Data/hora: 09/06/2024 03:49:34

Provedor de dados: 	Institutional Archive of Ifreme (ArchiMer)	
País: 	France	
Título: 	Influence of early diagenesis on geotechnical properties of clay sediments (Romania, Black Sea)	
Autores: 	Ballas, Gregory; Garziglia, Sebastien; Sultan, Nabil; Pelleter, Ewan; Toucanne, Samuel; Marsset, Tania; Riboulot, Vincent; Ker, Stephan.	
Data: 	2018-06	
Ano: 	2018	
Palavras-chave: 	Lacustrine clay sediment; Structured material; Sulfur cement; Carbonate cement; Early diagenesis; Weak layer.	
Resumo: 	The geotechnical properties of clay sediments were investigated using laboratory and in-situ measurements as part of the geohazard assessment in the Romanian sector of the Black Sea affected by landslides and seafloor deformation features. The sediments were characterized as predominantly high plastic silty clay of high compressibility, low undrained shear strength, low cohesion and moderate sensitivity. A shallow increase in shear strength exceeding the general trend could have been reconciled with evidence for the precipitation of iron sulfides and calcium carbonates related to early diagenetic reactions of sulfate reduction (e.g. cryptic sulfur cycle) and anaerobic oxidation of methane. Comparison of the compression behaviour of natural and reconstituted samples indicated that precipitation of these materials at particle contacts produced cementation. The analysis of deeper sediments sharing similar geochemical properties illustrated that the early precipitation of even low quantity of sulfur and carbonate cements allowed clays to develop sufficient strength to preserve an abnormal high water content even under tens of meters burial depth. Because this cementation process was observed to be associated with an enhanced sensitivity and a strain softening response to undrained shearing it was concluded that such early diagenesis should be considered as a key environmental factor, leading to weak layer formation that may influence the susceptibility of seafloor to failure.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	https://archimer.ifremer.fr/doc/00439/55064/56545.pdf

DOI:10.1016/j.enggeo.2018.04.019

https://archimer.ifremer.fr/doc/00439/55064/	
Editor: 	Elsevier Science Bv	
Relação: 	info:eu-repo/grantAgreement/EC/FP7/603418/EU//MIDAS	
Formato: 	application/pdf	
Fonte: 	Engineering Geology (0013-7952) (Elsevier Science Bv), 2018-06 , Vol. 240 , P. 175-188	
Fonte: 	2018 Published by Elsevier B.V.

info:eu-repo/semantics/openAccess

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