The Gyeongsang Basin of South Korea preserves unique Cretaceous ecosystems from the tectonically active East Asian margin. We describe an allochthonous macroflora from the lacustrine deposits of the lower-middle Albian (112-106 Ma) Jinju Formation. The assemblage is dominated by scale-and awl-leaved conifers with subordinate pteridophyte, pinaceous, and taxodiaceous elements, reflecting an overall semi-arid climate. However, it also contains mesic taxa associated with temperate-humid biomes of the northern hemisphere, including the voltzian conifer Krassilovia, seed-bearing units of doylealeans, and Umaltolepis. By integrating palynological records dominated by drought-tolerant taxa (Classopollis, Cicatricosisporites, Ephedripites, Exesipollenites), we reconstruct the Jinju ecosystem as a temperate intermontane savanna. Surrounded by mountains, including a high Andean-type coastal cordillera to the east, the basin experienced topographic aridity driven by a rain shadow. This geographic setting distinguishes the Jinju flora (paleolatitude 35-38 degrees N) from coeval subtropical floras of southeastern Asia, where aridity was driven by the subtropical high-pressure belt (20-30 degrees N) during the mid-Cretaceous supergreenhouse. While xeric shrubs and cheirolepidiaceous conifers dominated the regional landscape, the basin functioned as a hydrological refugium. Wetlands hosting mesic gymnosperms, gallery woodlands of taxodiaceous conifers (supported by a moderate abundance of inaperturate pollen), and distal pinaceous communities were likely sustained by non-meteoric water sources, such as montane runoff and groundwater recharge. Representing a medial stage of aridification within the Gyeongsang Supergroup, the Jinju flora demonstrates how regional topography can create unique temperate-semiarid ecosystems that diverge from the traditional subtropical-arid versus temperate-humid provincialism of the northern hemisphere. (c) 2026 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).