What is it about?
At mid-ocean ridges, movements on faults and elongated volcanic ridges has affected Earth's surface, leaving a washboard-like topography. This can be seen in Google Earth, for example. Some ridges and valleys run parallel to the spreading centres. These are abyssal hills formed by normal faults and volcanic ridges formed by eruption over dykes (much like the recent eruption on Iceland's Reykjanes Peninsula. Another set of valleys runs perpendicular to the abyssal hills, formed where the transform faults and other features offset the spreading ridge. How then does this process start off shortly after when continents rift to form new ocean basins? The ruggedness of the crust underlying the sediments of the Red Sea is partly revealed by the Earth's gravity field, which has now been worked out to better than 10 km resolution thanks to work with radar altimeters on satellites (water flows downhill to where the attraction is strongest). In the central Red Sea, this has revealed that the crust is segmented, much like other spreading ridges. However, that segmentation disappears about half way between the mid-line of the Red Sea and the coasts. We hypothesize that this is where new oceanic crust started to form.
Featured Image
Photo by Blind Rhino Media on Unsplash
Why is it important?
This forms part of growing evidence that the transition between stretched continental crust and the newer oceanic crust lies mid-way between the spreading centres and the coasts on either side.
Perspectives
The study was prompted by the work of Walter Smith and David Sandwell in inverting marine gravity anomalies for the topography of the seabed, a result that is now incorporated in Google Earth and other maps of the oceans. The inversion works if there is one important density interface that affects the gravity field and if there are some echo-soundings to derive the relationship (between gravity anomaly and water depth). In the case of the Red Sea, the basement below the Miocene evaporites and the seabed appear to be the most important interfaces. The article can be accessed here or by request from the authors. Shi, W., Mitchell, N.C., Kalnins, L.M., Stewart, I.C.F. and Izzeldin, A.Y., in press. Oceanic basement roughness in the central Red Sea In: N.M.A. Rasul and I.C.F. Stewart (Editors), Rifting and sediments in the Red Sea and Arabian Gulf regions. Taylor & Francis Ltd.
Dr Neil C. Mitchell
University of Manchester
Read the Original
This page is a summary of: Oceanic basement roughness in the central Red Sea, March 2024, Taylor & Francis,
DOI: 10.1201/9781003321415-11.
You can read the full text:
Contributors
The following have contributed to this page
