NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Cooling rates for lunar samples determined with a diffusion model for phosphide exsolutionA numerical model for diffusion-controlled phase growth has been applied to the exsolution of phosphide lamellae in lunar metal grains. Computer simulations reproduce observed composition profiles, and reveal the influence of cooling rate on dimensional and compositional parameters of phosphide and metal. At lower cooling rates, phosphide lamellae are larger and the concentration of P in the metal host close to the interface is lower. Cooling rates inferred for Apollo 16 samples, based on compositions and dimensions of the phosphide-metal grains, are mostly in the range 1-100 C/day. These rates correspond to burial depths of 5-0.5 m for melt rocks and 3-0.3 m for breccias. This is in good agreement with thicknesses of lunar cooling units determined by other techniques.
Document ID
19780057745
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Hewins, R. H.
(Rutgers University New Brunswick, N.J., United States)
Goldstein, J. I.
(Lehigh University Bethlehem, Pa., United States)
Date Acquired
August 9, 2013
Publication Date
January 1, 1977
Subject Category
Lunar And Planetary Exploration
Meeting Information
Meeting: Lunar Science Conference
Location: Houston, TX
Start Date: March 14, 1977
End Date: March 18, 1977
Accession Number
78A41654
Funding Number(s)
CONTRACT_GRANT: NGR-39-007-056
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available