The Tierra Blanca (TB) eruptive suite comprises the last four major eruptions of Ilopango caldera in El Salvador (≤45 ka), including the youngest Tierra Blanca Joven eruption (TBJ; ∼106 km³): the most voluminous event during the Holocene in Central America. Despite the protracted and productive history of explosive silicic eruptions at Ilopango caldera, many aspects regarding the longevity and the prevailing physicochemical conditions of the underlying magmatic system remain unknown. Zircon ²³⁸U‐²³⁰Th geochronology of the TB suite (TBJ, TB2, TB3, and TB4) reveals a continuous and overlapping crystallization history among individual eruptions, suggesting persistent melt presence in thermally and compositionally distinct magma reservoirs over the last ca. 80 kyr. The longevity of zircon is in contrast to previously determined crystallization timescales of <10 kyr for major mineral phases in TBJ. This dichotomy is explained by a process of rhyolitic melt segregation from a crystal‐rich refractory residue that incorporates zircon, whereas a new generation of major mineral phases crystallized shortly before eruption. Ti‐in‐zircon temperatures and amphibole geothermobarometry suggest that rhyolitic melt was extracted from different storage zones of the magma reservoir as indicated by distinct but synchronous thermochemical zircon histories among the TB suite eruptions. Zircon from TBJ and TB2 suggests magma differentiation within deeper and hotter parts of the reservoir, whereas zircon from TB3 and TB4 instead hints at crystallization in comparatively shallower and cooler domains. The assembly of the voluminous TBJ magma reservoir was also likely enhanced by cannibalization of hydrothermally altered components as suggested by low‐δ¹⁸O values in zircon (+4.5 ± 0.3‰).

中文翻译：

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Ilopango Caldera（萨尔瓦多）下长期存在且垂直扩展的岩浆系统中的锆石和熔体提取

Tierra Blanca（TB）喷发组包括萨尔瓦多（≤45 ka）的Ilopango破火山口的最后四次大喷发，包括最年轻的Tierra Blanca Joven喷发（TBJ；〜106 km ³）：这是全新世期间最大的一次事件。中美洲。尽管Ilopango破火山口的硅质爆发性喷发具有长期和生产性的历史，但有关潜在岩浆系统的寿命和主要理化条件的许多方面仍然未知。锆石²³⁸ U- ²³⁰TB组的地质年代学（TBJ，TB2，TB3和TB4）揭示了单个喷发之间连续且重叠的结晶历史，表明在最后一个ca内，在热和成分不同的岩浆储层中存在持续的熔体存在。80吉尔。锆石的寿命与先前确定的TBJ主要矿相的结晶时标<10 kyr相反。这种二分法是由流态熔体从含有锆石的富含晶体的难熔残渣中分离出来的过程解释的，而新一代主要矿物相在喷发前不久就结晶了。锆石中的钛温度和闪石地热气压计表明，流变质熔岩是从岩浆储层的不同存储区中提取的，这与结核菌丛爆发中独特但同步的热化学锆石历史表明了这一点。TBJ和TB2中的锆石表明在储层较深和较热的部分存在岩浆分化，而TB3和TB4中的锆石则暗示在较浅和较冷的区域内结晶。TBJ岩浆储集层的组装也可能由于低δ所表明的热液蚀变成分的相食化而增强了。而来自TB3和TB4的锆石则暗示在相对较浅和较冷的区域内结晶。TBJ岩浆储集层的组装也可能由于低δ所表明的热液蚀变成分的相食化而增强了。而来自TB3和TB4的锆石则暗示在相对较浅和较冷的区域内结晶。TBJ岩浆储集层的组装也可能由于低δ所表明的热液蚀变成分的相食化而增强了。锆石中的¹⁸ O值（+4.5±0.3‰）。