Earth-Science Reviews最新文献

{"title":"The ichnogenus Ophiomorpha Lundgren, 1891: Taxonomy and environmental distribution","authors":"Dirk Knaust","doi":"10.1016/j.earscirev.2024.104988","DOIUrl":"10.1016/j.earscirev.2024.104988","url":null,"abstract":"<div><div>The classic trace fossil <em>Ophiomorpha</em> ranks among the most common biogenic sedimentary structures on earth and has been widely reported from Mesozoic and Cenozoic strata. Originally thought to be restricted to shallow-marine environments, subsequently <em>Ophiomorpha</em> was also recognised in marginal-marine and deep-marine deposits. A proper application for palaeoenvironmental reconstructions is hindered by inadequately defined ichnospecies and gradual transitions among them. This review reveals five ichnospecies as valid, each of which occurs in a particular sedimentary environment. <em>Ophiomorpha saxonica</em> and <em>O. nodosa</em> are common in shallow-marine and nearshore environments. <em>Ophiomorpha nodosa</em> may cooccur and intergrade with <em>O. irregulairis</em>, which reaches far into marginal-marine environments with brackish-water conditions. <em>Ophiomorpha rudis</em> and <em>O. annulata</em> are deep-marine forms, probably reaching up to the upper continental slope. Care must be taken assigning burrows with a knobby lining from continental deposits to <em>Ophiomorpha</em>, which might be more conformable with other, similar ichnotaxa. Based on modern analogues and body fossils within their burrows, <em>Ophiomorpha nodosa</em> and partly <em>O. saxonica</em> are believed to result from the burrowing activity of callianassid shrimp. Decapod crustaceans belonging to Axiidea (mud shrimp, ghost shrimp and burrowing shrimp) and Gebiidea (mud lobsters and mud shrimp) are the likely producers of the other ichnospecies. A combined deposit- and suspension-feeding can be inferred for the tracemaker. Intimate association of <em>Ophiomorpha</em> with minute mud-lined burrows suggests the occurrence of brooding chambers and emergence of juvenile crustaceans.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 104988"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abrupt thaw and its effects on permafrost carbon emissions in the Tibetan Plateau: A remote sensing and modeling perspective","authors":"Yonghong Yi ,&nbsp;Tonghua Wu ,&nbsp;Mousong Wu ,&nbsp;Huiru Jiang ,&nbsp;Yuanhe Yang ,&nbsp;Brendan M. Rogers","doi":"10.1016/j.earscirev.2024.105020","DOIUrl":"10.1016/j.earscirev.2024.105020","url":null,"abstract":"<div><div>The Tibetan Plateau (TP) has the largest permafrost area in the low- and mid-latitudes. With warmer ground temperatures and ice-rich terrain, the TP permafrost is potentially more vulnerable to climate warming. Abrupt thaw induced by rapid ground ice melt and thermokarst process has become more frequent in the TP, which will likely have a large impact on the regional water and carbon exchanges. This review presents recent researches on the drivers of abrupt thaw, with a focus on the hillslope thermokarst, and advances in remote sensing and process-based modeling of abrupt thaw process and the permafrost carbon feedback in the TP, with a comparison to the Arctic studies. Ground ice content and local topography are the two main factors controlling the rate and form of abrupt thaw; however, a lack of accurate estimates of ground ice content distribution and challenges in characterizing lateral heat transfer and groundwater flows greatly limit modeling capability in representing fine-scale thermokarst processes at a regional scale. High resolution satellite remote sensing has been widely used to identify various thermokarst landforms across the TP. However, studies using multi-source remote sensing to quantify the thermokarst-induced soil volume ice and mass loss are still lacking, particularly in the TP, which are important for characterizing the permafrost carbon feedback with abrupt thaw. Integration of spatial information derived from multi-source remote sensing with process-based models will allow better characterization of abrupt thaw processes, which generally occur at scales finer than model grid cells and are difficult to parameterize for coarse-resolution global and regional models. This synthesis can inform future research on better representing abrupt thaw process not only in the TP region but extending to other permafrost areas as well.