Strike-slip related folding within the Malvinas/Falkland Trough (south-western Atlantic ocean)

ESTEBAN, FEDERICO D.; ORMAZABAL, JUAN PABLO; PALMA, FERMÍN; CAYO, LUBIN ERIC; LODOLO, EMANUELE; TASSONE, ALEJANDRO

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2020 vol. 98

0895-9811

TheMalvinas/Falkland Trough (M/FT) is an E-W trending bathymetric depression alongwhich runs the present-day South American-Scotia plate boundary. To the northof the M/FT lies the southern sector of the South Malvinas/Falkland Basin, and tothe south lies the Burdwood Bank, anelongated morphological high constitutingpart of the South Scotia Ridge. Analysis of bathymetric and slope maps,integrated with seismic reflection profiles, have allowed describing in detailthe M/FT in the sector comprised between 60° and 57° W. Data show the presenceof an array of folds forming a thin-skinned fold-and-thrust Belt (FTB),previously interpreted as an active compressional field. The thin-skinned FTB isdeveloped in a triangular-shaped area, which extends ca. 100 km in the E-Wdirection and 16 km in the N-S direction. Four parallel, asymmetric folds thatdevelop to progressively greater water depths (between 1600-2600 m depth)towards the north, with orientations ESE-WNW and lengths that vary between 22and 98 km, have been recognized. These folds are constituted by Late Cenozoic sedimentsthat are undeformed in the Malvinas/Falkland Trough. The development of folds, whichbegan in the late Miocene (ca. 7 Ma), was associated with the left-lateralstrike-slip tectonic regime of the Magallanes-Fagnano-Malvinas lineament, thewestern segment of the South American-Scotia plate boundary.