Palaeogeography, Palaeoclimatology, Palaeoecology最新文献_第5页

The Hirnantian-Rhuddanian succession in East Central United States: New implications for latest Ordovician to early Silurian sea level 美国中东部的希尔南梯-鲁达尼演替：奥陶世晚期至志留纪早期海平面的新意义

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-06 DOI: 10.1016/j.palaeo.2026.113548

Cole F. Farnam , Carlton E. Brett , Lincoln Shoemaker , Jisuo Jin , Robert J. Elias , Christopher B.T. Waid

A detailed understanding of the Late Ordovician to early Silurian glaciations and Hirnantian mass extinctions requires high resolution pattern and timing of sea level and climatic events. The record is particularly poorly known in the eastern USA, which was previously assumed to lack Hirnantian strata. Synthesis of new and previously reported biostratigraphic evidence and carbon isotope chemostratigraphy indicates that thin but widespread, fossiliferous upper Hirnantian strata are preserved in southern Ohio and southeastern Indiana. Elevated values of δ¹³C_carb, within and just beneath strata of the Ozarkodina hassi Zone, in siltstones and carbonates of the lower Whippoorwill Formation (new, herein) of the Cincinnati Arch in Ohio and Indiana, indicate the signature of the upper part of the Hirnantian isotopic carbon excursion (HICE). The presence of conodonts of the O. hassi Zone and brachiopods, corals, and a large dalmanitid trilobite belonging to the globally recognized Edgewood-Cathay fauna strongly supports a latest Hirnantian age for the Whippoorwill Formation. Sequence stratigraphy of the Whippoorwill Formation and the immediately overlying interval allowed for recognition of two thin (possibly 4th order) sequences in the Ohio and Indiana region (Hirnantian-2A (H2A), Centerville Member, and Hirnantian-2B (H2B), Belfast Member). The older Hirnantian (H1) sequence is absent in the greater Cincinnati region and probably truncated beneath the composite H2 or Cherokee Unconformity. Locally, the H2A and H2B sequences are truncated or completely removed beneath the higher Rhuddanian S1A erosion surface (base Brassfield Formation). In turn, the highly irregular lower Aeronian S2B erosion surface (base Oldham) can also locally cut deeply through lower Silurian, Hirnantian, and even upper Katian strata. Correlation of these sequences and their bounding unconformities across eastern North America reveals widespread sequences probably controlled by glacioeustasy during the latest Hirnantian and Rhuddanian.

要详细了解晚奥陶世到早志留世的冰期和希尔南梯的大灭绝，需要高分辨率的海平面和气候事件的模式和时间。美国东部的记录尤其不为人所知，此前人们认为那里缺乏希尔南梯地层。新的和先前报道的生物地层学证据和碳同位素化学地层学的综合表明，在俄亥俄州南部和印第安纳州东南部保存了薄而广泛的化石上Hirnantian地层。在俄亥俄州和印第安纳州辛辛那提Arch的Whippoorwill组下部粉砂岩和碳酸盐中，在Ozarkodina hassi带地层内部和地层下方的δ13Ccarb值升高，表明了Hirnantian同位素碳偏移（HICE）上半部分的特征。O. hassi带的牙形刺、腕足类动物、珊瑚和属于全球公认的Edgewood-Cathay动物群的大型dalmanitid三叶虫的存在，有力地支持了Whippoorwill组的最新Hirnantian时代。Whippoorwill组层序地层学及其上覆层序在俄亥俄州和印第安纳州地区识别了两个薄层序（可能是4级），分别是Centerville段Hirnantian-2A （H2A）和Belfast段Hirnantian-2B （H2B）。在大辛辛那提地区没有较老的Hirnantian （H1）层序，可能被截断在H2或Cherokee不整合之下。局部，H2A和H2B序列在较高的鲁达尼期S1A侵蚀面（基底Brassfield组）下被截断或完全移除。反过来，高度不规则的下Aeronian S2B侵蚀面（基地Oldham）也可以局部深入切割下志留纪，Hirnantian，甚至上Katian地层。这些序列与它们在北美东部的边界不整合的对比表明，这些序列很可能是在最新的希尔南天纪和鲁达尼世受到冰川游动的控制。

