near-shore during the summer surface currents 

 may range from to 37 cm/sec (0 to 0.75 knots). 

 Dygas et al. (1972) while observing a good corre- 

 lation of strength and directions of water currents 

 and wind, concluded that in the Simpson Lagoon 

 the bottom current velocity is on the order of 17.3 

 cm/sec. However, as a result of storm surge, sea 

 level in the coastal area may vary as much as 1.5 

 meters within a short time (Matthews, 1970; 

 Kinney et al. , 1972). Although tidal flats are not 

 extensive in the north coast of Alaska because of 

 low tidal range, some low lying deltaic areas may 

 often become waterlogged during the sea level 

 rise resulting from storm surge. 



Salinities of waters in the Colville Delta and 

 adjacent continental margin region range from 10 

 7oo to 65.9 7oo (Kinney et al., 1972; Schell and 

 Hall, 1972; Walker, 1972). Presumably, the 

 usually high saline waters are formed as a result of 

 great concentration of ions in water bodies en- 

 trapped between grounded ice; the ionic supply 

 being from deionization of saline ice. Primary- 

 productivity in the lagoonal area is relatively low; 

 most values ranged around 1 /Ltg C-hr (Alexander 

 and Billington, 1972). 



The continental facies of the North Slope Del- 

 tas are dominated by the coastal beaches, Harri- 

 son Bay, Simpson Lagoon, the far offshore and 

 nearshore barriers. The lagoon and Harrison Bay 

 are shallow, having a depth range of 0.8 to 3.5 m. 

 The barriers and bars are oriented roughly parral- 

 lel to the deltaic coastline, and locations of all 

 barriers in the area of study are confined to the 

 east of the Colville River confluence. The barrier 

 surfaces consist predominantly of gravels. With 

 the exception of the areas near river mouths, the 

 coastal beach essentially has gravelly and sandy 

 deposits, the size distributions of which have 

 been described by Naidu et al. (1970) and Dygas 

 et al. (1971). The open marine deltaic facies and 

 the adjacent shelf surface are presently being, 

 and/or have been modified, by ice gouging 

 (Reimnitz et al., 1972), and some of the offshore 

 bars seem to have originated by ice push. Com- 

 parative aerial photographic studies (Dygas et al. , 

 1972) reveal large scale morphological changes 

 in the Pingok and Thetis Islands over the past 20 

 years. The arctic deltaic environment under de- 

 scription differs from low-latitude deltas in sev- 

 eral ways. The more notable differences are the 



240 



absence of extensive sand dunes, flood plains, 

 tidal flats, and mangrove swamps together with 

 the common presence of coastal gravel deposits, a 

 deltaic plain dominated by tundra, and subjec- 

 tion of the entire area to strong ice stress condi- 

 tions for the major part of the year, as well as to 

 thermal erosion. 



MATERIALS AND METHODS 



Results presented in this report are based on 

 analyses of surface sediment samples that were 

 collected either by a Van Veen/Shipek grab sam- 

 pler or a short gravity corer. Most of the samples 

 from the continental margin region were collected 

 from the N.A.R.L. vessel R/V NATCHIK, and a 

 few from a Boston Whaler. Samples from the deep 

 water open marine evnironment were collected 

 during the WEBSEC-71 cruise of the USCGC 

 GLACIER. A few additional samples included in 

 this report (BSS Series) comprise a part of the 

 suite of short core sediments that were retrieved 

 by the USCGC STATEN ISLAND in 1968. 



Grain size distributions of sediments were 

 analyzed by the combined methods of sieving and 

 pipetting. Grain size statistical parameters were 

 calculated using the formulae given by Folk and 

 Ward (1958). Heavy minerals in three size 

 grades of the sand fraction were separated in 

 bromoform (Sp. Gr. 2.85). 



Clay mineral analysis was accomplished by 

 X-ray diffraction techniques. A Phillips Elec- 

 tronics Norelco X-ray diffractometer was em- 

 ployed, using Ni filtered Cu K_^ radiation. The 

 instrumental parameters used routinely, unless 

 otherwise specified, were '2°'2d per minute scan 

 speed, time constant 2, with l°-006 inch slits. 

 For bulk clay mineralogy, analysis was routinely 

 carried out on the <2)U, e.s.d. (equivalent spheri- 

 cal diameter) size material of sediments, follow- 

 ing the method described by Naidu et al. (1971). 

 Although gross clay mineralogy is normally 

 characterized fairly well by this analysis, often 

 there are ambiguities left unresolved without 

 more detailed investigations. Therefore, clay 

 mineral analyses were also conducted on subfrac- 

 tions of <2/x. e.s.d. particle size range for a 



