Ungrouped iron meteorites Tishomingo, Willow Grove, and Chinga, and group IVB iron meteorites, are Ni-rich. Similarities include enrichments of 10–100 × CI for some refractory siderophile elements, and equivalent depletions in more volatile siderophile elements. Superimposed on the overall enrichment/depletion trend, certain siderophile elements (P, W, Fe, Mo) are depleted relative to elements of similar volatility. All three ungrouped irons derive from parent bodies formed in the early Solar System. Willow Grove and Chinga are characterized by cosmic ray exposure corrected ¹⁸²W/¹⁸⁴W consistent with metal-silicate segregation on their parent bodies within 1–3 Myr of Solar System formation, within the age range determined for segregation of magmatic iron meteorite parent bodies, including group IVB irons. Tishomingo is characterized by a younger model age 4–5 Myr subsequent to Solar System formation, reflecting either late stage melting resulting from ²⁶Al decay, or an impact resetting. The discovery of stishovite in Tishomingo, indicating exposure to a minimum shock pressure of 8–9 GPa, is consistent with the latter.

Stishovite in Tishomingo and chromite included in troilite-daubréelite in IVB irons allows oxygen isotopic composition comparison between these meteorites. Different mass independent oxygen isotopic compositions of IVB irons and Tishomingo indicate genetically distinct parent bodies. By contrast, mass independent Mo isotopic compositions overlap within analytical uncertainties, indicating a similar, carbonaceous chondrite (CC) type genetic heritage. Molybdenum and ¹⁸³W isotopic data for Chinga and Willow Grove indicate derivation from CC type parent bodies. Willow Grove shares Mo and ¹⁸³W isotopic compositions with the Ni-rich South Byron Trio (SBT) grouplet and the Milton pallasite. These Ni-rich meteorites likely formed in the same general nebular environment as other CC planetesimals, likely the outer Solar System.

Highly siderophile element (HSE) abundances of Willow Grove and Tishomingo are similar to some IVB meteorites, consistent with formation by moderate degrees of fractional crystallization from initial metallic melts with low S and P, and modestly fractionated HSE. The comparable HSE abundances of Tishomingo and Willow Grove to some IVB irons, yet substantially higher Ni concentrations, indicate formation on parent bodies with lower bulk HSE abundances or HSE concentration in proportionally smaller volumes of metal. HSE abundances in Chinga are considerably lower than in IVB irons, highly fractionated, and processes responsible for these remain elusive.

For IVB irons and these ungrouped irons, high temperature condensation likely dominated the enrichment and depletion of the refractory and volatile siderophile elements, respectively. Parent body degassing may have also played a role. Relative depletion of volatile siderophile elements is not, however, a universal feature of high-Ni meteorites. The SBT and Milton pallasite are Ni-rich, but less depleted in the more volatile siderophile elements. Nickel enrichment was likely driven by oxidation of Fe metal during parent body accretion or core segregation. Oxidation of the Tishomingo and Willow Grove parent bodies may have occurred at ∼ IW + 1, indicated by relative Mo and W depletions due to metal/water reaction during differentiation. Late-stage reduction, indicated by the presence of Cr-bearing sulfides in Tishomingo and IVB irons, may have resulted from exhaustion of the oxidant.

未分组的铁陨石 Tishomingo、Willow Grove 和 Chinga 以及 IVB 组铁陨石富含镍。相似之处包括一些难熔亲铁元素的 10-100 × CI 富集，以及更易挥发的亲铁元素的等效耗尽。叠加在整体富集/耗尽趋势上，某些亲铁元素（P、W、Fe、Mo）相对于具有相似挥发性的元素被耗尽。所有三个未分组的铁都来自早期太阳系中形成的母体。Willow Grove 和 Chinga 的特点是宇宙射线曝光校正¹⁸² W/ ¹⁸⁴W 与其母体在太阳系形成的 1-3 Myr 内的金属硅酸盐偏析一致，在为岩浆铁陨石母体（包括 IVB 组铁）的偏析确定的年龄范围内。^{Tishomingo 的特征是在太阳系形成后年龄为 4-5 Myr 的年轻模型，这反映了由26} Al 衰变导致的晚期熔化，或撞击重置。在 Tishomingo 发现 stishovite，表明暴露在 8-9 GPa 的最小冲击压力下，与后者一致。

Tishomingo 中的 Stishovite 和 IVB 铁中的陨铁-daubréelite 中包含的铬铁矿可以比较这些陨石之间的氧同位素组成。IVB 铁和 Tishomingo 的不同质量独立氧同位素组成表明遗传上不同的母体。相比之下，与质量无关的 Mo 同位素组成在分析不确定性内重叠，表明具有相似的碳质球粒陨石 (CC) 型遗传遗产。Chinga 和 Willow Grove 的钼和^{183 W 同位素数据表明源自 CC 型母体。}Willow Grove 分享 Mo 和¹⁸³W 同位素组成与富镍的南拜伦三重奏 (SBT) 群和米尔顿橄榄石。这些富含镍的陨石很可能是在与其他 CC 小行星相同的一般星云环境中形成的，很可能是在太阳系外。

Willow Grove 和 Tishomingo 的高亲铁元素 (HSE) 丰度与一些 IVB 陨石相似，这与由具有低 S 和 P 的初始金属熔体的中等程度的分级结晶和适度分级的 HSE 形成的一致。Tishomingo 和 Willow Grove 的 HSE 丰度与一些 IVB 铁杆相当，但 Ni 浓度明显更高，这表明在母体上形成了具有较低体积 HSE 丰度或 HSE 浓度的金属体积比例较小。Chinga 中的 HSE 丰度远低于 IVB 熨斗，高度分馏，导致这些问题的过程仍然难以捉摸。

对于 IVB 铁和这些未分组的铁，高温冷凝可能分别主导了难熔和挥发性亲铁元素的富集和耗尽。母体脱气也可能起作用。然而，挥发性亲铁元素的相对消耗并不是高镍陨石的普遍特征。SBT 和 Milton pallasite 富含镍，但在更易挥发的亲铁元素中的消耗较少。镍富集可能是由母体增生或核心偏析过程中铁金属的氧化驱动的。Tishomingo 和 Willow Grove 母体的氧化可能发生在 ~ IW + 1，由分化过程中金属/水反应导致的相对 Mo 和 W 消耗表明。后期还原，表现为 Tishomingo 和 IVB 铁杆中存在含铬硫化物，