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Mafic igneous rocks are volumetrically limited in collisional orogens but are significant for revealing specific geological processes. The mafic intrusive rocks in the eastern Lhasa batholiths along the Parlung fault (the easternmost branch of the Jiali fault zone), southern Tibet, are commonly regarded as the easternmost mafic components of an inferred Shiquanhe–Nam Tso–Jiali–Parlung suture zone, which is assumed to mark a back-arc oceanic basin related to the southward subduction of the Bangong-Nujiang Meso-Tethyan Ocean. However, the petrogenesis and tectonic setting of the mafic intrusive rocks have been poorly constrained. In this paper, we present petrological, geochemical and geochronological data for this mafic suite and evaluate the tectonic implications. The mafic intrusive rocks can be approximately divided into pyroxene-amphibole cumulate and medium-grained and pegmatitic hornblende gabbros that are characterized by the occurrence of very calcic plagioclase (An = 80–92) and abundant amphibole crystals, indicating an H 2 O-enriched magmatic signature. Their whole-rock compositions, which include negative Nb and Ta anomalies, also suggest a subduction-modified setting. Zircon Lu Hf isotope data show that their magmas were formed by magmatic mixing between melts derived from enriched subcontinental lithospheric mantle and liquids derived from upwelling asthenosphere. Zircon U Pb dating results reveal crystallization ages of ~114–110 Ma for this mafic suite, corresponding to the late stage of regional granitic magmatism (~135–110 Ma) that was related to the Lhasa-Qiangtang collision after the closure of the Bangong-Nujiang Meso-Tethyan Ocean. Given that coeval mafic and felsic rocks are distinctly controlled by the Parlung fault, we suggest that asthenospheric upwelling due to the break-off of the subducted Bangong-Nujiang oceanic slab not only induced partial melting of the enriched subcontinental lithospheric mantle but also resulted in regional rifting/extension and the initial development of the eastern Jiali (Parlung) fault. • Early Cretaceous mafic magmatism along the eastern Jiali fault is demonstrated. • The mafic suite marks the initial development of the eastern Jiali fault. • The active Jiali fault zone might exploit and connect the pre-existing faults. [ABSTRACT FROM AUTHOR]

[Display omitted] • The ~91 Ma Chemen intrusion represents a magmatic product of the Late Cretaceous Gangdese magmatic 'flare-up' event. • The Chemen intrusion was derived from partial melting of Neo-Tethys oceanic crust during ridge subduction. • Compositions of zircon and apatite indicate that the Chemen intrusion has a high mineralization potential. • The mineralization potentials of some other Late Cretaceous intrusions may be limited due to low magma oxygen fugacities. Large-scale Late Cretaceous magmatic intrusions have been recognized in the southern Gangdese magmatic belt, although their genesis and mineralization potential remain controversial. In this paper, we present new zircon U-Pb ages, whole-rock compositions, and major- and trace element compositions of zircon and apatite from the Chemen granodioritic intrusion. When integrated with compiled literature data for other Late Cretaceous igneous rocks in the southern Gangdese belt, our new dataset provides new insight into their genesis and mineralization potential. The Chemen intrusion obtains a zircon U–Pb age of ~91 Ma, similar to the age of Late Cretaceous magmatic intrusions across the entire southern Gangdese belt. Both the Chemen and other Late Cretaceous intrusions have geochemical characteristics that resemble those of adakites. When considered alongside the coeval formation of mafic intrusive rocks, high-temperature adakitic charnockites, and thickening of continental crust in the region, ridge subduction is considered most likely to be responsible for this 'flare-up' event. The Ce4+/Ce3+ ratios in zircon and SO 3 contents of apatite from the Chemen granodiorites both indicate a high oxygen fugacity during crystallization. Further, trace elements in Chemen apatite indicate that the Chemen intrusion has a great mineralization potential; however, no mineralization has been found in some of the Late Cretaceous intrusions in the southern Gangdese belt. Compiled data show that these barren Late Cretaceous intrusions generally formed from magmas with a low oxygen fugacity. Thus, we speculate that the low oxygen fugacity of some Late Cretaceous intrusions may limit the extent to which mineralization may occur. [ABSTRACT FROM AUTHOR]