Universität zu Köln

Ozdemir, Seda, Schulz, Toni ORCID: 0000-0003-1248-7832, van Acken, David, Luguet, Ambre, Reimold, W. Uwe and Koeberl, Christian (2019). Meteoritic highly siderophile element and Re-Os isotope signatures of Archean spherule layers from the CT3 drill core, Barberton Greenstone Belt, South Africa. Meteorit. Planet. Sci., 54 (10). S. 2203 - 2217. HOBOKEN: WILEY. ISSN 1945-5100

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Abstract

Archean spherule layers represent the only currently known remnants of the early impact record on Earth. Based on the lunar cratering record, the small number of spherule layers identified so far contrasts to the high impact flux that can be expected for the Earth at that time. The recent discovery of several Paleoarchean spherule layers in the BARB5 and CT3 drill cores from the Barberton area, South Africa, drastically increases the number of known Archean impact spherule layers and may provide a unique opportunity to improve our knowledge of the impact record on the early Earth. This study is focused on the spherule layers in the CT3 drill core from the northeastern Barberton Greenstone Belt. We present highly siderophile element (HSE: Re, Os, Ir, Pt, Ru, and Pd) concentrations and Re-Os isotope signatures for spherule layer samples and their host rocks in order to unravel the potential presence of extraterrestrial fingerprints within them. Most spherule layer samples exhibit extreme enrichments in HSE concentrations of up to superchondritic abundances in conjunction with, in some cases, subchondritic present-day Os-187/Os-188 isotope ratios. This indicates a significant meteoritic contribution to the spherule layers. In contrast to some of the data reported earlier for other Archean spherule layers from the Barberton area, the CT3 core is significantly overprinted by secondary events. However, HSE and Re-Os isotope signatures presented in this study indicate chondritic admixtures of up to (and even above) 100% chondrite component in some of the analyzed spherule layers. There is no significant correlation between HSE abundances and respective spherule contents. Although strongly supporting the impact origin of these layers and the presence of significant meteoritic admixtures, peak HSE concentrations are difficult to explain without postdepositional enrichment processes.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Ozdemir, Seda UNSPECIFIED UNSPECIFIED UNSPECIFIED Schulz, Toni UNSPECIFIED orcid.org/0000-0003-1248-7832 UNSPECIFIED van Acken, David UNSPECIFIED UNSPECIFIED UNSPECIFIED Luguet, Ambre UNSPECIFIED UNSPECIFIED UNSPECIFIED Reimold, W. Uwe UNSPECIFIED UNSPECIFIED UNSPECIFIED Koeberl, Christian UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-132423
DOI:	10.1111/maps.13234
Journal or Publication Title:	Meteorit. Planet. Sci.
Volume:	54
Number:	10
Page Range:	S. 2203 - 2217
Date:	2019
Publisher:	WILEY
Place of Publication:	HOBOKEN
ISSN:	1945-5100
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MOUNTAIN LAND; IMPACT ORIGIN; EARLY EARTH; SYSTEMATICS; OSMIUM; BEDS; GEOCHEMISTRY; PLATINUM; KOMATIITES; IRIDIUM Multiple languages Geochemistry & Geophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/13242