Crustal Architecture and Nature of Continental Breakup Along a Transform Margin: New Insights From Tanzania‐Mozambique Margin

Abstract

AbstractThe Tanzania‐North Mozambique continental margin is a transform segment associated with Davie Fracture Zone (DFZ). The DFZ is described as an elongated linear oceanic fracture zone, commonly linked with the breakup between Eastern and Western Gondwana. We conducted a synthesized study using gravity, magnetic, and seismic data presenting the crustal architecture, geometry, and the kinematic nature of continental breakup along a transform margin. The crustal nature of DFZ, its role in forming kinematic linkage between two extensional margins during continental breakup processes, is focus of our study. The two extensional margins, Somalia‐Majunga and North Mozambique‐Antarctica, were linked via a 2,600‐km‐long dextral transform segment, partially overlapping with DFZ. Absence of classical rift indicators, weak signs of hyperextension, and abrupt ocean‐continent boundary suggest transform margin architecture. We redefined this feature as the Davie Transform System. The nature of deformation varies from transtensional pull‐apart in Tanzania to almost pure strike slip in North Mozambique. The southern transform segment exhibits abrupt change in ocean continent transition with a narrow zone of continental extension. This variation is recognized through the newly interpreted ocean‐continent boundary along this entire transform segment. Notably, within large pull‐apart systems in the north, the presence of fossilized incipient spreading center suggests that the extension had reached at quite advanced stages, characterized by significant thermal weakening as a consequence of strong magmatic activity. Through a series of reconstruction snapshots, we show the geodynamic evolution along the Tanzania‐North Mozambique margin explaining the role of Davie Transform System in the southward movement of Madagascar.