An Alaskan Jurassic Palaeomagnetic Pole and the Alaskan Orocline

Autor: David B. Stone, Duane R. Packer
Rok vydání: 1972
Předmět:
Zdroj: Nature Physical Science. 237:25-26
ISSN: 2058-1106
0300-8746
Popis: AS part of an effort to determine whether or not the curvature of the Alaskan orocline, as outlined by the Alaska Range and certain other geological features such as the Denali fault system, is of primary or secondary origin, oriented samples of Jurassic age were collected from sixteen sites in four areas along the arcuate trend of the oroclinal bending1,2 (Fig. 1). The geographic spread of the sites is about 1,100 km. The rock types sampled include fine-grained sandstones and silt-stones and granitic intrusives which have variable magnetic intensities and stabilities. Age control for each of the sedimentary sites was derived from fossil evidence3–5 and the ages of the batholiths were determined radiometrically6. All the samples were measured using a slow spinner magnetometer and were demagnetized in a two-axis tumbler7 in a 60 Hz alternating field. The demagnetization level used was selected on the basis of visual inspection of the demagnetization curves and the apparent stability of the data against further demagnetization.
Databáze: OpenAIRE
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