FN Archimer Export Format
PT J
TI The Bunce Fault and Strain Partitioning in the Northern Lesser Antilles
BT 
AF Laurencin, M.
   Marcaillou, B.
   Graindorge, David
   Lebrun, J.‐F.
   Klingelhoefer, Frauke
   Boucard, M.
   Laigle, M.
   Lallemand, S.
   Schenini, L.
AS 1:1;2:2;3:1;4:3;5:4;6:3;7:2;8:5;9:2;
FF 1:;2:;3:;4:;5:PDG-REM-GM-LAD;6:;7:;8:;9:;
C1 Laboratoire Géosciences Océan, UMR6538 CNRS‐UBO‐UBS, Université Bretagne Pays de Loire (UBL), Brest, Institut Universitaire Européen de la Mer Plouzané France
   Université Côte d'Azur, CNRS, Observatoire de la Côte d'Azur, IRD, Géoazur Valbonne France
   Géosciences Montpellier, UMR5243, Université des Antilles, CNRS, Université de Montpellier Montpellier France
   Géosciences Marines, Ifremer, ZI de la Pointe de Diable Plouzané France
   Géosciences Montpellier, CNRS, Université de Montpellier, Université des Antilles Montpellier France
C2 UBO, FRANCE
   UNIV NICE, FRANCE
   UNIV ANTILLES, FRANCE
   IFREMER, FRANCE
   CNRS, FRANCE
SI BREST
SE PDG-REM-GM-LAD
UM LGO
IN WOS Ifremer UPR
   copubli-france
   copubli-univ-france
IF 4.497
TC 8
UR https://archimer.ifremer.fr/doc/00511/62291/66526.pdf
   https://archimer.ifremer.fr/doc/00511/62291/66527.pdf
LA English
DT Article
CR ANTITHESIS
   ANTITHESIS 3
   ANTITHESIS LEG1
   ANTITHESIS LEG2
BO Pourquoi pas ?
   L'Atalante
AB Strain partitioning related to oblique plate convergence has long been debated in Northern Lesser Antilles. Geophysical data acquired during the ANTITHESIS cruises highlight that the sinistral strike‐slip Bunce Fault develops along the vertical, long, and linear discontinuity between the sedimentary wedge and a more rigid backstop. The narrowness of the 20‐ to 30‐km‐wide accretionary wedge and its continuity over ~850 km is remarkable. The Bunce Fault extends as far south as 18.5°N where it anastomoses within the accretionary prism where the sharp increase in convergence obliquity possibly acts as a mechanical threshold. Surface traces related to subducting seamounts suggest that 80% of the lateral component of the convergent motion is taken up by internal deformation within the accretionary prism and by the Bunce Fault. The absence of crustal‐scale, long‐term tectonic system south of the Anegada Passage casts doubt upon the degree of strain partitioning in the Northern Lesser Antilles. Plain Language Summary Lithospheric plates are frequently bounded by subduction zones where oceanic plates underthrust overriding plates. In most cases, this convergence is oblique to the margin, its resulting tectonic deformation is generally due to margin‐normal and margin‐parallel components of the plate convergence vector. At the Northern Lesser Antilles, the North American Plate subducts beneath the Caribbean Plate with oblique convergence increasing from Guadeloupe to Virgin Islands. This study aims to analyze and resolve the tectonic deformation along this margin. We acquired marine geophysical data during ANTITHESIS cruises (2014–2016) to image the seafloor and the crustal structure. We place a particular emphasis on the strike‐slip Bunce Fault, which extends over ~850 km, including a newly discovered 350‐km segment, 20–30 km landward from the trench. Although long strike‐slip faults have already been observed at oblique subduction zones, the proximity of the Bunce Fault to the trench is unprecedented. We conclude that the mechanical discontinuity between the sedimentary wedge and a more rigid backstop and the sharp increase in obliquity is likely to control the location of the trench‐parallel, strike‐slip deformation north of the Anegada Passage when strain partitioning to the south may be small or taken up in more diffuse pattern. 
PY 2019
PD AUG
SO Geophysical Research Letters
SN 0094-8276
PU American Geophysical Union (AGU)
VL 46
IS 16
UT 000490966700031
BP 9573
EP 9582
DI 10.1029/2019GL083490
ID 62291
ER

EF