关键词: 花岗岩, 火山—侵入不对称性, 岩浆动力学, 岩浆通道系统, 增量组装, 晶粥

Abstract: Granitic magma systems commonly exhibit a pronounced asymmetry between deep crustal emplacement and solidification (intrusion) and surface eruption (volcanism), with intrusive products greatly exceeding erupted products. Building upon Dezi Wang’s concept of a unified volcanic-intrusive magmatic system, this study introduces the framework of transcrustal magma plumbing systems and the dynamic crystal mush paradigm to explore the deep dynamic mechanisms responsible for the frequent failure of granitic magmas to erupt. The analysis is conducted from the perspectives of system behavior, transportpathway topology, and time-scale coupling. The results show that: (1) granitic magma systems fundamentally operate as dynamic crystal mush systems characterized by long-term cold storage and intermittent magma transport. As crystal contents progressively increase and exceed the ~60% rigid percolation threshold, the system enters a rheologically locked state marked by high viscosity and low permeability, resulting in a drastic decline in the long-distance transport capacity of melt and promoting progressive in situ solidification; (2) the crust acts as a triple “dynamic filter” composed of tectonic, gravitational, and thermal barriers that progressively screen ascending magmas. Neutral buoyancy levels, episodic opening of tectonic pathways, and rapid thermal dissipation collectively hinder the establishment of sustained transcrustal transport channels, causing most magma pulses to be trapped and frozen within the crust before reaching the surface; (3) granitic systems exhibit a pronounced mismatch of time scales. Chemical differentiation and isotopic homogenization generally occur over 105-106-year time scales, whereas the transient events capable of triggering pathway connection and eruption commonly last only years to centuries. Consequently, granitic systems display a characteristic behavior of “continuous chemical evolution but discontinuous dynamic transport”; (4) volatile behavior exerts dual dynamic effects. Early-stage volatile enrichment and exsolution may temporarily reduce melt viscosity and generate overpressure, thereby facilitating transient local pathway connection, whereas late-stage degassing promotes melt stiffening, rapid crystallization, and hydrothermal self-sealing, driving the system back into a rheologically locked state; and (5) during longterm incremental assembly, granitic magma systems exhibit a pulsed behavioral pattern characterized by “closed backgroundtransient connection-renewed closure.” Large granitic plutons essentially represent the cumulative products of repeated failed transient connection events, whereas eruptions constitute only rare peak events formed when the system temporarily departs from its stable state. This study emphasizes that the paradigm shift from the traditional static “large magma chamber” model to a dynamic “transcrustal crystal mush system” framework provides a unified magmatic-dynamic explanation for the widespread intrusive-dominated nature of granitic systems, and offers a new transcrustal system-dynamics framework for understanding longterm continental crustal evolution, thermal restructuring, and related mineralization processes. 

Key words: Granite, volcanic-plutonic asymmetry, magma dynamics, magmatic plumbing system, incremental assembly, crystal mush