@article{fdi:010096314,
  title = {{O}rigin and evolution of giant comet marks along the {N}orth {A}tlantic {D}eep-{W}ater flow on the {D}emerara plateau},
  author = {{B}lin, {P}. and {L}oncke, {L}. and {D}e {M}adron, {X}. {D}. and {Z}aragosi, {S}. and {F}auquembergue, {K}. and {G}ontharet, {S}. and {P}airaud, {I}. and {D}upont, {P}. and {C}aquineau, {S}andrine and {C}harriere, {B}. and {L}agarde, {R}. and {B}asile, {C}. and {S}ci {T}eam {D}iadem,},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {D}emerara {P}lateau, located in the equatorial {A}tlantic, is particularly well-suited for recording the activity of the {D}eep {W}estern {B}oundary {C}urrent ({DWBC}), which transports {N}orth {A}tlantic {D}eep {W}ater ({NADW}) southward into the {A}tlantic basin. {T}his current, active between 1500 and 3500 m depth, constitutes the deep part of the global thermohaline circulation and plays a crucial role in climate regulation. {T}he {D}emerara {P}lateau is remarkable for the abundance and wide distribution of comet mark-type sedimentary structures, which can reach several kilometres in length. {T}hese hydrodynamic bedforms, interpreted as erosional features associated with strong bottom currents, are currently used as proxies for deep currents velocities, with minimum formation thresholds estimated between 0.60 and 0.75 m/s according to the literature ({R}ebesco et al., 2014; {W}erner et al., 1980). {T}he {DIADEM} ({D}ive {A}t {DEM}erara) oceanographic cruise ({B}asile and {L}oncke, 2023) enabled detailed investigation of one such structure using a combination of complementary tools with the aim of better understanding their functioning and evolution with in-situ observation, physical records, and sampling. {T}hose new data were also combined with formerly acquired high-resolution seismic data, allowing a new vision of these bedforms their formation, and their evolution over time. {T}he main findings are the following: (1) comet-marks localize on carbonate mass transported blocs outcropping on the seafloor; (2) {C}learly show a polyphase evolution of the bedforms of comet mark presenting alternations of erosion and sedimentation phases. {T}he bedforms therefore record long-term variations in bottom current activity with an alternation of intense hydrodynamic events (erosion) and quieter hydrodynamic periods (deposition) through time, reflecting a complex hydrodynamic history; (3) {A}t present, comet-marks recorded a significant decrease in current velocity within the erosional zones located inside the comet tails associated with fined-grained sediments infill in this area, highlighting the need for cautious interpretation of such features as direct indicators of present-day current intensity; (4) {F}inally, a result that was not necessarily anticipated but documented by exploring those bedforms with the {N}autile submersible, comet-marks host quite important benthic and epibenthic biodiversity with a wide variety of associated species.},
  keywords = {{C}omet mark ; {D}eep western boundary current ; {N}orth atlantic deep water ; {D}eep sedimentation ; {D}emerara plateau ; {ATLANTIQUE} ; {ZONE} {EQUATORIALE}},
  booktitle = {},
  journal = {{M}arine {G}eology},
  volume = {493},
  numero = {},
  pages = {107717 [20 p.]},
  ISSN = {0025-3227},
  year = {2026},
  DOI = {10.1016/j.margeo.2026.107717},
  URL = {https://www.documentation.ird.fr/hor/fdi:010096314},
}