Conjugate volcanic passive margins in the austral segment of the South Atlantic – Architecture and development

The thorough interpretation of the South Atlantic long offset seismic lines provides a new view magmatic and crustal architecture evolution conjugate volcanic passive margins (VPM) along austral segment Ocean. In this study, we make synthesis previously published unpublished profiles that are reinterpreted consistently, and, for first time, displayed in view. seaward dipping reflector sequences (SDR) expose here three main structural types (inner, outer intermediate) can be distinguished based on both curvature reflectors topography at their downdip terminations. We observe specific correlation between thinning profile crust geometric attributes SDR. This suggests genetic relationship is discussed in-term rheological during magma-assisted lithospheric break-up. also featured moderate but significant asymmetry, with relative difference estimated to about 60% margin width, total volume SDR spatial distribution. A change toward more symmetric however observed when approaching highly area Walvis Ridge Rio Grande Rise. influence pre-rift inheritance, mode rifting coeval mantle dynamic put into balance explain global architecture. asymmetric domain, extrusive show evidences westward rift jumps participate develop wider African side. propose an thermal structure controlled by lithosphere asthenosphere boundary may have promoted formation margin. focusing last axis associated development thickest wedges above ultimate necking zone crust. Conversely early stages which appears segmented diachronous, final localization tectono-magmatic activity coarsely synchronous, least, northern half segment. further higher gradient than elsewhere thicker weaker preexisting continental intense input inferred promote very wide close