Journal of Palaeogeography最新文献

Multifactor controls on heterogeneous salinization in lacustrine basins: Insights from quantitative thresholds and triggering conditions 湖盆非均匀盐渍化的多因素控制：来自定量阈值和触发条件的见解

IF 2

Journal of Palaeogeography

Pub Date : 2026-02-04 DOI: 10.1016/j.jop.2026.100339

Zhen-Guo Qi , Fu-Jie Jiang , Fei-Long Wang , Hai-Feng Yang , Meng-Xing Liu , Zhou Fang , Xue-Yu Yao , Wei-Bing Shen , Tao Hu , Zhao Zhao , Yu-Qi Zhang , Bo Yang , Yu Zhang , Jing-Qi Zhou , Shuang Li , Meng-Yang Wang , Xiao-Wei Zheng

Salinity plays a critical role in lake ecosystems, organic matter enrichment, and source rock formation, and holds significant implications for oil and gas exploration. Therefore, the mechanisms underlying lacustrine salinization have attracted increasing attention. Previous studies of salinization mechanisms have often focused merely on correlations between various factors and salinity. This limited scope has created a gap in the study of quantitative thresholds and triggering conditions, which impedes a comprehensive understanding of heterogeneous salinization mechanisms across temporal and spatial scales. This study investigates the multifactorial controls on heterogeneous salinization of the Paleogene strata of the Bohai Bay Basin, quantitatively elucidating their influence and identifying distinct thresholds or triggering conditions for each factor. The results show that lacustrine salinization heterogeneity is governed by multiple factors, including evaporation, marine transgression, surface runoff and hydrothermal activity: 1) evaporation is the predominant driver of salinization when climatic aridity exceeds a critical threshold (Sr/Cu > 25); 2) mantle-derived hydrothermal fluids, not alone but in conjunction with formation brines, can lead to significant salinization; 3) marine transgression can cause substantial dissolved salt influx to lakes during prolonged and extensive transgression, and its salinizing effect is amplified during sustained arid climatic regimes; 4) surface runoff effectively reduces salinity, particularly near river mouths, and the dilution effect becomes significant only when the salinity exceeds 8 ‰. Collectively, evaporation and large-scale marine transgressions primarily control temporal heterogeneity in lacustrine salinization, whereas hydrothermal activity and surface runoff govern spatial heterogeneity.

盐度在湖泊生态系统、有机质富集和烃源岩形成中起着至关重要的作用，对油气勘探具有重要意义。因此，湖泊盐碱化的机制越来越受到人们的关注。以往对盐渍化机制的研究往往只关注各种因素与盐度之间的相关性。这一有限的范围造成了定量阈值和触发条件研究的空白，阻碍了对跨时空尺度非均质盐渍化机制的全面理解。本研究探讨了渤海湾盆地古近系地层非均匀盐渍化的多因素控制因素，定量地阐明了这些因素的影响，并确定了每个因素的不同阈值或触发条件。结果表明，湖泊盐渍化非均匀性受蒸发、海侵、地表径流和热液活动等多种因素的控制：1)当气候干旱超过临界阈值（Sr/Cu > 25）时，蒸发是盐渍化的主要驱动因素；2)地幔源热液，不是单独的，而是与地层盐水一起，可导致显著的盐化；3)海侵在长期和广泛的海侵过程中会导致大量溶解盐流入湖泊，在持续干旱气候条件下，其盐化作用被放大；4)地表径流有效降低了盐度，尤其是河口附近，只有当盐度超过8‰时，稀释效应才变得显著。总的来说，蒸发和大规模海侵主要控制湖泊盐渍化的时间异质性，而热液活动和地表径流控制空间异质性。

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引用次数: 0

Cambrian–Ordovician sedimentary environmental evolution and dolomitization in the Lower Yangtze region of China by sedimentary microfacies and geochemistry 中国下扬子地区寒武-奥陶系沉积环境演化与白云石化

IF 2

Journal of Palaeogeography

Pub Date : 2026-02-02 DOI: 10.1016/j.jop.2026.100338

Jia-Wei He , Tao Deng , Li-Juan Wang , Jun-Peng Guan , Yong-Biao Yang , Xiu-Mian Hu

