Thermochronological history of an orogen‐passive margin system: An example from northern Mozambique

Abstract

In this paper, we present a conceptual model to describe the post‐Pan‐African (<∼500 Ma) basement cooling pattern for NE Mozambique. The cooling history is derived from combined low‐temperature thermochronological dating methods comprising titanite, zircon and apatite fission track data. After Pan‐African orogenesis (∼620–530 Ma) the Precambrian basement was subject to extensional tectonics and a relatively slow Lower Ordovician to Recent cooling with rates of ∼2.2°C to 0.1°C Myr−1. Basement rock cooling was mainly a response to Late Paleozoic to Mesozoic rifting between northern Mozambique and East Gondwana during the opening of the Rovuma and Mozambique sedimentary basins. Meanwhile, different dynamic margin and basin types evolved along the eastern and southern continental margins of NE Mozambique. During the Late Carboniferous–Triassic an intracontinental rift opened between NE Mozambique and East Antarctica, and the fastest denudation was focused along the present southern continental margin. Since the Middle Jurassic, tectonic denudation along the Rovuma margin was localized in a narrow zone, some 30 km wide, associated with erosion along strike‐slip faults. In contrast, the Jurassic‐Cretaceous opening and ocean crust formation in the Mozambique Basin were accompanied with an unusually uniform Late Cretaceous cooling pattern over a large area (∼150,000 km2) of the basin hinterland. This pattern can be explained by isostatic and erosional response to magmatic underplating or differential stretching, whereby the old Pan‐African lithospheric structure appears to have important controls on later events.

Response of Cenozoic turbidite system to tectonic activity and sea-level change off the Zambezi Delta

“…The Zambezi valley that fed the Upper Mozambique Fan is characterized by steep walls, slope failure faults and chaotic sediment infill. BSR (Bottom Simulating Reflector) along the profile is identified on the continental rise indicating the presence of gas hydrates and free gas below it Africa (Brown et al 2014;Wildman et al 2016) and along the Malawi Rift system and in northern Mozambique (Daszinnies et al 2009;Emmel et al 2011), where fission track analysis show distinct period of cooling in the Late Cretaceous around ~75 Ma. This uplift could have resulted in a regional change in sea level affecting at least the shelf region over a relatively short time span.…”

“…1) and its African source regions therefore remain sparsely studied. In particular, the fan offers the possibility to understand the contentious Cenozoic uplift history of southern Africa (Brown et al 2014;Daszinnies et al 2009;Emmel et al 2011;Partridge and Maud 1987;Roberts and White 2010). The aim of this study is to fill this gap in knowledge via analysis of the fan's internal seismic stratigraphy in a new network of multi-channel seismic reflection (MCS) data, tied to stratigraphic information available from hydrocarbon industry studies in the Zambezi Delta Depression (ZDD) (Fig.…”

Postcollisional High-Grade Metamorphism, Orogenic Collapse, and Differential Cooling of the East African Orogen of Northeast Mozambique

“…11). A further reaching consideration of these observations, in addition to the thermal effects of M 3 and delamination, is that the relative cooling pattern was modified by different exhumation levels, caused for example by increased local uplift during prolonged collapse or even by far later Gondwana rifting and breakup (e.g., Emmel et al 2011). However, the Mecubú ri Group metasediments clearly mark a post-D 2 (postcollisional) paleo-surface of the Nampula Complex (figs.…”

“…530 and 500 Ma Ueda et al 2012). The subsequent thermal evolution of this part of the orogen has, however, not been fully documented, except for lowertemperature fission-track and limited 40 Ar/ 39 Ar studies (Daszinnies et al 2009;Emmel et al 2011).…”

Coastal evolution and associated titanium sand mineralisation of Jangamo district, Inhambane Province, Mozambique

“…The basin is characterised by a complex succession of Cretaceous to Quaternary age sedimentary rocks ( Fig. 3; Table 2) and unconsolidated sand deposits which rest unconformably on Karoo Supergroup sedimentary and volcanic rocks (Salman and Abdula 1995;Schlüter 2008;Emmel et al 2011). At the base of the post-Karoo sedimentary sequence is a very thick continental sediment known as the Red Beds Formation (Cilek 1989;Mashaba and Altermann 2015).…”