Ion microprobe and electron microprobe studies on magnesium isotopic abundances in olivine minerals from the Allende carbonaceous chondrite.

Magnesium isotopic compositions of olivine, spinel, and hibonite from the Murchison carbonaceous chondrite

The Mg isotopic compositions of olivine, spinel, and hihonite from the Murchison carbonaceous chondrite have been determined by secondary ion mass spectrometry. The olivines exhibit only marginal effects. They have no detectable intrinsic mass fractionation; however, after correcting for mass fractionation, the mean residual 26Mg/24Mg for the five grams is slightly in excess of the terrestrial ...

High Precision Magnesium Isotopic Measurement of Cai Minerals with Low Al/mg Ratio from Allende Utilizing a Nanosims 50l Ion Microprobe

Calcium isotopic ratios and rare earth element abundances in refractory inclusions from the Allende CV3 chondrite

Refractory inclusions in primitive meteorites are the oldest objects formed in the Solar System. They exhibit large massdependent isotopic effects in many elements, including Si, Mg and Ca, indicative of their complex origin. We report data for both mass-dependent (d) and mass-independent (e) Ca isotopic effects, and rare earth element (REE) abundances in six refractory inclusions from the Alle...

Electron microprobe and ion-selective microelectrode studies of fluid secretion in the salivary glands of Calliphora.

1. The concentrations of sodium, potassium, chloride and water in the cells, secretory canaliculi and the lumen of Calliphora salivary glands have been measured by microprobe analysis of frozen-hydrated sections. Free concentrations of K+ and Cl~ in all three compartments were measured with ion-selective microelectrodes. 2. Most of the quantitative data from the two techniques are in close agre...

Ion Microprobe Evidence for the Presence of Excess Mg in an Allende Anorthite Crystal

An ion microprobe ha~ been. used to observe Mg/"Mg in excess of normal values in anorthite crystals from Allende refractory mclus10ns. In one crystal, Mg excesses up to 40% above normal, correlated with AI/Mg, were. obser_ved. These ~xc~sses are many times larger than those observed by other techniques. T_he _correla~10n with Al(Mg mdicated tha_t the excess '"Mg in the Allende anorthite is unif...