Palaeogeography, Palaeoclimatology, Palaeoecology最新文献

{"title":"Late Holocene climate changes in the Northwest Iberian Peninsula reflect fluctuations in the relative dominance of Atlantic and Mediterranean climate zones","authors":"Uxía Fernández-Pérez ,&nbsp;Armand Hernández ,&nbsp;Alberto Sáez ,&nbsp;Rafael Carballeira ,&nbsp;Rouven Altrogge ,&nbsp;Luisa Santos ,&nbsp;Ricardo Prego ,&nbsp;Pedro M. Raposeiro ,&nbsp;Roberto Bao","doi":"10.1016/j.palaeo.2025.113034","DOIUrl":"10.1016/j.palaeo.2025.113034","url":null,"abstract":"<div><div>The northwestern Iberian Peninsula lies at the ecotonal transition between the Atlantic and Mediterranean bioclimatic regions, and mountain lakes in this region are sensitive to climate variability, preserving sedimentary records that are useful for studying past climate dynamics. In this paper, we reconstruct late Holocene climate through a high-resolution multiproxy analysis of a sediment core from Lake Ocelo, a high elevation lake. Analysis of sedimentological, geochemical, and biological proxies reveal regional hydroclimatic variability over the past three millennia, and allow the identification of climate phases that reflect the complex interplay between Atlantic and Mediterranean influences. The Subatlantic Period (c. 890–200 BCE) marks a transition to wetter conditions after the 2.8 ka climate event. The Roman Warm Period (c. 200 BCE–300 CE) shows increased aridity, suggesting an expansion of Mediterranean influence, and the wetter Dark Ages Period (c. 300–750 CE) indicates renewed Atlantic dominance. The drier Medieval Climate Anomaly (c. 750–1100 CE) reflects greater Mediterranean influence. The transition from the Medieval Climate Anomaly to the Little Ice Age (c. 1100–1300 CE), defined as a distinct climatic phase, marks a shift to wetter conditions. The Little Ice Age (c. 1300–1900 CE) exhibits alternating wet-dry subphases and prolonged ice cover, leading to stronger denitrification under a stronger regional Atlantic influence. The Industrial Era (c. 1850 CE–present) is characterized by a warming trend, increased lake productivity, and reduced terrigenous input. These findings highlight the sensitivity of the Atlantic–Mediterranean ecotonal boundary to climate shifts and provide insights for predicting future dynamics, including potential “Mediterraneanization” of the Atlantic zone.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"674 ","pages":"Article 113034"},"PeriodicalIF":2.6,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Redescription of Plesioschizothorax macrocephalus (Cyprinidae, Schizothoracini) from the Miocene of Lunpola Basin, Central Qinghai-Tibet Plateau, and its paleobiogeographic and paleogeographical implications","authors":"Tao Yang ,&nbsp;Feixiang Wu ,&nbsp;Chi Zhang ,&nbsp;Pengju He ,&nbsp;Dekui He ,&nbsp;Shuang Yang ,&nbsp;Qingming Qu ,&nbsp;Fujiang Liu","doi":"10.1016/j.palaeo.2025.113035","DOIUrl":"10.1016/j.palaeo.2025.113035","url":null,"abstract":"<div><div>The evolution of paleo-drainages on the Qinghai-Tibet Plateau is significant for understanding the paleogeographic, topographic, and the orogenic exhumation history. Fossils of freshwater fishes are helpful for understanding the biological and geological interplays in the ecosystem because they are usually restricted to the drainages, which are in turn constrained by tectonic events. This study re-examines <em>Plesioschizothorax macrocephalus</em>, a fossil cyprinid fish from the Lower Miocene of the Lunpola Basin in the 1970's. Our updated phylogenetic analysis based on total-evidence dating suggests that <em>Plesioschizothorax</em> is most closely related to extant <em>Percocypris</em>, a genus currently found in the Mekong, Salween, and Upper Yangtze Rivers. Their evolutionary split, estimated to have occurred in the Late Oligocene (ca. 26.60 Ma), coincides with the intensification of Asian monsoon in the central Qinghai-Tibet Plateau. Our ancestral distribution reconstructions indicate that the common ancestor of these two fishes likely inhabited the central Qinghai-Tibet Plateau. During the Late Oligocene (26.60 Ma) to Early Miocene (21.63 Ma), their descendants dispersed to the paleo-Mekong and Salween Rivers. We assume that the enhanced precipitation due to the strengthening of the Asian monsoon had led to an expansion of the upper paleo-Mekong and Salween Rivers during the Late Oligocene to Early Miocene, creating a hydrological connection with the paleo-lakes in the Lunpola Basin and thereby providing pathways for dispersal. This scenario implies that the current internal drainage systems in the central plateau likely formed after the Early Miocene.