Abstract

Modal analysis of new paleomagnetic results that have a skewed distribution from four plutons in the Kings Canyon National Park area, central Sierra Nevada, produces a pole position concordant with the results of Frei and others (1984) from the Yosemite area. These studies suggest (a) that stable magnetization resides in the more mafic plutons and inclusions in the Sierra Nevada and (b) that the amount of internal deformation within the central Sierra Nevada does not exceed a few degrees at the 95% confidence level.

The mean pole of both studies limits the relative displacement between the Sierra Nevada and cratonal North America to 6° ± 8° of clockwise rotation and 6° ± 6° of poleward displacement. The clockwise rotation agrees well with the model of Frei and others (1984) for Basin and Range extension, which predicts 2° of clockwise rotation for the Sierra Nevada. The poleward displacement suggests right-lateral shear of ∼600 km within the Basin and Range between 90 and ∼35 Ma.

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