Miocene fire intensification linked to continuous aridification on the Tibetan Plateau

Yunfa Miao (1, 2) , Fuli Wu (2) , Sophie Warny (3) , Xiaomin Fang (2) , Haijian Lu (4) , Bihong Fu (5) , Chunhui Song (6) , Xiaoli Yan (6) , Gilles Escarguel (7) , Yibo Yan (2) , Qingquan Meng (6) , Pilong Shi (5)

1 Northwest Institute of Eco-Environment and Resources
2 Key Laboratory of Continental Collision and Plateau Uplift
3 Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803, USA
4 Institute of Geology [Beijing]
5 RADI - Institute of Remote Sensing and Digital Earth
6 School of Earth Science & Key Laboratory of Mineral Resources in Western China
7 LEHNA - Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés

Although fire is considered an important factor in global vegetation evolution and cli- mate change, few high-resolution Miocene fire records have been obtained worldwide. Here, two independent micro-charcoal–based fire records from the northern Tibetan Plateau were analyzed; both show similar trends in micro- charcoal concentrations through time, with low abundances in the warmer Middle Miocene Climate Optimum (18–14 Ma) followed by a continuous increase throughout the late Mio- cene (14–5 Ma) cooling. Our detailed statistical analyses show that the micro-charcoal concen- tration trend is highly positively correlated to the trend in oxygen isotopes (δ18O, r = 0.94) and xerophytic species (%Xero, r = 0.95). We propose that the intensified fire frequency on the Tibetan Plateau mainly originated from the forest-steppe ecotone as a result of the continuous aridifica- tion in winter driven by the global cooling and decreased atmospheric pCO2 that occurred dur- ing 18–5 Ma, with a secondary control by the tectonic activity of the northern Tibetan Plateau.

Domaines: Biodiversité et Ecologie

Yunfa Miao, Fuli Wu, Sophie Warny, Xiaomin Fang, Haijian Lu, et al.. Miocene fire intensification linked to continuous aridification on the Tibetan Plateau. Geology, 2019, 47 (4), pp.303-307. ⟨10.1130/G45720.1⟩. ⟨hal-02095433⟩