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引用次数: 0

Dynamics of the Arabian Sea thermocline and monsoon-climate coupling mechanisms over the past 55,000 years: Multi-proxy paleoenvironmental reconstruction 过去55000年阿拉伯海温跃层动态和季风-气候耦合机制：多代理古环境重建

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-05 DOI: 10.1016/j.palaeo.2026.113544

Feng Wang , Yunhai Li , Min Chen , Xuan Ding , Yunpeng Lin

This study systematically reconstructed the variations in the thermocline of the Arabian Sea over the past 55,000 years and its responsive relationships with global climate events through multi-proxy analyses (including planktonic foraminiferal assemblages, Mg/Ca temperature reconstruction, carbonate content, and fragment rate, etc.) of the CJ08–22 sediment core from the Arabian Basin in the northwestern Indian Ocean. During the MIS3 stage (40–29 ka), the thermocline depth exhibited significant fluctuations, with the sea surface-thermocline temperature difference (ΔT) varying synchronously with Dansgaard-Oeschger (DO) events. Enhanced Indian summer monsoons during warm periods led to weakened upwelling (decreased ΔT), whereas intensified winter monsoons during cold periods triggered strengthened upwelling (increased ΔT). During the MIS2 glacial maximum (29–14 ka), the thermocline shallowed with stably high ΔT, reflecting persistent upwelling driven by strong winter monsoons and deep-water acidification (minimum CaCO₃ content). In the MIS1 Holocene (14 ka–), the thermocline deepened, with ΔT consistent with solar insolation. During the 8.2 ka event, the monsoon weakened in the short to medium term. After the establishment of the modern monsoon system, the upwelling intensified again. Principal component analysis of planktonic foraminifera reveals the antagonistic distribution between warm current species (such as Globigerinoides ruber) and upwelling species (such as Globigerina bulloides), suggesting the synergistic effect of the monsoon-driven Arabian Current and Ekman pumping. The thermocline variations in the Arabian Sea showed significant correlations with North Atlantic DO events, the Heinrich 1 event, and solar orbital forcing (20 ka precession cycle), indicating that high-latitude ice volume changes regulate low-latitude oceanic processes through atmospheric circulation (e.g., winter monsoons). This study provides new evidence for understanding the key role of the Arabian Sea in glacial-interglacial cycles, emphasizing that thermocline dynamics serve as a critical hub linking regional monsoon responses to global climate changes, which has implications for predicting the evolution of the Indian Ocean-monsoon system under future global warming.

通过对印度洋西北部阿拉伯盆地CJ08-22沉积物岩心的浮游有孔虫组合、Mg/Ca温度重建、碳酸盐含量、碎片率等多指标分析，系统重建了阿拉伯海近55000年来的温跃层变化及其与全球气候事件的响应关系。MIS3阶段（40 ~ 29 ka），温跃层深度出现显著波动，海面-温跃层温差（ΔT）与Dansgaard-Oeschger （DO）事件同步变化。暖期印度夏季季风增强导致上升流减弱（减少ΔT），而寒冷期冬季季风增强则引发上升流增强（增加ΔT）。在MIS2极盛期（29 - 14ka），温跃层变浅，稳定高ΔT，反映了强烈冬季季风和深水酸化（CaCO3含量最低）驱动的持续上升流。在MIS1全新世（14ka -），温跃层加深，ΔT与太阳日照一致。在8.2 ka事件中，季风在中短期内减弱。现代季风系统建立后，上升流再次加强。浮游有孔虫主成分分析显示暖流种（如gloigerinoides ruber）和上升流种（如gloigerina bulloides）之间存在拮抗分布，表明季风驱动的阿拉伯海流和Ekman泵的协同作用。阿拉伯海温跃层变化与北大西洋DO事件、Heinrich 1事件和太阳轨道强迫（20ka岁差周期）具有显著的相关性，表明高纬度冰量变化通过大气环流调节低纬度海洋过程（如冬季季风）。该研究为理解阿拉伯海在冰期-间冰期旋回中的关键作用提供了新的证据，强调了温跃层动力学是连接区域季风响应与全球气候变化的关键枢纽，这对预测未来全球变暖下印度洋季风系统的演变具有重要意义。

