Preliminary study on CO2 output of post-collisional K-rich volcanism in western Lhasa terrane
Estimating volcanic CO2 output in the geological past is important for understanding Earth's deep carbon emission and its impact on climate and environment.Here we focus on the post-collisional K-rich volcanism in western Lhasa terrane,Tibetan Plateau.Taking the K-rich volcanic rocks in Xungba,Sailipu,Bugasi,and Maiga as examples,we studied on CO2 content and degassing features of melt inclusions in olivine and pyroxene.The CO2 output of post-collisional K-rich volcanism in Lhasa terrane was estimated by combining parameters such as volcanic volume and rock ages.Our results show that CO2 content of gas bubble in volcanic rock melt inclusions in study area are range from 0.61％to 5.38％,and the CO2 annual output of Xungba,Sailipu,Bugasi,and Maiga volcanic rocks is estimated at(5.1±0.9)× 10-5 Pg/yr,(1.3±0.6)× 10-5 Pg/yr,(2.5±0.5)×10-4 Pg/yr and(1.5±0.2)×10-7 Pg/yr,respectively,yielding a sum of～(3.2±0.6)×10-4Pg/yr.Roughly extrapolating to the entire Lhasa terrane,the post-collisional K-rich volcanism may have a CO2 output of～0.006±0.001Pg/yr,consistent with the results of continental collision-derived CO2 flux model.Our results provide preliminary data for simulating deep CO2 emissions caused by the India-Asia collision during geological history.In the future,it is still necessary to optimize the research results based on obtaining more data to reduce the uncertainty caused by the differences in magma composition,eruption volume,and spatial-temporal distribution of post-collisional volcanic activity.
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