Late tectonic evolution of the Nampula Complex, NE Mozambique

Abstract

The Nampula Complex is the largest of several Proterozoic crustal blocks which makes up the crust of NE Mozambique. It is largely composed of supracrustal and intrusive gneisses, at upper amphibolite grade, with Mesoproterozoic protolith ages (1.15 to 1.05 Ga) and evidence for a Mesoproterozoic orogenic event (D1). The rocks underwent pervasive tectonic reworking during the late Neoproterozoic (“Pan-African”) collision orogeny at ca 550 Ma (D2), which led to the assembly of the various constituent blocks within this part of Gondwana. During this event, two small Neoproterozoic granulite remnant klippen were thrust over the Nampula Complex. The current distribution of rocks types and virtually all the fabrics seen in the rocks of the Nampula Complex are considered to be due to the Neoproterozoic orogeny which destroyed nearly all the evidence of earlier fabrics and structures (Macey et al., 2010). The Nampula Complex is bounded in the north by the ENE-trending Lúrio Belt, a polyphase structure which has been much debated over the years