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引用次数: 0

Middle Eocene hyperthermal seasonality from Paris Basin marine mollusks 巴黎盆地海洋软体动物中始新世高温季节特征

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-05 DOI: 10.1016/j.palaeo.2026.113547

Loïc Marlot , Damien Huyghe , Justine Briais , Mathieu Daëron , Christine Flehoc , Laurent Emmanuel , Didier Merle , Olivier Aguerre-Chariol , Franck Lartaud

The Earth has experienced hyperthermal events in the past, characterized by maximum durations of hundreds thousand years, significant magnitude, global extent, and drivers associated with increases in greenhouse gas concentrations, therefore making them potential analogues for current climate change. The Middle Eocene Climatic Optimum (MECO) that occurred 40 Ma ago, is marked by a CO₂-driven global warming of +4 to +6 °C, affecting global temperatures. Here, we present a detailed reconstruction of seasonal fluctuations in seawater temperatures during this warming event in littoral environment, based on geochemical analyses (δ¹⁸O and ∆₄₇) of shallow-marine mollusks from the Paris Basin. Our data show a stability in mean winter temperatures compared to pre-MECO conditions, but a marked warming of +10 °C in maximum estuarine water temperatures, with a seasonal temperature range increasing from 12 °C before the MECO to 22 °C at the climax of the event. We demonstrate that at mid-latitudes, annual maximum shallow-water temperatures increased from 30 ± 2 °C before the event to a maximum of 41 ± 4 °C at the warming peak. This pattern is associated with a seasonal regime characterized by dry summers and wet winters, implying that the Paris Basin experienced a super-hot summer Mediterranean climate during the MECO.

地球过去曾经历过高温事件，其特征是最长持续时间长达数十万年，规模巨大，全球范围广，以及与温室气体浓度增加相关的驱动因素，因此使其成为当前气候变化的潜在类似物。40 Ma前发生的中始新世气候最适期（MECO）以二氧化碳驱动的全球变暖+4 ~ +6°C为标志，影响了全球气温。本文基于巴黎盆地浅海软体动物的δ18O和∆47地球化学分析，详细重建了这次变暖事件中沿海环境海水温度的季节波动。我们的数据显示，与MECO前相比，冬季平均气温保持稳定，但河口最高水温明显变暖+10℃，季节性温度范围从MECO前的12℃增加到事件高潮时的22℃。研究表明，在中纬度地区，年最高浅水温度从事件前的30±2°C上升到变暖高峰时的41±4°C。这种模式与夏季干燥和冬季潮湿的季节性气候有关，这意味着巴黎盆地在MECO期间经历了一个超级炎热的夏季地中海气候。

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引用次数: 0

The reconstruction of the destroyed city floods of the Daming Prefecture during Ming Dynasty 明代大明州被毁城市洪水的重建

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-05 DOI: 10.1016/j.palaeo.2026.113546

Tianyu Du , Xueyan Ren , Junxia Yan , Yuecong Li , Yuejie Wu , Mingxia Xie , Shaoqing Guo , Wei Lv , Nan Yang , Qinghai Xu , Bing Li , Huayong Li

Under global warming, extreme climate events are increasing in frequency.

Floods remain major disasters due to their frequent occurrence and widespread impacts on human societies. Current observational data inadequately constrain rare high-magnitude flood events, so the reconstruction of paleoflood with long time scale is particularly important. Daming Prefecture was once the capital of seven dynasties and served as the “Beijing” of the Northern Song Dynasty (960–1127 CE), with a significant military status, but the city was destroyed by a flood disaster in Ming Dynasty (about 1400 CE), retains ancient flood deposits, which provide valuable material for reconstructing ancient floods. Through the AMS ¹⁴C and archaeological dating, we established an accurate time frame for the paleoflood. Beyond the field lithology, particularly the brown-red clay, we determined the flood layers in the second and fifth layers using indicators like pollen, grain size, and magnetic susceptibility. Notably, the elevated levels of fine silt (46.1 %), organic matter (4.7 %), tree and shrub pollen (30.8 %), Pinus (27.2 %), and fern spores (46.5 %) are key markers for identifying paleoflood events in the area. The extreme paleoflood depth that destroyed the city was estimated at least 2.1–3.3 m based on end-point elevation method. Furthermore, we found that the paleoflood in the region was primarily influenced by weak El Niño conditions and the northward shift of the Intertropical Convergence Zone. This provides a scientific basis for the future construction of water conservancy facilities, flood control measures, and soil erosion prevention in the region.

