NWA 16080 is a representative reduced CV carbonaceous chondrite (CV_red), consisting mainly of chondrules (47 vol%) and matrix (42 vol%), along with minor quantities of calcium- and aluminum-rich inclusions (CAI) and amoeboid olivine aggregates (AOA) (CAI + AOA, 6 vol%) and opaque minerals (5 vol%). The chondrules exhibit well-preserved outlines and can be categorized into Type I (Fa < 10) and Type II (Fa > 10). They primarily consist of magnesium-rich olivine, along with both low-Ca and high-Ca pyroxenes, and contain minor amounts of secondary plagioclase. Olivines present in chondrules display compositional zoning characterized whereas the matrix is composed of fine-grained olivine. Nickel-rich metal and nickel-poor sulfides are also present, along with trace amounts of magnetite. In contrast to standard oxidized CV chondrites (CV_ox), the presence of high metal, Ni-poor sulfides, and reduced magnetite in NWA 16080 indicates a more reduced parent-body environment. Shock metamorphism is classified as mild (S1), while terrestrial weathering is characterized as low (W2). Raman spectroscopy indicates a diverse spectrum of organic matter (OM) maturity: certain areas exhibit characteristics akin to other CV_red chondrites, whereas others reach maturity levels comparable to those observed in CV_ox chondrites. The Raman parameters indicate that this meteorite is classified as approximately type 3.4 to 3.5. The overlapping OM maturity with certain CV_ox chondrites provides a contradiction to the anticipated depth-thermal layering outlined in the onion-shell model. This suggests that the CV parent body probably experienced more intricate processes, including impacts and fluid-rock interactions, rather than merely depth-dependent heating.

The Damiao Fe-Ti-P deposit, located within the Damiao anorthosite complex in northeastern China, features Fe-Ti oxide ores and nelsonites that occur as irregularly inclined stratiform-like bodies, lenses, or veins with sharp contacts against anorthosite and gabbronorite. This deposit is characterized by abundant titanomagnetite that hosts diverse ilmenite exsolution textures, including blocky, lamellar, and cloth-like forms. In this study, we investigate the geochemistry and mineralogy of ilmenite exsolutions in titanomagnetite to understand their formation mechanisms and implications for the ore-forming process. Detailed petrographic observations and electron microprobe analyses reveal that the exsolution textures result from multiple mechanisms: oxy-exsolution due to titanomagnetite oxidation; subsolidus re-equilibration between magnetite and ilmenite involving elemental diffusion of Fe, Ti, Cr, Co, and Ni; and exsolution related to lattice defects caused by rapid cooling. Thermodynamic modeling using Gibbs free energy calculations, and the QUILF program indicates that blocky, lamellar, and cloth-textured ilmenite exsolutions formed at temperatures above and below the solid-solution solvus under decreasing oxygen fugacity. Additionally, our results indicate that the exsolution of zircon and pleonaste at ilmenite grain boundaries is attributed to the saturation and precipitation of elements like Zr and Al, due to the oxidation of titanomagnetite, rather than interactions between ilmenite and adjacent clinopyroxene. Reconstruction of the cooling history suggests that the oxygen fugacity of oxide–apatite gabbronorites was significantly higher than that of Fe-Ti-P ores. This confirms that increasing oxygen fugacity during magma evolution promoted immiscibility, leading to the formation of nelsonitic melts and ultimately the development of Fe-Ti-P ores.