This study investigates the petrogenesis of diatexite migmatites and leucogranites in a granulite facies terrain and quantifies the melt budget for it. The anatectic rock types in the Ashuanipi Subprovince are; 1) melt-depleted orthopyroxene metatexite migmatite, 2) secondary diatexite migmatite formed where anatectic melt intruded, entrained and accumulated in the metatexite, and 3) leucogranite.The FeO, MgO, TiO₂, Cr, Co and Sc contents of the diatexites are controlled by the fraction of entrained metatextite. However, most diatexites and many leucogranites are richer in (Na₂O+CaO) but depleted in K₂O relative to an anatectic melt + metatexite mixture. This, and the predominance of plagioclase + orthopyroxene frameworks in the diatexites indicates loss of fractionated melt. Mass-balance models using the metatexite and compositions of fractionated melts and crystallised solids obtained from simulated crystallisation of the anatectic melt indicate that “typical” diatexite formed by mixing ∼40% metatexite with ∼60% anatectic melt, then when 8 to 30% crystallised most (>73%) of the remaining melt was expelled, likely by shear-enhanced compaction. The processes making the diatexites and leucogranites expelled ∼50% of the initial amount of melt; some formed the K₂O-rich leucodiatexites and leucogranites in the terrain, but most escaped.A melt budget for the present Ashuanipi surface made by combining mass balance calculations and the area of each rock type reveals that it once held 3.05 times more melt than was generated there. The adjacent Opinaca Subprovince contains 10 times more leucogranite than partial melting there produced, moreover its leucogranites are compositionally similar to fractionated melts expelled from the Ashuanipi. Combining these crustal levels and assuming a gradient of 30^oC km^-1, then ∼400000 km³ of melt representing >68% of the total generated during crustal reworking in the Ashuanipi remained in the middle crust where temperatures were above the solidus.

中文翻译：

---

次生辉长岩的成岩作用和地壳重熔的熔体收支

这项研究调查了花岗石相地形中的辉绿岩辉石岩和白云岩的成岩作用，并量化了其熔体预算。阿斯华尼皮省的钙质岩类型为：1）贫化的邻苯二茂铁变质辉石岩，2）次生的半闪辉岩辉石岩，闪锌矿熔融物侵入，夹带并聚集在该变质岩中，3）辉光花岗岩，辉石中的FeO，MgO，TiO ₂，Cr，Co和Sc含量为由夹带的偏纺织物的比例控制。但是，大多数成岩岩和许多无色花岗岩中的（Na ₂ O + CaO）含量较高，而K _2的含量却不足相对于阳极熔体+陨石混合物为O。这以及斜长石中斜长石+邻位邻苯二甲骨架的优势表明损失了分级熔体。质量平衡模型使用的是变质岩，并通过模拟熔融结晶过程得到的分馏熔体和结晶固体成分，表明将40％的变质岩与60％的熔液混合，然后当8％至30％结晶时，会形成“典型”的变质岩。大部分（> 73％）的剩余熔体可能被剪切增强的压实排出。制作透辉石和无色花岗岩的过程排出了约50％的初始熔体。一些形成了K ₂地形中富含O的白闪石岩和白榴石岩，但大多数都逃脱了。通过结合质量平衡计算和每种岩石类型的面积得出的当前Ashuanipi表面的熔体预算显示，其曾经拥有的熔体比那里产生的熔体高3.05倍。相邻的奥皮纳卡次省包含的白云石比其所产生的部分熔融多10倍，此外，其白云石的成分类似于从Ashuanipi排出的分馏熔体。结合这些地壳水平，并假设梯度为30 ^o C km ^-1，那么约40万km ³的熔体（占Ashuanipi地壳再造过程中生成总量的68％）仍留在中地壳中，温度高于固相线。