The subduction-related Saindak porphyry Cu-Au deposit formed by remelting of a thickened juvenile lower crust underneath the Chagai belt, Pakistan

Oligocene–Miocene arc magmatic activities associated with the giant Reko Diq porphyry Cu–Au deposit, western Chagai arc, Balochistan, Pakistan

“…This period aligns with the magmatic and mineralization events recorded at the Saindak porphyry Cu-Au deposit (~22.2 and ~21.8 Ma; Wang, Zheng, et al, 2022; and the Reko Diq porphyry Cu-Au deposit (~12.9 and ~11.9 Ma; Razique et al, 2014;Perell o et al, 2008). The ore-forming tonalite, diorite porphyry and andesite associated with the deposit were found to have similar ages of approximately 22.2 ± 0.2 Ma.…”

“…The Eocene to Miocene intrusive rocks of ~150 km extension in the Chagai belt (Perell o et al, 2008) intruded the Sinjrani Volcanic Group and occurred as small isolated plutons and stocks at the west of the Chagai belt (Figure 2). Two phases of magmatism have been reported from the Chagai intrusive rocks, at an initial stage of dioritic to granodioritic with minor gabbro and quartz monzodiorite intrusions, prospered by intrusions of granodiorite, quartz monzonite and granite compositions (Ahmed et al, 1972;Breitzman et al, 1983;Jones, 1961;Perell o et al, 2008;Siddiqui, 1996;Siddique et al, 1987) (Breitzman et al, 1983;Perell o et al, 2008;Wang, Zheng, et al, 2022). The Sor-Koh intrusion belt is located to the west of the Chagai belt, consisting of small, separate plutons and stocks.…”

“…Previous research demonstrated that water-rich magma has the capability to dissolve volatiles throughout its evolution, which promotes enrichment and migration of ore-forming element (Richards et al, 2012;Wang, Zheng, et al, 2022). The high water content of the During partial melting of a mantle source under conditions of high oxygen fugacity, the majority of sulphur is eliminated in the form of sulphide, leading to the abundance of chalcophile-forming metals from the magma (Sun et al, 1989;Nardi et al, 2012).…”

“…These results are also consistent with previous findings that amphibole fractionation is rarely found and is usually followed by plagioclase removal (Hoskin, 2005;Martina et al, 2011). Wang, Zheng, et al, 2022). In addition to the indicators above, incompatible trace element ratios, such as Nb/U, can be used to identify the source region because they undergo minimal change during partial melting (Moyen, 2009;Sun et al, 2008).…”

“…The Chagai belt comprises prominent intrusive episodes known as the Sor‐Koh and Chagai intrusions. These intrusive episodes likely contain the emplacement of igneous rocks with multiple magmatism during the Eocene Sor Baroot (55 Ma), Ting‐Dargun (49 Ma), Talaran (45 Ma), Ganshero (36 Ma), Machi (24 Ma), Miocene Reko Diq (23–11 Ma), Saindak (22 Ma), Sor Baroot (17 Ma), Parrah‐Koh (12 Ma) and Durban Chah (10 Ma) (Breitzman et al, 1983; Perelló et al, 2008; Wang, Zheng, et al, 2022). The Sor‐Koh intrusion belt is located to the west of the Chagai belt, consisting of small, separate plutons and stocks.…”