Proterozoic massif-type anorthosites as the archetypes of long-lived (≥100 Myr) magmatic systems—New evidence from the Kunene Anorthosite Complex (Angola)

•We give new ID-TIMS and LA-ICPMS U–Pb ages, as well as detailed field observations from the Kunene Anorthosite Complex (KAC) of SW Angola.•High-precision U–Pb zircon and baddeleyite ages for anorthositic rocks from across the complex (n = 11) range between 1376 and 1438 Ma—a period of ~60 Myr.•Comagmatic pegmatoidal enclaves give ages of ~1500 Ma, indicating as much as 120 Myr between some of the earliest and latest crystallization products of the system.•We infer that the KAC represents a long-lived mushy magmatic system that was likely emplaced in distinct pulses. Proterozoic massif-type anorthosites are voluminous, plagioclase-dominated plutonic suites with characteristic intermediate compositions (An50±10) that represent mantle-derived magmas ponded at Moho depths and crystallized polybarically until emplacement at mid-crustal levels. We present new ID-TIMS and LA-ICPMS U–Pb ages, as well as detailed field observations from the Kunene Anorthosite Complex (KAC) of SW Angola. Our main objective in this work is to contextualize a variety of important petrographic and geochronological features of the KAC that have implications for Proterozoic anorthosite petrogenesis and the geological evolution of the SW Congo Craton. High-precision U–Pb zircon and baddeleyite ages for anorthositic rocks from across the complex (n = 11) range between 1376 and 1438 Ma—a period of ~60 Myr—showing that such systems may be remarkably long-lived. Dating of magmatic zircons from a comagmatic pegmatoidal enclave in the KAC, which also contains high-Al orthopyroxene megacrysts (HAOM), gives an age of ~1500 Ma, indicating as much as 120 Myr between some of the earliest and latest crystallization products of the system. These enclaves provide a snapshot of the liquid line of descent of the anorthosites and are compelling evidence for the comagmatic nature of the HAOM. Field evidence for block structure, magma mingling, and extreme textural heterogeneity in the KAC supports emplacement as multiple influxes of magma, of various volumes, carrying variable proportions of crystals and autoliths from below. We infer that the KAC represents a long-lived mushy magmatic system that was likely emplaced in distinct pulses. These observations refine our understanding of Proterozoic anorthosite petrogenesis. They also provide evidence for an array of magmatic processes operating at various levels of crystallinity that may create textural and chemical heterogeneity in evolving magma products at