Journal of Palaeogeography最新文献_第3页

IF 2

Journal of Palaeogeography

Pub Date : 2026-01-01

引用次数: 0

Palaeogene Sequoia leaves from Yunnan Province, China and their biogeographical significance 云南古近系红杉叶及其生物地理意义

IF 2

Journal of Palaeogeography

Pub Date : 2025-12-23 DOI: 10.1016/j.jop.2025.100322

Ren-Dan Yang , Ai Song , Li Wang , Li-Rong Jia , Shi-Hu Li , Shi-Tao Zhang , Quan-Fu Wu , Yi Gao , Jiang-Bo Meng , Xuan-Rong Yao , Min Deng , Shu-Feng Li , Tao Su

Sequoia was widely distributed across the Northern Hemisphere during the Cenozoic, yet our understanding of its biogeographic history remains limited due to relatively scarce fossil records in certain regions, particularly East Asia. A new Sequoia leaf fossil record from the Late Eocene to Early Oligocene in Yunnan Province of southwestern China displays morphological similarity to the fossil species S. maguanensis, such as an alternate leaf arrangement with a decurrent base, straight epidermal cell walls, and stomata surrounded by four subsidiary cells. Using the MaxEnt model and S. sempervirens (the only extant species of Sequoia) as a reference, we identified optimal potential distribution areas for Sequoia from the Palaeocene to the Pliocene. Our results indicate that Sequoia, which thrived in warm and humid conditions, progressively shifted its range southward as global temperatures declined from the Eocene to the Pliocene, contracting its habitat towards lower latitudes. Our analysis suggests that Sequoia likely originated in East Asia during the Early Cretaceous and subsequently spread to North America via the Bering Land Bridge. During the Palaeocene, it extended its range to Greenland and Svalbard, eventually reaching western Europe during the Eocene. In the Oligocene, Sequoia was widespread across Europe and reached Siberia, later expanding from East Asia to the Mediterranean and northern Thailand by the Miocene. Quaternary glaciations led to its near-complete disappearance in Eurasia and North America, with only remnant populations surviving along the western coast of the United States. This study also highlights the role of morphological stasis in Sequoia alongside the intensification of the monsoon climate as key factors contributing to its eventual disappearance in southwestern China.

红杉在新生代广泛分布于北半球，但由于在某些地区，特别是东亚地区化石记录相对较少，我们对其生物地理历史的认识仍然有限。云南晚始新世—早渐新世红杉叶化石的形态特征与古种S. maguanensis相似，均为基部下伸的交替排列，表皮细胞壁直，气孔由4个附属细胞包围。利用MaxEnt模型和红杉唯一现存种S. sempervirens作为参考，确定了古新世至上新世红杉的最佳潜在分布区。我们的研究结果表明，从始新世到上新世，随着全球气温的下降，红杉在温暖潮湿的环境中茁壮成长，其活动范围逐渐向南转移，栖息地向低纬度地区收缩。我们的分析表明，红杉可能起源于白垩纪早期的东亚，随后通过白令陆桥传播到北美。在古新世，它的活动范围扩大到格陵兰岛和斯瓦尔巴群岛，最终在始新世到达西欧。在渐新世，红杉在欧洲广泛分布，并到达西伯利亚，后来在中新世从东亚扩展到地中海和泰国北部。第四纪冰期导致它在欧亚大陆和北美几乎完全消失，只在美国西海岸幸存下来。该研究还强调了红杉形态停滞的作用以及季风气候的加剧是导致其在中国西南地区最终消失的关键因素。

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引用次数: 0

Genesis of fenestral fabrics in tidal flat dolomites of Cambrian Stage 4: Evidence from Western Henan, Southern North China Block 寒武纪第四期潮滩白云岩门扉组构成因：来自豫西、华北地块南部的证据

