The Paleocene-Eocene Cerro Munro pluton, to the east of the North Patagonian Batholith (NPB), is a tonalitic intrusion emplaced as a shallow, small, sub-circular tonalite-granodiorite body hosting abundant co-magmatic mafic microgranular enclaves (MME). Besides, the intrusive body is crosscut by radial porphyritic dikes and has been related to andesitic, dacitic and rhyolitic dikes, lava flows and ignimbrites cropping out at neighboring areas. Magmatic contacts between MME and host tonalites, together with their common geochemical features, suggest derivation from a common parental magma, although short-range mineralogical and geochemical differences point to an early crystallization of MME (chilled margins) at the sidewalls of ascent conduits or at shallow reservoirs. The established thermal gradient and the advance of the solidification front were responsible for the presence of the mafic microgranular and tonalitic subsystems and, in a continuous process, promoted the water saturation and the second boiling that finally account for the segregation of a water rich highly differentiated residual liquid. Hbl-Pl cumulate textures observed in the tonalites and mafic enclaves, as well as incompatible element-enriched rhyolitic melts record the results of this in-situ differentiation process. UPb zircon ages obtained from tonalites (57.1 ± 1.4 Ma), dacitic (55.4 ± 0.6 Ma) and rhyolitic (54.1 ± 0.7 Ma) dikes constrain an age of around 54 Ma for the final consolidation of the tonalitic magma and the crystallization of the expelled highly differentiated melts. This age coincides with the deposition of dacitic volcanic and volcanoclastic deposits to the north of the Cerro Munro pluton, which suggests that the fractionation process led to the extrusion of segregated melts, favored by extension, uplift and exhumation of an active rift tectonic setting.

中文翻译：

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通过成分岩浆分裂进行分馏：以阿根廷 Cerro Munro 为例

古新世-始新世 Cerro Munro 岩体位于北巴塔哥尼亚岩基 (NPB) 以东，是一个英闪长岩侵入体，呈浅层、小型、亚圆形英云闪长岩-花岗闪长岩体，含有丰富的同岩浆镁铁质微粒包体 (MME)。此外，侵入体被放射状斑岩岩脉横切，并与邻近地区出露的安山岩、英安岩和流纹岩岩脉、熔岩流和熔结岩有关。尽管短期矿物学和地球化学差异表明 MME（冷边缘）在上升管道的侧壁或在浅水库。所建立的热梯度和凝固前沿的推进导致了镁铁质微粒子系统和英调岩子系统的存在，并且在连续的过程中促进了水饱和度和二次沸腾，最终导致了富含水的高度分化的分离。残留液体。在英云闪长岩和镁铁质包体中观察到的 Hbl-Pl 累积结构，以及富含不相容元素的流纹岩熔体记录了这种原位分异过程的结果。从英英岩 (57.1 ± 1.4 Ma)、英安岩 (55.4 ± 0.6 Ma) 和流纹岩 (54.1 ± 0.7 Ma) 岩脉获得的 UPb 锆石年龄将英安岩岩浆最终固结和喷出物结晶的年龄限制在 54 Ma 左右。高度分化的熔体。这个时代与 Cerro Munro 岩体北部英安质火山岩和火山碎屑沉积物的沉积相一致，这表明分馏过程导致了分离熔体的挤出，这有利于活跃裂谷构造环境的延伸、隆起和折返。