Hibonite-(Fe), (Fe,Mg)Al12O19, is the Fe2+-dominant analog of hibonite CaAl12O19, discovered in a highly altered Ca-,Al-rich refractory inclusion from the Allende meteorite. It occurs as scattered micrometer-sized single crystals within an aggregate of hercynite (Fe,Mg)Al2O4, adjacent to nepheline, ilmenite, ferroan spinel, perovskite, and hibonite. The mean chemical composition determined by e...

Introduction: The results presented here are part of an investigation into the evolution of hydrothermal events associated with the Chicxulub impactites in Yu-catan, Mexico. The study focuses on alteration products in core samples recovered from the Yaxcopoil-1 drill hole, which is located some 60 kilometers from the center of the impact structure. This research contributes to the growing knowl...

Over the last decades, determination of ages in monazite using Electron Probe Microanalysis (EPMA) has progressed to the point that it is now considered as a routine procedure within several laboratories worldwide [1,2]. Nevertheless, the typical age errors of individual electron probe spots reported in the literature are an order of magnitude larger than attainable by Secondary Ion Mass Spectr...

Quantitative electron microprobe x-ray analyzer (EMX) assays of calcium concentrations in the aqueous and cornea of rabbits under various conditions, including experimental band keratopathy, are presented. Aqueous calcium values were significantly lowered in band keratopathy. The corneal calcium concentration remained constant in all the conditions tested throughout all layers of the cornea, wi...

The rate of aqueous humor formation sequentially across the pigmented (PE) and nonpigmented (NPE) ciliary epithelial cell layers may not be uniform over the epithelial surface. Because of the tissue's small size and complex geometry, this possibility cannot be readily tested by conventional techniques. Rabbit iris-ciliary bodies were divided, incubated, quick-frozen, cryosectioned, and freeze-d...

In this work, quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA) (called low-Z particle EPMA), Raman microspectrometry (RMS), and attenuated total reflectance Fourier transform infrared spectroscopic (ATR-FTIR) imaging were applied in combination for the analysis of the same individual airborne particles for the first time. After examining individual particles of microm...

Introduction: Trapped noble gases were discovered in chon-drules by laser microprobe noble gas analysis [1-3]. The observed noble gases were explained by solar gas acquisition in dust grains before the chondrule formation [1-3]. These results show importance of trapped noble gases in chondrites to understand environment and formation processes of chondrules. We performed the laser microprobe no...