Available online
Description
The programme looks at some of the evidence supporting the concept of sea floor spreading.
The programme looks at some of the evidence supporting the concept of sea floor spreading.
| Module code and title: | S101, Science: a foundation course |
|---|---|
| Item code: | S101; 07 |
| First transmission date: | 10-04-1979 |
| Published: | 1979 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:00 |
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| Producer: | Patricia McCurry |
| Contributors: | Geoff Brown; Chris Wilson |
| Publisher: | BBC Open University |
| Keyword(s): | Mid Atlantic ridge; Tectonic plates |
| Subject terms: | Basalt; Iceland; Lava |
| Footage description: | Film of Icelandic landscape. Geoff Brown, sitting on a rock, introduces the programme. He points out some of the features around him, a rift valley, horizontal displacement of ocean crust, etc. Film shots of the volcano which erupted Out of the sea at Surtsey in 1963. More shots of Icelandic landscape, of Reykjavik and of a hot water open air swimming pool. Geoff Brown, swimming in the pool, describes the origins of the hot springs and how they are exploited. Brown goes on to examine closely some of the pillow lavas on the Reykjanes peninsula. With the aid of animations, a model, and an event epoch chart, Geoff Brown examines magnetic anomalies of the Reykjanes ridge. He explains how these can be used to date the production of ocean floor material and goes on, briefly, to explain how sea floor spreading is caused by the production of new crust brought up from the magma along ocean ridges. Using a globe and several animations to illustrate his points, Chris Wilson examines the geometry of the Mid-Atlantic ridge and its associated transform faults. He demonstrates that the transform faults lie along small circles about a pole of rotation defined by the intersection of great circles at right angles to the faults. Wilson points out the pole of rotation for the spreading of the South Atlantic Ocean. Chris Wilson goes on to describe the distribution and movement of the earth's tectonic plates. With the aid of animated diagrams he explains what is meant by a destructive margin. He cites examples where plates of unequal and of equal density meet and explains the effects. Finally, he points out what happens when there is continent to continent collision. Shots of the Himalayas. |
| Master spool number: | 6HT/72877 |
| Production number: | 00525_1337 |
| Videofinder number: | 1182 |
| Available to public: | no |
