Strange Hot Waters and Minerals at the Bottom of the Red Sea 



John M. Hunt and David A. Ross 

 Woods Hole Oceanographic Institution 

 Woods Hole, Mass. 02543 



During the fall of 1966, the R/V CHAIN conducted an extensive 

 survey of the hot brine area of the Red Sea (21°10'N to 21°30'N). This survey 

 included: detailed bathymetry using radar reflecting buoys; measurements of 

 temperature v/ith conventional hydrocasts and a temperature telemetering 

 pinger; continuous seismic profiling; gravity and magnetic measurements; and 

 a detailed sampling of bottom sediments with free-fall, gravity, piston and, 

 box-coring techniques. This paper discusses some of the preliminary results of 

 this survey. 



The bathymetric survey showed three deeps (Fig. 1), which contain 

 hot highly saline water. These deeps are located in the central portion of the 

 Red Sea rift valley. The ATLANTIS II Deep is about 12 km long and 5 km 

 wide, and contains several small topographic highs. This deep is connected to 

 the smaller DISCOVERY Deep by a narrow channel; which is apparently 

 sufficiently high, at present, to prevent mixing of the hot saline waters. The 

 CHAIN Deep, which was discovered on this cruise, is situated in a saddle on 

 this channel. 



Temperature profiles of the brine areas were obtained with a temperat- 

 ure telemetering pinger, developed especially for this cruise by Benthos Inc. 

 (Ross and Tyndale, 1967). This pinger emits two pings within a one second 

 interval. The first ping is emitted every second, the second ping at a time 

 interval after the first, this time interval is a measure of temperature. The time 

 interval is maintained by a thermistor that produces a varying resistance which 

 controls the telemetering electronics. Both pings were received by the ships 

 12 kc echo sounder and recorded on a Precision Graphic Recorder. Temperature 

 could then be read directly from the P.G.R. In the Red Sea, a thermistor with 

 a range of 20°C to 70°C was used. The accuracy of the measurement was 

 ± 1.25°C. Determinations of absolute temperature were made by conventional 

 methods using high-range thermometers. The temperature telemetering pinger 



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