Geomorphology and Glacial Geology of the Martin River Glacier, Alaska

Аннотация

Divides the lower 17 km of this glacier and its periphery into four zones and discusses their land forms, water, plant and animal life as a dynamic system directly dependent on the glacier regime. The active zone is characterized by exposed and drift-covered ice, contorted and linear medial moraines, crevasses, superglacial streams and moulins and ice sinkhole lakes; its flow rate is 200-approx 100 m/yr. The intermediate zone is on flowing ice covered by drift up to 3 m thick and a dense vegetation cover. Many ice sinkhole lakes drain frequently via englacial or subglacial channels. The terminal zone which was active about 1650 AD is on dead ice, drift-covered and with Sitka spruce stands with more open areas than those in the intermediate zone. The glaciated zone is delineated by terminal moraine, moraine segments of probable late Wisconsin age and 21 successive lateral moraines, the seven lowest of which are of post-Wisconsin age.