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The volcanic-intrusive connection is critical for understanding the formation of transcrustal magma systems and the mechanisms driving magma eruption. Yet, the genetic links between abyssal intrusive rocks and acidic volcanic rocks remain poorly understood. Here, we present new data from the Dulan volcanic-intrusive complex, a tilted section of the East Kunlun orogenic belt, integrating zircon U Pb dating, trace elements, apatite and zircon Hf isotope geochemistry, and whole-rock geochemistry to investigate volcanic-intrusive connections and track crystal-melt segregation processes. The Dulan complex comprises rhyolite, granite porphyry, and granodiorite, all showing consistent zircon U Pb ages, rare earth element (REE) patterns, and εHf(t) values, suggesting a shared magma source. Glomerocrysts of plagioclase, alkali feldspar, and hornblende, along with antecrystic zircon and apatite, imply a cumulate affinity in granodiorite and granite porphyry. Compositional variations in whole-rock and accessory minerals indicate that plagioclase, apatite, and zircon fractionation significantly influenced magma evolution. We propose a two-stage crystal segregation process in a ∼ 2 Myr-long magma reservoir system. In the early stage, at ∼33 km depth, aqueous fluid influx initiated crystal-melt segregation, forming the Dulan granodiorite from residual mush. In the later stage, mafic melt and fluid injections caused crystal-melt segregation in a shallower reservoir at ∼12 km depth, with high-silica magma producing rhyolite, while residual mush consolidated into granite porphyry. Our findings suggest that volcanic-intrusive connections are more complex than mere compositional equivalence or complementarity, requiring multidimensional analysis through accessory minerals and whole-rock geochemistry. • Identification of zircon and apatite antecrysts supports a cumulate affinity for graniticintrusions. • Two-stage crystal segregation in a ∼ 2 Myr-long magma reservoir system produced the volcanic-intrusive complex. • Volcanic-intrusive connections are more complex than mere compositional equivalence or complementarity. [ABSTRACT FROM AUTHOR]

The forearc and back-arc region of the Andaman-Nicobar-Sumatra Subduction Zone are mainly submarine and poorly understood. To gain new insights sixty representative volcanic rocks were collected from the Andaman Sea region. Rock types range from basalt, basaltic andesite, andesite, dacite to rhyolite reflecting calc-alkaline, intermediate to acidic magma compositions. The rocks exhibit pronounced LREE enrichment with significant negative Nb, Ta and Ti anomalies and relative HREE depletion indicative of subduction zone related volcanism. The calc-alkaline rocks were generated by fractional crystallization along with crustal assimilation of older crustal rocks. A lower level of contamination is recorded in Barren Island samples, and mafic rocks from the Central Andaman Trough and Southern arc. Miocene zircon 238U/206Pb ages (10.8 ± 0.3 Ma, 19.8 ± 0.3 Ma and 19.5 ± 0.2 Ma) are recorded by West Sewell Ridge samples. Previous suggestions that hyperextended Malayan crust (Sundaland) existed below much of the Northern arc, Southern arc, Alcock and Sewell Rises and were later covered by volcanic crustal material is supported by the presence of inherited zircon cores and xenocrysts with ages spanning the Phanerozoic to Neoproterozoic (250, 320, 460–690, 800–1100, and 1400 Ma). These fit with the Malay-Sundaland as the main source of crustal contamination. • Andaman volcanic rock exhibit pronounced LREE enrichment with negative Nb, Ta, Ti anomalies and relative HREE depletion. • Calc-alkaline rocks were generated by fractional crystallization along with crustal assimilation of older crustal rocks. • The hyperextended Malayan crust (Sundaland) existed much below of the Northern arc, Southern arc, Alcock, and Sewell Rises. • Presence of zircon cores and xenocrysts of Triassic ages consistent with main phase of Malay Sundaland arc magmatism. • Older ages spanning from Phanerozoic to Neoproterozoic suggest Sundaland crust as a main source of crustal contamination. [ABSTRACT FROM AUTHOR]

The western part of the Singhbhum Craton preserves Paleo-Mesoarchean mafic greenstone lava flows, felsic tonalite-trondhjemite-granodiorite (TTG)-granite associations, and high-K granite and volcanic suites, similar to other Archean cratonic blocks. These successions are crucial components of early continental crust, and unravelling their respective petrogenetic relations is important for understanding the evolution from mafic to felsic crust. This study presents detailed investigations of zircon U Pb age and Hf isotope data from the Bonai TTG/gneiss-granite Suite, and the overlying Tamperkola high-K granite and rhyolite Suite. Our results indicate concurrent crystallization of the Bonai TTG gneiss (3316 ± 9 Ma), associated porphyritic high-K granite (3299 ± 9 Ma), and their amphibolite enclaves (3325 ± 9 Ma) with older, inherited zircon grains intercepting at 3586 ± 25 Ma. The entire Bonai Suite yields an overall juvenile Hf isotope composition (ɛHf (t) = −1.7 to +4.6, 95 % ɛHf (t) > 0). Combined with the mantle-like Hf isotope signatures of the inherited zircons grains (ɛHf (t) = +1.7 to +6.2), this indicates a Hf isotope evolution array with a mafic crustal 176Lu/177Hf ≈ 0.022. Considering that these grains represent the source of the TTGs, this implies lower crustal residence of ca. 300 Myr of the mafic precursor rocks. The Tamperkola high-K magmatic suite yields a crystallization age of 2810 ± 8 Ma with subchondritic Hf isotope composition (ɛHf (t) = −3.2 to −0.6). This Tamperkola Suite plots on the Hf isotope evolutionary array defined by the Bonai Suite and its mafic precursor, suggesting remelting of the Bonai (transitional) TTGs to produce these high-K granitoids in an internal reworking process. Our new and published data yield a threefold crustal evolution with (i) initial formation of the mafic crust at ca. 3586 Ma, (ii) subsequent residence for ca. 300 Myr and crustal reworking at ca. 3316–3299 Ma to form TTGs and (iii) their melting at ca. 2810 Ma to form high-K magmas. This succession of re-melting of igneous rocks drove the transition from mafic to felsic continental crust in the Singhbhum Craton. Given the consistent lithological sequence of predominantly mafic greenstone rocks, TTG-granite suites, and high-K granites observed across global cratons, this Paleo-Mesoarchean process likely reflects the order of crustal maturation in the Archean continental crust. • Bonai Suite formed at 3316-3299 Ma and have suprachondritic Hf isotope composition. • Inherited zircons indicate a juvenile mafic crustal source at 3586 Ma for Bonai Suite. • Tamperkola Suite emplaced at 2810 Ma and have subchondritic Hf isotope composition. • Threefold crustal reworking from early mafic crust to TTG-granite to high-K granite. [ABSTRACT FROM AUTHOR]