eprintid: 10184860
rev_number: 8
eprint_status: archive
userid: 699
dir: disk0/10/18/48/60
datestamp: 2024-01-08 13:07:30
lastmod: 2024-11-07 07:10:10
status_changed: 2024-01-08 13:07:30
type: article
metadata_visibility: show
sword_depositor: 699
creators_name: Meilijson, A
creators_name: Bialik, OM
creators_name: Boudinot, FG
creators_name: Bown, PR
creators_name: Benjamini, C
creators_name: Waldmann, ND
creators_name: Sepúlveda, J
title: Long-term carbon sequestration in the Eocene of the Levant Basin through transport of organic carbon from nearshore to deep marine environments
ispublished: pub
divisions: UCL
divisions: B04
divisions: C06
divisions: F57
keywords: Sedimentology, geochemistry, carbon cycle, transport deposits, organic matter
note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
abstract: This study addresses a specific component associated with mass transport complexes in marine systems: the role of hyperpycnal flows, dense shelf water cascading, submarine canyons, distributary channels, and other transport mechanisms in transferring organic matter from continental and shallow marine settings into deep-marine environments. We speculate that during the Eocene, allowing for only 0.1‰ of shelf carbon to be preserved through transport mechanisms would account for up to 13.7% of all organic carbon burial. As such, the potential to mobilize through this mechanism large quantities of organic carbon is significant. Our case study focuses on a 150 m Eocene sequence composed of organic-rich chalks interleaved with displaced neritic limestones. TOC values range between 1.5 and 14%, averaging 4.5%. Displaced limestones are composed of a variety of poorly cemented mud- and wackestones, with low-diversity assemblages of large benthic foraminifera associated with planktonic foraminifera, suggesting deposition under low-energy conditions within the oligophotic zone on the outer ramp. Transport overprints include soft-sediment deformation, partially lithified rip-ups, folds, small diapirs, bed-scale imbrication, brecciation and syn-sedimentary shear. These features indicate detachment, movement and emplacement following initial sedimentation, in some cases more than once. Emplacement occurs into a chalk facies that can vary in appearance from darker (higher TOC) and lighter (lower TOC) lithofacies. Combination between the sedimentological, petrophysical, and elemental analyses indicates shifts between autochthonous and allochthonous sedimentation, whereas the organic geochemical analysis reveals a correlation between modes of sedimentation and preservation/composition of organic matter. Organic richness seems to increase within intervals of allochthonous sedimentation, with lower TOC values within intervals of autochthonous sedimentation. Organic matter preservation is enhanced due to poor oxygenation of the sea floor, further depleted by rapid burial beneath mass-transport deposits, increasing sedimentation rates and thus organic matter preservation. Horizons rich in organic matter may be derived from three different sources: organic matter with a fingerprint of terrestrial sources (e.g., enhanced contribution of plant leaf waxes) transported from nearshore environments; an allochthonous marine fingerprint with sulfurized hopanoids, which seem to be reworked from pre-existing Cretaceous organic-rich carbonates entrained within fined-grained micro-turbidites in the para-autochthonous facies; and productivity-derived organic matter deposited on the seafloor of the deep marine environment. This study demonstrates how transport mechanisms allow for the long-term burial of organic carbon in marine systems. When taking into consideration similar processes reported to occur in the world oceans today, it is clear that sediment transport and long-term burial of organic carbon is a fundamental part of the global carbon cycle.
date: 2023-12-30
date_type: published
publisher: Elsevier BV
official_url: https://doi.org/10.1016/j.chemgeo.2023.121800
oa_status: green
full_text_type: other
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 2110666
doi: 10.1016/j.chemgeo.2023.121800
lyricists_name: Bown, Paul
lyricists_id: PRBOW20
actors_name: Bown, Paul
actors_id: PRBOW20
actors_role: owner
full_text_status: public
publication: Chemical Geology
volume: 642
article_number: 121800
issn: 0009-2541
citation:        Meilijson, A;    Bialik, OM;    Boudinot, FG;    Bown, PR;    Benjamini, C;    Waldmann, ND;    Sepúlveda, J;      (2023)    Long-term carbon sequestration in the Eocene of the Levant Basin through transport of organic carbon from nearshore to deep marine environments.                   Chemical Geology , 642     , Article 121800.  10.1016/j.chemgeo.2023.121800 <https://doi.org/10.1016/j.chemgeo.2023.121800>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10184860/1/Meilijson%20et%20al.%20accepted.pdf