The ungrouped achondrite Northwest Africa (NWA) 7325 parent body underwent a severe impact after primary crystallization, which completely melted plagioclase and partially melted pyroxene, followed by Mg diffusion into the adjacent plagioclase‐melt. The ²⁶Al‐²⁶Mg system was therefore modified, forming a pseudoisochron with an initial δ²⁶Mg^* of 0.094 ± 0.005‰ and an age of 4563.12 ± 0.33 Ma between the primary crystallization and subsequent impact event(s). The positive initial δ²⁶Mg^* can be interpreted by a model age of ~1.77 Ma after CAIs when a chondritic composition differentiated into a magma/rock with the Al/Mg ratio equivalent to that of NWA 7325 (~1.52). The LREE enrichments and a positive Eu anomaly suggest that the NWA 7325 parent magma formed by the melting of a plagioclase‐rich crustal lithology, which crystallized from a magma ocean. Differentiation of the magma ocean was prior to 1.77 Ma after CAIs. NWA 7325 is also unique by containing many rounded voids (5–6 vol%) interstitial to or enclosed in silicates, suggested to have formed by the leaching/vaporization of pre‐existing Fe‐Ca‐Mg‐Mn sulfides. This is supported by the similar morphology between voids and Cr‐bearing troilites, the discovery of relict oldhamite, and the highly reducing conditions of NWA 7325. The loss of pre‐existing sulfides could explain the unusual subchondritic Mn/Mg ratio of the bulk sample. Furthermore, the enrichment of moderately volatile elements (K/Th ratio ~2600–10,000) in the NWA 7325 parent body may result from the bonding with S^2‐ in silicate melts under highly reducing conditions. NWA 7325 therefore provides evidence of sulfur‐rich magmatism in the early solar system.

中文翻译：

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未成群的陨石西北非洲7325分化母体的早期富硫岩浆作用

未成群的西北非洲的长方陨石母体在初次结晶后受到了严重的冲击，其完全融化了斜长石和部分辉石，随后Mg扩散到相邻的斜长石熔体中。在²⁶ AL- ²⁶因此Mg系进行了修改，从而形成具有初始δ一个pseudoisochron ²⁶的Mg ^* 0.094±0.005‰和4563.12±0.33马的主结晶和随后的撞击事件（一个或多个）之间的年龄。正初始δ ²⁶的Mg ^*可以通过CAI后约1.77 Ma的模型年龄来解释，当时软骨岩成分以Al / Mg比等于NWA 7325（〜1.52）的方式分化为岩浆/岩石。LREE富集和正的Eu异常表明，NWA 7325母岩浆是由富含岩藻石的地壳岩性融化形成的，该岩浆从岩浆海中结晶出来。CAI后，岩浆海洋的分化发生在1.77 Ma之前。NWA 7325的独特之处还在于，它包含许多在硅酸盐之间或封闭在硅酸盐中的圆形空隙（5–6％（体积）），建议由先前存在的Fe-Ca-Mg-Mn硫化物的浸出/汽化形成。空隙和含铬三叶草之间的相似形貌，遗留的菱铁矿的发现以及NWA 7325的高度还原条件都支持了这一点。预先存在的硫化物的损失可以解释整体样品中异常的软骨下锰/镁比。此外，NWA 7325母体中中等挥发性元素的富集（K / Th比〜2600–10,000）可能是由于与S的键合所致。硅酸盐中的^2‐ in在高度还原的条件下熔化。因此，NWA 7325提供了早期太阳系中富硫岩浆作用的证据。