The modification of magma through mixing or through assimilation of country rocks is commonly inferred from various chemical and isotopic features of magmatic rock suites and supported by a variety of field evidence, including features indicative of interaction between two magmas, disaggregation of solids in magma, and varied antecryst populations in volcanic and plutonic rocks. The increased recognition that mushes are important long-term reservoirs of magma, and that they play an important role in magmatic processes, suggests that the processes of magma mixing and country rock assimilation probably involves mushes. This paper investigates field evidence related to the behaviour of granitic mushes, in an attempt to understand their behaviour and assess their contribution to compositional variation in granitic rocks.

Mushes, defined here as solids with interstitial melt, are permeable materials open to the invasion of extraneous melts. These can react with the crystalline framework and mix with or expel the original resident melt. This is the first step in either magma mixing or rock assimilation, and is recorded by ghost structures in migmatites, the loss of melt from a dyke to a mushy host rock, or patchy hybridization of microgranitoid enclaves (ME).

The melt-filled porosity of mushes implies that they have an inherent physical weakness, which makes them subject to disaggregation and liquefaction through the combined effects of physical erosion, increased melt fraction, and pore pressure increase. As mushes disaggregate, solids may continue to react with their melt-rich surroundings. This is the second step in hybridization or assimilation, which tends to mask the history of exchange and the role of mushes.

The history of granitic magmas starts with their extraction from a mushy migmatitic source or from a mushy cumulate, a process that controls their variable cargo of residual or cumulate crystals. These magmas may subsequently intrude, infiltrate and assimilate mushy wall-rocks or mushy xenoliths, or intrude, infiltrate and mingle with mushy mafic intrusions, forming mushy microgranitoid enclaves. The resulting magmas may themselves become temporary mushes, capable of being infiltrated by extraneous magmas before being liquefied and remobilized. Thus, mushes may play multiple and variable roles during the evolution of a single magma batch, facilitating magma mixing and wall-rock assimilation because mushes relax the energetic and physical constraints of these processes. Beyond providing opportunities for hybridization and assimilation, crustal mush columns provide multiple opportunities for magma batches to alternate between periods dominated by fractional crystallization and mush development, and periods dominated by remelting and mush remobilization, generating magmas with complex histories and varied geochemical signatures.

通过混合或同化围岩对岩浆的改造通常可以从岩浆岩组的各种化学和同位素特征中推断出来，并得到各种实地证据的支持，包括表明两种岩浆之间相互作用的特征、岩浆中固体的解聚以及火山岩和深成岩中的不同祖先群。越来越多的人认识到糊状物是重要的岩浆长期储存库，并且它们在岩浆过程中起着重要作用，这表明岩浆混合和围岩同化过程可能涉及糊状物。本文调查了与花岗岩糊状物行为相关的现场证据，试图了解它们的行为并评估它们对花岗岩成分变化的贡献。

糊状物，这里定义为具有间隙熔体的固体，是对外来熔体侵入开放的可渗透材料。这些可以与结晶框架反应并与原始驻留熔体混合或排出。这是岩浆混合或岩石同化的第一步，并通过混合岩中的幽灵结构、岩脉熔体流失到糊状主岩或微花岗岩飞地 (ME) 的斑片状杂交来记录。

糊状物的熔体填充孔隙率意味着它们具有固有的物理弱点，这使得它们通过物理侵蚀、熔体分数增加和孔隙压力增加的综合作用而发生解聚和液化。随着糊状物解聚，固体可能会继续与其富含熔体的环境发生反应。这是杂交或同化的第二步，它往往掩盖了交换的历史和糊状物的作用。

花岗岩岩浆的历史始于它们从糊状混合岩源或糊状堆积物中提取，这一过程控制着其残余或堆积晶体的可变货物。这些岩浆随后可能侵入、渗透和同化糊状围岩或糊状捕虏体，或侵入、渗透并与糊状基性侵入体混合，形成糊状微花岗岩飞地。由此产生的岩浆本身可能会变成暂时的糊状物，在液化和再流动之前能够被外来的岩浆渗透。因此，糊状物在单个岩浆批次的演化过程中可能扮演多种不同的角色，促进岩浆混合和围岩同化，因为糊状物放松了这些过程的能量和物理约束。除了提供杂交和同化的机会，