在全球变暖的背景下，极端气候事件的发生频率越来越高。洪水因其频繁发生和对人类社会的广泛影响而成为主要灾害。目前的观测资料对罕见的高震级洪水事件约束不足，因此对长时间尺度的古洪水进行重建显得尤为重要。大明府曾是七朝都城，是北宋（公元960-1127年）的“北京”，具有重要的军事地位，但在明朝（公元1400年左右）被洪水摧毁，保留了古代洪水沉积物，为重建古代洪水提供了宝贵的资料。通过AMS 14C和考古测年，我们确定了古洪水发生的准确时间框架。除了野外岩性，特别是棕红色粘土，我们还利用花粉、粒度和磁化率等指标确定了第二层和第五层的洪水层。其中，细粉土（46.1%）、有机质（4.7%）、乔灌木花粉（30.8%）、松类（27.2%）和蕨类孢子（46.5%）含量的升高是识别古洪水事件的关键标志。根据终点高程法估计，古洪水极端深度至少为2.1 ~ 3.3 m。此外，该地区的古洪水主要受弱El Niño条件和热带辐合带北移的影响。这为今后该地区的水利设施建设、防洪措施和水土流失防治提供了科学依据。

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引用次数: 0

Holocene precipitation change in an East Asian sandy land: Perspectives from the grain size records of multi-sections 东亚沙地全新世降水变化：来自多剖面粒度记录的视角

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-03 DOI: 10.1016/j.palaeo.2026.113545

Zhuo Yang , Dongmei Jie , Guizai Gao , Yutong Qian

Integrating multiple climate proxies is vital for advancing regional climate reconstruction. This study minimizes uncertainty among records by analyzing four aeolian-paleosol profiles (ADQ, HTGL, MJ, FX) within China's Horqin Sandy Land, using grain size as the primary climate proxy. Initially, end-member analysis was employed to separate the end-member components from the different profiles. By combining topsoil particle size data and modern meteorological monitoring data, the relationship between coarse-grained components and climate factors was established, providing strong evidence for the coarse-grained end-members in the sections that represent regional climate change. Based on this, we employed the regional averaging method to extract regional climate signals represented by coarse-grained end-member components from various profiles. Simultaneously, by integrating the locations of each profile with records of human activities, we investigated whether these climate signals were influenced by local signals. The results indicate that the regional climate signals derived from multiple profiles (grain size range: 77.77–566.88 μm) accurately reflect a precipitation trend in the region during the Holocene, which initially increased and then decreased. Furthermore, the end-member components representing regional climate signals in profiles from different locations may be affected by human activities and natural environmental factors, leading to the contamination of these signals with their respective local environmental signals.

综合多种气候指标对推进区域气候重建具有重要意义。本研究以粒度为主要气候指标，分析了中国科尔沁沙地4条风成-古土壤剖面（ADQ、HTGL、MJ、FX），最大限度地减少了记录中的不确定性。最初，采用端元分析从不同剖面中分离端元组分。结合表层土壤粒度数据和现代气象监测资料，建立了粗粒度组分与气候因子的关系，为代表区域气候变化剖面的粗粒度端元提供了有力证据。在此基础上，采用区域平均方法提取了以粗粒度端元分量为代表的区域气候信号。同时，通过将每个剖面的位置与人类活动记录相结合，我们研究了这些气候信号是否受到当地信号的影响。结果表明，多剖面（粒度范围77.77 ~ 566.88 μm）的区域气候信号准确反映了该区全新世降水先增加后减少的变化趋势。此外，代表不同地点剖面区域气候信号的端元分量可能受到人类活动和自然环境因子的影响，导致这些信号被各自的当地环境信号所污染。

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引用次数: 0

Dietary ecology of neotropical brocket deer: Evidence from mesowear and microwear analyses 新热带小鹿的饮食生态学：来自中磨损和微磨损分析的证据

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-02 DOI: 10.1016/j.palaeo.2025.113542

