TY - JOUR
T1 - Identification and tectonic implications of a tear in the South American plate at the southern end of the Lesser Antilles
AU - Clark, S. A.
AU - Sobiesiak, M.
AU - Zelt, C. A.
AU - Magnani, M. B.
AU - Miller, M. S.
AU - Bezada, M. J.
AU - Levander, A.
PY - 2008/11
Y1 - 2008/11
N2 - In the southeast corner of the Caribbean, westward subduction of (Atlantic) oceanic South America beneath the Lesser Antilles transitions to east-west transform motion between continental South America and the Caribbean plate. This geometry requires negatively buoyant, subducting, oceanic South American lithosphere to progressively detach from positively buoyant, continental South American lithosphere. The most widely accepted model is slab break-off, with oblique arc-continent collision and northwest dipping, continental subduction precipitating narrow rifting in the subducting slab. In contrast, the subduction-transform edge propagator (STEP) model conceptualizes progressive detachment along a vertical, dip-slip tear through the lithosphere, with stress focused at the edge of the propagating transform boundary. We present four types of seismic data to resolve the ongoing lithospheric detachment: local seismicity, receiver functions, wide-angle seismic velocity inversion, and a regional, balanced cross section constrained by petroleum industry data. These four data sets image a near-vertical tear extending through the entire lithosphere, revealing a key mechanism for the structural evolution of Venezuela.
AB - In the southeast corner of the Caribbean, westward subduction of (Atlantic) oceanic South America beneath the Lesser Antilles transitions to east-west transform motion between continental South America and the Caribbean plate. This geometry requires negatively buoyant, subducting, oceanic South American lithosphere to progressively detach from positively buoyant, continental South American lithosphere. The most widely accepted model is slab break-off, with oblique arc-continent collision and northwest dipping, continental subduction precipitating narrow rifting in the subducting slab. In contrast, the subduction-transform edge propagator (STEP) model conceptualizes progressive detachment along a vertical, dip-slip tear through the lithosphere, with stress focused at the edge of the propagating transform boundary. We present four types of seismic data to resolve the ongoing lithospheric detachment: local seismicity, receiver functions, wide-angle seismic velocity inversion, and a regional, balanced cross section constrained by petroleum industry data. These four data sets image a near-vertical tear extending through the entire lithosphere, revealing a key mechanism for the structural evolution of Venezuela.
KW - Jelly sandwich
KW - Lithospheric detachment
KW - Mantle dynamics
KW - STEP
KW - Slab break-off
KW - Tear
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U2 - 10.1029/2008GC002084
DO - 10.1029/2008GC002084
M3 - Article
AN - SCOPUS:66149174168
SN - 1525-2027
VL - 9
JO - Geochemistry, Geophysics, Geosystems
JF - Geochemistry, Geophysics, Geosystems
IS - 11
M1 - Q11004
ER -