Atmospheric palaeo-CO2 estimates based on the carbon isotope and stomatal data of Cheirolepidiaceae from the Lower Cretaceous of the Jiuquan Basin, Gansu Province

Middle Cretaceous pCO2 Variation in Yumen, Gansu Province and its Response to the Climate Events

“…Based on these models, the atmospheric CO 2 concentration over the Phanerozoic period (Wang et al, 2014) was reconstructed. These models also provide a correction for estimating the pCO 2 levels in the Phanerozoic (Haworth et al, 2005;Aucour et al, 2008;Ren et al, 2008;Passalia, 2009;Du et al, 2016;Sun B.N et al, 2016;Sun Y.W et al, 2016;Dai and Sun, 2017). In addition, the isotopic compositions of boron in marine foraminifera (Katz et al, 2010), the isotopic compositions of carbon in pedogenic carbonate (Weislogel et al, 2008;Huang et al, 2012), and marine alkenones (Pagani, 2002), as well as the traditional stomatal methods based on the plant fossil stomatal index (SI) and stomatal ratio (SR), were used to reconstruct the pCO 2 .…”

“…The SR method is mainly based on the SR values, which are calculated based on stomatal index of the nearest living equivalent species to the fossil plants (McElwain and Chaloner, 1995;Wang et al, 2014). The SR method is widely used to estimate the pCO 2 levels during the Mesozoic (Aucour et al, 2008;Du et al, 2016;Haworth et al, 2005;Passalia, 2009;Ren et al, 2008;Sun Y.W et al, 2016;Dai and Sun, 2017).…”

“…Recently, the mechanistic models based on the leaf gas exchange during photosynthesis have been widely applied to reconstruct the pCO 2 of the past. Konrad et al (2008) proposed the mechanistic theoretical model based on the stomatal data, photosynthesis, and gas exchange control (Sun B.N et al, 2016). Many scholars have used this model to estimate the pCO 2 levels in the Cenozoic (Grein et al, 2011(Grein et al, , 2013Roth-Nebelsick et al, 2012Sun B.N et al, 2016).…”

“…Konrad et al (2008) proposed the mechanistic theoretical model based on the stomatal data, photosynthesis, and gas exchange control (Sun B.N et al, 2016). Many scholars have used this model to estimate the pCO 2 levels in the Cenozoic (Grein et al, 2011(Grein et al, , 2013Roth-Nebelsick et al, 2012Sun B.N et al, 2016). The precondition to using this method is that the temperature during the plant growth period should be above 10°C, because the optimum temperature of woody plants for photosynthesis ranges between 10°C-35°C (Grein et al, 2013;Roth-Nebelsick et al, 2014;Sun B.N et al, 2016).…”

“…Many scholars have used this model to estimate the pCO 2 levels in the Cenozoic (Grein et al, 2011(Grein et al, , 2013Roth-Nebelsick et al, 2012Sun B.N et al, 2016). The precondition to using this method is that the temperature during the plant growth period should be above 10°C, because the optimum temperature of woody plants for photosynthesis ranges between 10°C-35°C (Grein et al, 2013;Roth-Nebelsick et al, 2014;Sun B.N et al, 2016). It is obvious that palaeoclimatic parameters (temperature and humidity) are important for the reconstruction of atmospheric CO 2 concentration using this model.…”