Universität zu Köln

Mannella, Giorgio, Zanchetta, Giovanni ORCID: 0000-0002-7080-9599, Regattieri, Eleonora, Perchiazzi, Natale, Drysdale, Russell N., Giaccio, Biagio ORCID: 0000-0002-7007-9127, Leng, Melanie J. and Wagner, Bernd ORCID: 0000-0002-1369-7893 (2020). Effects of organic removal techniques prior to carbonate stable isotope analysis of lacustrine marls: A case study from palaeo-lake Fucino (central Italy). Rapid Commun. Mass Spectrom., 34 (7). HOBOKEN: WILEY. ISSN 1097-0231

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Abstract

Rationale: The suitability of organic matter (OM) removal pre-treatments in isotopic studies of lacustrine carbonates is currently under debate. Naturally occurring OM seems to have a negligible effect on the bulk isotopic composition of carbonates compared with changes induced by pre-treatments. This study provides further insights into the possible effects induced by commonly used pre-treatments on natural lacustrine carbonates. Methods: Sixteen samples from the Fucino F1-F3 lacustrine succession (Abruzzo, central Italy) were characterised for their mineralogical and geochemical composition and each was split into three identical aliquots. One aliquot was left untreated while the remaining two were treated with NaOCl and H(2)O(2)dilutions. The same treatment was applied to an internal standard consisting of pure Carrara marble. The treated and untreated samples were analysed for their carbon (delta C-13 values) and oxygen (delta O-18 values) isotope compositions using an Analytical Precision AP2003 isotope ratio mass spectrometer. Results: The samples had variable proportions of endogenic and detrital components, the detrital portion being more (less) abundant during colder (warmer) climate phases. We observed that neither the NaOCl nor the H(2)O(2)treatment was able to completely remove OM and therefore there was selective removal of compounds within the OM pool. A possible effect of pre-treatment is the loss of carbonates intimately interspersed within the OM, as suggested by the evolution of isotopic ratios towards the local detrital array. Conclusions: Our study highlights sample-specific changes in geochemistry associated with sample pre-treatments; however, such changes do not seem to lead to either systematic and/or predictable isotopic shifts. We suggest that the suitability of NaOCl or H(2)O(2)pre-treatments for OM removal should be evaluated on a case-by-case basis. In the specific case of lacustrine marls from palaeo-lake Fucino containing relatively low amounts of OM and in which both detrital and endogenic carbonates occur, both pre-treatments should be avoided.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Mannella, Giorgio UNSPECIFIED UNSPECIFIED UNSPECIFIED Zanchetta, Giovanni UNSPECIFIED orcid.org/0000-0002-7080-9599 UNSPECIFIED Regattieri, Eleonora UNSPECIFIED UNSPECIFIED UNSPECIFIED Perchiazzi, Natale UNSPECIFIED UNSPECIFIED UNSPECIFIED Drysdale, Russell N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Giaccio, Biagio UNSPECIFIED orcid.org/0000-0002-7007-9127 UNSPECIFIED Leng, Melanie J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wagner, Bernd UNSPECIFIED orcid.org/0000-0002-1369-7893 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-336969
DOI:	10.1002/rcm.8623
Journal or Publication Title:	Rapid Commun. Mass Spectrom.
Volume:	34
Number:	7
Date:	2020
Publisher:	WILEY
Place of Publication:	HOBOKEN
ISSN:	1097-0231
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language HYDROGEN-PEROXIDE; MATTER REMOVAL; OXYGEN; SKELETAL; PRETREATMENT; VARIABILITY; DELTA-C-13; VALUES; KA Multiple languages Biochemical Research Methods; Chemistry, Analytical; Spectroscopy Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/33696