Thermal and chemical evolution in the early Solar System as recorded by FUN CAIs: Part II – Laboratory evaporation of potential CMS-1 precursor material

· by · in , ,

Ruslan A. Mendybaev, Curtis D. Williams, Michael J. Spicuzza, Frank M. Richter, John W. Valley, Alexei V. Fedkin, Meenakshi Wadhwa

Geochimica et Cosmochimica Acta
In Press, Accepted Manuscript
Available online 21 October 2016

LINK

“We present the results of laboratory experiments in which a forsterite-rich melt estimated to be a potential precursor of Allende CMS-1 FUN CAI was evaporated into vacuum for different lengths of time at 1900°C. The evaporation of this melt resulted in residues that define trajectories in chemical as well as magnesium, silicon and oxygen isotopic composition space and come very close to the measured properties of CMS-1. The isotopic composition of the evaporation residues was also used to determine the kinetic isotopic fractionation factors [α2,1 (vapor-melt) defined as the ratio of isotopes 2 and 1 of a given element in the evaporating gas divided by their ratio in the evaporating source] for evaporation of magnesium (α25,24 for 25Mg/24Mg), silicon (α29,28 for 29Si/28Si) and oxygen (α18,16 for 18O/16O) from the forsterite-rich melt at 1900°C. The values of α25,24 = 0.98383±0.00033 and α29,28 = 0.99010±0.00038 are essentially independent of change in the melt composition as evaporation proceeds. In contrast, α18,16 changes from 0.9815±0.0016 to ∼ 0.9911 when the residual melt composition changes from forsteritic to melilitic. Using the determined values of α25,24 and α29,28 and present-day bulk chemical composition of the CMS-1, the composition of the precursor of the inclusion was estimated to be close to the clinopyroxene+spinel+forsterite assemblage condensed from a solar composition gas. The correspondence between the chemical composition and isotopic fractionation of experimental evaporation residues and the present-day bulk chemical and isotopic compositions of CMS-1 is evidence that evaporation played a major role in the chemical evolution of CMS-1.”

Related posts (automatically generated):

  1. Thermal and chemical evolution in the early Solar System as recorded by FUN CAIs: Part I – Petrology, mineral chemistry, and isotopic composition of Allende FUN CAI CMS-1
  2. Calcium-aluminum-rich inclusions with fractionation and unidentified nuclear effects (FUN CAIs): II. Heterogeneities of magnesium isotopes and 26Al in the early Solar System inferred from in situ high-precision magnesium-isotope measurements
  3. Modeling the evaporation of CAI-like melts, and constraining the origin of CH-CB CAIs
  4. Model Calculations for Evaporation of AOA and CAI Melts: Implications for the Bulk CAIs Compositions of CV3 and CH-CB Chondrites
  5. The Formation of Type B CAIs: Evolution from Type A CAIs
  6. The Evolution of the Protoplanetary Disk Recorded by Nucleosynthetic Isotope Variations of Variable Stellar Origin in Refractory Inclusions
  7. Making the Planetary Material Diversity During the Early Assembling of the Solar SystemOPEN ACCESS 
  8. 36Cl-36S in Allende CAIs: Implication for the Origins of 36Cl in the Early Solar System
  9. The origin of volatile element depletion in early solar system material: Clues from Zn isotopes in chondrulesOPEN ACCESS 
  10. Alteration of CAIs as recorded by 36S/34S as a function of 35Cl/34S
Tags: , , ,