video record
Media not available in the Digital Archive
Description
From cored samples of rocks and sediments retrieved from the deep ocean bed much can be learnt about the history of the oceans and the evolution of their basins. This is the prime function of the d...eep sea Drilling project (DSDP). This programme concentrates on one DSDP drill site in the Pacific Ocean. Site 167 situated on the Magellan rise, which was particularly rich in sediment. Using this site techniques for elucidating paleo-temperatures and for monitoring productivity in the geological past are demonstrated. By combining results from Site 167 with data from other sites a model of the evolution of the Pacific basin is touched upon.
Metadata describing this Open University video programme
Module code and title: S334, Oceanography
Item code: S334; 03
First transmission date: 1978
Published: 1978
Rights Statement:
Restrictions on use:
Duration: 00:24:00
+ Show more...
Producer: Andrew Crilly
Contributors: Ian Gass; Graham Jenkins; Mel Peterson; Nick Shackleton
Publisher: BBC Open University
Keyword(s): Calcium carbonate compensation depth; Glomar challenger; Magellan rise; Microfossils; Oxygen isotope method; Pacific; Palaeotemperatures; Planktonic organisms; Sediments; Deep sea drilling project
Footage description: Ian Gass, at the Core Repository, Scripps Oceanographic Institute, introduces the programme. Mel Peterson explains the purpose and origins of the Deep Sea Drilling Project. Shots of maps and of work being carried out on board Glomar Challenger as he talks. With the aid of animated diagrams, Ian Gass explains how deep sea sediments are built up from planktonic organisms. He goes on to explain the nature of the calcium carbonate compensation depth. Mel Peterson lists the particular objectives for the drilling of Leg 17. A large map of the Pacific is shown in the background as he talks. Peterson goes on to explain why one particular site, Site 167 on the Magellan Rise, was of special interest to researchers. Ian Gass lists some of the information which could be determined from an examination of the borehole cores of site 167. Graham Jenkins, with the aid of diagrams, list the chronology and rock unit types of a 1200 metre core from site 167. Pointing to large models of microfossils found in rock unit two of one of the cores, Jenkins discusses some of the planktonic life which was deposited there. Jenkins goes on to explain how an examination of microfossils can allow one to date various rock layers from ocean floor cores and to determine rates of sedimentation. Nick Shackleton, in his laboratory at Cambridge, describes the oxygen isotope method of estimating palaeotemperatures. He picks up various pieces of equipment and looks through an optical microscope as he talks. Shackleton goes on to demonstrate such an analysis. The temperature data over a period of time from a Site 167 core is shown on a graph. Graham Jenkins describes an alternative method for determining palaeotemperatures which involves the study of present-day planktonic foramonifera. Ian Gass, with a geological map of the Pacific Ocean floor, puts forward two possible environments in which the basalts at Site 167 could have been produced. Animated diagrams indicate that the Magellan Rise at Site 167 has characteristics of both types. Gass goes on to interpret the data discussed above. He uses a model which illustrates the 'hot-spot' (mantle plume) theory to track the possible route of the Magellan Rise back to an original position on the East Pacific Rise 135 million years ago. Animated diagrams (computer animation) help to illustrate his points. Gass next checks to see how his track of the Magellan Rise fits the sedimentological and palaeontological record. Graphs and an animation help to illustrate his points. Film shots of Glomar Chellenger leading into - Credits.
Master spool number: 6HT/72551
Production number: 00525_1295
Videofinder number: 504
Available to public: no