Mapping the complexity of Transform Margins
AbstractTransform margins are a function of the pre-existing crustal architecture (pre-transform) and the interplay of syn- and post-transform geodynamic processes. We use a suite of geospatial databases to investigate four transform margins: East Africa (Davie Deformational Zone, DDZ), Equatorial Africa, and the South African and Falkland (Malvinas) margins (Agulhas-Falkland Fracture Zone, AFFZ). The East African margin is the most complex of the four. This is a consequence of Late Jurassic - Early Cretaceous transform motion affecting highly heterogeneous crust, and post-transform deformation that varies along the margin. Equatorial Africa most closely adheres to traditional definitions of “transform margins”, but actually comprises two principal transform systems - the Romanche and St. Pauls, dictated by the pre-transform distribution of mobile belts and West African craton. All four margins are spatially associated with volcanism, and each exhibits narrow uplifts associated with transpression or transtension. But the causal relationship of these features with transform processes differ. Volcanism along the East African margin is pre- and post-transform. Syn-transform volcanism on the AFFZ is spatially limited, with the AFFZ possibly acting as a conduit for magmatism rather than as a causal driver. Transform margins are varied and complex and require an understanding of pre-, syn- and post-transform geodynamics.
Dataset, including a photo-guide, of alien plants sold in traditional medicine markets and healthcare outlets in three South African cities, specifically by traders of Indian, West African, East African, and Chinese origin.