María Fernanda Martínez-Polanco

Neotropical deer exhibit remarkable diversity, particularly within the genus Mazama. Traditional species identification relied on morphological traits such as unbranched antlers; however, these features are now recognized as evolutionary convergences linked to similar environmental adaptations. Recent genetic analyses have reclassified Mazama into three genera—Subulo and Passalites—and reassigned one species to Odocoileus. Given the elusive nature of these small deer, this study investigates their dietary ecology through integrated dental wear analyses, specifically mesowear and microwear. A total of 357 specimens from eight cervid taxa—Mazama americana, M. bricenii, M. nana, M. rufina, M. temama, Subulo gouazoubira, Odocoileus pandora, and Passalites nemorivagus—were examined, spanning a broad geographic range from Mexico to Argentina. Mesowear analysis reveals a dietary gradient from strict leaf browsing in O. pandora, M. bricenii, and M. nana to more abrasive mixed feeding in S. gouazoubira, M. americana, and P. nemorivagus, with notable intraspecific variability in some taxa. Microwear patterns support these distinctions and highlight significant local dietary variation within species, despite overall stability in mesowear scores across countries. These findings demonstrate both ecological specialization and flexibility among Neotropical cervids and underscore the value of combined meso- and microwear approaches to reconstruct feeding strategies. This study provides essential baseline data for paleoecological and archaeological research, as well as for conservation studies of elusive brocket deer.

新热带鹿表现出显著的多样性，特别是在马扎马属。传统的物种鉴定依赖于形态学特征，如未分枝的鹿角；然而，这些特征现在被认为是与相似的环境适应有关的进化趋同。最近的遗传分析已经将Mazama重新划分为三个属- subbulo和passalites -并将一个物种重新分配给Odocoileus。考虑到这些小鹿难以捉摸的性质，本研究通过综合牙齿磨损分析来研究它们的饮食生态，特别是中观磨损和微磨损。研究了从墨西哥到阿根廷的8个鹿科分类群（mazama americana、M. bricenii、M. nana、M. rufina、M. temama、Subulo gouazoubira、Odocoileus pandora和Passalites nemorivaga）共357个标本。细观分析显示，从pandora、M. bricenii和M. nana的严格食叶到S. gouazoubira、M. americana和P. nemorivagus的较为粗糙的混合食性，在某些分类群中存在显著的种内变异。微磨损模式支持了这些区别，并突出了物种内部显著的地方饮食差异，尽管中磨损评分在各国总体上保持稳定。这些发现表明了新热带生物的生态专门化和灵活性，并强调了中观和微观相结合的方法对重建摄食策略的价值。本研究为古生态学和考古学研究以及对小鹿的保护研究提供了重要的基础数据。

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引用次数: 0

Two-stage Jurassic tectono-geomorphological evolution of the Yili-Central Tianshan: Insights into its role in shaping the Mesozoic-Cenozoic Landscape 伊犁-中天山侏罗系两期构造地貌演化及其对中新生代地貌形成的影响

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-02 DOI: 10.1016/j.palaeo.2025.113541

Dunfeng Xiang , Qigui Mao , Zhiyong Zhang , Songyan Liu , David Chew , Lin Wu , Nan Wang , Chao Guo , He Yang , Wenjiao Xiao

The Jurassic tectonic and geomorphic evolution of the Chinese West Tianshan (CWTS) remains controversial, with conflicting models proposing either regional peneplanation or a local topographic relief. We present the first integrated detrital apatite U-Pb geochronology and trace element geochemistry dataset from Jurassic strata in the Yili and Bayanbulak Basins, complemented by previously published detrital zircon U-Pb data, to constrain the Jurassic tectono-geomorphic evolution of the CWTS. Our results demonstrate that early Early Jurassic sediments in the northern Yili Basin were primarily sourced from the North Tianshan-northern Yili Block and central Yili Block, reflecting topographic barriers that restricted southern sediment input. By the late Early Jurassic, these barriers were eroded, enabling south-derived detritus (460–400 Ma) from the southern Yili-Central Tianshan to reach the northern Yili Basin, signaling diminished topographic relief. In contrast, the Bayanbulak Basin recorded consistent provenance from the southern Yili-Central Tianshan throughout the Jurassic, indicating sustained high topography in this domain. These findings reveal a two-stage Jurassic evolution in the Yili-Central Tianshan region: Early Jurassic uplift with proximal sedimentation likely driven by far-field stresses from the Qiangtang collision or Mongol-Okhotsk closure, followed by the late Early to Late Jurassic regional peneplanation, interrupted by a persistent relief in the southern Yili-Central Tianshan. The two-stage Jurassic tectono-geomorphological evolution of the Yili-Central Tianshan reveals a north-to-south, time-transgressive planation across the region, and demonstrates the critical influence of inherited Mesozoic structures on the present-day landscape.

