The Pará-Maranhão and the Amapá Megaslide Complexes – Characteristics of Giant Submarine Landslides in the Foz do Amazonas Basin – Brazilian Equatorial Margin

Recently, through 2D seismic analyses, great megaslide deposits were identified in SE and NW steeper slopes of the Foz do Amazonas Basin. Now in this work, previous acquired seismic data was reinterpreted and time correlated with well data to better investigate two mass transport complexes (MTCs). These two MTCs are developed at steep slope settings adjacent to the Amazon Fan: to SE the Para-Maranhao Megaslide Complex and to NW the Amapa Megaslide Complex. Such deposits can mobilize thick siliciclasticseries (up to 1,000 m thick) as a combination of debris flows, slided blocks and compressivelly-deformed allochtonous masses downslope over areas as large as thousands of km2, leaving behind large scars (as high as ~700m) that strongly impact the sea-bottom morphology. In the context of megaslides, the instability is most likely induced by levels of weak overpressuredshales revealed by previous studies on gravity tectonics across the Foz do Amazonas Basin.