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 105020"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142790089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reply to Holliday et al. regarding the Carolina Bays","authors":"Antonio Zamora","doi":"10.1016/j.earscirev.2024.105024","DOIUrl":"10.1016/j.earscirev.2024.105024","url":null,"abstract":"<div><div>The paper by Holliday, et al. (2023) tries to establish that the major axes of the elliptical Carolina Bays are not oriented toward the Great Lakes and that the bays are well documented ice-melt landforms known as kettles. Both of these propositions are inaccurate. The paper relies on outdated references from before LiDAR was in common use and before the Nebraska basins had been discovered. The orientations of the Carolina Bays can be determined accurately by fitting them with ellipses using the least squares method. The argument that the Carolina Bays are ice-melt landforms can be dismissed by referencing the extent of the Laurentide Ice Sheet and permafrost during the Last Glacial Maximum.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 105024"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A review of the granite concept through time","authors":"Eloi González-Esvertit ,&nbsp;Claudia Prieto-Torrell ,&nbsp;Paul D. Bons ,&nbsp;Àngels Canals ,&nbsp;Josep Maria Casas ,&nbsp;Marlina A. Elburg ,&nbsp;Enrique Gomez-Rivas","doi":"10.1016/j.earscirev.2024.105008","DOIUrl":"10.1016/j.earscirev.2024.105008","url":null,"abstract":"<div><div>Granitic rocks are ubiquitous worldwide in ancient and active tectonic settings, representing powerful sources of information about the Earth's past and present geodynamic behaviour. Numerous recent milestones fostering our knowledge of granites would have not been possible without a long-lasting, sometimes controversial, discussion on their origin and significance that has taken place over the last two centuries. Here we present a chronological review of how granites have been defined and interpreted in the context of the major theories that have successively governed the history of Earth Science. The main authors, scientific approaches, interpretations, and type-localities that have influenced knowledge about granitic rocks are summarized from the 18th and 19th centuries, when Earth Science was governed by the Neptunism, Plutonism and Uniformitarianism paradigms, to the acceptance of the Plate Tectonics theory and the very end of the magmatism vs. transformism debate in the late 20th century. Some of the most influential scientific advances in Earth Science, such as the invention of the polarizing microscope and the birth of geochemistry, as well as the role of schools of thought in these successive debates, are further discussed. Moreover, we review the recent and ongoing discussions on the mechanisms of magma generation, segregation, ascent and emplacement leading to the formation of granitic batholiths, as well as the observational, analytical, experimental, and numerical modelling approaches currently used for investigating granitic rocks. The history of granite science is classified into different periods of stasis or “normal” science, which were followed by scientific revolutions triggered by a growing number of inconsistencies. Our current understanding of granitic rocks is inevitably influenced by the preceding paradigms and disputes. Consequently, gathering and valuing the chronology, historical milestones, and overall evolution of ideas and theories on what granites are is crucial for the future directions of granite research.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 105008"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polycyclic Andean-type orogenic evolution of the Dunhuang block in NW China: A result of Paleozoic reconfiguration of oceanic subduction systems","authors":"Jérémie Soldner ,&nbsp;Karel Schulmann ,&nbsp;Pavla Štípská ,&nbsp;Yingde Jiang ,&nbsp;Robert Anczkiewicz ,&nbsp;Chao Yuan ,&nbsp;Zongying Huang","doi":"10.1016/j.earscirev.2024.104984","DOIUrl":"10.1016/j.earscirev.2024.104984","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Despite numerous studies of metamorphic and magmatic rocks from the Dunhuang block, its protracted Cambrian to Permian geodynamic evolution as well as its role in the final amalgamation of the Tarim−North-China Craton Collage during the Pangea assembly, remain controversial. In order to understand the evolution of the Dunhuang block in the frame of Paleozoic plate tectonics, we review and synthetize recently published &lt;em&gt;P−T&lt;/em&gt; data along with geochronological and geochemical data for its northern, central and southern mountain ranges, which we placed in the context of structural observations. Zircon and monazite U−Pb ages combined with &lt;em&gt;P−T&lt;/em&gt; constraints determined for Ordovician to Devonian metamorphic rocks reveal that M&lt;sub&gt;1&lt;/sub&gt; and