IF 2

Journal of Palaeogeography

Pub Date : 2025-12-22 DOI: 10.1016/j.jop.2025.100321

Wen-Yi He , Yong-An Qi , Ming-Yue Dai , Zhen Zhang , Yao-Gang Du , Min Wang

Abundant fenestral fabrics are widely developed in microcrystalline dolomite, algal clump dolomite, and stromatolitic dolomite of Cambrian Stage 4 on southern North China Block. The paper aims to elucidate the genesis of fenestral fabrics and their relevance to palaeoenvironmental and palaeoclimatic conditions. The fenestral fabrics comprise micron-to millimetric (bird's-eye structures) and centimetric voids, predominantly infilled with calcite and gypsum, with minor occurrences of dolomite. Raman spectral data indicate that organic matter is more concentrated at the edges of fenestral fabrics than in the dolomite matrix or the fabric cores, suggesting that these structures may represent potential accumulation zones for gas bubbles, possibly linked to microbial decomposition. The dolomite sediments consolidated under the exposed, arid, and hot climate conditions, preserving these gas bubbles as micropores. Increased evaporation led to the desiccation and shrinkage of the dolomite sediments, which in turn enlarged the original micropores into larger voids, thereby creating the necessary space for the formation of fenestral fabrics. The calcite and gypsum crystals in fenestral fabrics were interpreted as products of significant Ca²⁺ loss from the dolomite matrix during the transformation of high-magnesium calcite to dolomite, coupled with the Ca²⁺ precipitation from high-salinity brine into fenestral fabrics. This rarely documented fabric type, defined by a dolomite matrix with calcite infill, contributes novel petrographic and geochemical evidence that refines current models of fenestral fabric formation, and supports new interpretations of palaeoenvironmental and palaeoclimatic conditions in ancient evaporitic systems.

华北地块南部寒武系四期微晶白云岩、藻团白云岩和叠层石白云岩中广泛发育丰富的门扉织构。本文旨在阐明门扉组构的成因及其与古环境和古气候条件的关系。门框结构包括微米到毫米（鸟眼结构）和厘米级的空隙，主要由方解石和石膏填充，少量白云石出现。拉曼光谱数据表明，相对于白云岩基质或织物芯，有机质更集中在门扉结构的边缘，这表明这些结构可能是气泡的潜在聚集区，可能与微生物分解有关。白云岩沉积物在暴露、干旱和炎热的气候条件下固结，将这些气泡保存为微孔。蒸发量的增加导致白云岩沉积物的干燥和收缩，从而使原有的微孔扩大为更大的空隙，从而为门框织物的形成创造了必要的空间。门扉织物中的方解石和石膏晶体被解释为高镁方解石向白云石转变过程中白云石基质中Ca2+的大量损失，以及高盐度盐水中Ca2+沉淀到门扉织物中的产物。这种罕见的由方解石充填的白云岩基质定义的织物类型，提供了新的岩石学和地球化学证据，改进了目前的门扉织物形成模型，并支持了对古代蒸发系统古环境和古气候条件的新解释。

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引用次数: 0

Petrogenesis of the Early Paleozoic S-type granites within the Wuyi Terrane: Implications for the tectonic evolution of the South China Block 武夷地体早古生代s型花岗岩的岩石成因及其对华南地块构造演化的启示

