Exploring the igneous chondrule bearing partially melted Antarctic and deep‐sea micrometeorites

We report 14 Antarctic and 15 deep‐sea partially melted micrometeorites containing ~71 to 458 μm rounded, porous, and intact igneous objects. These objects likely represent non‐porphyritic igneous chondrules. Analyzing these objects allows us to better relate them to the constituents of their parent bodies, thereby improving our understanding of the chondrule properties inherent to micrometeorite precursors. Seven identified Antarctic spherules and all deep‐sea spherules primarily exhibit radial pyroxene (Rp) textures; one Antarctic composite spherule contains an Rp object embedded within an olivine matrix. Additionally, four Antarctic spherules show barred olivine (Bo) textures, two of which are surrounded by igneous rims, while two other Antarctic spherules show cryptocrystalline (Cc) textures. The bulk major and minor element oxides for the Rp objects vary significantly: MgO ~25.4 to 39.0 wt%, Al 2 O 3 ~ 0.03 to 3.23 wt%, SiO 2 ~ 44.7 to 55.1 wt%, CaO ~0.02 to 2.72 wt%, Cr 2 O 3 ~ 0.18 to 1.44 wt%, MnO ~0.18 to 1.51 wt%, and FeO ~11.4 to 22.1 wt%. The chemical compositions of the pyroxene within the Rp spherules suggest they originate primarily from unequilibrated–equilibrated ordinary chondrites (UOC–EOC) rather than carbonaceous chondrites. Conversely, the glass chemical compositions of the Cc spherules (MgO ~32.9 to 42.4 wt% and FeO ~0.73 to 10.5 wt%; En98‐83) largely support an origin from chondritic carbonaceous materials. Atmospheric entry heating has progressively altered the chemical composition of the Bo spherules beyond recognition from their original chondrule states. Ultimately, their collective chemical compositions suggest that these spherules may consist of chondrules similar to non‐porphyritic chondrules in carbonaceous and ordinary chondrites. Based on their textures and mineralogy, these spherules indicate that the parent sources of these micrometeorites are chondrule‐bearing asteroid bodies.