ARCHIVE PAPER Published in Jan/Feb 1973, Vol. 7, No. 1

Project FAMOUS Planning Mid-Atlantic Ridge Investigation

J. R. HEIRTZLER

A little more than 15 years ago it was realized that a seascape that is very different from that on land. the mid-ocean mountain, or ridge, is probably the largest physiographic feature on earth. In the last few years, The discovery of ridge axis activity resulted from the however, it has been discovered that this ridge system is an work of oceanographic research ships and by advances in active feature that moves the continents and seafloor as our understanding of earthquakes, many of which occur on great plates over the earth's surface and at surprisingly rapid or near the axis of the mid-ocean ridge. Although there are rates. Deep-earth material weUs up at the ridge axis and a few islands on or near the ridge axis they are not typical pushes the seafloor away from it. The forces involved are of the ridge beneath the deep sea and they cannot be used shaping the seafloor and are different from those forces to study most features. To make a detailed study of the shaping land features. This fact, taken with the fact that fundamental geologic processes occurring, an effort has erosive forces are also different on the seafloor will lead to recently been initiated by a group of oceanographic laboratories located around the Atlantic ocean shores.

Some of the questions that this group hopes to PROJECT FAMOUS S\JRVEY AND STUDY AREAS answer include: 30· 20· .w'W 45· -- ,~oo fATHOMS I) Is new material brought up to the seafloor ------1000 F'ATMOMS like volcanic material on land or is it emplaced in long linear features paralleling the axis of ridge? Are thermal springs created on the seafloor?

2) What is the nature of the new seafloor? What will laboratory analysis show of the fresh rocks and associated liquids and gases?

35· 3) What is the subbottom structure in the axis where a rift valley is found? What is the structure of the mountains bounding the valley and on out to the flanks of the ridge? PJsure I, Locadon of the main FAMOUS study area lIOuthor the Giant fracture zones cut the ridge. Is the Al:orea. A secondary area has been designatecl north or the Azores ir weather Is UJlfavorable in the prime area. Some of the other areas structure near these different than else- which have been studied are indicated. where?

Summer 2006 Volume 40, Number 2 65 ~ 4) What determines the distribution of thin From the inception of this program it was felt that sediment cover near the ridge axis? Are the submersibles would need to be employed for visual observa· concentrations of heavy metals, occasionally tion, detailed mapping of land forms and accurate sampling. found on the mid-ocean axis, the by- Accordingly plans were made for three main efforts: product of special geologic processes active there? a) Surveys, including those made by surface ships and deep towed devices. These and other questions relating especially to the Mid-Atlantic Ridge were discussed by a group of scientists b) Training for diving personnel, i.e., both at a National Academy of Sciences workshop held in scientists and pilots, on land and on pre- January, 1972. Key research programs were recommended ridge dives. to solve some of the major questions. c) Dives on the ridge which would be of a In early 1971 French and American scientists had preliminary nature in 1973 but full scale in begun discussions for a detailed study of the Mid-Atlantic 1973. Ridge. The project was called Project FAMOUS for French-American Mid-Ocean Undersea Study. It seemed The surveys are planned to learn as much as possible important that a fair weather portion of the Mid-Atlantic about the area before the more expensive and complex Ridge be selected and that this area be near a port so manned submersibles are utilized. To this end a series of manned submersibles could be used. An area at approxi- mapping projects is being undertaken to lead the scientist mately 36°N (Figure 1) was tentatively selected and the from a regional picture down to a detailed one (Figure 2). The ships R/V KNOR,R, HA YES and DU1TON have utilized echo sounding systems with approximately 30°,6° and about 2° respectively. The CHARCOT and ATLANTIS

PROJECT FAMOUS II will complete geophysical surveys in late 1972. In 1973 C!N!RAL 5<:H!DU\! the DISCOVERY will make a comprehensive side scan 1971 19n 1973 191. sonar survey between 36° and 37°N latitude, the

MAJOR SHACKLETON and other ships will study earthquakes and ~A"'Nltfa M[['INGoS KNORR will utilize the Scripps Institution of Oceanog- raphy deep-towed fish for near-bottom investigations. The MIZAR plans to use the Libec camera system for large area JO

OIJI'tI. .••• ': I """"'. I ~•..•..•••'!ll water and measurements of bottom currents and gross ~.ufCHJ;~=;--: . geophysical structure. :'-SP-""09-:

figure 2. Genenl Schedule or operations as or late 1972. ThiI Because of the relatively short time that submersibles schedule is frequently updatecllll projects evolve.• will be on the bottom it is important that diving scientists utilize their time efficiently. A special training program is being undertaken to acquaint both scientists and pilots with dry land terrain characteristics that may be similar to that (ust measurements were made to determine that it was on the floor of the Mid-Atlantic Ridge. Trips to Iceland and typical. An aeromagnetic survey was undertaken. A charac- to the Afar region of East Africa will be made for that teristic magnetic anomaly identifies the axis of the ridge sO purpose. Test dives in the submersibles will be made, by the ridge axis and its offsets were identified quickly from selected scientists, off the east coast of the United States the air. An analysis of the magnetic anomalies also and in the Mediterranean, and in 1973 on the Mid-Atlantic determines a spreading rate of about 1.5 cm/yr, which is Ridge itself. A special navigation system will be used on believed to be typical of the North Atlantic. some of the submersible and deep-tow surveys and a number of new sampling and data logging instruments are Since this general area was found satisfactory, meet· comple!ing development and testing. ings in the United States and France developed the basic plan of the FAMOUS Program under an existing bilateral The Project FAMOUS area, by 1974, will probably be agreement between the two countries. Since that time one of the best known portions of the Mid-ocean Ridge British, Canadian, Russian, and other scientists and ships, system and will be prime candidate for deep hard rock have joined the project. drilling when that technology is developed in a few years.

66 Marine Technology SocietyJournal ~