| 松辽盆地上白垩统泉头组轨道驱动化学风化及古气候意义 |
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| 引用本文：李祥,黄永建,张治锋,杨大明.2026.松辽盆地上白垩统泉头组轨道驱动化学风化及古气候意义[J].地球学报,47(4):885-894. |
| DOI：10.3975/cagsb.2025.110611 |
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| 基金项目:本文由国家自然科学基金项目(编号: 42272134; 41972112)资助。 |
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| 中文摘要:松辽盆地国际大陆科学钻探工程获取了中国东北松辽盆地近完整的陆相白垩纪沉积记录, 为了解白垩纪陆地气候变化提供了绝佳机遇。本研究展示了松科1井南孔(SK-1s)泉头组三、四段(K2q3-4)高分辨率的化学风化记录。结果表明, 在K2q3-4的Rb/Sr和K/Ti数据序列中识别到了17.54 m、7.0~8.4 m、3.9 m的沉积旋回, 分别对应~100 ka短偏心率、~42 ka斜率和~23 ka岁差旋回信号。K2q3-4化学风化替代性指标Rb/Sr和K/Ti受到了米兰科维奇周期的调控。通过对Rb/Sr岁差信号的调制, 发现在偏心率极大值, 强岁差振幅的气候效应(如降雨增强和地表径流增强)增加了化学风化强度, 促使盆地表现为湿润气候, 同时由于季节差异的增大, 古季风增强, 为松辽盆地带来了更多的水分。晚白垩世松辽盆地位于亚洲板块的东缘, 毗邻古太平洋, 季风系统与西风带相互作用的古气候模式可能诱发了松辽盆地泉头组三、四段化学风化指标呈现周期性变化。 |
| 中文关键词:晚白垩世 松辽盆地 化学风化 轨道驱动 气候模式 |
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| Orbitally Forced Chemical Weathering in the Upper Cretaceous Quantou Formation in the Songliao Basin: Implications for Paleoclimate Change |
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| Abstract:The International Continental Scientific Drilling Project carried out in the Cretaceous Songliao Basin has recovered a complete Cretaceous terrestrial sedimentary record in northeastern China, providing a unique opportunity to understand the Cretaceous continental climate change. In this study, we present a high-resolution chemical weathering record of Members 3 and 4 of the Quantou Formation (K2q3-4) from the SK-1 South borehole. The findings show that the chemical weathering proxies Rb/Sr and K/Ti of the K2q3-4 are regulated by the Milankovitch cycles. A short eccentricity of 17.54 m (~100 ka), obliquity of 7.0–8.4 m (~42 ka), and precession cycles of 3.9 m (~23 ka) were recognized in the Rb/Sr and K/Ti data series. By modulating the Rb/Sr precession signal, it was found that during the maximum eccentricity, the climate effects of strong precession amplitudes (such as enhanced rainfall and surface runoff) increased the intensity of chemical weathering, causing the Songliao Basin to exhibit a humid climate. At the same time, due to the increase in seasonal differences, the ancient monsoon strengthened, resulting in increased rainfall in the Songliao Basin. The Late Cretaceous Songliao Basin was located on the eastern side of the Asian plate, adjacent to the Paleo-Pacific Ocean. The interaction between the monsoon system and the westerlies in the paleoclimate model may be the potential reason for the periodic changes in the chemical weathering proxies of Members 3 and 4 of the Quantou Formation in the Songliao Basin. |
| keywords:Late Cretaceous Songliao Basin chemical weathering orbital forcing paleoclimatic pattern |
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