Crystal-hosted melt embayments and melt inclusions partially record magmatic processes at depth, but it is not always obvious how to interpret this record. One impediment is our incomplete understanding of how embayments and melt inclusions form. In this study, we investigate the formation mechanism of embayments and melt inclusions during quartz growth to quantify the relationship between the compositions of the entrapped and average melt. We study the growth of embayments and inclusions through direct numerical simulations that couple the growth of a crystal surface with the evolution of the concentrations of incompatible components in the surrounding melt. We find that H₂O is more enriched in the interior of defects on crystal surface compared to the exterior. The resultant lower disequilibrium in the defect interior causes lower growth rate than in the exterior, elongating the defect into an embayment. If crystal growth stops, the composition in the embayment equilibrates with the average melt within days to months. If crystal growth continues until the embayment neck closes, a melt inclusion forms. The melt entrapped by both embayments and melt inclusions is enriched in incompatible components, such as H₂O and CO₂. In addition to inclusion size, the enrichment of incompatible components in melt inclusions also depends on component diffusivity and the crystal growth regime. High-diffusivity components like H₂O have similar enrichment levels in all scenarios, while lower-diffusivity components like CO₂ are more enriched in melt inclusions with smaller sizes or formed in continuous crystal growth.

中文翻译：

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通过直接数值模拟破译有关石英托管海湾和熔体包裹体中编码的岩浆成分的线索

晶体熔体海湾和熔体包裹体部分记录了深部岩浆过程，但如何解释这一记录并不总是显而易见的。障碍之一是我们对海湾和熔体包裹体如何形成的不完全了解。在这项研究中，我们研究了石英生长过程中海湾和熔体包裹体的形成机制，以量化截留熔体和平均熔体成分之间的关​​系。我们通过直接数值模拟研究海湾和夹杂物的生长，将晶体表面的生长与周围熔体中不相容成分浓度的演变结合起来。我们发现与外部相比，H ₂ O在晶体表面缺陷的内部更加丰富。由此产生的缺陷内部较低的不平衡性导致比外部更低的生长速率，从而将缺陷拉长成海湾。如果晶体生长停止，海湾中的成分会在几天到几个月内与平均熔体达到平衡。如果晶体生长持续到海湾颈部闭合，就会形成熔融夹杂物。被海湾和熔体夹杂物截留的熔体富含不相容组分，例如H ₂ O和CO ₂。除了夹杂物尺寸外，熔体夹杂物中不相容组分的富集还取决于组分扩散率和晶体生长状态。 H ₂ O等高扩散率组分在所有情况下都具有相似的富集水平，而CO ₂等低扩散率组分在较小尺寸的熔体包裹体中或在连续晶体生长中形成的情况下更富集。