HYDROLOGY OF THE BRANSFIELD STRAIT 7 



the above information and as much of the older information as possible has been 

 used. 1 



At the south-west end of the Bransfield Strait lie the islands of Snow, Smith, Low, 

 Hoseason, Intercurrence, Brabant, Trinity and Deception. The soundings show that 

 these islands are connected by submarine ridges with different saddle-depths. To the 

 east of Smith Island a channel of greater depth than 600 m. occurs, which connects with 

 the south-west basin of the Bransfield Strait. A channel, possibly deeper than 500 m., 

 may occur south of Low Island, also giving access to the south-west basin which is 

 described later. Between Snow Island and Deception Island the depth is nowhere 

 greater than 250 m., although between the latter island and Livingston Island a depth 

 of over 500 m. exists. The submarine ridge between Deception and Trinity Islands has 

 a saddle-depth of probably between 700 and 800 m. There is also a possibility of a 

 slightly increased depth near Trinity Island. However, in the area contained by the 

 triangle formed by the islands of Deception, Low and Hoseason, depths between 1300 

 and 1400 m. are recorded. Thus at the south-west end of the Bransfield Strait a basin is 

 present whose boundaries are the islands and ridges connecting the islands of Snow, 

 Smith, Low, Hoseason, Trinity and Deception, and whose greatest depth is probably 

 not more than 1400 m. 



The second and larger basin in the Bransfield Strait runs south-west and north-east. 

 It begins at the shoal on which Deception Island stands, and continues until that of 

 Clarence Island is reached. A slight constriction of its width occurs south-south-east 

 of Bridgeman Island where the sea-bottom rises to a depth of 1200 m. from the 

 surface ; on both north-east and south-west sides depths greater than 2000 m. are 

 reached. This basin lies closer to the South Shetland Islands than to Trinity Peninsula 

 and Graham Land owing to the steepness of the very narrow continental slope on the 

 south-east side of the South Shetlands, and the more gentle sloping of the extensive 

 continental shelf on the coast of Graham Land and Trinity Peninsula. At the north-east 

 end of this basin there is evidence of two confining submarine ridges. To the north the 

 'Meteor' obtained an echo-sounding of 199 m. some 13 miles approximately west- 

 south-west of Elephant Island, whilst the R.R.S. ' Discovery II ' on a course just west 

 of north in the gap between Elephant Island and King George Island obtained 

 gradually diminishing echo-soundings with a minimum depth of 223 m. at 6i° 14' S, 

 56 39' W. Thus there is some evidence for assuming the existence of a continuous 

 continental shelf between Elephant and King George Islands. To the east the wide 

 continental shelf north of Joinville Island in the direction of Clarence Island has been 

 shown to be considerably extended and a large area of just over 300 m. was found by 

 echo-soundings. Thus to the east of the Bransfield Strait there is also some evidence of 



1 It is to be noted that a number of the earlier soundings cannot be plotted on recent charts. Surveys 

 undertaken during the course of our work have shown that the existing charts were inaccurate, and though 

 much still remains to be done, especially off Trinity Peninsula, the coast-line of some part of the South 

 Shetlands has been corrected and the positions of a number of the islands have been revised. The corrections 

 have been incorporated in the latest Admiralty charts. A number of the early soundings were fixed by land 

 bearings, and they cannot be transferred to the new charts unless the original data are available. 