M&lt;sub&gt;2&lt;/sub&gt; metamorphic events define a clockwise &lt;em&gt;P−T&lt;/em&gt; evolution and distinctly hot metamorphic gradients. Ordovician to Devonian protracted garnet growth evidenced by low (Yb/Gd)&lt;sub&gt;N&lt;/sub&gt; ratios in metamorphic zircon and monazite, together with low Th/U ratios, negative ε&lt;sub&gt;Hf&lt;/sub&gt;(t) and Eu anomalies in magmatic and metamorphic zircon, mark a period of continuous metamorphism accompanied by crustal reworking during thickening of a previously thermally softened crust. Zircon and monazite U−Pb ages suggest that the early Paleozoic D&lt;sub&gt;1&lt;/sub&gt;-M&lt;sub&gt;1&lt;/sub&gt; and D&lt;sub&gt;2&lt;/sub&gt;-M&lt;sub&gt;2&lt;/sub&gt; events started ca. 10 m.y. earlier and lasted longer in the northern and central ranges compared to the southern range consisting of significantly older crustal basement components. In all three mountain ranges, the formation of an E-W trending steep cleavage related to D&lt;sub&gt;3&lt;/sub&gt;-M&lt;sub&gt;3&lt;/sub&gt; event was concomitant with emplacement of numerous late Devonian to Carboniferous diorites and I-type granitoids. The negative ε&lt;sub&gt;Hf&lt;/sub&gt;(t) of magmatic zircon and high (Yb/Gd)&lt;sub&gt;N&lt;/sub&gt; ratios in metamorphic zircon and monazite show that a magma-assisted N-S-directed shortening event responsible for further crustal reworking started in the late Devonian and lasted over 60 m.y. The latest Permian M&lt;sub&gt;4&lt;/sub&gt; metamorphic event, restricted mainly to the southern range, defines anticlockwise &lt;em&gt;P−T&lt;/em&gt; paths associated with the emplacement of high-K calc-alkaline granitoids. This event is characterized by the increasing from negative to positive zircon ε&lt;sub&gt;Hf&lt;/sub&gt;(t) values, suggesting input of juvenile crustal and mantle-derived material. High metamorphic gradients and the petrogenesis of magmatic arc-related rocks intruding a Precambrian basement suggest that the Dunhuang block developed as a supra-subduction continental hot orogenic system formed above subducting oceanic plates similar to the northern and southern margins of the American Cordillera. Our data show that its evolution was related to two kinematically independent early to middle and late Paleozoic orogenic cycles. In the context of plate tectonic reconstructions, the revised chronology of events points to the kinematic int","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 104984"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Canary hotspot revisited: Refutation of the Hawaii paradigm and an alternative, plate-based hypothesis","authors":"Francisco Anguita ,&nbsp;Carlos Fernández ,&nbsp;Álvaro Márquez ,&nbsp;Ricardo León ,&nbsp;Ramón Casillas","doi":"10.1016/j.earscirev.2024.105038","DOIUrl":"10.1016/j.earscirev.2024.105038","url":null,"abstract":"<div><div>Fifty years after the first modern hypotheses on the origin of the Canary Islands were put forward, a consensus on this topic seems more and more elusive. Earth scientists use increasingly sophisticated methods to refine hypotheses like the mantle plume, but they often acknowledge that the model is plagued with many inconsistencies. This work is centred around four main ideas: 1) To falsify (in the sense of <span><span>Popper, 1959</span></span>) the Hawaii paradigm for the Canary Islands, 2) to define this group of islands as a weakened lithospheric intraplate feature, hence introducing a plate-based paradigm, 3) to prove a genetic connection between the Canaries and the Atlas Mountains, and 4) to integrate for the first time the Canary Islands in the Nubia Plate kinematics.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 105038"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response to Zamora regarding the Carolina Bays","authors":"Vance T. Holliday ,&nbsp;Tyrone L. Daulton ,&nbsp;Patrick J. Bartlein","doi":"10.1016/j.earscirev.2024.105025","DOIUrl":"10.1016/j.earscirev.2024.105025","url":null,"abstract":"<div><div>The author misconstrues our comments. We simply present the research and opinions of other investigators. We are well-aware that the landscape of the Atlantic Coastal Plain in the southeastern U.S. was never glaciated.