The early Paleogene was a typical greenhouse climate period in the Cenozoic, during which a series of rapid and short-lived warming events（termed “hyperthermals”） occurred. Hyperthermals were characterized by negative carbon isotope excursion. Among them, the Dan-C2 thermal event of the early Danian is considered to be the first to occur after the biological mass extinction at the end of the Cretaceous; thus, its environmental significance and ecological effects have received widespread attention. However, as research continues, controversies regarding the Dan-C2 event continue to grow:（1） The global significance is controversial;in the marine records, the δ 13 C negative excursions during the Dan-C2 event were restricted to planktonic foraminifera and bulk records in parts of the Atlantic and Tethys Oceans, while benthic foraminifera rarely recorded this event, suggesting that it may only be a regional carbon perturbation event. Furthermore, the warming indicated by the oxygen isotopes(δ 18 O) of bulk and planktonic foraminifera during this event was limited to surface waters in parts of the North Atlantic, with evidence of warming in bottom waters generally lacking. At the same time, although evidence of the terrestrial Dan-C2 event has been discovered, the terrestrial records still have significant deficiencies in terms of quantification, chronology, and continuity compared with the marine records, which makes it difficult to conduct in-depth and effective comparisons between the terrestrial and marine records; therefore, the global significance of the Dan-C2 event is questioned.（2） The trigger mechanism is controversial; the high-precision chronological frame shows that the Dan-C2 event occurred at the eccentricity maximum, indicating that the orbital cycle had a certain influence on the event. Simultaneously, the temporal coincidence of the Dan-C2 event with the last phase of the eruption of the Deccan Traps volcanism implies that greenhouse gas emissions from volcanic activity may have contributed to warming during the Dan-C2; however,the relative magnitudes of both contributions to the event is difficult to assess. Future research should focus on the following:（1） Exploring the variability of the Dan-C2 event records in different areas and revealing the reasons for the absence of deep-ocean water records.（2） Establishing more reliable terrestrial records and further exploring the global significance of the Dan-C2 event and its triggering mechanism.

由于化石燃料大量燃烧,大气CO2浓度跟温度都呈现快速上升趋势,这两者之间的关系是学术界研究的热点.地质历史时期发生过多次的快速增温事件,伴随着大气CO2浓度的增加,通过研究这些气候相似型可以为上述问题提供参考和借鉴.白垩纪晚期-古近纪早期(约67～52Ma)是地质历史时期中典型的温室气候期,在这一时期发生了一系列快速和短暂的增温事件(热事件).热事件的发生伴随着碳同位素负偏移(CIE)、碳酸盐补偿深度(CCD)变浅、大气中CO2含量增加及温度升高等现象,一些热事件同时还出现了环境变化和生态效应.这给我们提供了机会来研究气候变化和碳循环之间的耦合规律,帮助我们更好地预测未来气候、环境和生物变化.文章根据最新的研究成果,对白垩纪晚期-古近纪早期的热事件识别、触发机制及碳来源作了综述并提出展望.目前全球近200个地点发现系列热事件记录,绝大部分记录来自海相沉积,陆相沉积记录很少;热事件的触发机制主要有天文轨道周期、火山活动、地外天体撞击、构造抬升作用等观点;热事件碳来源主要有泥炭、永久冻土、甲烷水合物、火山及地外天体.在今后的热事件研究中应加强:1)陆相记录及其与海相记录的对比研究;2)不同热事件触发机制研究,尤其是古新世-始新世极热事件(PETM)、马斯特里赫特期末期增温事件(LMWE)等这些能够造成严重环境变化和生态效应的热事件;3)碳来源方面的研究,进一步了解几大碳库碳释放的通量和特征,并且结合地质记录、模型模拟及示踪元素来揭示热事件的碳来源.