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"674 ","pages":"Article 113035"},"PeriodicalIF":2.6,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144116957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of wetland foraging and body size on bison hair sulfur, nitrogen, and carbon isotope compositions: Implications for wildlife conservation, archaeology, and palaeoecology","authors":"Jessica Z. Metcalfe ,&nbsp;Wes Olson","doi":"10.1016/j.palaeo.2025.113033","DOIUrl":"10.1016/j.palaeo.2025.113033","url":null,"abstract":"<div><div>Palaeoecological and archaeological reconstructions using stable isotopes rely on understanding isotopic processes in modern ecosystems. This study examines how sulfur, nitrogen, and carbon isotope values (<em>δ</em>³⁴S, <em>δ</em>¹⁵N, and <em>δ</em>¹³C) of modern plains and wood bison (<em>Bison bison bison</em> and <em>Bison bison athabascae</em>) hair records foraging selectivity and size-related metabolic differences in a C₃-dominated mixed woodland environment: Elk Island National Park (EINP), Alberta, Canada. Terrestrial grasses on the margins of wetlands in EINP had substantially lower <em>δ</em>³⁴S and higher <em>δ</em>¹⁵N than grasses in dry environments, signalling the potential for modern and ancient herbivore tissue <em>δ</em>³⁴S and <em>δ</em>¹⁵N values to record wetland versus dryland foraging. Bison hair <em>δ</em>³⁴S and <em>δ</em>¹⁵N differed between wood and plains bison subspecies, with lower <em>δ</em>³⁴S and higher <em>δ</em>¹⁵N values in wood bison hair suggesting they consumed more plants growing in wetland habitats. Adult females and juveniles consumed a greater proportion of wetland plants than adult males, reflecting differential group dynamics and foraging decisions. Bison body size was positively (linearly) correlated with hair <em>δ</em>¹³C and negatively (non-linearly) correlated with hair <em>δ</em>¹⁵N, but uncorrelated with hair <em>δ</em>³⁴S. We hypothesize that increased body size requires greater reliance on gut microbial proteins to build body tissues (increasing hair <em>δ</em>¹³C), and that larger-bodied individuals have greater nitrogen use efficiency and lower-quality diets (decreasing hair <em>δ</em>¹⁵N). Our results suggest that (palaeo)ecological and archaeological researchers should consider the extent to which habitat selectivity and metabolic effects related to sex, age and body size can influence herbivore tissue isotopic compositions.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"675 ","pages":"Article 113033"},"PeriodicalIF":2.6,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144138314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Triassic evolution of source-to-sink drainage systems in the North Ordos Basin of central China: Impact of asynchronous uplift history","authors":"Yanhua Xu ,&nbsp;Dengfa He ,&nbsp;Di Li ,&nbsp;Hanyu Huang ,&nbsp;Xiang Cheng","doi":"10.1016/j.palaeo.2025.113012","DOIUrl":"10.1016/j.palaeo.2025.113012","url":null,"abstract":"<div><div>A pattern of asynchronous uplift influenced drainage reorganization in the North Ordos Basin (NOB) of central China in Triassic times. In this study, the source-sink system of the NOB was reconstructed, and the source area was identified, based on an analysis of petrology, geochronology, and palaeocurrent direction analysis, offering a new perspective on the interaction between deep tectonic processes and surface responses in the northern part of the North China Block (N-NCB). Our zircon age data reveal three prominent peaks for the Palaeoproterozoic, Mesoproterozoic, and Upper Palaeozoic, suggesting that the N-NCB may have acted as the source area for the NOB. During the Late Triassic interval, increased zircon ages (1500–1800 Ma) indicate an enhanced influx of detrital material from the central N-NCB. Furthermore, analysis of thin sections and petrographic modal compositions indicates a change in source areas from solely recycled orogenic sources to a combination of recycled orogenic and magmatic arc sources. The youngest zircon ages (∼233.6 Ma) from the tuffaceous siltstone mark this transition, with palaeocurrent data supporting a change in the source area from the western to the central N-NCB after this time. This transition underscores the impact of the asynchronous uplift of the N-NCB on the source-to-sink system of the NOB, providing an innovative perspective for reconstructing the southward subduction process of the Okhotsk Plate and associated back-arc extension along the N-NCB.