Abstract

The Martin River Glacier, in south-central Alaska, was studied only casually prior to the first expedition sent there in 1962 from the University of North Dakota. Subsequently, reports have been published on almost all aspects except the glacial history, which has been difficult to ascertain. The interpretation is now presented that the outermost terminal moraine of the Martin River Glacier, in south-central Alaska, is anomalously late Wisconsin in age; all lateral moraines converge at or upglacier from this moraine, indicating that if the glacier ever extended farther downvalley, the evidence is still missing. It is possible, however, that prior to that time, the glacier wasa tide-water glacier.

The debris-veneered, dead-ice area near the present terminus of the glacier marks the maximum Neoglacial advance, which culminated about 1650 A. D. Although the main lobe has been thinning and retreating ever since, a small moraine formed during a 1910 advance is present in the valley of the Charlotte Lobe.

Tree-ring measurements document the past 400 yrs of this glacier and permit the interpretation that the striking change in degree of soil development, at the 14th of the 21 successive lateral moraines of the Charlotte Lobe, separates the Neoglacial from the Late Wisconsin ice levels.

The close proximity of the Neoglacial limit of the Martin River Glacier to the terminal moraine is most likely the result of tectonic uplift of the Chugach Mountains in Neoglacial time. The change effected in the accumulation area may have resulted in diversion of more ice from the Bagley Ice Field into the Martin River Glacier. It may also have initiated the surging flow that has occurred in this and the neighboring Bering Glacier. Neoglacial uplift has complicated the interpretation of the past history of the Martin River Glacier.

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