Offshore Somalia: crustal structure and implications on thermal maturity

T he crustal structure along the passive margin of offshore Somalia has remained largely unknown, due to limited geological and geophysical data collection during the long period of political instability and civil war. The extent of geological information in the area has for many years been restricted to regional-scale features defined from poor quality legacy seismic data (Bunce and Molnar, 1977) and potential field data (Coffin and Rabinowitz, 1987; Rapolla et al., 1995). These observations allowed the development of early plate reconstruction models for Africa and Madagascar. However, since 2012 the region has experienced a period of relative political stability following the inauguration of the Federal Government of Somalia. Two 2D seismic acquisition programmes were undertaken in 2014 and 2016. The newly acquired seismic data have facilitated the development of new theories and understanding of the evolution of the Somalian passive margin (Kearns et al., 2016). In this study, we integrate newly acquired long offset seismic data with wells and regional satellite gravity and magnetic data, to critically assess the structural configuration, and map the continental to oceanic crust transition. We use gravity modelling techniques to support our observations. We also discuss the possible implications of our findings on source rock thermal maturity.