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"674 ","pages":"Article 113012"},"PeriodicalIF":2.6,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extreme flood events in the Yi and Shu river basins of the Haidai region (Shandong Province, China) during the late Holocene: Implications for future risk prediction","authors":"Tianyu Shi ,&nbsp;Xiaodong Miao ,&nbsp;Hongyuan Shen ,&nbsp;Qiumin Zhai ,&nbsp;Songna Wang","doi":"10.1016/j.palaeo.2025.113011","DOIUrl":"10.1016/j.palaeo.2025.113011","url":null,"abstract":"<div><div>Modern floods in the Yi and Shu river basins (YSRs), the largest mountain torrent channels in the Haidai region, Shandong Province, China, are often triggered by monsoonal rainfall, shaping the fluvial landscape through frequent inundations. However, our understanding of flood events remains limited due to short observational records and their limited spatial distribution. The lack of long and complete palaeoflood records limit our understanding of extreme flood events, hindering risk prediction and prevention efforts. In this study, we examine the sediment characteristics of two palaeoflood profiles in the YSRs and, based on twelve optically stimulated luminescence (OSL) ages, four ¹⁴C ages, and grain size-sensitive components, identified three exceptional palaeoflood periods: 4.1–3.9 ka, 3.4–2.9 ka, and 0.88–0.7 ka, along with a less severe flood period during 0.7–0.1 ka. An analysis of pollen records, stalagmite data, historical flood records, and El Niño-Southern Oscillation (ENSO) activity reveals a strong correlation between palaeofloods in the YSRs basin and other major rivers (Yellow River, Huai River, Han River, and Yangtze River) with a significant negative correlation to the intensity of the East Asian Summer Monsoon and a positive correlation to the ENSO intensity. These palaeoflood events are typically closely linked to global climate shifts during the late Holocene, including the 4.2 ka event, the 2.8 ka event, and the Little Ice Age. Simultaneous occurrences of climatic deterioration (arid and cold) and palaeofloods during 4.1–3.9 ka and 3.4–2.9 ka may have contributed to cultural disruptions during the Late Longshan Culture period and the decline of the Shang culture in the Haidai area. We argue that these hydroclimatic events are regional expressions of global climate phenomena, and the identified palaeofloods offer key insights into how East Asian rivers respond to global climate change.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"674 ","pages":"Article 113011"},"PeriodicalIF":2.6,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Examining potential drivers of variation in the carbonate-collagen stable carbon isotope offset of modern and Late Pleistocene ungulates from C3-dominant ecosystems","authors":"Laura C. Eastham ,&nbsp;Robert S. Feranec","doi":"10.1016/j.palaeo.2025.113014","DOIUrl":"10.1016/j.palaeo.2025.113014","url":null,"abstract":"<div><div>The stable carbon isotope composition (δ¹³C) of mammalian hard tissues offers a powerful tool for understanding the ecology of modern and fossil species. Over the past 40 years, the offset between δ¹³C values measured in structural carbonate and collagen (Δ_ca-co) has been used as an indicator of trophic category. However, several recent studies have demonstrated substantial variation in the Δ_ca-co values of herbivores, raising calls for caution in the use of static Δ_ca-co values to interpret trophic relationships. To better clarify mechanisms driving variation in herbivore Δ_ca-co, we examined the relationship between δ¹³C_carbonate and δ¹³C_collagen in modern and Late Pleistocene ungulates from C₃-dominant ecosystems in the Americas and Eurasia. Factors investigated included diet, digestive physiology, and tissue type. Our results showed considerable variation in herbivore Δ_ca-co, underscoring the need for caution when applying static values to reconstruct trophic position. We found a consistent diet-driven pattern in Δ_ca-co values (grazer &gt; mixed feeder &gt; browser). Identifying this pattern in modern and ancient species adds to growing evidence for the generalizability of the relationship between herbivore diet and Δ_ca-co. In contrast, the fossil data set showed evidence counter to predictions based on physiology: non-ruminants displayed higher Δ_ca-co values and a greater rate of increase in δ¹³C_carbonate relative to δ¹³C_collagen than ruminants. Finally, tissue type substantially influenced Δ_ca-co, with values derived from teeth generally higher and more variable than from bone. This work highlights the potential for herbivore Δ_ca-co to serve as a refined indicator of dietary ecology in modern and ancient ecosystems.