The Jurassic magmatic arc is located on the southern margin of the Gondwanan arc, in which Jurassic subduction-related Cu-Au and Miocene collision-related Cu-Mo porphyry deposits are developed. However, little is known about the diagenetic links between subduction- and collision-related porphyry Cu deposits. In this paper, Nd isotope, ΔFMQ and Eu/Eu^* value mapping has been carried out within the Jurassic magmatic arc, based on published whole-rock major and trace elements, Sm-Nd isotope and zircon trace elements data. The mapping results show that the main development area of Jurassic subduction-related porphyry Cu-Au deposits has high εNd(t) and young Nd mode ages during the Jurassic period, which exhibit juvenile crustal features, while the development location of Miocene collision-related porphyry Cu-Mo deposits is near the interface of the crustal contact between the old and juvenile crust during the Jurassic period. Jurassic porphyry Cu-Au deposits were basically developed in areas with high ΔFMQ and Eu/Eu^* value magmas during the Jurassic period, and Miocene porphyry Cu-Mo deposits were developed in areas that exhibit either areas of high ΔFMQ and low Eu/Eu^* value or areas of low ΔFMQ and Eu/Eu^* values during the Jurassic period. This indicates that during the Jurassic period, the magma in the area where the Jurassic porphyry Cu-Au deposits are located had higher oxygen fugacity and water content compared to the magma in the area where the Miocene porphyry Cu-Mo deposits were developed. Water-rich and oxidised magmas provided sufficient S and metallogenic metals for the development of Jurassic porphyry Cu-Au deposits by inhibiting early sulphide saturation of deeper magmas. Comparatively, the magma of the Miocene porphyry Cu-Mo development region may have failed to reach conditions that inhibited early sulphide saturation in the deeper magma due to the mixing of ancient crustal components, which triggered early sulphide saturation, leading to the formation of large amounts of Cu-bearing lower crustal accretion and inhibiting its mineralisation in the Jurassic. The Indian-Eurasian collision resulted in the bottom intrusion of thermochondritic melts, which triggered the remelting of Cu-bearing lower crustal heap crystals, providing a favourable source of metals for the formation of the Miocene porphyry Cu-Mo deposits.