Available online
Description
This programme looks at the conflicting geological and geophysical evidence for the formation of the Red Sea and of other, older oceans.
This programme looks at the conflicting geological and geophysical evidence for the formation of the Red Sea and of other, older oceans.
| Module code and title: | S335, Surface and sedimentary processes: case studies in Earth sciences |
|---|---|
| Item code: | S335; 12 |
| First transmission date: | 23-09-1979 |
| Published: | 1979 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:00 |
| + Show more... | |
| Producer: | P. L Firstbrook |
| Contributors: | Ian Gass; Peter Styles |
| Publisher: | BBC Open University |
| Keyword(s): | Afar triangle; Geophysics; Heat flow; Magnetic anomalies; Pillow lavas; Sea-floor spreading; Sinker effect |
| Footage description: | Ian Gass introduces the programme. He points to a model of the Red Sea area as he talks. Gass briefly sums up the evidence which suggests that the entire marine area of the southern Red Sea is underlain by oceanic crust. Peter Styles discusses some of the geophysical evidence, particularly the magnetic anomolies which are present in the Red Sea. He uses graphs and diagrams to illustrate that there are two types of anomalies present. Going on to examine the magnetic anomolies more closely, Styles concludes that they indicate a two phase spreading of the Red Sea basin. Several graphs are shown to support this hypothesis. Ian Gass disputes the above hypothesis of a two phase spreading of the Red Sea basin. He suggests the possibility of a three phase spread based on volcanic evidence from the Afar triangle. A model of the area and a histogram illustrate his points. Peter Styles brieily defends his hypothesis. Pointing to a map of Europe and Africa at about 30 million years ago, Ian Gass discusses some of the evidence which throws light on why the continental plate split in the Red Sea Area rather than elsewhere. An animated diagram is also shown. Ian Gass briefly sums up the events which he thinks led up to the splitting of the continental plate in the Red Sea basin. Keith Cox tries to apply the mechanism which produced the Red Sea to explain why the older oceans, such as the Atlantic formed. He lists three main mechanisms and shows, with the aid of a map of the North Atlantic area, that the first mechanism, the location of younger weaker areas of crust, holds true here. Cox next shows that the "Sinker Effect" is not always an important factor in the splitting of continental plates. He goes on to discuss the third factor, subcontinental heating, as a possible general cause. Diagrams and a map illustrate his points. Keith Cox discusses an additional factor not obtained from studies of the Red Sea, that of compositional differences in the earth's mantle. Finally Cox summarises the various causative mechanisms which may have been responsible for the formation of the Red Sea and of other, older oceans. |
| Master spool number: | HOU3329 |
| Production number: | FOUS047Y |
| Videofinder number: | 2004 |
| Available to public: | no |