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 105025"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal evolution of aeolian sedimentary landscapes on the southern Tibetan Plateau during the late Quaternary: A review and recent advances","authors":"Junhuai Yang ,&nbsp;Shengqian Chen ,&nbsp;Zhiyong Ling ,&nbsp;Canyi Zhang ,&nbsp;Linkai Wang ,&nbsp;Haoyu Wang ,&nbsp;Shuyuan Wang ,&nbsp;Fuyuan Gao ,&nbsp;Ivan Lizaga ,&nbsp;Fei Wang ,&nbsp;Shengli Yang ,&nbsp;Fahu Chen","doi":"10.1016/j.earscirev.2024.105035","DOIUrl":"10.1016/j.earscirev.2024.105035","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The aeolian deposits on the southern Tibetan Plateau (TP) are one of the most important environmental archives preserved at the highest altitudes worldwide, containing extensive information about both the current and past landscapes and environments of Earth's Third Pole. Over the past three decades, these deposits have attracted considerable attention in Quaternary paleoclimate research. Nevertheless, our understanding of these high-altitude aeolian deposits is significantly less than that for similar deposits in the low-altitude regions of the Eurasian continent. To better comprehend this important archive, it is essential to integrate knowledge from various perspectives. However, there is a lack of consensus regarding their formation, distribution, chronology, provenance, and paleoclimatic history across different timescales. Here, based on our recent field investigations and new data, along with previously published data, we present the results of a systematic analysis of aeolian deposits on the southern TP. Our principal results and findings are: (1) We present up-to-date maps of the aeolian deposits, consisting of an overview map of the overall spatial distribution, and six high-resolution regional maps highlighting details of the depositional areas. Loess and sand dunes have accumulated within the six subdomains, following the global pattern of dust accumulation along rivers in arid and semi-arid regions. (2) Based on paleomagnetic and ESR dating, the oldest aeolian sediments were formed during the middle Pleistocene. The probability density of 220 OSL and AMS &lt;sup&gt;14&lt;/sup&gt;C ages reveals that 98.7 % of the young sediments accumulated since the last interglacial, with the majority (66.4 %) forming during the Holocene. A comparison of age clusters with records of ice volume, temperature, precipitation, vegetation, and paleolakes revises previous hypotheses regarding the factors influencing dust deposition, emphasizing the dominant control of climate change. (3) The aeolian sediments are of local origin and their sources remained relatively stable over time. Quantitative analysis of 48 samples using geochemical fingerprinting showed that the aeolian sediments are a mixture of various clastic materials derived from upstream areas, with the predominant contribution from sand dunes (58.7 %). (4) We examined the climatic evolution of this region and its driving mechanisms during the middle to late Pleistocene and the Holocene. This analysis suggests that changes in cold and warm season insolation were the primary external drivers of moisture and dust activity on both orbital and sub-orbital scales. The winter mid-latitude Westerlies and the Indian summer monsoon, which are influenced by these seasonal insolation variations, regulated the moisture evolution, while the near-surface winds, primarily driven by cold season insolation and influenced by ice volume and oscillations in North Atlantic climate, played a significant role in modulat","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 105035"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Terminal Ediacaran–Terreneuvian revolutions in Siberia","authors":"Vasiliy V. Marusin","doi":"10.1016/j.earscirev.2024.105009","DOIUrl":"10.1016/j.earscirev.2024.105009","url":null,"abstract":"<div><div>The global reorganizations of marine ecosystems in the terminal Ediacaran and Terreneuvian include two breakthroughs (Cambrian Information Revolution and Agronomic Revolution) followed by the Cambrian Substrate Revolution in the Cambrian Series 2–Furongian. The first two attribute to colonization of new ecological niches by burrowing bilaterians and their gradual expansion within the marine realm. The ichnological record of siliciclastic sequences shows that these processes were most intense in the offshore zone, as compared to more proximal and distal shelf successions. For carbonate basins, the spatial and temporal dynamics of these two revolutions are still poorly understood. The Siberian Platform around the Precambrian–Cambrian transition shows a wide distribution of the marine carbonate facies and hence has high potential for studying the associated endobenthic ecosystem transformations. This study summarizes the results of paleoichnological studies in the terminal Ediacaran and Terreneuvian strata (∼550–521 Ma) in nine regions of the Siberian Platform periphery. The ichnoassemblages are grouped in three stratigraphic intervals (terminal Ediacaran, Fortunian Stage, Cambrian Stage 2) and attributed to