The Lower Yangtze region in China hosts extensive Early Paleozoic dolomitic sequences, yet their sedimentary environments and genetic mechanisms remain poorly constrained. This study integrates carbonate microfacies analysis with geochemical data (major, trace, and rare earth elements) from three studied sections (Mufushan, Lunshan, Tangshan) and two drill cores (Sure 1 and Sure 2) to elucidate the depositional evolution and dolomitization of the Cambrian–Ordovician Guanyintai, Lunshan, and Honghuayuan formations. Totally 15 types of carbonate microfacies were identified, revealing a transition from supratidal sabkha (e.g., powder-crystal dolostone with geopetal structures) to shallow shoal environments (e.g., dolomitized oolitic grainstone). Geochemical signatures (MgO–CaO covariation, Sr depletion, and REY patterns) indicate that the Guanyintai Formation dolostone formed via reflux penetration of Mg²⁺ enriched brines in shallow burial settings, while the Lunshan Formation experienced superimposed burial and hydrothermal dolomitization, evidenced by saddle dolomite textures and positive δEu anomalies. Contrarily, the Honghuayuan Formation limestones exhibit significant terrigenous input (elevated Al₂O₃, Zr, and SiO₂). This study establishes a dual-phase genetic model for Cambrian–Ordovician dolostone in Lower Yangtze region, emphasizing the interplay of evaporative reflux and hydrothermal activity. These findings provide critical insights for predicting dolostone reservoir distribution and optimizing hydrocarbon exploration in analogous marine carbonate systems.

中国下扬子地区拥有广泛的早古生代白云岩层序，但其沉积环境和成因机制尚不清楚。本研究结合塔里木盆地木浮山组、轮山组、唐山组3个剖面和2个岩心的地球化学资料（主量、痕量、稀土元素），对寒武系—奥陶系观音台组、轮山组和红花园组的沉积演化和白云化作用进行了研究。共鉴定出15种碳酸盐岩微相类型，揭示了由潮上沉积环境（如具有地质构造的粉晶白云岩）向浅滩沉积环境（如白云化鲕粒岩）的过渡。地球化学特征（MgO-CaO共变、Sr亏缺和REY模式）表明观音台组白云岩是浅埋藏条件下富Mg2+盐水回流渗透形成的，而轮山组则是由鞍状白云岩结构和正δEu异常表现出的叠加埋藏和热液白云化作用。红花园组灰岩则表现出明显的陆源输入（Al2O3、Zr和SiO2含量升高）。本文建立了下扬子地区寒武—奥陶系白云岩的双相成因模式，强调了蒸发回流与热液活动的相互作用。这些发现为预测类似海相碳酸盐岩体系的白云岩储层分布和优化油气勘探提供了重要见解。

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引用次数: 0

Seismic geomorphology of the Late Miocene submarine channels in the Southern Taranaki Basin 塔拉纳基盆地南部晚中新世海底水道的地震地貌

IF 2

Journal of Palaeogeography

Pub Date : 2026-01-28 DOI: 10.1016/j.jop.2026.100337

Muchamad Ocky Bayu Nugroho , Piyaphong Chenrai , Dicky Harishidayat

The Late Miocene submarine channel is proven to be a sand-prone deposit in Southern Taranaki, offshore New Zealand. A depositional model of a submarine channel is important to understanding its architecture, geomorphology, and evolution. Identifying sand-prone deposits as potential hydrocarbon reservoirs in submarine channel systems is challenging due to their complex architectures, multi-phase channel histories, and intricate vertical and lateral connectivity. In this study, one high-quality 3D seismic reflection dataset and two exploration wells have been analyzed and interpreted using seismic facies, seismic geomorphology, and a seismic attribute approach (slicing technique), resulting in 18 channels in 4 stratigraphic units during the Late Miocene. In addition, the lithological proportion of sand and shale and its stacking pattern, supported by biostratigraphic data, indicate the presence of a submarine channel in this area. Temporal changes in channel characteristics were observed, including shifts in channel orientation, variations in channel dimensions, and a progressive decrease in sinuosity. These changes reflect the influence of dynamic depositional processes controlled by tectonic activity, seafloor topography, sea-level fluctuations, and sediment supply. Favorable reservoir potential within this submarine channel system is associated with multi-episode cut-and-fill processes, including amalgamated channels and lateral accretion deposits, which collectively contribute to the development of sand-prone facies. The insights from this study contribute to a broader understanding of deepwater channel evolution in tectonically active, sediment-rich settings. The conceptual model developed provides a transferable framework for interpreting similar systems in other continental margin basins worldwide, particularly low-angle slope channel systems within foreland basin settings. This makes it a valuable analog for analyzing channel systems in data-limited or frontier regions.

