A new 87Sr/86Sr record of Cretaceous marine invertebrates from the palaeo-Pacific and its implication for stratigraphical and palaeoenvironmental reconstructions. (November 2022)

• Record Type: Journal Article
• Authors: Zakharov, Yuri D.; Kuznetsov, Anton B.; Gavrilova, Anastasia A.; Stativko, Vladislav S.
• Is Part Of: Cretaceous research. Volume 139(2022)
• Publication Date: 2022-11
• Subjects: Cretaceous Sr-isotope stratigraphy -- Brachiopods -- Molluscs -- Koryak Upland -- Magellan Seamounts -- British Columbia; Geology, Stratigraphic -- Cretaceous -- Periodicals; 551.77
• DOI: 10.1016/j.cretres.2022.105298
• Languages: English
• ISSNs: 0195-6671

Abstract

Abstract: We present the first strontium isotope data of Cretaceous marine invertebrates from north-eastern Russia and the Magellan Seamounts. These provide evidence of a late Turonian age (91.2–90.4 Ma) for the upper part of the Penzhinskaya Formation (Koryak Upland) and a late Coniacian date (90.4–86.4 Ma) for the cephalopod-bearing deposits of the Magellan Seamounts. In addition, they yield information on seasonal variations in the 87 Sr/ 86 Sr ratio in marginal marine environments during the late Turonian. These data raise doubts about a previously postulated hiatus spanning the Turonian–Santonian interval. Our results reveal a close temporal correlation between Sr-isotope excursions and the major Oceanic Anoxic Events (OAEs), which suggests a causal link. However, the link between the late Santonian–early Campanian Sr-isotope minimum and Oceanic Anoxic Event 3 (OAE-3) has yet to be fully resolved and requires additional evidence. Highlights: Sr-isotope data from the Cretaceous of paleo-Pacific are observed. The age of the cephalopod-bearing deposits of the Koryak Upland and the Magellan Seamounts has been updated. Data on the seasonal variation of 87 Sr/ 86 Sr ratio in the Late Turonian are presented. Problems of the seasonal Sr-isotope variation are discussed.