| Summary: | To reconstruct the palaeovegetation and palaeoclimate in the Baise Basin during the Oligocene, in this work, we analyzed sporopollen fossils from the Fuping Formation in this region. Thirty-four genera sporopollen fossils are found and divided into two assemblages: (Ⅰ) Abietineaepollenites-Quercoidites-Polypodiaceaesporites Assemblage and (Ⅱ) Abietineaepollenites-Pinuspollenites-Pediastrum Assemblage. The age of assemblage Ⅰ and Ⅱ are mid-Rupelian to Oligocene, and late-Rupelian to early-Chattian to Oligocene, respectively. The paleovegetation changed from conifer-broad leaf forest with fern vegetation growing at the bottom to coniferous forest. Through the study of the characteristics of the palynological assemblages, assemblage Ⅰ represents a subtropical humid climate condition with relatively high humidity, while assemblage Ⅱ represents a humid climate condition in the subtropical zone. The coexistence approach of the nearest living relatives of the palynomorphs shows that during the period of the mid-Rupelian to the early Chattian of the Oligocene, the mean annual precipitation (MAP) was 797.5-1 293.7 mm, and the mean annual temperature (MAT) was 11.3-22.6℃ in the Baise Basin. The characteristics of this basin were a northern subtropical climate during the mid-Rupelian to the early Chattian. However, the present Baise Basin is located in the southern subtropics(MAT: 22.0℃, MAP: 1 070.5 mm). The difference between the Oligocene and today may be related to the "right-rotation" of the Asian Plate caused by the collision between the Cenozoic Indian Plate and the Asian Plate.
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