Universität zu Köln

Binnie, Steven A., Nishiizumi, Kunihiko, Welten, Kees C., Caffee, Marc W. and Hoffmeister, Dirk ORCID: 0000-0002-8178-557X (2019). Lunar surface processes inferred from cosmogenic radionuclides in Apollo 16 double drive core 68002/68001. Geochim. Cosmochim. Acta, 244. S. 336 - 352. OXFORD: PERGAMON-ELSEVIER SCIENCE LTD. ISSN 1872-9533

Full text not available from this repository.

Abstract

Measurements of cosmogenic Be-10, Al-26 and Cl-36 in Apollo 16 double drive core 68002/68001 are combined with a high resolution digital surface model of the sampling site to investigate the surface processes on the Moon. We find both a significant deficit of solar cosmic ray (SCR)-produced Al-26 and a lack of SCR-produced Cl-36 in the top 3-5 g/cm(2) of the lunar regolith. The topographic model shows the core was taken from just inside a crater with a rim diameter of 25-30 cm. These observations are consistent with regolith removal and displacement by a shallow impact that occurred on the order of 100 kyr ago, or less. Our findings are also compatible with shallow mixing, or gardening, of the lunar regolith to depths of a few cm, a value often found in other lunar cores over the similar to 10(6) yr averaging times of Al-26 and Mn-53 measurements. More definitive regolith mixing depth estimates are not possible due to the likelihood of disturbance in the top of the core as a result of sampling and/or handling. Our results support the hypothesis that the lunar surface experiences more frequent disturbances by small primary and secondary impacts than has previously been assumed. Additionally, we find no evidence that fine-grained ejecta from the 2.0 Myr old South Ray Crater impact reached this site. If the layer of fine-grained ejecta that reached the sampling site from the South Ray Crater was no more than a few cm thick, this absence can be explained by the erosion that formed the small, relatively recent crater at the coring location. (C) 2018 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Binnie, Steven A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Nishiizumi, Kunihiko UNSPECIFIED UNSPECIFIED UNSPECIFIED Welten, Kees C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Caffee, Marc W. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hoffmeister, Dirk UNSPECIFIED orcid.org/0000-0002-8178-557X UNSPECIFIED
URN:	urn:nbn:de:hbz:38-140962
DOI:	10.1016/j.gca.2018.09.036
Journal or Publication Title:	Geochim. Cosmochim. Acta
Volume:	244
Page Range:	S. 336 - 352
Date:	2019
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Place of Publication:	OXFORD
ISSN:	1872-9533
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language DEPTH PROFILES; CRATER; IMPACT; MOON; LANDSLIDES; TRANSPORT; BE-10; SITES Multiple languages Geochemistry & Geophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/14096