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Description

A brief review of the general geology and tectonic setting of the Aleutian Island Arc is presented, followed by an account of the paleo-magnetism of selected areas. Paleomagnetic results are presented for Tertiary and Quaternary volcanic rocks from Shemya and Adak Islands. The specimens were collected and measured using standard paleomagnetic methods. Alternating field demagnetization techniques were applied to test the stability of the remanence and to remove unwanted secondary components of magnetization. The variation of the intensity of the NRM with the bulk susceptibility is discussed from the standpoint of the magnetic stability of the rocks. Mid-Late Tertiary and Quaternary specimens satisfy several criteria of magnetic stability in igneous rocks, and derived pole positions are thought to reflect the ambient geomagnetic field at the time of the origin of the rocks. By comparison, the remanent magnetization of Early Tertiary rocks investigated is less stable and yields uncertain results in terms of pole positions. The paleomagnetic results from the various sites are discussed with respect to the background geology of each island. Paleomagnetic pole positions derived from the results are compared with pole positions from other Tertiary and Quaternary sites in North Pacific tectonic belts.

Publication Date

7-17-1970

Keywords

Geology, Paleomagnetism, Alaska, Aleutian Islands

Handle

http://hdl.handle.net/11122/15428

Outline geology of the Aleutian Islands with paleomagnetic data from Shemya and Adak Islands

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