晚中新世海底通道被证明是新西兰近海塔拉纳基南部的一个易砂矿床。海底水道的沉积模型对于理解其构造、地貌和演化具有重要意义。由于海底水道系统的结构复杂、多相水道历史以及复杂的垂直和横向连通性，将易砂沉积物识别为潜在的油气藏是一项挑战。本研究利用地震相、地震地貌学和地震属性方法（切片技术）对一个高质量的三维地震反射数据集和两口探井进行了分析和解释，得到了晚中新世4个地层单元的18个通道。此外，生物地层资料支持的砂、页岩岩性比例及其堆积模式表明该区存在海底通道。观察到通道特征的时间变化，包括通道方向的变化，通道尺寸的变化以及弯曲度的逐渐减少。这些变化反映了受构造活动、海底地形、海平面波动和沉积物供应控制的动态沉积过程的影响。该海底水道体系的有利储层潜力与多期填切作用有关，包括合并水道和侧向吸积沉积，共同促进了倾向砂相的发育。这项研究的见解有助于更广泛地了解构造活跃、富含沉积物的深水水道的演化。所建立的概念模型为解释世界上其他大陆边缘盆地的类似系统，特别是前陆盆地背景下的低角斜坡河道系统提供了一个可转移的框架。这使得它成为分析数据有限或前沿地区的信道系统的有价值的模拟。

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引用次数: 0

Middle Llandovery (Silurian) stromatoporoids from Baingoin, Xizang (Tibet), China 西藏（西藏）班固中陆相（志留系）层孔虫

IF 2

Journal of Palaeogeography

Pub Date : 2026-01-23 DOI: 10.1016/j.jop.2026.100336

Juwan Jeon , Zhong-Yang Chen , Guang-Xu Wang , Yuan-Dong Zhang

Silurian stromatoporoids from the Qinghai–Tibetan Plateau remain poorly known, with only limited documentation in this critical palaeogeographic region. We provide the first systematic description of Aeronian (Llandovery) stromatoporoids from the lower Dongka Group in Xizang (Tibet), China. Three species are described: Cystostroma dongkaense sp. nov., Clathrodictyon shiqianense Dong and Yang, 1978, and Ecclimadictyon gejingae sp. nov. The assemblage is dominated by clathrodictyids, continuing a global trend of clathrodictyid dominance that began in the Katian (Late Ordovician) and expanded globally during the late Hirnantian. These stromatoporoids indicate that the Lhasa terrane was situated at subtropical to tropical latitudes during the early Silurian. Shared occurrences of Clathrodictyon taxon from Xizang and South China indicate potential faunal connectivity between these regions during the early Silurian. This work expands the geographic and stratigraphic distribution of early Silurian stromatoporoids and also provides new insights into post-extinction recovery dynamics and the resilience of stromatoporoid calcification mechanisms after the Late Ordovician mass extinction.

青藏高原志留系的叠层孔虫仍然鲜为人知，在这个关键的古地理区域只有有限的文献记录。本文首次系统描述了西藏东卡群下Aeronian （llanddovery）叠孔虫。其中，Cystostroma dongkaense sp. nov., Clathrodictyon shiqianense Dong and Yang, 1978 ., Ecclimadictyon gejingae sp. 11 .。该组合以Clathrodictyon为主，延续了从晚奥陶世（Katian）开始的Clathrodictyon在全球范围内占优势的趋势。这些层孔状体表明拉萨地体在志留纪早期处于亚热带至热带纬度。西藏和华南地区在早志留世时出现的克拉氏分类群的共同分布，表明这两个地区之间存在着潜在的动物连通性。本研究扩展了早志留世叠层孔类的地理和地层分布，为研究晚奥陶世大灭绝后叠层孔类的恢复动态和钙化机制的弹性提供了新的认识。

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引用次数: 0

First documentation of late Silurian and earliest Devonian (Lochkovian) conodonts from biostromes and mud mounds in Truong Son Terrane of the Indochina Composite Terrane: Geological significance 印度支那复合地体张松地体生物层和泥丘中晚志留世和早泥盆世（洛克柯夫世）牙形刺的首次文献记录：地质意义

IF 2

Journal of Palaeogeography

Pub Date : 2026-01-19 DOI: 10.1016/j.jop.2026.100326

Zhong-Yang Chen , Mongkol Udchachon , Hathaithip Thassanapak , Jian-Feng Lu , Xiang Fang , Wen-Jie Li , Clive Burrett

Late Silurian to Early Devonian conodonts are first documented from the marl–limestone alternations, with biostromes and mud mounds, succession in the north of the Loei fold belt, in the Truong Son Terrane of the Indochina Composite Terrane in NE Thailand. Species found include Wurmiella excavata, Panderodus unicostatus, Zieglerodina eladioi, Belodella resima, Neopanderodus aequabilis, Belodella anomalis, and Icriodus? sp. indet. Seven major lithofacies of sedimentary rocks were identified and interpreted as shallower to deeper marine environments in a warm, tropical zone. The sequence was deposited to the east of a Silurian rhyolitic volcanic arc with which it interdigitates and is regarded as a part of an arc or back-arc basin. A Siluro-Devonian arc shows that this part of the Indochina Composite Terrane rifted away from Gondwana in or prior to the Silurian.