IF 2

Journal of Palaeogeography

Pub Date : 2025-12-19 DOI: 10.1016/j.jop.2025.100320

Yuan-Yuan Tang , Yu Shi , Guo-Dong Jin

The Early Paleozoic tectonic evolution of the South China Block (SCB) remains a subject of considerable debate, particularly regarding whether it resulted from intracontinental orogeny or the subduction–collision process. The Wuyi Terrane (WYT), located at the center of the Wuyi–Yunkai orogen, plays a crucial role in understanding the petrogenesis of the Early Paleozoic magmatic products and tectonic evolution of the SCB. This study presents zircon U–Pb ages, geochemical analyses, and Lu–Hf isotopic data for the Fufang and Guixi granitic plutons located within the WYT. Zircon U–Pb dating results indicate that these granites were formed during the Early Paleozoic (ca. 437–436 Ma), and negative zircon ε_Hf(t) values (−20.7 to −6.2) suggest an ancient crustal source for the granites. These contemporaneous granites, characterized by peraluminous to strongly peraluminous compositions, are classified as high-K calc-alkaline to shoshonitic series and are recognized as highly fractionated S-type granites. They exhibit enrichment in Rb, Th, U, K, and Pb, while showing depletions in Ba, Sr, Nb, Ta, P, and Ti. The observed variations in Eu anomalies suggest differing source compositions and magmatic processes between the two plutons. Based on the geochemical and isotopic evidence, we propose that the Fufang granites originated from the partial melting of crustal meta-sedimentary rocks, without the contribution of mantle-derived materials, whereas the Guixi granites resulted from the partial melting of a heterogeneous crustal source predominantly composed of meta-sedimentary rocks, with a minor contribution from meta-igneous rocks. The granites underwent varying degrees of feldspar-dominated fractional crystallization throughout their magmatic evolution. In conjunction with their post-collisional geochemical characteristics and the regional tectonic frameworks, we suggest that the Early Paleozoic tectonic evolution of the SCB was characterized by intracontinental orogeny, with the formation of the Fufang and Guixi granites occurring during the intracontinental lithospheric extensional phase that followed collisional compression.

华南地块早古生代构造演化至今仍是一个争论颇多的问题，特别是它是由陆内造山运动还是俯冲碰撞过程引起的。武夷地体位于武夷-云开造山带的中心，对认识早古生代岩浆产物的岩石成因和南海构造演化具有重要意义。本文研究了位于怀冬期的阜方和贵溪花岗质岩体的锆石U-Pb年龄、地球化学分析和Lu-Hf同位素数据。锆石U-Pb定年结果表明，这些花岗岩形成于早古生代（约437 ~ 436 Ma），锆石εHf(t)值为负（- 20.7 ~ - 6.2），表明花岗岩来源于古地壳。这些同生花岗岩具有过铝质至强过铝质的特征，属于高钾钙碱性—粗玄石系，属于高分选s型花岗岩。它们表现出Rb、Th、U、K和Pb的富集，而表现出Ba、Sr、Nb、Ta、P和Ti的缺失。观测到的Eu异常变化表明两个岩体的源成分和岩浆作用不同。根据地球化学和同位素证据，我们认为阜方花岗岩起源于地壳变质沉积岩的部分熔融，没有幔源物质的贡献，而贵溪花岗岩则是由以变质沉积岩为主的非均质地壳源的部分熔融形成的，变质火成岩的贡献较小。花岗岩在岩浆演化过程中经历了不同程度的长石为主的分晶作用。结合碰撞后地球化学特征和区域构造格架，认为南海早古生代构造演化具有陆内造山作用的特征，阜方和贵溪花岗岩形成于碰撞挤压后的陆内岩石圈伸展期。

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引用次数: 0

New species of Amphicyon (Mammalia, Carnivora) from the Middle Miocene strata of Xin'an, Henan, China 河南新安中新世中地层两栖类新种（哺乳纲，食肉目）

IF 2

Journal of Palaeogeography

Pub Date : 2025-12-17 DOI: 10.1016/j.jop.2025.100319

Arya Farjand , Qi-Gao Jiangzuo , Zhao-Qun Zhang , Paul Rummy , Mehdi Khoshnamvand , Shun-Dong Bi

The Amphicyonidae are an extinct group of large carnivorans that appeared during the Late Eocene in North America but thrived during the Miocene epoch in Eurasia. In China, Amphicyon has been recognized with three species; however, all are identified from limited material. A partial cranium discovered from the late Middle Miocene strata of Xin'an, Henan, central China, significantly improves our understanding of Amphicyon in China, Europe, and North America. It suggests the uniquity of this Amphicyon species, namely Amphicyon zhinu sp. nov., which is distinguishably smaller in size and differs in the morphology of its maxillary teeth. Therefore, the presence of these four different species of Amphicyon in North China during the Middle Miocene Climate Optimum verifies the high diversity and suggests an evolutionary divergence.

