Latest Cretaceous (Maastrichtian) climate of the Koryak Upland of North-East Russia based on a quantitative analysis of a palaeo-polar flora

High-Latitude Dinosaur Nesting Strategies during the Latest Cretaceous in North-Eastern Russia

“…This formation is a 1000 m thick continental sequence, the exact age of which is still debated. The bone-bearing layers are either dated as (1) early late Maastrichtian considering that the formation is underlain by marine deposits of late Maastrichtian age and overlain by marine sediments of the Kokuy Unit, which contain poorly preserved plant fossils and the latest Maastrichtian invertebrate fauna [10,37,38] or (2) late Campanian-early Maastrichtian considering that underlying and overlapping deposits do not directly contact marine layers containing stratigraphically important forms of mollusk fossils. Furthermore, the dinosaur remains were found together with plant representative of the Kakanaut flora, allowing the assignment of the bone-and plantbearing layers to the Gornaya River phytostratigraphic horizon dated as late Campanian, possibly early Maastrichtian [39].…”

“…In a recent quantitative analysis of the Kakanaut palaeoflora using the Climate Leaf Analysis Multivariate Program (CLAMP), Zolina et al [10] calculated a mean annual air temperature (MAAT) of 12.2 ± 2.0 • C for the Kakanaut area, located during the Maastrichtian at a paleolatitude of about 75 • N [40]. This temperature of 12.2 ± 2.0 • C would correspond today to a mean annual meteoric water δ 18 O mw value of −8.4 ± 1.0‰, according to the recently established δ 18 O mw -MAAT relationship [55].…”

“…It can, therefore, be assumed that the average δ 18 O p value of dinosaur teeth reflects the mean δ 18 O w value of local surface waters and that these ingested waters are of meteoric origin. The consistency of both air temperatures provided by Zolina et al [10] and δ 18 O w value estimated from dinosaur δ 18 O p can be tested using the δ 18 O p value measured on three bulk scales of lepisosteids (Table 1). The measured value of 14.2‰ indicates that these scales have mineralized from the local water δ 18 O w value of −8.2‰ at a temperature of about 17 • C according to the phosphate-water temperature scale proposed by Lécuyer et al [59].…”

“…Due to their exceptional range of body mass, from a few grams to several tens of tons, non-avian dinosaurs might have had various reproductive strategies adapted to their physiological and anatomical peculiarities [7]. Paleoclimate studies document that such harsh near-polar conditions existed during the Cretaceous [8][9][10].…”

Flora, vegetation and climate assessment of the Early/Middle Miocene Parschlug flora indicates a distinctly seasonal climate

“…Climate Leaf Analysis Multivariate Program (CLAMP) is a multivariate statistical technique for quantitative determination of a range of palaeoclimate parameters based on foliar physiognomy of woody dicotyledonous angiosperms. CLAMP was first introduced by Wolfe (1993) and subsequently this technique has been refined (Wolfe and Spicer 1999, Spicer 2000, Spicer et al 2004), methodologically modified (e.g., Teodoridis et al 2011b, Yang et al 2011, Teodoridis and Mazouch 2017, Zolina et al 2020 and updated using gridded meteorological data (Spicer et al 2009(Spicer et al , 2020 and new CLAMP calibration data (e.g., Jacques et al 2011, Khan et al 2014, Yang et al 2015.…”