A mid-altitude area in southwestern China experienced a humid subtropical climate with subtle monsoon signatures during the early Oligocene: Evidence from the Ningming flora of Guangxi
A mid-altitude area in southwestern China experienced a humid subtropical climate with subtle monsoon signatures during the early Oligocene: Evidence from the Ningming flora of Guangxi
复制标题
渐新世早期中国西南中海拔地区经历了湿润的亚热带气候和微妙的季风特征：来自广西宁明植物区系的证据
DOI：
10.1016/j.palaeo.2021.110601
复制
发表时间：
2021-08-19
影响因子：
3
通讯作者：
Sun, Bai-Nian
中科院分区：
文献类型：
--
作者：
Ling, Chen-Chen;Ma, Fu-Jun;Sun, Bai-Nian
渐新世标志着当前“冰室”时代的开始，并见证了亚洲季风系统（AMS）的发展和演变。本文对中国南方广西渐新世早期宁明植物区系进行了分析，以研究基于气候叶分析多元程序（CLAMP）衍生的气候代理的AMS。 CLAMP结果表明，宁明植物区系的主导气候为亚热带湿润气候，夏季炎热，冬季温暖。尽管降水季节性记录较弱，但其强度约为今天华南季风气候的一半，表明季风信号非常弱。尽管降雨季节性较弱，但宁明植物区系在地貌空间中的位置表明，叶子表现出季风适应的形态，与今天暴露于印度尼西亚-澳大利亚季风（I-AM）和过渡季风区（受东亚季风、南亚季风和I-AM影响）的植被相当。叶子的建筑特征表明，宁明植物群生长在潮湿的亚热带气候下，具有微妙的季风特征。尽管在如此微妙的季风影响下很难区分亚洲季风的不同区域，但根据南亚的树叶特征，可以推断渐新世早期的宁明盆地面临着类似于今天受I-AM影响的气候状况。此外，还应用湿焓法定量重建了宁明盆地的古海拔。这种方法表明，渐新世早期的古海拔估计类似于 1.24-1.35 +/- 0.52 km，这表明宁明盆地的古海拔下降发生在渐新世早期（鲁佩勒期）之后。 CLAMP结果表明，渐新世早期的宁明地区处于中海拔，经历了湿润的亚热带气候，具有微妙的季风特征。
The Oligocene marked the beginning of the present 'icehouse' epoch and witnessed the development and evolution of the Asian monsoon system (AMS). In this paper, the early Oligocene Ningming flora of Guangxi, southern China, is analysed to investigate the AMS based on climate proxies derived from Climate Leaf Analysis Multivariate Program (CLAMP). CLAMP results suggest that the prevailing climate experienced by the Ningming flora was humid subtropical with hot summers and warm winters. Although the record of precipitation seasonality is muted, it is about half as strong as that seen today in monsoon climates of South China, indicating a very weak monsoonal signal. Despite suggesting weak rainfall seasonality, the position of the Ningming flora in physiognomic space indicates that leaves exhibit monsoon-adapted morphologies, comparable to today's vegetation exposed to the Indonesia-Australia monsoon (I-AM) and the transitional monsoon area (influenced by the East Asia monsoon, South Asia monsoon and I-AM). Leaf architectural signatures reveal that the Ningming flora grew under a humid subtropical climate with subtle monsoon signatures. Although it is difficult to distinguish the different domains of the Asian monsoon under such a subtle monsoon influence, based on leaf signatures from southern Asia, it can be inferred that the Ningming Basin during the early Oligocene was exposed to a climate regime similar to that today influenced by the I-AM. In addition, the moist enthalpy method was applied to quantitatively reconstruct the paleoelevation of the Ningming Basin. This approach suggests a paleoelevation estimate of similar to 1.24-1.35 +/- 0.52 km for the early Oligocene, suggesting that a drop in paleoelevation of the Ningming Basin took place after the early Oligocene (Rupelian). The CLAMP results suggest that the early Oligocene Ningming area was at a mid-altitude and experienced a humid subtropical climate with subtle monsoon signatures.