Available online
Description
The programme examines the evidence for the movement and collison of continents with a look at the youngest, of the collision zones, the Alpine Himalayan mountain chain. Evidence for an older colli...son zone, the Hercynian is also discussed towards the end of the programme.
The programme examines the evidence for the movement and collison of continents with a look at the youngest, of the collision zones, the Alpine Himalayan mountain chain. Evidence for an older colli...son zone, the Hercynian is also discussed towards the end of the programme.
| Module code and title: | S237, "The Earth, structure, composition and evolution" |
|---|---|
| Item code: | S237; 16 |
| First transmission date: | 10-10-1981 |
| Published: | 1981 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:25:00 |
| + Show more... | |
| Producer: | Stuart Carter |
| Contributors: | Geoff Brown; John Wright |
| Publisher: | BBC Open University |
| Keyword(s): | Alpine; Animation; Cornwall; Himalayan mountains; Lizard Peninsular; Oman; Pangaea; Plate tectonics; Sedimentary rocks; Tethys |
| Footage description: | John Wright, on a beach in Cornwall, introduces the programme. He points out the heavily folded sedimentary rocks in the cliffs behind him. Using a series of globes, Geoff Brown points out the areas of stable continental crust and also the two major areas of young mountain chains and recent volcanism. With the aid of a globe and an animated map of the world, Brown traces the movement of the continents over the past 200 million years. Using further animations, Brown traces the movement of the subcontinent of India over the same period. He points out that as it and the African continent collided with Eurasia the Alpine Himalayan chain was formed. With the aid of a world map showing ocean floor magnetic anomalies, Brown explains what the evidence is for the sequence of continental drift described above. With the aid of diagrams (some animated) Geoff Brown describes the upward thrusting of the sedimentary strata during the closure of Tethys and the building of the Alpine Himalayan chain. Over aerial shots.of the Swiss Alps, commentary points out some of the severe folding which took place during their formation. The deformation is so severe in places that older, darker rocks are found on top of younger, lighter rocks. Ian Gass, in the studio, explains how ophiolites (fragments of oceanic lithosphere) get emplaced into fold mountain belts. He looks at one particular ophiolite, the Oman ophiolite, which is the largest in the world. Graphs, diagrams and satellite photographs all help to illustrate his points. Gass continues with his explanation. He uses a model to illustrate how the Oman ophiolite formed. He goes on to explain how the location of the subduction zore in this area can be determined. The programme switches back to John Wright on a beach in Cornwall. Using a sketch pad, he indicates the location of an ancient fold belt, the Hercynian, which stretched from central Europe through Cornwall to North America. Wright looks at several outcrops in the area to illustrate how Alpine Himalayan features can be used to interpret an older continental collision zone like the Hercynian. Geoff Brown, in the studio, discusses the difficulty of determining even earlier continental collison zones. With the aid of a graph, he points to several other possibles which have been identified as far back as the Archaean. |
| Production number: | FOUS202R |
| Videofinder number: | 1606 |
| Available to public: | no |
