Paleomagnetism of Paleogene rocks of the Central—East Kamchatka and Komanorsky Islands: tectonic implications

Abstract Paleomagnetic investigation of Paleocene—Eocene to Miocene rocks has been carried out at five localities in the Eastern Kamchatka and Komandorsky Islands. After thermal and af cleanings, consistent paleomagnetic directions were isolated for a number of formations. Data from the Kronotsky Peninsula and Medny Island passed both the fold and reversal tests and thus can be considered as reliable; other results are of lower quality. All the results were derived from sedimentary rocks, and thus the corresponding paleolatitudes may be biased due to inclination errors. A limited collection of basalts yielded inclination values systematically lower than those in sediments; this anomaly was tentatively explained by shape anisotropy. The correctness of paleolatitude estimations was thus left unproved. Several models of the Northern Pacific tectonic evolution were suggested and analyzed, but the authors failed to find a model that was fully compatible with paleomagnetic, kinematic and geological data