ton corer 20 feet in length was utilized to ob- 

 tain sedimentary material. The cores were re- 

 turned to the United States where they will be 

 exposed to X-rays to determine the types and 

 extent of sedimentary structures which are not 

 otherwise visible. In addition, chemical analy- 

 ses will be made on the sediments to determine 

 carbonate or sulfate concentrations and source 

 rock composition. 



The U.S. Coast Guard Oceanograpkic Unit: 

 The program conducted by the U.S. Coast 

 Guard Oceanographic Unit consisted of physi- 

 cal oceanographic measurements, determina- 

 tions of dissolved oxygen, pH, and nutrients, 

 and bottom photography. Personnel making up 

 the Unit's field party included: 



Gary L. HUFFORD Oceanographer 



LT James M. SEABROOKE, 



USCG Oceanographer 



MSTI Peter R. SAN JULE, 



USCG Oceanographic 



Technician 

 S02 Robert C. MURRELL, 



USCG Oceanographic 



Technician 

 MST2 Kenneth THOENI, USCG - Oceanographic 



Technician 

 YN2 Dwight E. OLSON, USCG - _ Oceanographic 



Technician 

 MST3 Bruce B. EDWARDS, 



USCG Oceanographic 



Technician 



Initially, the cruise was to be conducted over 

 an eighty day period, starting in early January 

 and ending on April first. However, GLACIER 

 was assigned to first break a channel to 

 McMurdo Station and met unexpectedly heavy 

 ice concentrations, which delayed the start of 

 IWSOE '69 until mid-Februry. The cruise 

 lasted till March 24, 1969. 



Station Procedure 



On February 13, GLACIER departed Punta 

 Arenas, Chile. It was tentatively agreed to con- 

 centrate the investigations in the southeastern 

 part of the Weddell Sea in the area of the cur- 

 rent meter arrays planted during IWSOE '68 

 until their recovery. However, the ship ran 

 into heavy ice that was impenetrable sixty 

 miles from the current meter arrays. After 

 several unsuccessful attempts were made, it 

 was necessary to abandon recovery of the ar- 

 rays during IWSOE '69. A series of stations 

 were then taken in the area. 



The initial procedure followed by the ship 

 upon arriving at station depended largely on 

 ice conditions. During IWSOE '69 heavy ice 

 concentrations were encountered, and only 

 twenty-seven oceanographic stations were 

 taken. It was usually possible to ease the ship's 

 bow into an ice floe and by slowly turning the 

 screws, hold the bow in the floe until it froze, 

 at the same time clearing a small area on ei- 

 ther side aft of brash ice. This provided a clear 

 area in which to lower oceanographic equip- 

 ment. This procedure was adopted instead of 

 the one utilized during IWSOE '68, i.e., easing 

 the starboard side against a floe. It was neces- 

 sary to keep both sides clear for work due to 

 the addition of a starboard luffing crane and 

 winch. 



Although station plans were constantly 

 changing owing to a number of circumstances, 

 a station usually consisted of a Nansen cast, 

 bottom photography, an STD cast, piston cor- 

 ing and bottom trawls and dredges. 



Satellite navigation contributed greatly to 

 the success of station position determination. 

 No navigational aids are available in the Wed- 

 dell Sea, and celestial navigation is hampered 

 by generally overcast skies. Since the accuracy 

 of satellite navigation is not affected by either 

 clouds or indistinct horizon, use of this method 

 during the expedition yielded accurate posi- 

 tions. 



Data Acquisition and Initial Analysis 



A summary of data collected at each station 

 is presented in table 1. 



Temperature Data 



Teflon-lined Nansen bottles were equipped 

 with two protected reversing thermometers 

 and, at alternate depths below 150 meters, 

 with unprotected thermometers. Sampling 

 depths were approximately 0, 10, 25, 50, 75, 

 100, 150, 200, 300, 400, 500, 600, 700, 800, 1000, 

 1250, 1500 meters and at 300 meter intervals 

 below 1500 meters, except that several bottles 

 were placed at 25 meter intervals near the bot- 

 tom. 



With the ship firmly held in the ice on most 

 stations, a zero wire angle was generally ob- 

 tained and an acoustic depth-telemetering pin- 

 ger was placed on the wire to make it possible 

 to obtain samples within a few meters of the 

 bottom. 