中国西天山的侏罗纪构造和地貌演化至今仍有争议，不同的模式提出了区域性的透蚀或局部的地形起伏。本文首次建立了伊力盆地和巴音布鲁克盆地侏罗系地层的碎屑磷灰石U-Pb年代学和微量元素地球化学数据，并结合之前发表的碎屑锆石U-Pb数据，以约束CWTS侏罗系构造地貌演化。研究结果表明，伊犁盆地北部早侏罗世早期沉积物主要来自北天山-北伊犁地块和中部伊犁地块，反映了地形障碍对南部沉积物输入的限制。早侏罗世晚期，这些屏障被侵蚀，使得来自伊犁南部-中天山的南源碎屑（460-400 Ma）到达伊犁盆地北部，表明地形起伏减弱。而巴音布鲁克盆地在整个侏罗纪时期从南伊犁-中天山记录了一致的物源，表明该地区持续的高地形。这些发现揭示了伊犁-中天山地区侏罗纪演化的两个阶段：早侏罗世隆升和近端沉积可能是由羌塘碰撞或蒙古-鄂霍次克闭合的远场应力驱动的，随后是早侏罗世晚期至晚侏罗世的区域侵平，被伊犁-中天山南部的持续起伏所打断。伊犁-中天山侏罗系两期构造地貌演化揭示了该地区由北向南的时海侵夷平，并揭示了继承的中生代构造对现今地貌的重要影响。

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引用次数: 0

A semi-quantitative ichnological approach to relative oxygen reconstruction: A case study over the Cenomanian-Turonian Oceanic Anoxic Event 2 in west-Central Alberta, Canada 相对氧重建的半定量技术方法：以加拿大阿尔伯塔省中西部塞诺曼尼亚-土伦尼亚海洋缺氧事件2为例

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-12-31 DOI: 10.1016/j.palaeo.2025.113539

Sara K. Biddle, Murray K. Gingras

An exceptionally well-preserved organic-rich mudstone core from the Cenomanian-Turonian Oceanic Anoxic Event 2 (OAE2) interval in the Canadian Western Interior Seaway offers an excellent opportunity for comprehensive ichnological analysis of paleo‑oxygen fluctuations. Vertical trends in burrow size and diversity (i.e., Size-Diversity Index - SDI) have previously served as a proxy for relative oxygenation in low-oxygen stratigraphic settings. We note two factors that greatly impact oxygenation interpretations of SDI: (1) high bioturbation intensities or reworking dominantly by small (meiofaunal) animals lead to a large underestimation of ichnofossil diversity; and (2) paleoenvironmental stressors other than lowered oxygen levels (e.g., fluctuating salinity, reduced food availability, and rapid sedimentation). A semi-quantitative relative oxygen equation is proposed to account for these complexities and better proxy bottom water oxygenation over the interval. The equation combines diversity counts, burrow sizes, and bioturbation intensity (all indicators of high oxygenation), scaled with total organic carbon measurements (the presence of which is interpreted as an indicator of low oxygenation, corroborated by carbon isotope measurements over the interval). Integrating ichnological data with total organic carbon measurements accounts for the diminution and low diversity that may stem from a multitude of physicochemical factors. The results suggest that the bottom water oxygen fluctuated continuously and only very rarely, if at all, reached persistent anoxia. The proposed equation offers a repeatable approach to integrate ichnological and TOC data, providing a better ichnological-oxygen proxy for organic-rich mudstones.

