Work

Magma transfer and pluton growth: Modelling short- and long-term processes by thermo-mechanical two-phase flow including the heat pipe mechanism

Year: 2025

Type: article

Abstract: This study investigates the conditions sustaining long-lived molten plutons in the middle to upper crust, driven by lower crustal melting due to magmatic underplating and episodic melt extraction. Using 2D two-phase flow models solving conservation equations for mass, composition, momentum, and energy, and assuming a simplified melting law, we examine the interplay between long-term magmatic processes (e.g., lower crust heating, melt generation, segregation, diapiric ascent) and short-term dynamics (e.g., magma extraction, dyke ascent, emplacement). A novel melt extraction and intrusion formulation is introduced, varying parameters such as melt extraction volume threshold, intrusion depth, size, and geometry. Results indicate that smaller extraction thresholds lead to more frequent intrusions, increasing total melt volume in the intrusion and prolonging pluton lifespan. Intrusion geometry strongly influences melt accumulation: small radii (~2 km) favor significant melt volumes, while larger zones (>4 km) promote rapid freezing. Circular intrusions retain heat longer than dyke- or sill-like intrusions. Frequent intrusions promote vertical stacking of melt batches, pluton floor subsidence, and compositional stratification. Model-derived magma supply rates (0.05–0.09 km³/yr per extraction pulse; 0.0002–0.001 km³/yr averaged over the total time extraction events) align with observed Central Andean magmatic systems. Melt extraction accelerates heat transport, producing early heat flux peaks (0.5–2 Myr) via the heat pipe mechanism, introduced in geoscience literature as a rapid transport of heat and mass through the lithosphere. This effect, quantified by a Nusselt number, increases with greater extracted melt volumes and shallower intrusions. Comparison with Central Andean heat flux data suggests a heat pipe Nusselt number of ~3.5, indicating extraction and intrusion enhance heat transport by this factor. These findings provide insights into the interplay between magmatism, heat transfer, and pluton evolution in continental crust.

Source: Tectonophysics

DOI: 10.1016/j.tecto.2025.230968

Authors: Harro Schmeling, Gabriele Marquart, Herbert Wallner, Roberto Weinberg

Institutions: Goethe University Frankfurt, RWTH Aachen University, Monash University

Language: English

Topic: Geological and Geochemical Analysis

Subfield: Geophysics

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,190

Funders: Deutsche Forschungsgemeinschaft, Monash University