Recording the largest gabbro-anorthositic complex worldwide: The Kunene Complex (KC), SW Angola

•The Kunene Complex extends below the Kalahari sediments, doubling its previously known size.•The lopolith geometry massif-type anorthosite complex shows gabbroic bodies.•Intrusion of the KC was favoured by a large NE-SW-trending inherited pre-Mesoproterozoic structure. The Kunene Complex (KC) repre...

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Bibliographic Details
Published in:Precambrian research 2022-09, Vol.379, p.106790, Article 106790
Main Authors: Rey-Moral, Carmen, Mochales, Tania, Merino Martínez, Enrique, García Lobón, Jose Luis, López Bahut, María Teresa, Martín-Banda, Raquel, Feria, María Carmen, Ballesteros, Dianne, Machadinho, Ana, Alves, Daniela
Format: Article
Language:English
Subjects:
2.5D modelling
Angola
Gravity modelling
Kunene Complex (KC)
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Summary:•The Kunene Complex extends below the Kalahari sediments, doubling its previously known size.•The lopolith geometry massif-type anorthosite complex shows gabbroic bodies.•Intrusion of the KC was favoured by a large NE-SW-trending inherited pre-Mesoproterozoic structure. The Kunene Complex (KC) represents a large Mesoproterozoic igneous body, mainly composed of anorthosites and gabbroic rocks that extends from SW Angola to NW Namibia (18000 km2, N-S trend, and ca. 350 km long and 25–50 km wide). Although the KC has been studied from a cartographic and geochemical point of view, little is known about its structure at depth below the sedimentary deposits of the Kalahari basin. Hence, we use available satellite gravity data to estimate its extent and to unravel its morphology at depth. The Bouguer anomaly map depicts a gravity gradient from the coast (+200 mGal) towards eastern Angola (-150 mGal), which is explained by the transition from a young, dense and thin basaltic oceanic crust, formed during the Mesozoic Atlantic rifting, to an old, light and thick Archaean to Proterozoic continental crust (Congo Craton), to the east. The outcropping KC interrupts the gravity trend, showing at the western, southwestern and northeastern sides, several positive and isolated gravity anomalies linked to gabbroic intrusions associated to KC (ca. 50 km wavelength and −90 mGal). In contrast, the anomalies found at the central part of the massif (50 km wavelength and 
ISSN:0301-9268
1872-7433
DOI:10.1016/j.precamres.2022.106790