在泰国东北部印度支那复合地体的张松地体中，在Loei褶皱带北部的泥灰岩-泥灰岩交替、生物层和泥丘演替中首次记录了晚志留世至早泥盆世的牙形刺。已发现的物种包括：挖掘Wurmiella， Panderodus unicostatus, Zieglerodina eladioi, Belodella resima, Neopanderodus aequabilis， Belodella anomalis和Icriodus？sp. indet。确定了7种主要的沉积岩岩相，并将其解释为温暖热带地区较浅到较深的海洋环境。该层序沉积于志留纪流纹岩火山弧以东，与之互指，被认为是弧或弧后盆地的一部分。一条志留纪-泥盆纪弧表明，这部分印度支那复合地体在志留纪或志留纪之前从冈瓦纳脱离。

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引用次数: 0

The first fossil flower of Malpighiaceae from India sheds light on the historical biogeography of a mostly Neotropical family 来自印度的第一个malpiighiaceae的化石花揭示了一个主要是新热带家庭的历史生物地理学

IF 2

Journal of Palaeogeography

Pub Date : 2026-01-01 DOI: 10.1016/j.jop.2025.100313

Ashif Ali , Rafael Felipe de Almeida , Mahasin Ali Khan , Raman Patel , Rajendra Singh Rana

A fossil flower affinity to an extinct Malpighiaceae taxon, recovered from the early Eocene (∼55–52 Ma) of Gurha Opencast Lignite Mine, Rajasthan, western India, helps to underscore the evolutionary significance of this angiosperm lineage in the Indian Cenozoic history. Based on several macromorphological traits, a new fossil genus and species of Malpighiaceae, named Eomalpighia indica Ali, R.F. de Almeida, and Khan gen. et sp. nov., is proposed. Additionally, a continental ancestral range reconstruction was performed using the generic molecular phylogeny of Malpighiaceae and the BioGeoBEARS package for historical biogeography to discuss the phylogenetic placement of this new fossil and its significance for Malpighiaceae biogeography. The fossil specimen is characterized by one anterior petal and four lateral petals, eglandular; one posterior sepal and four lateral sepals, clawed at the base, eglandular, elliptic; four stamens, free, anthers with two thecae; presence of gynoecium in the center with a trilobed apex. The newly described fossil flower is best placed as an ancestor of the tribe Acridocarpeae due to its unique morphology and fossil distribution. The ancestral range reconstruction evidenced that Malpighiaceae likely had two different dispersal waves from the Neotropics to the Paleotropics, taking place at the beginning (55.0–45.0 Ma) and the end (52–50 Ma) of the Eocene Climate Optimum Maximum. The first wave dispersed through Antarctica, and the second wave through the Boreotropics. This study provides insights into the taxonomy, evolutionary history, morphological evolution, and paleoecological implications of Malpighiaceae lineages in India.

在印度西部拉贾斯坦邦Gurha露天褐煤矿的始新世早期（~ 55-52 Ma）发现的一种已灭绝的malpiighiaceae分类群的花化石，有助于强调这一被子植物谱系在印度新生代历史中的进化意义。基于几个宏观形态特征，提出了一种新的麻瓜科化石属和种，命名为Eomalpighia indica Ali， R.F. de Almeida, and Khan gen. et sp. nov.。此外，利用Malpighiaceae的一般分子系统发育和历史生物地理学的biogeobars软件包进行了大陆祖先范围的重建，讨论了该新化石的系统发育定位及其对Malpighiaceae生物地理学的意义。化石标本的特征是一个前花瓣和四个侧花瓣，腺状；一后萼片和四侧萼片，爪状在基部，腺状，椭圆形；四雄蕊，离生，花药具二花萼；中心有雌蕊，先端有三叶。由于其独特的形态和化石分布，新描述的化石花最适合作为tribe Acridocarpeae的祖先。祖先范围的重建表明，从新热带到古热带可能有两次不同的扩散波，分别发生在始新世气候最适最大值的开始（55.0 ~ 45.0 Ma）和结束（52 ~ 50 Ma）。第一波穿过南极洲，第二波穿过北方热带。本研究对印度麻瓜科植物的分类、进化历史、形态演化和古生态意义等方面提供了新的认识。

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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