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Jagt-Yazykova E.A., Zonova T.D. (2012) Paleogeography of Cretaceous Ammonoids of the Pacific Coast of Russia. Stratigrafia. Geologicheskaja korrelacja, 20 (3): 295-315.

This work presents the results of a study of the biogeographical distribution of Late Albian-Maastrichtian ammonites, found in sequences of the Pacific coast of Russia. The taxa typical of the Pacific Realm were identified, and their distribution traced beyond the borders of this region. In addition, species-migrants, distributed within the studied area were established. As a results of our works, a high level of endemism of ammonite fauna of the East of Russia was noted (75–88% of endemic species, on average). The bipolarity, previously established in the distribution of ammonoids within the Pacific Paleobiogeographical Realm, as well as their high regional provincialism, was confirmed. The following division of the studied area into faunal ammonite provinces in the Late Cretaceous was proposed: Arctic Province; Boreal-Pacific Province, including northeastern Russia (Chukotka Peninsula, the Koryak Upland, Penzhyna Gulf) and the boreal coast of North America (Alaska Peninsula, Arctic Canada and British Columbia); Northwest Pacific Province, including the Primorye Territory, Sakhalin and Shikotan Islands, the japanese Islands; Northeast Province of the Pacific (the western coast of the United States and Mexico); Southwest Pacific (Australia, New Zealand, Oceania) and Southeast (the western coast of South America and Antarctica, Seymour and james Ross Islands) Provinces. This division is confirmed by data on inoceramid species. In addition, levels of global transgressions and general sea level rise, associated with the appearances of most of widespread marine taxa in the Pacific shelf seas, are established. These include Late Albian, Cenomanian-Turonian boundary, Late Coniacian, Late Campanian, Early-Late Maastrichtian boundary. Moreover, migration of ammonites occurred due to the Tethys Ocean extension and followed the northern sea straits in the Arctic Ocean and within the Pacific Realm, depending on warm currents. Both the counter and one-way migrations were established.

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