Trace-element geochemistry and U–Pb dating of perovskite in kimberlites of the Lunda Norte province (NE Angola): Petrogenetic and tectonic implications

Castillo-Oliver, Montgarri; Galí, Salvador; Melgarejo, Joan Carles; Griffin, William L.; Белоусова, Е. А.; Pearson, Norman J.; Watangua, Manuel; O’Reilly, Suzanne Y.

doi:10.1016/j.chemgeo.2015.12.014

Cited by 36 publications

(23 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Volcanism took place at the landward extension of the Cuanza seamount chain built on oceanic crust, which acted as a sedimentary barrier between the Benguela and Cuanza basins (Hudec and Jackson, 2002). Reactivation of deep lithospheric faults during Early Cretaceous rifting was associated with kimberlite and carbonatite magmatism concentrated along the 50-90 km-wide Lucapa tectonic corridor extending to the NE of the Namibe basin (Comin-Chiaramonti et al, 2011;Castillo-Oliver et al, 2016).…”

Section: Syn-rift To Post-rift Volcanic Rocksmentioning

confidence: 99%

Dynamic uplift, recycling, and climate control on the petrology of passive-margin sand (Angola)

Garzanti

Dinis

Vermeesch

et al. 2018

Sedimentary Geology

View full text Add to dashboard Cite

The subequatorial Angolan continental margin offers excellent conditions to test textbook theories on the composition of passive-margin sediments generated in different climatic and tectonic regimes. We use here comprehensive petrographic, heavy-mineral, geochemical and zircongeochronology datasets on modern fluvial, beach, shelfal, and deep-marine sands and muds collected from hyperarid northern Namibia to hyperhumid Congo to investigate and assess: a) how faithfully sand mineralogy reflects the lithological and time structures of source rocks in a tectonically active rifted margin; b) in what climatic and geomorphological conditions the mark of *Revised manuscript with no changes marked Click here to view linked References "The present is the key to the past" Archibald Geikie, The Founders of Geology "From this gateway Moment a long eternal lane stretches backward: behind us lies an eternity. Must not what ever can happen, already have happened, been done, passed by before? And if everything has already been here before, what do you think of this moment, dwarf? " Friedrich Nietzsche, Thus Spoke Zarathustra, On the Vision and the Riddle. 9 mineral assemblages and chemical-weathering proxies in river muds (Dinis et al., 2017). Kaolinite, supplied in abundance to the coast by most major Angolan rivers, is largely generated in the wet hinterland, and particularly on ancient flat surfaces decreasing in elevation westward and separated by escarpments of variable relief. Expansive clays, instead, are mainly formed in Meso-Cenozoic basins located in dryer areas along the coast. As a consequence, the smectite/kaolinite ratio is  1 in arid southern Angola, decreases rapidly in the semiarid Benguela region, and is very low in the more humid north with the exception of muds carried by the Longa, Cuanza, and Bengo rivers cutting across the Meso-Cenozoic Cuanza basin in their lower course. 2.5. River systems Apart for the Congo (4,000,000 km 2 , length 4700 km), the largest Angolan rivers draining into the Atlantic Ocean are the Cunene ( 110,000 km 2 ,  1050 km) and the Cuanza ( 150,000 km 2 ,  960 km). The Longa, Queve, Curoca, and Mebridege are  300 km-long and drain  20,000 km 2 each; the Catumbela and Coporolo are 200-250 km-long and drain  15,000 km 2 (Fig. 1B). Of similar length are the Loge, Dande, Bengo, and Bero, which also drain more than 10,000 km 2 each, and another dozen ephemeral rivers draining between 2000 and 7000 km 2. Three major rivers are sourced in the very same area between the cities of Huambo and Katchiungo at  1800 m a.s.l. on the dynamically uplifted Bié-Huila dome: the Queve draining northward, the Cunene draining southward, and the Cubango branch of the Okavango draining southeastwards across the Kalahari (Fig. 1). The Cuanza is instead sourced in the Kalahari and flows northwards around the Angola Block. These river courses may have formed soon after opening of the South Atlantic, although the modern configuration with radial drainage of the Biè-Huila dome was acquired much more recentl...

