Hokkaido University · Physics and Astronomy
Professor Noriyuki Kawasaki's research lab specializes in cosmochemistry and planetary sciences, focusing on the isotopic and mineralogical analysis of primitive meteoritic materials to unravel the formation and evolution of the early solar system. The lab employs advanced secondary ion mass spectrometry (SIMS) to investigate oxygen and aluminum-magnesium isotope systems in calcium-aluminum-rich inclusions (CAIs), chondrules, and other refractory components from carbonaceous chondrites and returned asteroid samples. Key research directions include tracing the isotopic heterogeneity of the solar nebula, understanding the timing and conditions of CAI formation, and reconstructing the dynamic processes such as radial transport and multiple melting events in the protoplanetary disk. The lab also emphasizes the development of precise analytical standards for SIMS to improve data accuracy in isotope geochemistry.
Figures are computed from collected data and may differ slightly.
TS34 is a Type B1 Ca-Al-rich inclusion (CAI) from the Allende CV3 chondrite, consisting of spinel, melilite, Ti-Al-rich clinopyroxene (fassaite) and minor anorthite in an igneous texture. Oxygen and magnesium isotopic compositions were measured by secondary ion mass spectrometry in spots of known chemical composition in all major minerals in TS34. Using the sequence of formation from dynamic crystallization experiments and from chemical compositions of melilite and fassaite, the oxygen isotopic
The extraterrestrial materials returned from asteroid (162173) Ryugu consist predominantly of low-temperature aqueously formed secondary minerals and are chemically and mineralogically similar to CI (Ivuna-type) carbonaceous chondrites. Here, we show that high-temperature anhydrous primary minerals in Ryugu and CI chondrites exhibit a bimodal distribution of oxygen isotopic compositions: <sup>16</sup>O-rich (associated with refractory inclusions) and <sup>16</sup>O-poor (associated with chondrul
Abstract– Different oxygen isotopic reservoirs have been recognized in the early solar system. Fluffy type A Ca‐Al‐rich inclusions (CAIs) are believed to be direct condensates from a solar nebular gas, and therefore, have acquired oxygen from the solar nebula. Oxygen isotopic and chemical compositions of melilite crystals in a type A CAI from Efremovka CV3 chondrite were measured to reveal the temporal variation in oxygen isotopic composition of surrounding nebular gas during CAI formation. The
Abstract Coarse‐grained, igneous Ca‐Al‐rich inclusions (CAIs) in CV chondrites formed through multiple melting events. We conducted in situ O‐isotope analysis and Al‐Mg systematics by secondary ion mass spectrometry of relict and overgrown minerals from a partial melting event in an Allende Type B CAI, Golfball. Golfball has a Type B CAI bulk composition and a unique structure: a fassaite‐rich mantle enclosing a melilite‐rich core. Many of the blocky melilite crystals in the core have irregularl
Abstract Al–Mg mineral isochron studies using secondary ion mass spectrometry (SIMS) have revealed the initial 26 Al/ 27 Al ratios, ( 26 Al/ 27 Al) 0 , for individual Ca‐Al‐rich inclusions (CAIs) in meteorites. We find that the relative sensitivity factors of 27 Al/ 24 Mg ratio for SIMS analysis of hibonite, one of the major constituent minerals of CAIs, exhibit variations based on their chemical compositions. This underscores the critical need for using appropriate hibonite standards to obtain
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