sedimentary environments within the models of siliciclastic shelf and/or carbonate ramp. The evolution of the ichnoassemblage structure is evaluated applying the ecosystem engineering and ecospace occupation analyses. The study reveals that the terminal Ediacaran fossil record of the Siberian Platform lacks undisputed trace fossils. In the Terreneuvian, the general patterns of spatiotemporal development of endobenthic communities in the carbonate-associated marine environments generally coincided with those in the siliciclastic basins. The study shows that the greatest innovations in the organism-sediment interactions attributed to the first two Cambrian revolutions happened near the beginning of the Fortunian Stage and Cambrian Stage 2, respectively. However, some important interactions typical for the Agronomic Revolution (e.g., deep infaunal tiering, spreiten burrows) first appeared during the Fortunian.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 105009"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dispersed organic matter from pre-Devonian marine shales: A review on its composition, origin, evolution, and potential for hydrocarbon prospecting","authors":"Qingyong Luo ,&nbsp;Fariborz Goodarzi ,&nbsp;Ningning Zhong ,&nbsp;Nansheng Qiu ,&nbsp;Xiaomei Wang ,&nbsp;Václav Suchý ,&nbsp;Imran Khan ,&nbsp;Xiaowei Zheng ,&nbsp;Bei Liu ,&nbsp;Omid H. Ardakani ,&nbsp;Ye Zhang ,&nbsp;Dahua Li ,&nbsp;Jin Wu ,&nbsp;Zilong Fang ,&nbsp;Ruitan Shi ,&nbsp;Christian B. Skovsted ,&nbsp;Hamed Sanei ,&nbsp;Yaohui Xu ,&nbsp;Jia Wu ,&nbsp;Wenxin Hu ,&nbsp;Guoqiang Duan","doi":"10.1016/j.earscirev.2024.105027","DOIUrl":"10.1016/j.earscirev.2024.105027","url":null,"abstract":"<div><div>The pre-Devonian shales are important natural archives, preserving extensive information on paleobiology, paleoenvironment, and paleoecology, and also acting as important hydrocarbon source rocks for both unconventional and conventional petroleum systems. In China, however, most of the pre-Devonian shales are postmature, resulting in a gradual convergence in the chemical composition and structure of organic matter (OM). This convergence complicates OM identification under optical microscope, making it challenging to trace its genesis and evolution due to similar optical characteristics. Additionally, the absence of true vitrinite particles poses an additional challenge in the evaluation of thermal maturity of these shales, a challenge that has persisted for decades. This study compares detailed optical characteristics and genesis of selected OM types, namely, graptolite, vitrinite-like maceral (VLM), solid bitumen (SB) in the pre-Devonian shales to improve identification and differentiation between these macerals. The physicochemical evolution of OM is reviewed based on the naturally and artificially matured samples, with emphasis on the organic petrology and petroleum production in some of the most extensively studied pre-Devonian shales globally. VLM and graptolites exhibit higher reflectance and stronger anisotropy than co-occurring in-source SB, with their reflectance as indicators to evaluate OM maturity in these marine shales. VLM can be distinguished from SB by its elongate and syndepositional occurrence, and from graptolites by the characteristic biological structures of graptolite. The origin of VLM is hypothesized to be a product of early diagenetic anaerobic biodegradation of lamalginite and/or bituminite in the Precambrian shales, although its origin in the Cambrian shales remains unclear. On the other hand, in-source SB is derived from the transformation of liptinites or from the cracking of the residual petroleum, or a combination thereof. Graptolites are associated with high total organic carbon (TOC), S₁, S₂, and hydrogen index (HI) contents, with kerogen predominantly classified as Type II-III, indicating significant hydrocarbon generation potential. Notably, in-source SB plays a significant role in gas generation. In the early mature pre-Devonian shales, OM mainly consists of lamalginite and bituminite; whereas in-source SB becomes the dominant OM in the postmature pre-Devonian shales. Non-granular graptolites are commonly observed in the Ordovician-Silurian Wufeng–Longmaxi shales, contributing significantly to OM. A comparison of naturally and artificially matured samples suggests that low-maturity liptinites transform into SB as thermal maturity increases. This finding is essential for reconstructing the original composition and hydrocarbon potential of these economically significant marine shales.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 105027"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}