Universität zu Köln

Marchi, S., Drabon, N., Schulz, T., Schaefer, L., Nesvorny, D., Bottke, W. F., Koeberl, C. and Lyons, T. (2021). Delayed and variable late Archaean atmospheric oxidation due to high collision rates on Earth. Nat. Geosci., 14 (11). S. 827 - 839. BERLIN: NATURE PORTFOLIO. ISSN 1752-0908

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Abstract

The oxygenation of Earth may have been delayed due to high late Archaean extraterrestrial impact rates, which acted as a fluctuating sink of atmospheric oxygen, according to a reassessment of past impactor fluxes and atmospheric chemistry modelling. Frequent violent collisions of impactors from space punctuated the geological and atmospheric evolution of early Earth. It is generally accepted that the most massive collisions altered the chemistry of Earth's earliest atmosphere, but the consequences of Archaean collisions for atmospheric oxidation are little understood. Early Archaean (4.0-3.5 billion years ago (Ga)) impact flux models are tightly constrained by lunar cratering and radiometric data. Further, a record of the late Archaean (3.5-2.5 Ga) impact flux is provided by terrestrial impact spherule layers-formed by collisions with bodies >= 10-20 km in diameter-although this record is probably incomplete and significant uncertainties remain. Here we show, on the basis of an assessment of impactor-related spherule records and modelling of the atmospheric effects of these impacts, that current bombardment models underestimate the number of late Archaean spherule layers. These findings suggest that the late Archaean impactor flux was up to a factor of ten higher than previously thought. We find that the delivered impactor mass was an important sink of oxygen, suggesting that early bombardment could have delayed Earth's atmosphere oxidation. In addition, late Archaean large impacts (>= 10 km) probably caused drastic oscillations of atmospheric oxygen, with an average time between consecutive collisions of about 15 Myr. This pattern is consistent with a known episode of atmospheric oxygen oscillation at similar to 2.5 Ga that is bracketed by large impacts recorded by Bee Gorge (similar to 2.54 Ga) and Dales Gorge (similar to 2.49 Ga) spherule layers.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Marchi, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Drabon, N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schulz, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schaefer, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Nesvorny, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bottke, W. F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Koeberl, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lyons, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-594948
DOI:	10.1038/s41561-021-00835-9
Journal or Publication Title:	Nat. Geosci.
Volume:	14
Number:	11
Page Range:	S. 827 - 839
Date:	2021
Publisher:	NATURE PORTFOLIO
Place of Publication:	BERLIN
ISSN:	1752-0908
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language BARBERTON GREENSTONE-BELT; OS ISOTOPE SIGNATURES; ICDP DRILL CORE; SPHERULE LAYERS; SOUTH-AFRICA; SIDEROPHILE ELEMENT; HEAVY BOMBARDMENT; HAMERSLEY BASIN; MOUNTAIN LAND; BILLION YEARS Multiple languages Geosciences, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/59494