Hamilton explains that while Continental Lithosphere is as much as 93 miles thick, the "Oceanic Lithosphere" is much thinner - up to perhaps six miles. Indeed, the oceanic crust makes up only 0.099% of earth's mass, according to Hamilton. Oceanic lithosphere is a product of the volcanic magma that pushes up to force tectonic plates aside. As new oceanic lithosphere is actually formed the heat that comes up with the magma "escapes the interior as this new lithosphere emerges from below" in the Red Sea and elsewhere where there are tectonic plates spreading.
As the lithosphere cools, it contracts and then "moves away from the ridge, traveling across the seafloor to subduction zones." This process is technically called "seafloor spreading." After the lithosphere has been on the Red Sea floor for a while, it thickens up, Hamilton writes, and as it becomes even denser than the mantle just below it, it sinks into the earth (called "subduction") at a "steep angle" which cools the interior below the tectonic plates.
As a side note to undersea spreading, Hamilton mentions that as a rule all continents drift laterally along the "...convecting system of the mantle away from hot mantle zones toward cooler ones"; this is called continental drift, and "most" continents are either moving toward cooler parts of the mantle of earth. Or they are sitting on a cooler part of the earth's mantle. Africa is the one exception to this geologic rule, Hamilton continues. Africa was at one time - several hundred million years ago - the "core" of Pangaea, the "supercontinent" that broke into the continents that make up the earth's main land masses today.)
Meantime, the New York Times reported in 1987 that information about the spreading of sea floors is easier to come by thanks to "remote-controlled instruments and a new generation of manned deep-diving vessels." These technological developments have helped - and will continue to help - scientists learn more about how oceans and continents are being split apart. The training for proper use of these technologies was given in the late 1980s to 3,500 scientists from 78 countries; during the training session it was projected by Rodey Batiza of Northwestern University that they may be "a million volcanic mountains on the floor of the Pacific Ocean," most directly related to tectonic plate movement and magma surging upwards.
Among the 3,500 scientists there was "wide agreement" that the energy that is pushing the tectonic plates apart under seas and oceans comes "chiefly from the heat of radioactive decay inside the earth." Moreover, two scientists (Dr. R.W. Girdler of the University of Newcastle-upon-Tyne in England and P.R.K. Simpson) stated that magnetic instruments have indicated that the Africa plate and Arabian plate are "an unusual case" in which a "sea-floor spreading penetrates deep into a continent" (more on this topic will be discussed later in the paper).
This article was written, and the conference was held, well before the confirmation of the split under the Red Sea; still, at the time of the conference the scientists reported that the rift under the Red Sea was spreading at the rate of "about one inch per year"; and the rifting continues north through the gulf of Aqaba into the Dead Sea rift valley; that spreading rate is only have of the rate under the Red Sea.
RED SEAFLOOR RUPTURING: RECENT RESEARCH
The National Sciences Foundation (NSF) (Fall, 2006) MARGINS Newsletter No. 17, reports on the rupturing continental lithosphere dynamics in the northern and central Red Sea. In the narrative references are made to a recent an initiative launched to better understand "continental expansion" and how that transcends into ocean spreading. In this report - with data gathered from scientists from Massachusetts Institute of Technology, Penn State University and the University of Kansas - scientists explain that before studying the rupturing issues beneath the seafloor of the Red Sea, logistical and political issues had to be ironed out. The scientific collaborations that had been planned for this project - with scientists from Egypt, Sudan, Jordan, Eritera, and Saudi Arabia, were not workable.
Unfortunately due to the current security situation and political climate in the Middle East, the NSF...could not longer consider U.S.-led marine geophysical experiments in the Red Sea at this time" (Reilinger, 2006). This political dilemma sheds light on the fact that there is a great deal of tension, first, between the Muslim states in the Middle East and the West in general, and secondly, the United States is engaged in a controversial war in Iraq - and the U.S. supports Israel of course - which contributes to the deep rift (not unlike the tectonic rift beneath the Red Sea) between the Arab / Muslim states and U.S. And unfortunately, science becomes involved even though the empirical studies proposed for the Red Sea had nothing whatsoever to do with politics or gathering intelligence.
Still several aspects of the geophysical dynamics under the Red Sea are explored in the 2006 NSF report, based on significant research conducted prior to the Red Sea region (not just the sea but the surrounding and bordering territories) being designated an "ancillary site." The beginning of the separation of the Arabia from the Nubia (African tectonic plate) is believed to have happened in the Miocene epoch. This separation was a kind of "counterclockwise rotation of Arabia relative to Nubia," Reilinger et al. report.
That counterclockwise rotation continues to this day, the report explains, and it directly results in "increasing spreading rates" and also a "total extension from north to south" in the Red Sea. The scientists in this report characterize the spreading as "characterized by the early stages of continental breakup." The mid-ocean ridge and the magnetic anomalies associated with the ridge is so well developed, the report continues, that it has become "an ideal location to study the transition from rupturing continental lithosphere to full ocean spreading."
Also included in the MARGIN Newsletter No. 17 (Fall 2006) is a report by scientists (Stocki, et al., 2006) that points out there has been "Limited knowledge of how extensional strain is spatially and temporally distributed along the continental margins" of the rift under the Red Sea. That is to say, the story of how the rift technically and specifically took place has been hampered by the "scarcity of datable...volcanic rocks," and the gathering of this information has been hampered by fact that the "post-rift sedimentary rocks" are buried deeply with the rift.
Meanwhile, the Saudi Arabian Geological Survey has cooperated with the National Science Foundation (notwithstanding the prevention [because of political tensions] of addition research into the Red Sea mentioned earlier in this paper) to launch a "comprehensive low-temperature thermochronometric investigation...to determine the timing, origin, and geometry of extensional faulting and rift flank exhumation." This research was done primarily along the central and northern portion or the Red Sea that is actually within the territory of Saudi Arabia.
This is important, recent research, and the report indicates that more than 400 samples were taken (thermochronometric samples) to attempt to solve the puzzle of when the faulting (rifting) actually occurred. The results of those samples have not been released, but the detailed narrative that describes the process and the importance of this science adds to the theme of this paper that indeed the seafloor and its rifting beneath Red Sea is one of the most fascinating and important geological resources on the planet.
RED SEA HYDROTHERMAL PROCESSES: LINK to LIFE & LINK to MARS
The study of the Red Sea's hydrothermal dynamics - processes that occur as a result of the spreading of the seafloor and continue within the process of rifting / spreading - is proving to be useful as scientists study the history of the planet Mars. According to an article in the Australian Journal of Earth Sciences (Pirajno, et al., 2005), of all the tectonic plates on earth that might be somewhat similar to the "one-plate" geologic formation on Mars, the African plate is the "closest analogue" to Mars. Indeed, Africa has been "stationary" for about 65 million years, Pirajno writes on page 348 of his journal article. That length of time in one fairly stationary place among the planet's plates means for science that the crustal uplifts, the rifts and the "intraplate volcanism have not been recycled by convergent margin tectonics." And that fact would help scientists in their research on why Mars went from a planet with plenty of rivers and oceans and likely some form of life to a hot, dry, wasteland as it is today.
The East African Rift System, Pirajno continues, could well be an "analogue for the great rift system of Valles Marineris on Mars." Finding an example on earth that matches up well with what astrophysicists and geologists believe to be a great rift system on Mars allows the research related to…