Figure 4
From: Large-scale sill emplacement in Brazil as a trigger for the end-Triassic crisis
Modeled cumulative CO2 production (red lines) and peak fluxes (black lines) per sill based on data from borehole ATZ (Fig. a; organic, Fig. b; inorganic), OAST (Fig. c; organic, Fig. d; inorganic) and MAST (Fig. e; organic, Fig. f; inorganic). (a) The organic CO2 production increases from the background value (52 ton/m2) after the first sill emplacement, and peaks at 102 ton/m2 after the last. The total organic CO2 production due to sill heating is 50 ton/m2. Peak organic CO2 fluxes vary from 2 to 363 kg/m2/yr. (b) The total inorganic CO2 production is 47 ton/m2. Peak inorganic CO2 fluxes vary from 52 to 1936 kg/m2/yr. (c) The organic CO2 production increases from the background value (70 ton/m2) after the first sill emplacement, and peaks at 118 ton/m2 after the last. The total organic CO2 production due to sill heating is 48 ton/m2. For the three sills emplaced in the upper Paleozoic series, the organic CO2 production is 22 ton/m2, whereas for the two sills emplaced in lower Paleozoic sedimentary rocks, the organic CO2 production is 27 ton/m2. Peak organic CO2 fluxes are significantly lower for sills emplaced in upper Paleozoic sedimentary rocks (95 to 356 kg/m2/yr) compared to sills emplaced in the lower Paleozoic ones (up to 2794 kg/m2/yr). (d) The total inorganic CO2 production is 4 ton/m2. There is no inorganic CO2 production for the two sills emplaced in lower Paleozoic sedimentary rocks. Peak inorganic CO2 fluxes vary from 190 to 1122 kg/m2/yr. (e) The organic CO2 production increases from the background value (100 ton/m2) after the first sill emplacement, and peaks at 154 ton/m2 after the last. The total organic CO2 production due to sill heating is 54 ton/m2. The organic CO2 production is 47 and 7 ton/m2 from contact metamorphism of upper- and lower Paleozoic sections, respectively. Peak organic CO2 fluxes vary from 64 to 573 kg/m2/yr. Note that there are no peaks for sill #4 and #9. Sills that are closely spaced could affect the same sedimentary rocks. As sill #3 and #8 are thicker and were emplaced prior to the respective sills #4 and #9, the CO2 was already generated when sill #4 and #9 were emplaced. (f) The total inorganic CO2 production is 49 ton/m2. There is no inorganic CO2 production for the four sills emplaced in lower Paleozoic sedimentary rocks. For the sills emplaced in the in upper Paleozoic series, the peak inorganic CO2 fluxes vary from 711 to 2235 kg/m2/yr. Note that there are no peaks for sill #5 and #9. Sill #5 is close to the lower Paleozoic section, and affects more or less only clastic sedimentary rocks (no marl), whereas sill #8, which is thicker and were emplaced prior to sill #9, already affected the sedimentary rocks surrounding sill #9.