show abstract

Section: Syn-rift To Post-rift Volcanic Rocksmentioning

confidence: 99%

Dynamic uplift, recycling, and climate control on the petrology of passive-margin sand (Angola)

Garzanti

Dinis

Vermeesch

et al. 2018

Sedimentary Geology

View full text Add to dashboard Cite

show abstract

“…1) (Marzoli et al, 1999). Similar Sr-Nd isotope compositions for Catanda lavas, the 116-133 Ma Lunda Norte kimberlites (Castillo-Oliver et al, 2016) and Cretaceous carbonatites (Alberti et al, 1999) in the Lucapa corridor ( Fig. 1) may indicate that Cretaceous kimberlites and carbonatites, and Pleistocene Catanda carbonatite-aillikite magmas have tapped similar (convective) mantle sources.…”

Section: Discussionmentioning

confidence: 93%

“…Major structural features of the East Africa Rift System (EARS) are from Chorowicz (2005). Inset shows location of the Catanda Complex, Lucapa Corridor, Kwanza seamounts, and major Triassic and Cretaceous kimberlite, carbonatite and alkali basalt occurrences (Marzoli et al, 1999;Jelsma et al, 2013;Castillo-Oliver et al, 2016). Grey shaded area indicates free-air, crust-corrected positive gravity anomaly above 15 mGal (after Forte et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

Southwestern Africa on the burner: Pleistocene carbonatite volcanism linked to deep mantle upwelling in Angola

Giuliani

Campeny

Kamenetsky

et al. 2017

Geology

Self Cite

View full text Add to dashboard Cite

The origin of intraplate carbonatitic to alkaline volcanism in Africa is controversial. A tectonic control, i.e., decompression melting associated far-field stress, is suggested by correlation with lithospheric sutures, repeated magmatic cycles in the same areas over several Myr, synchronicity across the plate, and lack of clear age progression patterns. Conversely, a dominant role for mantle convection is supported by the coincidence of Cenozoic volcanism with regions of lithospheric uplift, positive free-air gravity anomalies and slow seismic velocities. To improve constraints on the genesis of African volcanism, here we report the first radiometric and isotopic results for the Catanda complex, which hosts the only extrusive carbonatites in Angola. Apatite (U-Th-Sm)/He and phlogopite 40Ar/39Ar ages of Catanda aillikite lavas indicate eruption at ~500-800 ka, >100 Ma after emplacement of abundant kimberlites and carbonatites in this region. The lavas share similar HIMU-like Sr-Nd-Pb-Hf isotope compositions with other young mantle-derived volcanics from Africa (e.g., Northern Kenya Rift; Cameroon Line). The position of the Catanda complex in the Lucapa corridor, a long-lived extensional structure, suggests a possible tectonic control for the volcanism. The complex is also located on the Bié Dome, a broad region of fast Pleistocene uplift attributed to mantle upwelling. Seismic tomography models indicate convection of deep hot material beneath regions of active volcanism in Africa including a large area encompassing Angola and northern Namibia. This is strong evidence that intraplate late-Cenozoic volcanism, including the Catanda complex, resulted from the interplay between mantle convection and pre-existing lithospheric heterogeneities. only notable exceptions are Late Cretaceous and Paleogene alkaline volcanic centers in southern Namibia, possibly related to the passage of hot spots currently in the South Atlantic (Reid et al., 1990). Regions of active and recent volcanism coincide with some of the several swells (i.e., topographic highs) that characterize the surface morphology of the African continent (e.g., Burke, 1996). These zones are characterized by positive free-air gravity anomalies (e.g., Burke, 1996; Al-Hajri et al., 2009) and slow seismic velocities in the mantle (e.g., Forte et al., 2010; French and Romanowicz, 2015), suggesting that sublithospheric convection plays a significant role in sustaining the high topography of the swells and triggering intraplate volcanism (Fishwick and Bastow, 2011). With evidence for tectonic, lithospheric and convective controls, the ultimate trigger(s) of mantle-derived Cenozoic intraplate volcanism in Africa remains unresolved. To contribute to this discussion, we report the first geochronological and radiogenic isotope results for aillikite (i.e., carbonate-rich ultramafic lamprophyre) lavas from the Catanda volcanic complex in central Angola (Fig. 1 and Fig. DR1 inSupplementary Material). This complex also includes the only extrusive carbonatites documented in Ango...

