Textures and compositions of minerals can be used to infer the physiochemical conditions present within magmatic systems. Given that plagioclase is an abundant phase in many magmatic systems, understanding the link between texture and process is vital. Here, we present a database of textural and compositional data for > 1800 plagioclase crystals in mid-ocean ridge basalt from the Gakkel Ridge (Arctic Ocean) to investigate the physiochemical conditions and processes that govern the formation of plagioclase textures and compositions. The Gakkel basalts have high modal crystal contents (up to 50%). The crystal cargo is complex, with both individual plagioclase and glomerocrysts showing large variations in crystal habit, zoning and resorption. The most common types of zoning are reverse and patchy; we attribute patchy zoning to infilling following either skeletal growth or resorption. Resorption is abundant, with multiple resorption events commonly present in a single crystal, and results from both magmatic recharge and decompression. Periods of strong undercooling, distinct to quench crystallisation, are indicated by matured skeletal crystals and thin normally zoned melt inclusion-rich bands following resorption. Individual samples often contain diverse textural and compositional plagioclase groups. Furthermore, most plagioclase is not in equilibrium with its host melt. Finally, the porous open structures of some glomerocrysts suggest that they represent pieces of entrained disaggregated mush. We interpret this to indicate that the crystal cargo is not generally phenocrystic in origin. Instead, plagioclase crystals that formed in different parts of a mush-dominated plumbing system were entrained into ascending melts. The textures of individual crystals are a function of their respective histories of (under)cooling, magma mixing and decompression. The morphologies of melt inclusion trapped in the plagioclase crystals are associated with specific host crystal textures, suggesting a link between plagioclase crystallisation processes and melt inclusion entrapment. The database of plagioclase presented herein may serve as a template for the interpretation of plagioclase textures in magmatic systems elsewhere.

中文翻译：

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洋中脊玄武岩（北冰洋加克尔海脊）中斜长石纹理的意义

矿物的结构和成分可用于推断岩浆系统内存在的物理化学条件。鉴于斜长石是许多岩浆系统中丰富的相，了解结构和过程之间的联系至关重要。在这里，我们提供了来自 Gakkel 海脊（北冰洋）的洋中脊玄武岩中超过 1800 个斜长石晶体的结构和成分数据的数据库，以研究控制斜长石结构和成分形成的物理化学条件和过程。Gakkel 玄武岩具有高模态晶体含量（高达 50%）。晶体货物很复杂，单个斜长石和球晶在晶体习性、分区和吸收方面都表现出很大的变化。最常见的分区类型是反向分区和零散分区。我们将斑片状分区归因于骨骼生长或吸收后的填充。再吸收是丰富的，单晶体中通常存在多个再吸收事件，并且是岩浆补给和减压的结果。与淬火结晶不同的强过冷期由成熟的骨架晶体和再吸收后薄的正常分区的富含熔体夹杂物的带指示。各个样品通常包含不同的结构和成分斜长石组。此外，大多数斜长石与其主体熔体不处于平衡。最后，一些球晶的多孔开放结构表明它们代表夹带的分解糊状物的碎片。我们将此解释为表明晶体货物通常并非起源于斑晶。相反，在以糊状为主的管道系统的不同部分形成的斜长石晶体被夹带到上升的熔体中。单个晶体的结构是它们各自的（欠）冷却、岩浆混合和减压历史的函数。斜长石晶体中截留的熔体夹杂物的形态与特定的主体晶体结构相关，表明斜长石结晶过程和熔体夹杂物截留之间存在联系。本文提出的斜长石数据库可以用作解释其他地方岩浆系统中的斜长石纹理的模板。