两栖动物科是一种已经灭绝的大型食肉动物，它们出现在始新世晚期的北美洲，但在中新世时期的欧亚大陆繁盛起来。在中国，两栖类已被确认为3种；然而，所有这些都是从有限的材料中识别出来的。在中国中部河南新安中中新世晚期地层中发现的部分头骨，极大地提高了我们对中国、欧洲和北美两栖动物的认识。这表明这个两栖动物物种的独特性，即Amphicyon zhinu sp. nov.，它的体型明显较小，上颌牙齿的形态也不同。因此，这四种两栖类在中中新世气候最适时期在华北地区的存在，证实了两栖类的高度多样性，表明其存在进化分化。

引用次数: 0

Ecological stability of late Maastrichtian benthic foraminifera amidst Deccan volcanism 德干火山活动中马斯特里赫特晚期底栖有孔虫的生态稳定性

IF 2

Journal of Palaeogeography

Pub Date : 2025-12-06 DOI: 10.1016/j.jop.2025.100317

Subham Patra , Kebenle Kesen , Gerta Keller , Thierry Adatte , Jahnavi Punekar

The late Maastrichtian witnessed profound disruptions in biogeochemical cycles, leading to the fifth mass extinction at the Cretaceous–Paleogene (K/Pg) boundary. At Bidart section (France), the final ∼60 kyr of the Maastrichtian coincide with mercury (Hg) peaks, low magnetic susceptibility, evidence of biological stress and taphonomic alteration in planktic foraminifera, indicative of an ocean acidification event. While this event primarily appears to be a surface-ocean phenomenon, previous studies also documented a minor rise in benthic foraminiferal test fragmentation beginning 0.5 m below the K/Pg boundary, with a pronounced spike at the boundary itself.

A detailed investigation of benthic foraminifera in biozone CF1 at Bidart section (France) reveals a diverse and balanced assemblage preceding the K/Pg boundary, with minimal taphonomic alterations. At the K/Pg boundary, infaunal populations diminished, diversity declined sharply, test fragmentation intensified, yet paradoxically, the absolute abundance of genera rose markedly. Preferential preservation is evident in the dominance of robust taxa (Cibicidoides spp., Coryphostoma spp.), while a high fragmentation index reflects strong taphonomic dissolution and time-averaging. A plausible explanation for this could be CO₂-rich waters mixing into the ocean interior over 100–1000 years, driving dissolution during the ∼10,000-year deposition of the K/Pg boundary red clay. The stark contrast between the planktic and benthic census and morphometric data at Bidart section clearly constrains any Deccan-related calcification stress to the surface mixed layer. Lastly, the integrated planktic and benthic considerations re-emphasize a need to carefully separate taphonomic signals from true ecological stress.

马斯特里赫特晚期生物地球化学循环被严重破坏，导致了白垩纪-古近纪（K/Pg）界线上的第五次大灭绝。在Bidart剖面（法国），马斯特里赫特的最后~ 60 kyr与汞（Hg）峰值、低磁化率、浮游有孔虫生物应激和地学改变的证据一致，表明海洋酸化事件。虽然这一事件主要是表面海洋现象，但先前的研究也记录了底栖有孔虫试验破碎的轻微上升，从K/Pg边界以下0.5 m开始，边界本身出现明显的峰值。对法国Bidart剖面CF1生物带底栖有孔虫的详细调查表明，在K/Pg边界之前，底栖有孔虫的组合多样化且平衡，地层学变化很小。在K/Pg边界上，动物种群数量减少，多样性急剧下降，试验破碎化加剧，而属的绝对丰度却显著上升。较强的分类群（Cibicidoides spp., Coryphostoma spp.）具有明显的优先保存优势，而较高的碎片化指数反映了较强的埋藏分解和时间平均。对此，一个合理的解释可能是，在100-1000年的时间里，富含二氧化碳的水混合到海洋内部，在K/Pg边界红粘土的沉积过程中，导致了溶解。Bidart剖面的浮游生物和底栖生物普查数据与形态测量数据之间的鲜明对比，清楚地限制了任何与decan有关的钙化应力到表面混合层。最后，对浮游生物和底栖生物的综合考虑再次强调需要仔细地将地学信号与真正的生态压力分开。

