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Abstract

Intra-oceanic convergent margins represent one of the primary sites for the generation of juvenile continental crust through subduction-related processes. Magmas in these systems are derived from mantle sources with minimal continental input and preserve direct evidence of source components, magma differentiation, and crustal maturation. Most modern intra-oceanic arcs remain submerged, limiting direct observation of their crustal architecture and petrogenetic evolution. Fossil arcs that have been accreted and uplifted above sea level therefore provide invaluable archives for reconstructing the complete life cycle of intra-oceanic arc systems. Among these, the Greater Antilles Arc, a major segment of the Great Arc of the Caribbean, preserves one of the most extensive and accessible records of long-lived intra-oceanic subduction system spanning the Early Cretaceous to the Eocene. The central Cuban segment, where forearc ophiolites and mélanges, volcanic-plutonic sequences, and arc-related metamorphic complexes are well exposed, offers an exceptional window into the temporal and structural evolution of an intra-oceanic arc from its initiation to collisional termination. This study examines the temporal, geochemical, and structural evolution of the Greater Antilles Arc system through three complementary investigations. First, a regional synthesis integrating over 650 radiometric ages and more than 1500 geochemical analyses from subduction-related rocks across Cuba, Hispaniola, Puerto Rico, and the Virgin Islands identified three major stages of arc evolution: subduction initiation, magmatic and metamorphic climax, and the waning of subduction magmatism and collisional termination. The temporal overlap between peak magmatism and emplacement of the Caribbean Large Igneous Province suggests a transient plume-arc interaction, most pronounced in the retro-arc region. Building on the regional framework, the second part of the study focuses on the Mabujina Amphibolite Complex in central Cuba, a tectonically important arc-related metamorphic assemblage formed during active arc development, and long debated in regional tectonic reconstuctions. Petrochemical and isotopic data provide new constraints indicating that the protolith represents a proximal segment of the Caribbean arc, rather than a far-traveled exotic terrane derived from the Pacific realm. The accretionary event occurred during the mid-Cretaceous, when oblique convergence cross Caribbean arc system promoted a transspressional regime. At a finer scale, the third component of this study investigates the Central Cuban Arc segment, which preserves an exceptional ~60 Myr record of magmatism from subduction initiation to collisional termination. Field, geochemical, and geochronological data reveal a transition from early submarine tholeiitic to Late Cretaceous calc-alkaline magmatism. Pressure-senstive geochemical proxies and thermobarometric estimates indicate increasingly complex magma storage, progressive crustal thickening, and enhanced magmatic differentiation through time. Amphibole-bearing magmas tapped lower crustal levels approaching present-day Moho depths during major plutonism shortly after athe accretionary event. The mantle source remained largly homogeneous, with limited slab input, demonstrating that intra-oceanic arc systems can generate juvenile continental crust prior to collision. Collectively, these results provide a comprehensive reconstruction of the Greater Antilles Arc as a natural laboratory for studying intra-oceanic arc construction, accretion, and crustal differentiation. Integration of regional and local datasets defines the Greater Antilles Arc as a long-lived oceanic arc that evolved from tholeiitic to calc-alkaline magmatism and progressively developed a hydrous, transcrustal plumbing system capable of generating proto-continental crust. This study offers new insights into the mechanisms of crustal growth and differentiation at intra-oceanic convergent margins.