A comparative study on the mineralogy, chemistry and chronology of the Apollo 16 crystalline impact melt breccias. Part II: Chronology.


Autoria(s): Reimold, W.U.; Bansal, B.M.; Wiesman, H.; Wooden, J.L.; Mackinnon, Ian D.R.; Nyquist, L.E.
Data(s)

01/03/1982

Resumo

The controversy on how to interpret the ages of lunar highland breccias has recently been discussed by James [1]. Are the measured ages testimony of true events in lunar history; do they represent the age of the ancient crustal rocks, mixed ages of unequilibrated matrix-phenocryst relationships, or merely thermal events subsequent to the formational event ? It is certain from analyses of terrestrial impact melt breccias that the melt matrix of whole impact melt sheets is isotopically equilibrated due to the extensive mixing process of the early cratering stage [2,3]. It has been shown that isotopic equilibration takes place between impact melt matrix and target rock clasts therein, with the intensity of isotopic exchange depending on the degree of shock metamorphism, thermal metamorphism and the size of the clasts [4]. Therefore, impact melt breccias - if they are relatively clast-poor and mineralogically well studied - can be considered to be the most reliable source for information on the impact history of the lunar highland.

Formato

application/pdf

Identificador

http://eprints.qut.edu.au/58957/

Publicador

Lunar and Planetary Institute

Relação

http://eprints.qut.edu.au/58957/1/13th_LPSC_impact_melt.pdf

http://adsabs.harvard.edu/full/1982LPI....13..644R

Reimold, W.U., Bansal, B.M., Wiesman, H., Wooden, J.L., Mackinnon, Ian D.R., & Nyquist, L.E. (1982) A comparative study on the mineralogy, chemistry and chronology of the Apollo 16 crystalline impact melt breccias. Part II: Chronology. In Lunar and Planetary Science Conference, Lunar and Planetary Institute, Houston Texas, USA, pp. 644-645.

Direitos

Copyright 1982 Lunar and Planetary Institute.

Fonte

Institute for Future Environments

Palavras-Chave #040302 Extraterrestrial Geology #Apollo 16 breccias #impact melt breccias #isotopic analyses #lunar highlands samples #mineralogy
Tipo

Conference Paper