Bottom studies involving physiography, sedimentation, and paleontology indicated that there was pre-Pleistocene fluvial erosion when the land stood higher relative to sea level, followed by modification of trunk systems by valley glaciers, then submergence of much of the archipelago, and finally emergence. Tertiary headlands are still submerged more than 400 meters. Following these physiographic and crustal events, Arctic sedimentation occurred.

Sediments from lake, river, delta, protected bay, channel, and ocean environments were studied. River and delta environments were selected as classical depositional sites, and others were interpreted from this norm. In fluvial deposits, a direct relationship of decrease in size of detritus with distance of transport occurs together with reduction in percentage, mean size, and number of heavy mineral species. Where river gradients lower abruptly, sedimentary particles decrease immediately from gravel to sand and silt. In deltas, decrease in size is exponential with distance of transport, and deposits consist chiefly of silt and mud. There, contours on lithofacies maps protrude seaward over bathymetric contours indicating prograding of clastic sediments due to marine regression or relat ve crustal uplift.

Offshore, no progressive variation in texture exists, due to occurrences of ice-rafted material and lack of sufficient currents. Where currents exist, as in mid-channel areas, sediments are better sorted. Thus, anomalous distributions of sediments arise wherein nearshore deposits in channel areas consist of fine material, but in mid-channel areas they are coarser. Occurrences of coarse marine sands off seaward tips of islands are

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due to reworking of the submerged clastic Beaufort Formation cropping out along the western Arctic coast, and to occurrences of drowned headlands consisting of unconsolidated coarse materials.

Spectrochemical analyses indicate that certain elements and clay minerals in bottom sediments are related to nearby geological formations and that the clay minerals are detrital. This indicates past rigorous physical conditions with negligible chemical activity.

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