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"674 ","pages":"Article 113014"},"PeriodicalIF":2.6,"publicationDate":"2025-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Holocene vegetation and environmental changes of peat ecosystems in southwestern and northeastern Amazonia","authors":"B. Wang ,&nbsp;H. Behling","doi":"10.1016/j.palaeo.2025.113010","DOIUrl":"10.1016/j.palaeo.2025.113010","url":null,"abstract":"<div><div>Amazonia plays a significant role in the global climate change, hydrological cycle, biodiversity conservation, especially in the carbon (C) cycle. Amazonia likely contains the most extensive peat C stock in the tropics. Easily degraded, these Amazonian peat ecosystems are at risk of changing from representing a large C sink to a major C source, impacting global cycles. Thus, it is essential to understand how the peat ecosystems in Amazonia developed and the past drivers of changes. Most palaeoecological research on these peat ecosystems has focused on the northwestern Amazonia. Although the representative peat ecosystems in southwestern (SW) and northeastern (NE) Amazonia have been investigated for vegetation dynamics, peat and organic C accumulation, climate, human activities, hydrology, and geomorphology, our knowledge of peat ecosystem evolution is still insufficient. Therefore, in this paper, we first summarize the recently published palaeoecological studies for representative peat ecosystems in SW and NE Amazonia, and the modern and Holocene regional climate. We reconsider the mechanisms of the representative peat ecosystems combined with other related palaeoecological studies under the regional climate framework. Finally, we compare the conditions of peat ecosystems in SW and NE Amazonia. Through the present comparison, we find that the development of peat ecosystems depends on local settings in Amazonia. The onset of the peat ecosystem is mainly driven by river dynamics in SW Amazonia, but is strongly influenced by the Atlantic sea level in low-lying areas in NE Amazonia. The local factors also include geomorphology, fluvial dynamics, local climate, and human activities. Various influencing factors cause diverse processes in peat ecosystems, whether in vegetation successions or peat and C accumulation rates. It is worth noting that regional human activities may indirectly play an important role in peat ecosystem development in both SW and NE Amazonia. This study helps to further understand the mechanism of the development of tropical peat ecosystems, which is important for the modeling, conservation, and management of tropical peat ecosystems.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"673 ","pages":"Article 113010"},"PeriodicalIF":2.6,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143942507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detrital zircon UPb geochronology of the Cenozoic succession in the southern Tarim Basin: Implications for the northward expansion of the West Kunlun Orogen and the evolution of intracontinental convergence in the northwestern Tibetan Plateau","authors":"Chunyang Li ,&nbsp;Kaixuan An ,&nbsp;Xiubin Lin ,&nbsp;Yong Li ,&nbsp;Xianzhang Yang ,&nbsp;Liang Zhang ,&nbsp;Cai Chen ,&nbsp;Shujun Liang ,&nbsp;Xiaochun Wei ,&nbsp;Yang Qu ,&nbsp;Xinyue Zhao ,&nbsp;Jialun Huang ,&nbsp;Hanlin Chen ,&nbsp;Shubing Li","doi":"10.1016/j.palaeo.2025.113006","DOIUrl":"10.1016/j.palaeo.2025.113006","url":null,"abstract":"<div><div>The collision between the Indian and Eurasian plates led to the formation of the Tibetan Plateau and the development of a broad zone of intracontinental deformation. Situated in the northwestern Tibetan Plateau, the West Kunlun Orogen is a key region for examining intracontinental responses to the far-field effects of the India–Eurasia collision. However, the nature of convergence between the Tarim Basin and the West Kunlun Orogen remains uncertain. The West Kunlun Orogen consists of the northern and southern West Kunlun terranes and the Songpan-Ganzi terrane, each exhibiting distinct zircon U<img>Pb geochronological signatures. In this study, we apply detrital zircon U<img>Pb geochronology and related analyses to nine Cenozoic sediment samples from the Keliyang section and one sample from the Sangju River to investigate source-to-sink relationships and the uplift history of the West Kunlun Orogen. Our results reveal a significant shift in sedimentary provenance, transitioning from sources in the Songpan-Ganzi and southern West Kunlun terranes during the deposition of the Bashibulake, Keziluoyi, Anjuan and Pakabulake formations to the northern West Kunlun terrane during the deposition of the Artux Formation. This shift indicates a northward expansion of the West Kunlun Orogen, accompanied by a migration of the deformation front from the Tam Karaul Fault to the Tiklik Fault. These findings support a transition in convergence dynamics between the Tarim Basin and the West Kunlun Orogen shifted from a crustal-scale coupling mode with pure-shear thickening to a decoupled mode characterised by southward underthrusting of the Tarim Basin's lower crust.