加拿大西部内陆海道塞诺曼—土伦尼亚海洋缺氧事件2 （OAE2）段保存异常完好的富有机质泥岩岩心为古氧波动的综合技术分析提供了极好的机会。洞穴大小和多样性的垂直趋势（即大小多样性指数- SDI）以前被用作低氧地层环境中相对氧合的代表。我们注意到两个影响SDI氧合解释的因素：(1)高生物扰动强度或主要由小型（小动物）动物进行的重加工导致对鱼类化石多样性的严重低估；(2)除低氧水平外的古环境压力因素（如盐度波动、食物供应减少和快速沉积）。提出了一种半定量的相对氧方程来解释这些复杂性，并更好地代表整个层段的底水氧合。该方程结合了多样性计数、洞穴大小和生物扰动强度（所有高氧合的指标），并用总有机碳测量值（有机碳的存在被解释为低氧合的指标，并得到了区间内碳同位素测量值的证实）进行了标度。将技术数据与总有机碳测量相结合，可以解释可能由多种物理化学因素引起的多样性减少和低多样性。结果表明，底部水的氧气持续波动，只有很少的情况下，如果有的话，达到持续缺氧。所提出的方程提供了一种可重复的方法来整合技术和TOC数据，为富有机质泥岩提供了更好的技术-氧代表。

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引用次数: 0

Enhanced Asian monsoon hydroclimate instability during the mid-DO21 21世纪中期亚洲季风水文气候不稳定性增强

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-12-29 DOI: 10.1016/j.palaeo.2025.113519

Ziqi Mu , Tian Ma , Hao Lu , Dianbing Liu

The internal structure of Dansgaard-Oeschger (DO) events and its regional correlation provide key insights into climate anomalies under stable conditions, but remain poorly constrained due to geologic proxy uncertainties. Here a high-resolution stalagmite (∼ 9-year-resloved) δ¹⁸O record from Jiangjun Cave, central China was presented to reconstruct Asian summer monsoon (ASM) history across Marine Isotope Stage (MIS) 5a/4 (83–71 thousand years before present, ka). Our result revealed a two-phase structure of ASM variability during mid-DO21. Between 82.8 and 80.4 ka (Phase I), limited δ¹⁸O variance indicated relatively stable ASM intensity. Between 80.4 and 78.8 ka (Phase II), a ∼ 1.4-fold increase in decadal- to centennial-scale δ¹⁸O fluctuations reflected enhanced ASM variability. However, the δ¹⁵N-inferred Greenland temperature was higher and exhibited greater oscillations during the early mid-DO21, followed by a cooling and muted variability later, indicating opposite high- and low-latitude patterns during mid-DO21. We proposed that sea ice dynamics and Atlantic Meridional Overturning Circulation (AMOC) strength modulated the migration of Westerly jet, which in turn governed the inland moisture transport into the ASM region. During Phase I, a northerly-positioned Westerly jet amplified temperature fluctuations over Greenland with limited ASM variability. In Phase II, a southerly-displaced jet suppressed transport of proximal monsoonal moisture, while the periodic sea-ice variability induced latitudinal oscillations in the jet stream. These oscillations repeatedly altered the dominant moisture sources, thereby generating rapid decadal- to centennial-scale ASM fluctuations. Thus, our results highlighted multi-stage hydroclimate variability within interstadials and provided new insights into the role of sea-air-ice interactions in regulating low-latitude climate.

Dansgaard-Oeschger （DO）事件的内部结构及其区域相关性为稳定条件下的气候异常提供了关键见解，但由于地质代理的不确定性，仍然缺乏约束。本文利用中国中部蒋军洞的高分辨率石笋（~ 9年分辨率）δ18O记录，重建了亚洲夏季风（ASM）在海相同位素阶段（MIS） 5a/4（距今8.3 ~ 7.1万年）的历史。我们的结果显示，在21世纪中期，ASM的变化具有两相结构。在82.8 ~ 80.4 ka（第一阶段），δ18O变化有限，表明ASM强度相对稳定。在80.4 - 78.8 ka （II期）之间，年代际至百年尺度δ18O波动增加了~ 1.4倍，反映了ASM变异性的增强。然而，δ 15n推断的格陵兰岛温度在do21中期早期较高且振荡较大，随后变冷且变弱，表明在do21中期存在相反的高纬和低纬模式。海冰动力学和大西洋经向翻转环流（AMOC）强度调节了西风急流的迁移，西风急流又控制了内陆水汽输送到大西洋中部地区。在第1阶段，一股位于北方的西风急流放大了格陵兰岛上空的温度波动，但ASM变率有限。在第二阶段，南移的急流抑制了近端季风水汽的输送，而周期性的海冰变率引起了急流的纬向振荡。这些振荡反复改变了主要的水汽来源，从而产生了快速的年代际到百年尺度的海平面波动。因此，我们的研究结果突出了间带内的多阶段水文气候变率，并为海-气-冰相互作用在调节低纬度气候中的作用提供了新的见解。

