video record
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Description
The programme compares the composition of the Earth's upper mantle, oceanic and upper and lower continental crusts. It goes on to look at the structure and composition of the continental crust bene...ath Scotland.
Metadata describing this Open University video programme
Module code and title: S237, "The Earth, structure, composition and evolution"
Item code: S237; 03
First transmission date: 28-03-1981
Published: 1981
Rights Statement:
Restrictions on use:
Duration: 00:24:00
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Producer: Barrie Whatley
Contributors: Stephen Drury; Sandie Smith
Publisher: BBC Open University
Keyword(s): Continental crust; Feldspar; Garnet; Mica; Mineral; Oceanic crust; Olivine; Pyroxene; Seismic refraction; Upper mantle
Footage description: Over shots of a cut-away model of the Earth which shows its layer structure, Sandy Smith introduces the programme. Steve Drury explains, with the aid of a model, why samples of continental and oceanic crust as well as upper mantle materials can be obtained fairly easily at the surface. To illustrate the differences which are found in the materials of the different layers of the earth, Steve Drury looks at specimens from each. Accompanying animated tables give their respective mineral compositions. The samples are granite, granulite, gabbro and peridotite. Drury goes on to discuss the silicon and magnesium content of the rock specimens above. Again animated tables are used to illustrate the propertions found in each. Drury next looks at the less abundant elements found in the rock speciments above, in particular nickel and potassium contents. Thin sections and a bar chart are shown. Pointing to a topographical model of Scotland which shows a simplified version of the surface geology, Sandy Smith introduces the second part of the programme which will be continued in TV 4 and deals with the structure and composition of the continental crust beneath Scotland. Steve Drury explains and demonstrates a technique, seismic refraction, which was used to survey the sub-surface geology of Scotland in 1974 (the LISPB Survey). Sandy Smith joins in. Shots of the topographical model of Scotland and animated diagrams illustrate their points. Sandy Smith uses the topographical model of Scotland to point out the velocity structure found in the LISPB Survey to the north of the Southern Uplands Fault, In order to see what these layers look like, Steve Drury visits an outcrop where the 6 km. per second layer reaches the surface. He identifies the rocks as metamorphic sandstone and classifies them as part of the Caledonian orogeny. Steve Drury demonstrates a field instrument which analyses the radioactive isotopes found in the rocks. He uses it for a geochemical analysis of the Caledonian metamorphosed rocks above. Sandy Smith briefly summarises the programme. Credits.
Production number: FOUS161S
Videofinder number: 1590
Available to public: no