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The submarine Azores Plateau: Evidence for a waning mantle plume?

Beier C, Genske F, Huebscher C, Haase K, Bach W, Nomikou P (2022)

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Publication Type: Journal article

Publication year: 2022

Journal

Book Volume: 451

Article Number: 106858

DOI: 10.1016/j.margeo.2022.106858

Abstract

The submarine Azores Plateau in the Central Northern Atlantic has generally been considered to represent a large igneous plateau formed some 10 Ma by widespread volcanism, however a lack of age progression amongst the younger submarine and subaerial volcanism, an irregular distribution of platform-related magmas east and west of the Mid-Atlantic Ridge, a strong tectonic stress regime, and a lack of abundant tholeiitic compositions that reflect initial, high degrees of melting is not easily explainable in the framework of a classic, long-lived mantle plume model. Here, we present new bathymetric and seismic data from the submarine Azores Plateau obtained during cruises M113/1 and M128 with the German R/V Meteor. Our new data combined with prior geochemical and petrological studies indicate that the majority of the western Azores Plateau may indeed have formed during the arrival of a short-lived mantle melting anomaly at 10 Ma. However, our new data also indicate that volcanism <2 Ma is extremely localized and along structural features that result from plate reorganisation in the vicinity of the diffuse triple junction of the Eurasian, Nubian and North American plates, and that much of the easternmost Azores Plateau is magmatically inactive. Our model implies not only that the actual flood basalt province of the Azores is only some 30% of what has been previously estimated but may not have formed from a typical large-scale, long-lived mantle plume. Instead, excess melting as evident from the anomalously shallow water depth and the presence of islands in the Azores may be the result of a volumetrically small-scale melting anomaly in the upper mantle which is in its waning stages as evident from the localised distribution of magmatic activity at <1 Ma. Our model also solves the conundrum of a potential asymmetry of the recent submarine and subaerial volcanism both east and west of the Mid-Atlantic Ridge which instead is the result of an interacting upper mantle anomaly and the complex plate tectonic domain in the vicinity of the triple junction of the Eurasian, Nubian and North American plates.

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How to cite

APA:

Beier, C., Genske, F., Huebscher, C., Haase, K., Bach, W., & Nomikou, P. (2022). The submarine Azores Plateau: Evidence for a waning mantle plume? Marine Geology, 451. https://dx.doi.org/10.1016/j.margeo.2022.106858

MLA:

Beier, Christoph, et al. "The submarine Azores Plateau: Evidence for a waning mantle plume?" Marine Geology 451 (2022).

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