USGS1947
During the summer of. 1947, U. S. Geological Survey Party No. 2 made a reconnaissance survey of the area between Awuna River and the divide north of the Kigalik River. The westernmost observations were made along the Awuna anticline to longitude about 157°30' W. and along the Kigalik anticline to longitude about 156°55'W. The easternmost work was done along the Knife Blade Ridge anticline at a longitude of about 154°30'W. Not all of this area was traversed, but a general idea of the area studied may be had by noting the distribution of dip and strike symbols on Figure 1. Parts of this area had been previously visited by Smith 1/ in 1927 as a part of his traverse from Allakaket to the Arctic Coast. In the period from about July 10 to August 5 his party ascended the Awuna River and Birthday Creek, portaged over the Kigalik-Awuna divide at Birthday Pass, and descended the Kigalik River to its mouth. Various parties in the field season of 1946 worked in areas not far distant. Webber 2/ began his field work near the headwaters of the Meade River and measured a section across the Kigalik anticline about 25 miles beyond the westernmost observations made on that structure by Party No. 2. Work by Chapman and Thurrell 3/ along the Colville River parallels at a distance of three or four miles work by Party No. 2 in the vicinity of Knife Blade Ridge. The easternmost observations by Party No. 2 in the vicinity of Knife Blade Ridge are about 11 miles west of the area south of Maybe Creek mapped by Ray and Fischer.4/ Of the 1947 work of other field parties that of Thurrell 5/ along the Colville River is most closely related to this report. His thickness from the base of Zone A to his Trace No. 5 is included in Column 1 of Figure 3. Webber's work 6/ along the Ikpikpuk and Titaluk Rivers is also in a closely related area. Party No. 2 moved through this area by weasel, the weasels being used extensively on the daily traverses. The party assembled at Umiat late in May and was flown out to a lake about one mile west of the Ikpikpuk River at latitude 69°40' N. where the weasels and initial supplies had been previously cached. Early in June the party moved south into the area in which it was to begin work. For the next several weeks the party worked in the area north of the Kigalik River, moving westward along the divide north of that river. At this time considerable work was done south of the Kigalik River, west of longitude 154°40'W. No closure was detected along the Kigalik anticline. Shortly after the middle of July the party moved southwestward to the vicinity of the Awuna anticline where a westerly plunge had been suggested from the study of aerial photographs. The general route of the party from then on was eastward along the divide between the Awuna and Kigalik Rivers. Due to the need to reach a food cache further east very little data was gathered in the area between Birthday and Section Creeks. It was intended to work this area by one or two spike trips from the camp at the head of Section Creek. However, after constructing a cross-section from data gathered by the party along Section Creek and by Thurreli in the area between the Colville and Awuna Rivers it became apparent that the strata exposed along the axis of the Awuna anticline were stratigraphically below the base of Zone A. It thus appeared that there would be little point in attempting to gather additional data in the area between Birthday and Section Creeks. The party continued eastward, working along the south flank of the Kigalik anticline. On September 1, the party camped about one mile west of the summit of Knife Blade Ridge. Because of unfavorable weather at this time only a small amount of field work was accomplished in the next week. Enough data was gathered to give a general picture of the structure here, but the data on stratigraphy and structure is far from exhaustive. On September 9 the party moved eastward, camping that night about 3 miles northeast of :Wolf Creek, and arriving at Umiat on the afternoon of September 10. Aerial photographs were carried in the field and used to record the points at which observations were made. A considerable amount of data was recorded on the photographs. Approximate elevations were obtained, at first by aneroid barometers, and later by more sensitive airplane altimeters. Plane table and alidade were used in local traverses in the area north of the Kigalik River to obtain dips and strikes by the 'three-point method. Nearly all other dips and strikes recorded were measured by Brunton compass. Dips of 5° or less in the area south of the Kigalik River should, in general, be considered as dip components with only the approximate strike shown. These low dips were taken on bedding traces* where it was usually impossible to observe an accurate strike with the Brunton.