• journal_title：Geological Society of America Bulletin
• Contributor：Christopher G. DiLeonardo ; J. Casey Moore ; Susan Nissen ; Nathan Bangs
• Publisher：Geological Society of America
• Date：2002-
• Format：text/html
• Language：en
• Identifier：10.1130/0016-7606(2002)114<0051:COISAF>2.0.CO;2
• journal_abbrev：Geological Society of America Bulletin
• issn：0016-7606
• volume：114
• issue：1
• firstpage：51

The application of three-dimensional seismic reflection and coherence imaging to the study of the décollement zone of the Barbados Ridge accretionary complex has provided new insights into the relationships among internal structure, fluid flow, and previously unrecognized strike-slip faulting. Combined coherence and seismic amplitude imaging of the décollement zone reveal anomalous northeast-trending lineaments parallel to and abutting zones of high- amplitude, negative-polarity reflections. Analysis of these lineaments shows them to be penetrative structures dipping southeast with apparent reverse dip-slip offset. Isopach mapping of the accretionary wedge indicates significant right-lateral displacement across these structures. These faults apparently channel fluid flow within the décollement zone, and the prominent northeast- trending conduits so formed are readily visible as high-amplitude, negative-polarity reflections. Additionally, north-northeast– trending zones of variable coherence and high positive amplitude are inferred barriers to up-structure fluid-migration pathways.

Movement along strike-slip structures probably alternates with displacement along the décollement zone. Northeast- trending strike-slip faults extend for >13 km, crossing the length of the survey area and into the incoming oceanic plate. Active arc-oblique strike-slip faulting of the décollement zone beneath the Barbados Ridge accretionary wedge implies a stress regime in that σ₁ is fixed and σ₂ and σ₃ either transpose with time or are nearly equal. This state of stress may be a common occurrence in forearc tectonism and may have led to the formation of many, as yet unrecognized, arc-oblique strike-slip faults at convergent margins.