show abstract

“…It commonly crystallizes directly from the kimberlite magma [40]. Therefore, pristine primary perovskite grains in both kimberlites and carbonatites are often used for geochemical investigations and, in particular for U-Pb dating [5,6,10,12,13,[16][17][18][19][20][21]41,42]. However, it has been proved that different perovskite generations can occur in the same kimberlite.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, Ti-rich oxides from kimberlite groundmass, such as Ti-rich spinel [3] and perovskite [4], could supply information about the evolution of kimberlitic magmas. Finally, perovskite [5,6] and rutile [7,8] could also be used to determine the kimberlite emplacement age. However, in many cases these minerals undergo complex alteration processes during the hydrothermal or supergene late stages of the kimberlite crystallization sequence that could disturb the petrogenetic interpretations based on geochemical data.…”

Section: Introductionmentioning

confidence: 99%

Styles of Alteration of Ti Oxides of the Kimberlite Groundmass: Implications on the Petrogenesis and Classification of Kimberlites and Similar Rocks

Melgarejo

Castillo-Oliver

2018

Minerals

Self Cite

View full text Add to dashboard Cite

The sequence of replacement in groundmass perovskite and spinel from SK-1 and SK-2 kimberlites (Eastern Dharwar craton, India) has been established. Two types of perovskite occur in the studied Indian kimberlites. Type 1 perovskite is found in the groundmass, crystallized directly from the kimberlite magma, it is light rare-earth elements (LREE)-rich and Fe-poor and its ∆NNO calculated value is from −3.82 to −0.73. The second generation of perovskite (type 2 perovskite) is found replacing groundmass atoll spinel, it was formed from hydrothermal fluids, it is LREE-free and Fe-rich and has very high ∆NNO value (from 1.03 to 10.52). Type 1 groundmass perovskite may be either replaced by anatase or kassite along with aeschynite-(Ce). These differences in the alteration are related to different f (CO 2) and f (H 2 O) conditions. Furthermore, primary perovskite may be strongly altered to secondary minerals, resulting in redistribution of rare-earth elements (REE) and, potentially, U, Pb and Th. Therefore, accurate petrographic and chemical analyses are necessary in order to demonstrate that perovskite is magmatic before proceeding to sort geochronological data by using perovskite. Ti-rich hydrogarnets (12.9 wt %-26.3 wt % TiO 2) were produced during spinel replacement by late hydrothermal processes. Therefore, attention must be paid to the position of Ca-Ti-garnets in the mineral sequence and their water content before using them to classify the rock based on their occurrence.

show abstract

Trace-element geochemistry and U–Pb dating of perovskite in kimberlites of the Lunda Norte province (NE Angola): Petrogenetic and tectonic implications

Cited by 36 publications

References 48 publications

Dynamic uplift, recycling, and climate control on the petrology of passive-margin sand (Angola)

Dynamic uplift, recycling, and climate control on the petrology of passive-margin sand (Angola)

Southwestern Africa on the burner: Pleistocene carbonatite volcanism linked to deep mantle upwelling in Angola

Styles of Alteration of Ti Oxides of the Kimberlite Groundmass: Implications on the Petrogenesis and Classification of Kimberlites and Similar Rocks

Contact Info

Product

Resources

About