{"title":"Ecological stability of late Maastrichtian benthic foraminifera amidst Deccan volcanism","authors":"Subham Patra , Kebenle Kesen , Gerta Keller , Thierry Adatte , Jahnavi Punekar","doi":"10.1016/j.jop.2025.100317","DOIUrl":"10.1016/j.jop.2025.100317","url":null,"abstract":"<div><div>The late Maastrichtian witnessed profound disruptions in biogeochemical cycles, leading to the fifth mass extinction at the Cretaceous–Paleogene (K/Pg) boundary. At Bidart section (France), the final ∼60 kyr of the Maastrichtian coincide with mercury (Hg) peaks, low magnetic susceptibility, evidence of biological stress and taphonomic alteration in planktic foraminifera, indicative of an ocean acidification event. While this event primarily appears to be a surface-ocean phenomenon, previous studies also documented a minor rise in benthic foraminiferal test fragmentation beginning 0.5 m below the K/Pg boundary, with a pronounced spike at the boundary itself.</div><div>A detailed investigation of benthic foraminifera in biozone CF1 at Bidart section (France) reveals a diverse and balanced assemblage preceding the K/Pg boundary, with minimal taphonomic alterations. At the K/Pg boundary, infaunal populations diminished, diversity declined sharply, test fragmentation intensified, yet paradoxically, the absolute abundance of genera rose markedly. Preferential preservation is evident in the dominance of robust taxa (<em>Cibicidoides</em> spp.<em>, Coryphostoma</em> spp.), while a high fragmentation index reflects strong taphonomic dissolution and time-averaging. A plausible explanation for this could be CO<sub>2</sub>-rich waters mixing into the ocean interior over 100–1000 years, driving dissolution during the ∼10,000-year deposition of the K/Pg boundary red clay. The stark contrast between the planktic and benthic census and morphometric data at Bidart section clearly constrains any Deccan-related calcification stress to the surface mixed layer. Lastly, the integrated planktic and benthic considerations re-emphasize a need to carefully separate taphonomic signals from true ecological stress.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"15 1","pages":"Article 100317"},"PeriodicalIF":2.0,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Control of deep-water sedimentation on rift margin by non-coaxial fault linkage system: a case study from the steep slope of the Dongying Depression, Bohai Bay Basin, China 非同轴断裂联动系统对裂谷边缘深水沉积的控制——以渤海湾盆地东营坳陷陡坡带为例

IF 2

Journal of Palaeogeography

Pub Date : 2025-12-06 DOI: 10.1016/j.jop.2025.100318

Rong-Heng Tian , Ben-Zhong Xian , Qian-Ran Wu , Peng Chen , Naveed Ur Rahman , Lin Zhao , Peng-Yu Wang , Wen-Miao Zhang

