The Oligocene represents a transitional phase from a “hot-house” to a “cold-house” climate. Central Asia has undergone substantial environmental changes and tectonic events; however, we know little about how these tectonic events shaped the climate and biodiversity in Central Asia. Here, we present a detailed study on the early Oligocene palaeobotanical record in Kazakhstan using various qualitative and quantitative techniques of palaeoenvironmental reconstruction. According to our data, mixed mesophytic and coniferous–deciduous forest vegetation existed in a warm-temperate, largely humid yet seasonal climate, while western Kazakhstan tended to be warmer and wetter compared to eastern Kazakhstan. Our results suggest that after the Eocene–Oligocene transition, the climate became cooler and more seasonal causing the disappearance of subtropical elements. Compared to the present-day, the climate was substantially warmer and wetter, supporting forest vegetation in the study area.

中文翻译：

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中亚早渐新世气候和植被背景下的鲁佩利亚哈萨克斯坦植物群

渐新世代表了从“温室”气候到“冷宫”气候的过渡阶段。中亚经历了巨大的环境变化和构造事件；然而，我们对这些构造事件如何塑造中亚的气候和生物多样性知之甚少。在这里，我们使用各种古环境重建的定性和定量技术对哈萨克斯坦早期渐新世古植物记录进行了详细研究。根据我们的数据，中生植物和针叶-落叶混合森林植被存在于暖温带、大部分潮湿但季节性的气候中，而与哈萨克斯坦东部相比，哈萨克斯坦西部往往更温暖、更潮湿。我们的结果表明，在始新世-渐新世过渡之后，气候变得凉爽和季节性，导致亚热带元素消失。与现在相比，气候明显温暖湿润，支持研究区的森林植被。