Genesis of the early Cretaceous porphyritic granitoid: New insights from the Hongling skarn polymetallic metallogenesis, NE China
Year: 2025
Type: article
Abstract: • The Hongling ore-forming materials derived form the early Cretaceous granitic magmatism. • The Hongling early Cretaceous granitoids form via crystal melt segregation, involving intergranular melts from dense crystal mush. • The Hongling's early Cretaceous granitoids' intergranular melt segregation is critical for Fe-Pb-Zn deposition, concentrating fertilized fluids from a homogenized magma chamber. The Hongling skarn Fe–Pb–Zn deposit is situated in the Lindong district of eastern Inner Mongolia, southern Great Hinggan Range. Previous investigations have established that the metallogenic fluid and ore-forming material at Hongling originated from the magmatic system, with mineralization temporally coinciding with the early Cretaceous granitic emplacement (ca. 142–143 Ma). Petrogenetic studies further suggest that the Hongling granitoids share comparable magmatic origins and evolutionary pathways with regional contemporaneous intrusions. In this contribution, we integrate new zircon U-Pb geochronology, whole-rock geochemistry, and Sr-Nd-Hf-S-Pb isotopic analyses of porphyritic granitoids and associated sulfides with existing regional datasets to: (1) constrain the magmatic evolution of Hongling intrusives; (2) discriminate between mineralized and barren intrusion characteristics; and (3) elucidate metallogenic processes. In situ sulfur (δ 34 S = −2.8 ‰ to +1.1 ‰) and lead ( 206 Pb/ 204 Pb = 18.292 to 18.303) isotopic signatures from ore minerals demonstrate a predominant magmatic derivation..The porphyritic granitoids exhibit transitional Sr-Nd-Hf isotopic compositions (( 87 Sr/ 86 Sr) i = 0.7065–0.7091, ε Nd ( t ) = −1.25 to +0.69, and ε Hf ( t ) = +0.12 to +8.39), consistent with partial melting of juvenile lower crustal sources. Comparative analysis with regional coeval plutons reveals that the Lindong mineralized intrusions underwent crystal-melt segregation processes, with the Hongling porphyritic phase representing interstitial melts extracted from crystal-rich mush zones.. Subsequent reactivation of these segregated melts facilitated efficient extraction and concentration of ore-forming fluids, ultimately leading to Fe-Pb-Zn mineralization through fluid-rock interaction in skarn systems.
Source: Ore Geology Reviews
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,310
OpenAlex ID: W4409413303