 和 + 5.7）落在 MtAp 岩石（+ 6.6 至 + 7.2）和宿主闪长岩之间，这表明 IOCG 事件与具有更多地壳性质的流体有关。 Nd(εNd _i  <+5.7)成分高于MtAp矿化。这可能反映了 MtAp 原岩中的 Nd 与深层岩浆热液源的混合，很可能是相当于母体闪长岩的未暴露侵入体。硫同位素组成（δ ³⁴ S，+ 0.3 至+ 3.4‰）与岩浆源一致。