Crustal and upper mantle structure of Botswana

Abstract

I am deeply grateful to my teacher Dr. Amin Ismail. You are my geophysical teacher, all what I achieved return back to you. My deep gratitude goes to the staff members and my teaching assistant friends at Geology Department at Helwan University. Special thanks to Dr. Yahia Alqazaz, Dr. Al Ibiary, and Dr. Mostafa Gharib to faciliate my paper work and helping me extending my study leave to finish my PhD studies at ITC. Special thanks go to my relatives and friends back home in Egypt. You have been always there via the WhatsApp and Facebook making me feel at home. My father and mother, thank you, I owe you everything. To my brother and sisters, thank you for the support through the whole journey. To my wife, thank you for your love and inspiration. It was a tough journey, I know, but the joy was having you beside me. To my daughter, Nour, thank you my tiny beautiful light.

Mapping the Thermal Structure of Southern Africa From Curie Depth Estimates Based on Wavelet Analysis of Magnetic Data With Uncertainties

“…Figure 1). Along the Okavango Rift Zone in the north-western part of Botswana, z b is shallow ranging from 8 to 15 km, which coincides with the thermal perturbation of Okavango Rift (Leseane et al, 2015) and crustal thinning (Fadel et al, 2020). Toward the eastern part of Botswana, an intermediate Curie depth is estimated, which coincides with the Zimbabwe Craton and the old Magondi and Limpopo belts in this area.…”

“…The Cenozoic era is characterized by the emergence of the initial rifts caused by the spread of the EARS to the South. Seismically active fault systems indicate that rifting is developing in the Okavango Rift Zone (ORZ) in northern Botswana (Schmitz & Bowring, 2003), with the EARS potentially extending to central Botswana as well (Fadel et al, 2020). The different tectonic domains with different tectonic history and different ages (varying from old Cratonic lithosphere, mobile belts, and Phanerozoic rifting to flood basalt volcanism combined with the plateau uplift and the terminus of the EARS) make southern Africa an open laboratory to study and map the variations of Curie depth along with different domains which have different tectonic history and current thermal states.…”

“…The Namaqua-Natal domain is characterized by a remarkable continental-scale magnetic anomaly, namely, the Beattie Magnetic Anomaly (BMA; described by Scheiber-Enslin et al, 2014;Cornell et al, 2011). It extends over Heat flow NGHF (Lucazeau, 2019;Pollack et al, 1993) Geometrical Depth to basement CRUST1.0 model (Laske et al, 2013) Depth to Moho Gravity inversion (Uieda & Barbosa, 2017) with seismic constraints (Fadel et al, 2020;Youssof et al, 2013) Depth of lithosphere LithoRef18 (Afonso et al, 2019) Table 1 Summary of Used Data Sets 1,100 km from the western to the eastern coastal margins. To the North, the Kalahari magnetic lineament (Reeves, 1978) is characterized by short-wavelength magnetic anomaly which is interpreted as the western boundary of the Kaapvaal Craton.…”

Shear‐Wave Velocity Structure of the Southern African Upper Mantle: Implications for Craton Structure and Plateau Uplift

“…2.1 Ga Bushveld event within the Kaapvaal Craton (Figure 1). Karoo rifts and sedimentary basins developed across much of southern Africa during the breakup of Gondwana, and, today, rifting is ongoing within the East African Rift System, which extends to the southwest to the Okavango Rift Zone in northern Botswana and to the southeast into central Mozambique (Domingues et al, 2016;Fadel et al, 2020).…”

Gravity derived crustal thickness model of Botswana: Its implication for the Mw 6.5 April 3, 2017, Botswana earthquake

“…6B). In addition, a relatively thin crust at the northeastern tip of Botswana in the Okavango Rift Zone is correlated with a low shear-wave velocity zone in the mantle (~150 km), which is interpreted as the East African Rift System (EARS) expression at northern Botswana (Fadel, 2018;Fadel et al, 2020). Fadel et al (2020) have suggested that the EARS expression at the northern tip of Botswana extends to the Incipient Okavango Rift region and the Moiyabana Epicentral regions through weak crustal zones.…”