The extinction of non‐avian dinosaurs and its cause(s) have been a matter of debate for several decades. Here we measured Hg and its isotopic composition, heavy metals, and magnetic parameter in a terrestrial basin in southeastern China. Hg exhibited anomalies from 66.4 to 65.6 Ma, with near‐zero to positive Δ 199 Hg values, which reflected the eruption of Deccan Traps (DT) magma. In addition, Hg anomalies coincided with the gradual extinction of non‐avian dinosaurs, thereby consistent with the hypothesis that DT played a key role in the mass extinction. Analysis of paleoclimatic records showed that both the Late Maastrichtian warming event (LMWE) and Dan‐C2 event occurred at the maxima of the 405‐kyr long eccentricity cycle, and the onset of the dinosaur decline was earlier than the LMWE, suggesting that the LMWE played an ancillary role in the mass extinction. The mechanism of how DT caused the mass extinction requires further investigation.

陆相地层中K-Pg位置的确定对白垩纪末期陆地生态系统演化过程(尤其是非鸟类恐龙灭绝)的研究意义重大,目前世界范围内的陆相K-Pg研究集中在中高纬度地区,如北美及中国的东北地区.位于低纬度地区的南雄盆地虽然也开展了大量的工作,成为中国陆相白垩系-古近系地层划分对比的标准,但是不同的研究者从不同的角度提出了4条可能的界线,因此关于其具体的位置仍有待进一步确定.本文对4条界线前后的样品进行了总汞(Hg)含量、环境磁学、地球化学等参数的测定,并与全球记录进行了对比.结果 显示:(1)总Hg含量在浈水组上段和上湖组坪岭段明显升高,且表现出剧烈的峰谷波动,结合已有的年代结果,可以将Hg的异常高值归因为德干高原火山喷发,界线1位于Hg异常区间的中部,也是火山喷发的中期,符合全球K-Pg界线与火山喷发的时间关系;(2)重建的古气候演化曲线揭示出盆地红色沉积物记录了马斯特里赫特期末期的热事件(～66.2Ma,LMWE),从4条界线与该事件的联系上看,也只有界线1最接近南雄盆地真实的K-Pg界线.

Determining the location of the Cretaceous-Paleogene (K-Pg) boundary in terrestrial strata is highly significant for studying the evolution of terrestrial ecosystems at the end of the Cretaceous (especially the extinction of non-avian dinosaurs). At present, research on terrestrial K-Pg boundaries worldwide is concentrated in the middle and high latitudes, such as North America and Northeast China. Although many studies have also been carried out in the Nanxiong Basin, located at low latitudes (which has become the standard for dividing and comparing the continental K-Pg stratigraphy in China), many researchers have proposed four possible boundaries from different perspectives. Therefore, the exact location remains to be determined. In this study, the total mercury (Hg) content, environmental magnetism, geochemistry, and other parameters for the samples collected near the four boundaries were determined and compared with existing records. Results indicated that: 1) The total Hg content significantly increased in the upper part of the Zhenshui Formation and Pingling part of the Shanghu Formation with sharp fluctuations. As per latest dating results of Deccan Traps, the significantly high Hg value was attributed to the Deccan Traps eruption. Boundary 1 was located in the middle of the Hg anomaly interval, which was consistent with the relationship between the global K-Pg boundary and time of volcanic eruption. 2) The reconstructed paleoclimate evolution curve revealed that the red sediments in the basin recorded the late Maastrichtian warming event (66.2 Ma). Regarding the relationship between the four boundaries and this warming event, only boundary 1 was found to be closest to the real K-Pg boundary of the Nanxiong Basin.

本文通过对2003-2013年采用融合算法反演的MODIS气溶胶光学厚度数据进行分析，对内蒙古气溶胶光学厚度的时空分布特征进行推测。以MODIS-Aqua月尺度数据产品MYD08_M3为数据源，利用envi 5.3提取研究区AOD值，并在ArcGis平台对影像进行后期处理。同时下载了内蒙古主要城市的大风日数月均值和相对湿度月均值，采用相关分析法和趋势分析法计算研究区AOD与其相关性。主要得出以下结论：（1）内蒙古的AOD值在东北部地区最高，均值为0.35，最低值出现在中部地区，均值为0.17。（2）全年AOD峰值出现在春季和夏季，均值分别为0.38 和0.28。春季峰值主要受沙尘影响，夏季峰值是由于雨季到来导致空气中水汽含量增加。（3）大风日数与内蒙古AOD相关性较强，相对湿度与内蒙古AOD的相关性并不显著。