Understanding the evolution of the segmented synsedimentary fault linkage, which controls the accommodation development, sediment infill, and stratigraphic architecture, is essential for reconstructing rift histories and exploring natural resources. This study investigates the tectono-sedimentary processes in the steep slope of the Dongying Depression within the Bohai Bay Basin rift system, eastern China by utilizing three-dimensional seismic and drilling data. A classification scheme for non-coaxial extensional fault linkage styles is proposed, categorizing them into two types—partial linkage and through-going hard linkage—with eight subtypes based on geometric architectures, evolutionary stages, and segment-scale activity. Statistical analysis of the length and separation distance of the main border fault (the Chennan Fault) reveals that non-coaxial linkage systems are pervasive along the northern rift margin of the Dongying Depression. These systems controlled the development of its irregular zigzag geometry. Furthermore, analysis of non-coaxial convergent fault linkage processes provides the most plausible explanation for the initial morphology of the large paleo-gullies observed on the steep slope. Seismic-geomorphologic mapping and borehole dataset allow us to constrain the spatial and architectural variability of depositional systems along the rift margin. The results demonstrate that non-coaxial fault linkage processes control deep-water depositional types: basinal fans dominate during partial linkage phases, while nearshore subaqueous fans develop under through-going linkage conditions. Non-coaxial fault segment activity influences sediment input directions: uniform fault activity promotes longitudinal transport systems, whereas heterogeneous activity controls oblique delivery along dominant fault segments. This study enhances the understanding of non-coaxial fault systems and their sedimentary responses, providing a reliable basis for hydrocarbon exploration in the steep slopes of lacustrine rift basins.

研究控制可容纳发育、沉积充填和地层构型的分段同沉积断裂链的演化，对于重建裂谷历史和勘探自然资源具有重要意义。利用三维地震资料和钻井资料，研究了渤海湾盆地裂谷系东营坳陷陡坡带的构造-沉积过程。提出了非同轴张拉断层连接类型的分类方案，根据构造、演化阶段和段尺度活动性将其划分为部分连接和贯通连接两种类型，并划分为8个子类型。对主边界断裂（陈南断裂）长度和分离距离的统计分析表明，东营坳陷北部断陷边缘普遍存在非同轴联动体系。这些系统控制着不规则之字形几何的发展。此外，对非同轴会聚断层联动过程的分析为陡坡上观测到的大型古沟的初始形态提供了最合理的解释。地震地貌填图和钻孔数据使我们能够约束裂谷边缘沉积体系的空间和结构变异性。结果表明，非同轴断裂联动过程控制着深水沉积类型，在部分联动阶段以盆地扇为主，而在全程联动条件下则发育近岸水下扇。非同轴断层段活动影响沉积物输入方向：均匀断层活动促进纵向输送系统，而非均匀断层活动控制沿主要断层段的斜向输送。该研究增强了对非同轴断裂体系及其沉积响应的认识，为湖相裂谷盆地陡坡带油气勘探提供了可靠的依据。

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引用次数: 0

Organic matter accumulation in limestone-marl alternations of the middle Permian Maokou Formation, Sichuan Basin, China, and its response to the interglacial–glacial transition 四川盆地中二叠统茅口组灰岩-泥灰岩交替带有机质聚集特征及其对间冰期-冰期过渡的响应

