Magmatic evolution during proto-oceanic rifting at Alu, Dalafilla and Borale Volcanoes (Afar) determined by trace element and Sr-Nd-Pb isotope geochemistry

Watts, Emma J.; Gernon, Thomas M.; Taylor, Rex N.; Keir, Derek; Pagli, Carolina

doi:10.1016/j.lithos.2023.107311

Cited by 2 publications

(1 citation statement)

References 69 publications

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“…This is consistent with S-P receiver function studies which image a weak LAB beneath Afar at ∼70 km depth (Lavayssiere et al, 2018). The range of depths for the LAB suggested by seismic imaging is broadly consistent with petrological modeling which suggest the top of the Afar melt zone, and by implication the LAB, is at ∼65-85 km depth (Ferguson et al, 2013;Watts et al, 2023). Figures 3b-3e shows the reference model for the evolution of linkage between the DMH and ASAL segments.…”

Section: Geodynamic Model Setupsupporting

confidence: 85%

To Rotate or to Link? The Connection Between the Red Sea and Gulf of Aden Rifts in Central Afar

Muluneh,

Brune,

Pagli

et al. 2024

Geophysical Research Letters

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Central Afar is shaped by the interaction between the Red Sea (RS) and Gulf of Aden (GoA) rifts. While there have been several studies conducted in the region, we know surprisingly little about the mechanism of connection between these two rift branches. Here we use high‐resolution 3D lithospheric scale geodynamic modeling to capture the evolution of linkage between the RS and GoA rifts in central Afar. Our results demonstrate that the two rifts initially overlap and interact across a broad zone of faulting and vertical axis block rotation. However, through time, rift overlap is abandoned in favor of direct linkage which generates a series of localized en‐echelon basins. The present‐day direct linkage between the two rifts is supported by geodetic observations. Our study reconciles previously proposed models for the RS and GoA rift connection by considering spatial and temporal evolution of the rifts.

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Section: Geodynamic Model Setupsupporting

confidence: 85%

To Rotate or to Link? The Connection Between the Red Sea and Gulf of Aden Rifts in Central Afar

Muluneh,

Brune,

Pagli

et al. 2024

Geophysical Research Letters

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Protracted Magma Evolution and Transcrustal Magmatic Plumbing System Architecture at Erta Ale Volcano (Afar, Ethiopia)

Pin,

Chazot,

France

et al. 2024

Journal of Petrology

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The Afar region is one of the only places on Earth where magmatic continental rifting and associated ongoing break-up processes are exposed onshore. The several active magmatic segments there are characterized by contrasted morphologies, crustal thicknesses, magma production rates, and magma-tectonic styles. In the Erta Ale Range rift segment, extension is magmatically accommodated, making the range the ideal place to study the magmatic behavior of a mature rift segment. Erta Ale Range comprises sub-segments with magma compositions ranging from basalts to rhyolites, but only the Erta Ale Volcano (EAV) sub-segment is active, where only basaltic compositions have been reported so far. Here, we show for the first time protracted differentiation at EAV that is not expressed volcanically at the surface, but is rather accessible via unique cognate gabbroic and microgabbroic blocks, and recorded by mixing with erupted basaltic magmas. These cognate samples record previously unknown mushy and evolved parts of the EAV plumbing system. To constrain their origin and evolution, we measured the major and trace element compositions of the bulk rocks, interstitial glasses, and melt inclusions. We also measured the oxygen isotopic compositions of olivine crystals, interstitial glasses, and melt inclusions. By combining these results with textural relationships and oxy-thermo-barometry calculations, we discuss magma differentiation and storage conditions, as well as magmatic interactions during transport through the crust. Comparison of our results with rhyolite-MELTS thermodynamic models highlights that protracted fractional crystallization is the main process of magma evolution, and when associated with reactive porous flow is capable of forming the evolved compositions observed (up to 75 wt.% SiO2). We also use the model outputs to quantify distinct steps of igneous differentiation in both shallow and deep crustal reservoirs, and we highlight significant interactions with hydrothermally altered wall rocks. We discuss this model within the geological contexts of the Erta Ale Range rift segment and the larger Afar region, and highlight contrasts with mature oceanic systems to argue that the region is not in the final stages of continental break-up.

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Magmatic evolution during proto-oceanic rifting at Alu, Dalafilla and Borale Volcanoes (Afar) determined by trace element and Sr-Nd-Pb isotope geochemistry

Cited by 2 publications

References 69 publications

To Rotate or to Link? The Connection Between the Red Sea and Gulf of Aden Rifts in Central Afar

To Rotate or to Link? The Connection Between the Red Sea and Gulf of Aden Rifts in Central Afar

Protracted Magma Evolution and Transcrustal Magmatic Plumbing System Architecture at Erta Ale Volcano (Afar, Ethiopia)

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