Kimberlites in a Karoo graben of northern Mozambique: Tectonic setting, mineralogy and Rb-Sr geochronology

Bingen, Bernard; Barton, Erika S.; Daudi, E.; Manuel, Sandra; Moniz, A. C.

doi:10.2113/gssajg.110.1.111

Cited by 10 publications

(4 citation statements)

References 19 publications

(2 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Locally, these fabrics are well‐oriented for reactivation under the region's ENE‐trending minimum principal compressive stress, and so they may have guided the trajectory of some EAR faults in Malawi (Hodge, Fagereng, Biggs, et al., 2018; Kolawole et al., 2018a; Ring, 1994; Scholz et al., 2020; S. M. Dawson et al., 2018; Wedmore, Williams, et al., 2020; Williams et al., 2019). These metamorphic fabrics may have also influenced regional Upper Permian to Lower Jurassic “Karoo” rifting (Catuneanu et al., 2005; Key et al., 2007; Wopfner, 2002). In central and northern Malawi, the EAR cuts across Karoo‐age NW‐SE trending basins (Accardo et al., 2018; Ring, 1994; Versfelt & Rosendahl, 1989), while in southern Malawi, Karoo‐age faults in the NW‐SE trending Shire Rift Zone have likely been reactivated during EAR deformation (Figure 2; Castaing, 1991; Habgood, 1963; Kolawole et al., 2021; Wedmore, Williams, et al., 2020).…”

Section: Malawi Seismotectonicsmentioning

confidence: 99%

“…M. Dawson et al, 2018;Williams et al, 2019). These metamorphic fabrics may have also influenced regional Upper Permian to Lower Jurassic "Karoo" rifting (Catuneanu et al, 2005;Key et al, 2007;Wopfner, 2002). In central and northern Malawi, the EAR cuts across Karoo-age NW-SE trending basins (Accardo et al, 2018;Ring, 1994;Versfelt & Rosendahl, 1989), while in southern Malawi, Karoo-age (Wedmore et al, 2021), and earthquake locations from the Sub-Saharan Africa Global Earthquake Model Catalog (SSA-GEM; Poggi et al, 2017).…”

Section: Malawi Seismotectonicsmentioning

confidence: 99%

See 1 more Smart Citation

The Malawi Active Fault Database: An Onshore‐Offshore Database for Regional Assessment of Seismic Hazard and Tectonic Evolution

Williams

Wedmore

Scholz

et al. 2022

Geochem Geophys Geosyst

View full text Add to dashboard Cite

We present the Malawi Active Fault Database (MAFD), an open‐access (https://doi.org/10.5281/zenodo.5507190) geospatial database of 113 fault traces in Malawi and neighboring Tanzania and Mozambique. Malawi is located within the East African Rift's (EAR) Western Branch where active fault identification is challenging because chronostratigraphic data are rare, and/or faults are buried and so do not have a surface expression. The MAFD therefore includes any fault that has evidence for displacement during Cenozoic East African rifting or is buried beneath the rift valley and is favorably oriented to the regional stresses. To identify such faults, we consider a multidisciplinary data set: high‐resolution digital elevation models, previous geological mapping, field observations, seismic reflection surveys from offshore Lake Malawi, and aeromagnetic and gravity data. The MAFD includes faults throughout Malawi, where seismic risk is increasing because of population growth and its seismically vulnerable building stock. We also investigate the database as a sample of the normal fault population in an incipient continental rift. We cannot reject the null hypothesis that the distribution of fault lengths in the MAFD is described by a power law, which is consistent with Malawi's relatively thick seismogenic layer (30–40 km), low (<8%) regional extensional strain, and regional deformation localization (50%–75%) across relatively long hard‐linked border faults. Cumulatively, we highlight the importance of integrating onshore and offshore geological and geophysical data to develop active fault databases along the EAR and similar continental settings both to understand the regional seismic hazard and tectonic evolution.

show abstract

Section: Malawi Seismotectonicsmentioning

confidence: 99%

Section: Malawi Seismotectonicsmentioning

confidence: 99%

The Malawi Active Fault Database: An Onshore‐Offshore Database for Regional Assessment of Seismic Hazard and Tectonic Evolution

Williams

Wedmore

Scholz

et al. 2022

Geochem Geophys Geosyst

View full text Add to dashboard Cite

show abstract

“…This period corresponds to rifting related to dispersal of Gondwana and more specifically to dextral translation of Madagascar relative to the African plate, and initiation of seafloor spreading between the Antarctic and African plates (e.g., Rakotosolofo et al, 1999;Torsvik et al 2002). At the regional-scale, the age of 112 ± 14 Ma is quite close to the intrusion age of kimberlite at 140.5 ± 1.7 Ma in the Maniamba graben (Key et al, 2007) and overlaps with deposition of the Aptian (125-112 Ma) Macomia Formation in the Rovuma Basin (Key et al, 2008).…”

Section: Gold Mineralization In a Tectonic Settingmentioning

confidence: 58%

The Niassa Gold Belt, northern Mozambique – A segment of a continental-scale Pan-African gold-bearing structure?

Bjerkgård

Stein

Bingen

et al. 2009

Journal of African Earth Sciences

Self Cite

View full text Add to dashboard Cite

“…The fissure‐type basalts in the Chire‐Urema Graben (Figure 1c) yield K‐Ar whole rock ages of 137–115 Ma and are associated with crustal extension in Cretaceous times [ Lächelt , 2004; Nairn et al , 1991]. Similarly kimberlites intruding into the Metangula Basin give a Rb‐Sr phlogopite age of ∼141 ± 2 Ma [ Key et al , 2007]. In southernmost Malawi thermochronological results are reported from the Chilwa alkaline province (Figure 1c) by Eby et al [1995].…”

Section: Geodynamic Setting and Geological Overviewmentioning

confidence: 99%

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

et al. 2011

View full text Add to dashboard Cite

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.

show abstract

Kimberlites in a Karoo graben of northern Mozambique: Tectonic setting, mineralogy and Rb-Sr geochronology

Cited by 10 publications

References 19 publications

The Malawi Active Fault Database: An Onshore‐Offshore Database for Regional Assessment of Seismic Hazard and Tectonic Evolution

The Malawi Active Fault Database: An Onshore‐Offshore Database for Regional Assessment of Seismic Hazard and Tectonic Evolution

The Niassa Gold Belt, northern Mozambique – A segment of a continental-scale Pan-African gold-bearing structure?

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

Contact Info

Product

Resources

About