IF 2

Journal of Palaeogeography

Pub Date : 2025-11-28 DOI: 10.1016/j.jop.2025.100312

Feng-Bin Liu , Liang-Biao Lin , Bo-Lin Zhang , Yu Yu , Yong Dan , Si-Yu Liu

The deposition of limestone-marl alternations (LMAs) with elevated organic matter (OM) content within the Middle Permian (Guadalupian) Maokou Formation of the Sichuan Basin, China, was influenced by the interglacial–glacial transition. However, the mechanisms of OM accumulation remain unclear. This study examines OM accumulation in the first member of the Maokou Formation (i.e., the Mao I Member) from the Hegou and Zaodu sections using multiple geochemical proxies, with a focus on its response to climatic shifts during the interglacial–glacial transition. OM accumulation was primarily influenced by this climatic transition through two interrelated processes: (1) by regulating the intensity of chemical weathering (Rb/Sr) in nearshore shallow-platform environments, which in turn controlled terrigenous nutrient input (Ti/Al); and (2) by enhancing upwelling in distal deeper waters (Cd/Mo), thereby stimulating primary productivity (OCAR, PAR, Cu_XS, and Ni_XS). These mechanisms overcame the typical constraints of an oxygenated carbonate platform setting (where Ce anomalies are mostly <1.3), exerting a stronger control on OM accumulation than redox conditions. As glacial conditions intensified, the dominant mode of OM accumulation in the Mao I Member shifted from a detrital-driven regime—characterized by high terrigenous input (Ti/Al) and clay-mediated preservation (Al₂O₃)—to a hybrid system jointly regulated by both detrital input and upwelling-related nutrient delivery (Cd/Mo). In this latter phase, enhanced upwelling compensated for the decline in terrigenous nutrients. OM accumulation persisted even under oxygenated bottom-water conditions. This finding contrasts with the anoxia-dependent models typical of high OM shales and underscores the predominance of productivity over preservation factors in this icehouse carbonate platform. The transition toward glacial conditions is evidenced by the decreasing Rb/Sr ratios, indicating weakened chemical weathering, and declining Ti/Al ratios, signifying reduced terrigenous input. Our findings elucidate how multi-factor interactions govern OM accumulation in mixed carbonate–clastic systems and provide valuable constraints for predicting the stratigraphic distribution and quality of potential hydrocarbon source rocks in such settings.

四川盆地中二叠统瓜达鲁普系茅口组灰泥-泥灰岩互变沉积受间冰期-冰期过渡的影响，有机质含量较高。然而，OM积累的机制尚不清楚。利用多种地球化学指标，研究了河沟段和灶渡段茅一段OM的富集特征，重点研究了其对间冰期-冰期气候变化的响应。这种气候转变主要通过两个相互关联的过程影响有机质积累：(1)通过调节近岸浅台地环境的化学风化强度（Rb/Sr），从而控制陆源养分输入（Ti/Al）；(2)通过增强远端深水（Cd/Mo）的上升流，从而提高初级生产力（OCAR、PAR、CuXS和NiXS）。这些机制克服了典型的含氧碳酸盐岩台地环境的限制（其中Ce异常大多为<；1.3），比氧化还原条件对OM聚集的控制更强。随着冰川条件的加剧，茂一段有机质的主要积累模式从碎屑驱动模式（以高陆源输入（Ti/Al）和粘土保存（Al2O3）为特征）转变为碎屑输入和上升流相关的养分传递（Cd/Mo）共同调节的混合系统。在后一阶段，增强的上升流弥补了陆源营养物质的减少。即使在含氧的底水条件下，OM积累也持续存在。这一发现与高有机质页岩典型的缺氧依赖模型形成对比，并强调了在这个冰库碳酸盐岩台地中，生产力比保存因素更重要。Rb/Sr比值下降，表明化学风化作用减弱；Ti/Al比值下降，表明陆源输入减少。我们的发现阐明了多因素相互作用如何控制混合碳酸盐岩-碎屑体系中OM的聚集，并为预测这种环境下潜在烃源岩的地层分布和质量提供了有价值的约束。

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引用次数: 0

Grallatorid–eubrontid tridactyl track assemblages from Lower Jurassic, Sichuan Province, China: Insights into theropod diversity, locomotion and behavior 四川下侏罗统食食兽脚亚目-前翼类三趾亚目足迹组合：对兽脚亚目多样性、运动和行为的认识

IF 2

Journal of Palaeogeography

Pub Date : 2025-11-27 DOI: 10.1016/j.jop.2025.100311

Li-Da Xing , Shan Jiang , Qi-Yan Chen , Yong Ye , Guang-Zhao Peng , Anthony Romilio , Hendrik Klein , Yan-Yi Gong

The Sichuan Basin in southwestern China is home to the most extensive theropod track record in the Lower Jurassic of China, comprising a range of minute-to medium-sized tracks that form the grallatorid–eubrontid (GE) plexus. The majority of these had previously been discovered in the Ma’anshan Member of the Ziliujing Formation. New material described herein is from the Wuli tracksite that suggests a flourishing paleoecological scene in a temporary waterfront habitat. Upon reviewing the GE plexus at different scales, we consider the locomotion style of these early theropod trackmakers, which likely included the ‘grounded-running’ gait of extant birds, as well as the possibility of a tail trace that may be related to intra- or interspecific interactions.

