Carbon cycle models based on extreme changes in δ13C: an example from the lower Mississippian

The TICE event: Perturbation of carbon–nitrogen cycles during the mid-Tournaisian (Early Carboniferous) greenhouse–icehouse transition

“…The large (3-6‰) positive δ 13 C carb shift within the S. isosticha Zone of the two study sections, herein named the 'mid-Tournaisian carbon isotope excursion' (TICE), is a global event that has previously been documented at multiple locales in North America (Mii et al, 1999;Saltzman et al, 2000Saltzman et al, , 2004Saltzman, 2002Saltzman, , 2003aGrossman et al, 2008;Henry, 2011), Europe (Bruckschen and Veizer, 1997;Bruckschen et al, 1999;Buggisch et al, 2008), and Russia (Saltzman et al, 2004). This C-isotope event has been ascribed to an increase in the burial flux of organic carbon (Mii et al, 1999;Saltzman et al, 2000Saltzman et al, , 2004Saltzman, 2003b;Buggisch et al, 2008).…”

“…2b). Therefore, the study intervals in both sections fall mainly within the S. isosticha Zone, an interval that coincided with one of the largest positive δ 13 C carb excursions of the Phanerozoic (Bruckschen and Veizer, 1997;Mii et al, 1999;Saltzman et al, 2000Saltzman et al, , 2004Saltzman, 2002Saltzman, , 2003aBuggisch et al, 2008;Henry, 2011). This δ 13 C carb excursion is herein named the 'mid-Tournaisian carbon isotope excursion' (TICE).…”

“…Spatial heterogeneity of the TICE is evident in other sections globally as well. For example, the magnitude of the C-isotope shift was~4‰ with the peak values of~4‰ in the Dinant Basin of Belgium, and the magnitude was as large as 8‰ with peak values of~7‰ in the Pahranagat Range of the United States (Saltzman et al, 2000(Saltzman et al, , 2004 (Fig. 4).…”

“…The positive δ 18 O shift of the mid-Tournaisian was accompanied by a prominent positive excursion in carbonate carbon isotopes (δ 13 C carb ), herein named the 'mid-Tournaisian carbon isotope excursion' (TICE), that has been reported in North America, Europe, and Russia (Bruckschen and Veizer, 1997;Mii et al, 1999;Saltzman et al, 2000Saltzman et al, , 2004Saltzman, 2002Saltzman, , 2003aBuggisch et al, 2008;Henry, 2011). This δ 13 C carb excursion has generally been ascribed to a transient increase in the fraction of organic carbon burial and a consequent lowering of atmospheric CO 2 concentrations, which could have served as the trigger for continental glaciation during the mid-Tournaisian (Saltzman, 2002;Buggisch et al, 2008).…”

“…This C-isotope event has been ascribed to an increase in the burial flux of organic carbon (Mii et al, 1999;Saltzman et al, 2000Saltzman et al, , 2004Saltzman, 2003b;Buggisch et al, 2008). This might have resulted from increases in marine productivity and the sinking flux of organic carbon, or from changes in ocean circulation that favored more rapid burial and preservation of a constant sinking flux of organic carbon.…”