Small‐scale elemental abundance variations in Ryugu particles from touchdown 1

Abstract Ryugu materials closely resemble CI chondrites' mineralogical, chemical, and isotopic compositions; yet minor but resolvable differences in certain elemental abundances are evident. In this study, the bulk chemical compositions of eight individual Ryugu particles (1.5–4.3 mg) from the first touchdown site (TD1) were determined using triple–quadrupole inductively coupled plasma mass spectrometry (TQ‐ICP‐MS). These samples show broad abundance ranges (0.4–4 × CI) for elements commonly hosted in minor secondary phases including P, Ca, Mn, Sr, Y, Ba, and rare earth elements (REE), and display distinct covariation patterns among these elements. Combining our data with previous analyses of TD1 Ryugu particles, we identified three compositional types: Type 1 particles are enriched by >20% in P, Ca, Mn, Sr, and REE relative to the Ryugu average; Type 3 particles are depleted by >20% in these elements but show slight enrichments (up to 30%) in siderophile and chalcophile elements; Type 2 particles have most elemental abundances within ±20% of the Ryugu average. These wide abundance ranges reflect heterogeneous distribution (nugget effect) of minor secondary minerals within Ryugu's parent body. Such heterogeneity provides insights into the evolving conditions of alteration fluids and the consequent elemental fractionation patterns.