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"673 ","pages":"Article 113006"},"PeriodicalIF":2.6,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143935852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dietary fidelity of Miocene ungulates in the context of environmental change in the Mojave Region, western North America","authors":"Fabian Cerón Hardy ,&nbsp;Xiaoming Wang ,&nbsp;Chelsie N. Bowman ,&nbsp;Yang Wang ,&nbsp;Catherine Badgley","doi":"10.1016/j.palaeo.2025.113013","DOIUrl":"10.1016/j.palaeo.2025.113013","url":null,"abstract":"<div><div>The fossil record of mammals preserves evidence for dietary adaptations that allowed lineages to persist in dynamic ecosystems for tens of millions of years. We investigated ecological attributes of fossil mammals during the middle to late Miocene (17.5–8.5 Ma) in the western Mojave region of North America to evaluate the response of herbivorous ungulates to paleoenvironmental changes. Herbivores may utilize the same food resources across generations, relying on relationships with vegetation and habitats established over multiple generations. We employed stable isotopes of carbon and oxygen from ancient soils and herbivore tooth enamel to evaluate changes in vegetation and herbivore diets. We compiled isotopic data from published studies of three sequences from the warm Miocene Climatic Optimum and added new data from the Dove Spring Formation, which formed during the cooler Middle Miocene Climatic Transition. Herbivorous ungulates exhibited dietary fidelity for nearly nine million years, selectively consuming C₃ plants even as C₄ vegetation became more prevalent on the landscape. High oxygen stable isotope ratios in comparison to equids suggest that ancestral antilocaprids and camelids were likely facultative drinkers. These findings reveal enduring dietary preferences that enabled these herbivores to persist amid the profound environmental transitions of the Miocene.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"673 ","pages":"Article 113013"},"PeriodicalIF":2.6,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143948498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neoproterozoic mafic magmatism (ca. 790–780 Ma) in the western Jiangnan Orogen of South China, and its implication for a slab rollback origin","authors":"Caihua Kou ,&nbsp;Yanxue Liu ,&nbsp;Jiang Li ,&nbsp;Shengkai Jin","doi":"10.1016/j.palaeo.2025.113008","DOIUrl":"10.1016/j.palaeo.2025.113008","url":null,"abstract":"<div><div>In this paper, we present geochemical data for a Neoproterozoic basalt (from Ximalian) two clinopyroxenite intrusions (Tangtou, Mahai), and three gabbroic intrusions (Datan, Longsheng, and Youziping) in the Longsheng area of northern Guangxi, China. This area is located in the western part of the Jiangnan Orogen of the South China Block. Secondary ion mass spectrometry (SIMS) U<img>Pb zircon dating of the Xiamalian basalt, Youziping gabbro, and Mahai clinopyroxenite yielded concordia ages of 786.0 ± 5.6 Ma, 788.9 ± 4.8 Ma, and 780.1 ± 4.7 Ma. Geochemically, the Ximalian basalt and Tangtou clinopyroxenite, as well as three gabbroic rocks, have arc-like geochemical affinities characterized by moderate light rare earth element (LREE) enrichment (La_N/Yb_N = 2.79–9.45), pronounced negative Nb<img>Ta anomalies, and relatively low Nb/La ratios (with an average of 0.52). They have variable εNd(t) (−4.5 to 3.9) and positive εHf(t) (6.5–8.5) values. We thus conclude that these rocks were derived from the mantle wedge in a subduction setting via partial dehydration melting of the lithospheric mantle metasomatized by dehydrated fluids. In contrast, the Mahai clinopyroxenite exhibits ocean island basalt (OIB)-like signatures, including LREE enrichment (La_N/Yb_N = 11.87–22.25), a lack of negative Nb, Ta, and Ti anomalies; and positive εNd(t) (0.5–1.5, with one exception of −2.9) and εHf (t) (3.0–3.5) values. We infer that the Mahai clinopyroxenite was generated by partial decompression melting of the upwelling asthenospheric mantle in an extensional setting. Based on the regional geology, as well as the results of this study and previous publications, we conclude that the arc-type rocks analyzed in this study were generated under geodynamic processes triggered by the rollback of the subducted slab in a subduction setting. The OIB-like rocks were related to the break-off of the rolled-back slab, which created an extensional setting and enabled asthenospheric upwelling and partial melting.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"673 ","pages":"Article 113008"},"PeriodicalIF":2.6,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143948871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}