中国西南部的四川盆地是中国下侏罗统最广泛的兽脚亚目足迹记录的所在地，包括一系列分钟至中等大小的足迹，形成了grallatorid-eubrontid （GE）丛。其中大部分已在自流井组马鞍山段发现。本文描述的新材料来自Wuli轨道遗址，表明在一个临时的滨水栖息地有一个繁荣的古生态场景。在回顾了不同尺度的GE神经丛后，我们考虑了这些早期兽脚亚目追踪者的运动方式，其中可能包括现存鸟类的“地面奔跑”步态，以及可能与种内或种间相互作用有关的尾巴痕迹的可能性。

引用次数: 0

Late Jurassic manganese microbial carbonates of West Siberian oil and gas basin: Diagnostic features, environmental sedimentation, secondary transformations 西西伯利亚油气盆地晚侏罗世锰微生物碳酸盐：诊断特征、环境沉积、次生转化

IF 2

Journal of Palaeogeography

Pub Date : 2025-11-27 DOI: 10.1016/j.jop.2025.100316

Latypova Margarita , Gafurova Dina , Churkina Valeria , Kalmykov Anton , Kalmykov Georgy

This study focuses on the investigation of Late Oxfordian–Early Tithonian manganese microbial carbonates (MC) found at the top of the Georgiev regional stage in the Western Siberian oil and gas basin. In some isolated areas, these MC are oil reservoirs. However, these rocks are still one of the least studied sediments in the carbonate interval at the boundary of the Bazhenov and Georgiev subregional stage. We have described their geochemical, lithological and mineralogical composition in detail. Based on the characteristics of MC, we assumed their formation settings. The elevated MnO content, associated with microbial processes, and the high concentration of biophilic elements, both suggest the active involvement of organic matter in the formation and development of microbial sediments. The isotopic composition of carbon in the microbial carbonates further supports a biogenic source of carbon dioxide playing an important role in the formation of these deposits. We have established that the Late Jurassic manganese MC were intensely secondary altered, partially recrystallized and calcified by catagenetic processes. Isometric pyrite crystal aggregates with kutnohorite fragments were formed at the contacts between kutnohorite and calcite zones. We suggest that the presence of caverns and high reservoir potential in the microbial carbonates from the Yem-Egovskaya field of the Krasnoleninsky arch may be attributed to intense secondary catagenetic alterations.

本研究对西西伯利亚盆地格奥尔基耶夫区域阶段顶部发现的晚牛津世—早铁东世锰微生物碳酸盐（MC）进行了研究。在一些孤立的地区，这些MC是油藏。然而，这些岩石仍然是巴切诺夫和格奥尔基耶夫分区域阶段边界碳酸盐层间研究最少的沉积物之一。我们详细地描述了它们的地球化学、岩性和矿物组成。根据MC的特点，我们假设了它们的地层设置。与微生物过程相关的MnO含量升高，以及亲生物元素的高浓度，都表明有机质积极参与了微生物沉积物的形成和发育。微生物碳酸盐中碳的同位素组成进一步支持二氧化碳的生物源在这些矿床的形成中起着重要作用。研究表明，晚侏罗世锰矿砾岩经历了强烈的次生蚀变、部分再结晶和钙化作用。在黄铁矿与方解石带接触处，形成了含黄铁矿碎片的等长黄铁矿晶体聚集体。我们认为，Krasnoleninsky拱的Yem-Egovskaya油田微生物碳酸盐中存在溶洞和高储层潜力可能是由于强烈的次生变质作用。

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引用次数: 0