Data di Pubblicazione:
2022
Citazione:
From rifting to oceanization in the Gulf of Aden: Insights from 2D numerical models / A. Bollino, A. Regorda, R. Sabadini, A.M. Marotta. - In: TECTONOPHYSICS. - ISSN 0040-1951. - 838:(2022 Sep 05), pp. 229483.1-229483.19. [10.1016/j.tecto.2022.229483]
Abstract:
We investigate the evolution of the Gulf of Aden from rift initiation to the development of active oceanic
spreading center by means of 2D thermo-mechanical numerical models, in which the formation of oceanic crust
and serpentinite due to the hydration of the uprising mantle peridotite has been implemented. Our analysis
highlights that evolution of the models is characterized by four main tectonic phases: a) a first phase (phase I)
characterized by low deformation rates throughout the divergent crustal blocks, except near the future ridge
where a high crustal velocity gradient generates an intense strain rates; b) a second phase (phase II) during which
the crust undergoes an intense, stable and widespread strain, with the localization of the thinning near the future
ridge that ends into crustal breakup c) a third phase (phase III) that characterizes the post- crustal breakup
evolution of the models during which a mechanical relaxation of the system and a continuum decreasing of the
strain rate can be observed, until the occurrence of lithospheric breakup, and d) fourth phase (phase IV) that lasts
up to the end of the evolution and during which the two continental blocks move rigidly. We also find that the
timing of mantle serpentinization is not affected by the initial thermal configuration of the lithosphere, but a
relationship with the crustal thickness can be observed. Rather, the timing of mantle partial melting strongly
depends on the initial thermal conditions of both the lithosphere and the crust. We constrain the crustal and
lithospheric thickness at 40 and 150 km, respectively, considering the timing of breakup that occurs 20 Myr after
the onset of the extension for 0.05% percentage of mantle hydration (in agreement with magma-poor rift
margins). Finally, model prediction supports the hypothesis that the Gulf of Aden developed as a slow passive rift
of a thin lithosphere with a thick crust and the variation of the features along the passive margins could be
related to a lateral variation in the amount of H2O in the mantle, which determines different timing in the mantle
melting.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
2D numerical modeling; Continental rifting; Oceanic spreading; Gulf of Aden
Elenco autori:
A. Bollino, A. Regorda, R. Sabadini, A.M. Marotta
Link alla scheda completa: