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