Very primitive ultramafic igneous rocks occur at Mt. La Queglia (Abruzzo, Italy). They form a strongly deformed sill–dyke system now tilted vertically. These rocks were initially classified as alnöite and, subsequently, have been suggested to be a carbonatitic olivine melilitite. However, further investigation and interpretation of these rocks is needed due to the presence of hand-specimen-scale textural variation suggesting a complex petrogenesis. We study the texture, mineral chemistry, and whole-rock geochemistry to define three main rock-types. (1) A brecciated rock with an ocellar texture composed of calcite pseudomorphs after olivine and melilite, plus fresh diopside in a groundmass of mica, aegirine, garnet, calcite, apatite, perovskite, titanate and chlorite. Zoned ocelli in this rock show an amoeboid shape, agglutination, and menisci typical of a plastic state. (2) A quenched rock showing a spinifex texture containing long feathery phenocrysts of cpx and mica suspended in a groundmass of nepheline, aegirine, apatite, Ti–rich magnetite, plus abundant calcite and some K-feldspar and zeolites. (3) A coarse-grained rock is composed of calcite plus intergranular glauconite, a mixture of spinel mineral group and Ti–rich magnetite, accessory barite, pyrite, and chabazite-K. The igneous rocks at Mt. La Queglia show extreme SiO₂-undersaturation (33.5–37.3 wt% SiO₂), high MgO contents and TiO₂/Al₂O₃ ratios. Rock-type 1 has a lower Mg number Mg# = 100 × [Mg/(Mg + Fe²⁺)], higher Ca number Ca# = 100 × [Ca/(Ca + Mg)], high Cr (up to 720 ppm) Ni (up to 379 ppm), higher rare earth elements (REE) contents as well as La/Lu ratio, compared to rock-type 2. Perovskite and chromite accumulation seems an important agent during rock differentiation. Rock-type 3 shows REE cross-over with rock-type 2 suggesting light (L)REE concentration in a carbothermal residuum. Mt. La Queglia rocks are an end-member compared to other Upper Cretaceous and Paleogene Italian lamprophyres, suggesting a low degree of melting of a HIMU (a colloquialism for “high-μ”; referring to mantle domains with high ²³⁸U/ ²⁰⁴Pb) garnet-bearing mantle source.

非常原始的超镁铁质火成岩出现在 Mt. La Queglia（意大利阿布鲁佐）。它们形成了现在垂直倾斜的强烈变形的窗台-堤坝系统。这些岩石最初被归类为铝锌矿，随后被认为是碳酸盐质橄榄石橄榄石。然而，由于存在手工标本尺度的纹理变化，表明存在复杂的岩石成因，因此需要对这些岩石进行进一步的调查和解释。我们研究了质地、矿物化学和全岩地球化学，以定义三种主要的岩石类型。(1) 一种具有眼状结构的角砾岩，由橄榄石和黄橄榄石之后的方解石假晶，加上云母、白云母、石榴石、方解石、磷灰石、钙钛矿、钛酸盐和绿泥石基体中的新鲜透辉石组成。这块岩石中的单眼呈变形虫状，凝集，和典型的可塑性状态的半月板。(2) 一种淬火后的岩石，显示出一种尖晶石质地，含有长长的羽毛状 cpx 和云母斑晶，悬浮在霞石、白云母、磷灰石、富钛磁铁矿以及丰富的方解石和一些钾长石和沸石的基体中。(3) 粗粒岩石由方解石加粒间海绿石、尖晶石矿物群和富钛磁铁矿、副重晶石、黄铁矿和菱沸石-K的混合物组成。La Queglia 山的火成岩显示出极高的 SiO 尖晶石矿物群和富钛磁铁矿、副重晶石、黄铁矿和菱沸石-K 的混合物。La Queglia 山的火成岩显示出极高的 SiO 尖晶石矿物群和富钛磁铁矿、副重晶石、黄铁矿和菱沸石-K 的混合物。La Queglia 山的火成岩显示出极高的 SiO_2-欠饱和（33.5–37.3 wt% SiO ₂），高MgO含量和TiO ₂ /Al ₂ O ₃比率。岩石类型 1 的 Mg 数较低 Mg# = 100 × [Mg/(Mg + Fe ²⁺)]，更高的 Ca 数 Ca# = 100 × [Ca/(Ca + Mg)]，高 Cr（高达 720 ppm）Ni（高达 379 ppm），更高的稀土元素 (REE) 含量以及 La/ Lu 比率，与岩石类型 2 相比。钙钛矿和铬铁矿的聚集似乎是岩石分化过程中的重要因素。岩石类型 3 显示 REE 与岩石类型 2 交叉，表明碳热渣中的轻 (L) REE 浓度。与其他上白垩统和古近纪意大利灯石相比，La Queglia 山岩石是末端成员，表明 HIMU 的熔融程度较低（“高μ”的俗语；指的是具有高²³⁸ U/ ²⁰⁴ Pb的地幔域) 含石榴石的地幔源。