THE CHUKCHI SEGMENT OF THE UDA-MURGAL AND OKHOTSK-CHUKOTKA VOLCANIC BELTS: AGE AND TECTONIC ENVIRONMENTстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 12 августа 2020 г.
Аннотация:We present new data on the geology, geochronology, and geochemistry of volcanic complexes of the Uda–Murgal andOkhotsk–Chukotka belts that expose on the left bank of the Anadyr’ River in its middle course. The structural relationships between thestratons, supplemented by the U–Pb and 40Ar/39Ar dates of volcanics, indicate at least three compression events at this segment of the Pacificmargin during the Cretaceous: pre-Aptian, early Albian, and late Turonian. The complexes of the Uda–Murgal and Okhotsk–Chukotkabelts are separated by an early Albian unconformity, but the other two unconformities are also well pronounced. The studied segment ofthe Uda–Murgal belt evolved in the ensialic island arc setting till the Barremian. In the Aptian, after the accretion of the island arc to thecontinent, volcanism reactivated on the Andean-type margin. The main geochemical difference between the Uda–Murgal and Okhotsk–Chukotka belts is the different volume portions of silicic rocks. The less significant difference in the contents of trace elements indicates achange in the composition of the mantle protolith. The complexes of the Okhotsk–Chukotka belt show signs of geochemical zoning, bothlongitudinal and transverse relative to the strike of the continent–ocean boundary.