Reconstructing the level of the central Red Sea evaporites at the end of the Miocene

Mitchell, Neil C.; Shi, Wenyu; Izzeldin, A.Y.; Stewart, Ian

doi:10.1111/bre.12513

Cited by 19 publications

(13 citation statements)

References 166 publications

(363 reference statements)

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“…The transition coincides with changes in crustal seismic velocities (Tramontini and Davies 1969;Davies and Tramontini 1970;Egloff et al 1991). Symmetrical pairs of anomalies, which are indicative of oceanic crust (Hall, 1989), can be observed around the central Red Sea spreading axis to about this transition, thus dating it at 10 Ma (Mitchell et al 2021;Okwokwo et al 2022). However, those anomalies vary in spatial frequency, with high-frequency anomalies typical of normal seafloor spreading present to ~5 Ma but much smoother, low-frequency anomalies on crust older than 5 Ma.…”

Section: Introductionsupporting

confidence: 52%

Oceanic basement roughness in the central Red Sea

Shi,

Mitchell,

Kalnins

et al. 2024

Rifting and Sediments in the Red Sea and Arabian Gulf Regions

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The Red Sea is a rare example of a continental rift proceeding to an oceanic basin. In the central Red Sea, the transition to oceanic spreading appears to have occurred at ~10 Ma, but unusually low frequencies of magnetic anomalies suggest that spreading may have occurred in spreading centres that were buried beneath the evaporites before ~5 Ma. We continue our investigation of this area by assessing the basement roughness (the root-mean-square variation of basement relief) along profiles across and parallel to the spreading axis. The across-axis roughness can be compared with that of typical abyssal hill topography formed by faulting and volcanism, whereas the axis-parallel roughness can be compared with variations due to the ridge segmentation.We estimated roughness values from depths of basement interpreted from acrossridge seismic reflection profiles. The best estimate of mean across-ridge roughness of 230 m overlaps with, but is generally smaller than, those observed over ultraslow spreading ridges, consistent with a ridge affected by a hotspot (here the Afar), which typically leads to smaller fault relief. Basement roughness values along ridge-parallel profiles were computed from the free-air gravity field using densities appropriate for oceanic crust and a modified Bouguer slab formula, since suitable ridge-parallel seismic profiles are not available. Errors arising from the slab approximation were investigated using forward 2D modelling and found to be ~30%. Correcting for this bias leaves roughness values within the range of values for the ultra-slow spreading Southwest Indian Ridge, which appears organised into segments due to magmatism concentrated at segment centres. Such an organisation has been suggested for the central Red Sea previously based on the segmented structure of gravity anomalies.The axis-parallel roughness values reach minima roughly mid-way between the coast and the axial trough, where the suggested transition from stretched continental to predominantly oceanic crust occurs. The basement relief due to ridge segmentation therefore appears to have grown gradually since continental breakup.

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Section: Introductionsupporting

confidence: 52%

Oceanic basement roughness in the central Red Sea

Shi,

Mitchell,

Kalnins

et al. 2024

Rifting and Sediments in the Red Sea and Arabian Gulf Regions

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“…From the stable ANS to the plate boundary, the Red Sea rift (Fig. 1a) is composed of 1) a coastal plain bounded by the external rift escarpments and underlain by tilted blocks and their accompanying syn-rift sediments 16 , 2) a smooth offshore shelf marked by a gradually increasing elevation toward the SSE 18 , and whose basement is blanketed by more than 1 km of Miocene evaporites 23,24,25 , and 3) a discontinuous 15-70-km-wide axial trough, essentially restricted to the Southern and Central Red Sea, where the oceanic crust and its rugged volcano-tectonic sea-floor are exposed except at the socalled "inter-trough zones" occupied by allochtonous salt flows 26,27,28,29 .…”

Section: Geological Backgroundmentioning

confidence: 99%

Persisting influence of continental inheritance on early oceanic spreading

MOULIN,

Jonsson

2024

Preprint

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Formation of new lithosphere at mid-oceanic ridges occurs through magmatic crustal accretion and cooling of the asthenosphere, and is essentially controlled by the spreading-rate, ridge segmentation, and eventual arrival of deeply-sourced hot mantle plumes. Its dependence on long-term inheritance is supposedly weak, except in cases where ridge segmentation is preconditioned by the reactivation of continental weak zones during the rifting phase. Here, we provide the first evidence that pre-rift lithospheric thickness variations constitute another forcing that may transmit influence from past Wilson cycles beyond the stage of continental break-up. This long-term control involves differential redistribution of heat/melt sources along young laterally-confined plume-assisted rifts. This is demonstrated here in the case of the Red Sea from the correlation between on-axis volcano-tectonic patterns, distribution of onshore volcanism, and lithospheric thickness variations of the rifted margins.

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“…The Red Sea widens at spreading half-rates that range from ~8.5 mm/yr in the south to <5 mm/yr in the north (Chu and Gordon, 1998 ArRajehi et al, 2010). Seafloor spreading, basement subsidence, and overburden loading have caused creep and extensive distortion of the evaporites over the younger oceanic basaltic crust since the earliest halite deposition (Guennoc et al, 1988;Heaton et al, 1995;Mitchell et al, 2021). Thick salt glaciers creep towards the central rift axis, and the front defines an escarpment several hundred meters high (Feldens and Mitchell, 2015).…”

Section: Rift Basin Evolution and Evaporite Depositionmentioning

confidence: 99%