Loading…

Tracing seafloor methane emissions with benthic foraminifera: Results from the Ana submarine landslide (Eivissa Channel, Western Mediterranean Sea)

The hypothesis that benthic foraminifera are useful proxies of local methane emissions from the seafloor has been verified on sediment core KS16 from the headwall of the Ana submarine landslide in the Eivissa Channel, Western Mediterranean Sea. The core MS312 from a nearby location with no known met...

Full description

Saved in:
Bibliographic Details
Published in:Marine geology 2012-01, Vol.291-294, p.97-112
Main Authors: Panieri, Giuliana, Camerlenghi, Angelo, Cacho, Isabel, Cervera, Cristina Sanchez, Canals, Miquel, Lafuerza, Sara, Herrera, Gemma
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The hypothesis that benthic foraminifera are useful proxies of local methane emissions from the seafloor has been verified on sediment core KS16 from the headwall of the Ana submarine landslide in the Eivissa Channel, Western Mediterranean Sea. The core MS312 from a nearby location with no known methane emissions is utilised as control. The core was analysed for biostratigraphy, benthic foraminiferal assemblages, Hyalinea balthica and Uvigerina peregrina carbon and oxygen stable isotope composition, and sedimentary structures. The upper part of the core records post-landslide deglacial and Holocene normal marine hemipelagic sediments with highly abundant benthic foraminifera species that are typical of outer neritic to upper bathyal environment. In this interval, the δ13C composition of benthic foraminifera indicates normal marine environment analogous to those found in the control core. Below the sedimentary hiatus caused by the emplacement of the slide, the foraminiferal assemblages are characterised by lower density and higher Shannon Index. Markedly negative δ13C shifts in benthic foraminifera are attributed to the release of methane through the seabed. The mean values of the 13C anomaly in U. peregrina are −0.951±0.208 in the pre-landslide sediments, and −0.269±0.152 in post-slide reworked sediments deposited immediately above the hiatus. The δ13C anomaly in Hyalinea balthica is −2.497±0.080 and −2.153±0.087, respectively. To discard the diagenetic effects on the δ13C anomaly, which could have been induced by Ca–Mg replacement and authigenic carbonate overgrowth on foraminifera tests, a benthic foraminifera subsample has been treated following an oxidative and reductive cleaning protocol. The cleaning has resulted, only in some cases, in a slight reduction of the anomaly by 0.95% for δ13C and
ISSN:0025-3227
1872-6151
DOI:10.1016/j.margeo.2011.11.005