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引用次数: 0

Late Holocene temperature changes in eastern North China reconstructed from branched glycerol dialkyl glycerol tetraethers (brGDGTs) 用支链甘油二烷基甘油四醚重建华北东部晚全新世温度变化

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-12-29 DOI: 10.1016/j.palaeo.2025.113530

Hongyu Song , Ying Wang , Huaying Wang , Can-Ge Li , Yuecong Li , Bing Li , Yawen Ge , Rongrong Wang , Xiuyun Sun , Ran Zhang , Hanfei You , Changhong Liu

Temperature is the climatic factor with the most significant impact on human society. Studying temperature changes during the late Holocene is crucial for understanding climate change mechanisms and predicting future trends. We measured the branched glycerol dialkyl glycerol tetraethers (brGDGTs) in a sediment core (CFD-E) from the Caofeidian Wetland in eastern North China and used the record to quantitatively reconstruct temperature changes during the late Holocene. The results show that the average mean annual temperature (MAT) in the eastern part of North China (from ∼3440 cal. yr BP to the present) was 11 °C, comparable to the current regional MAT of 11.2 °C. Overall, the MAT showed a slight increasing trend, with amplitudes not exceeding 1 °C. We identified six cold events, at approximately 3.2 ka, 2.8 ka, 2.5 ka, 1.5 ka, the cooling episode during the Medieval Climate Anomaly (MCA), and the possible Little Ice Age (LIA), with cooling amplitudes exhibiting a gradually decreasing temporal trend. The 3.2 ka event had the largest cooling amplitude; however, the cooling amplitude of this event elsewhere in this inland region was relatively low. We propose that this discrepancy resulted from the combined effects of a weakened Kuroshio Current and Yellow Sea Warm Current, which amplified the 3.2 ka cooling event in coastal regions relative to inland areas. Additionally, the possible LIA in the study area exhibited a relatively low cooling magnitude. We hypothesize that enhanced greenhouse gas forcing, combined with a strengthened Kuroshio Current and Yellow Sea Warm Current, muted the cooling signal associated with the LIA in the study area. The cooling episode during the MCA may have been driven by the weakening of the Yellow Sea Warm Current, caused by the combined weakening of the Kuroshio Current and the East Asian Winter Monsoon.

温度是对人类社会影响最大的气候因子。研究晚全新世的温度变化对理解气候变化机制和预测未来趋势具有重要意义。在华北东部曹非甸湿地沉积物岩心（CFD-E）中测量了支链甘油二烷基甘油四醚（brGDGTs），并利用该记录定量重建了晚全新世的温度变化。结果表明，华北东部地区（~ 3440 cal. yr BP至今）年平均气温（MAT）为11°C，与当前区域平均气温（11.2°C）相当。总体而言，MAT呈轻微上升趋势，幅度不超过1°C。我们发现了大约在3.2 ka、2.8 ka、2.5 ka和1.5 ka的6次冷事件，以及中世纪气候异常（MCA）期间的降温事件，以及可能的小冰期（LIA），冷却幅度呈现逐渐减小的时间趋势。3.2 ka事件冷却幅度最大；然而，该内陆地区其他地方的降温幅度相对较低。我们认为，这种差异是由减弱的黑潮和黄海暖流的共同作用造成的，它们放大了沿海地区相对于内陆地区的3.2 ka冷却事件。此外，研究区可能的LIA表现出相对较低的降温幅度。我们假设，温室气体强迫的增强，加上黑潮和黄海暖流的增强，减弱了与研究区域LIA相关的冷却信号。MCA期间的降温事件可能是由黑潮和东亚冬季风共同减弱造成的黄海暖流减弱所驱动的。

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引用次数: 0