Journal of Asian Earth Sciences最新文献

{"title":"Petrogenesis of the early-middle Paleozoic granites in northern Wuyi, South China: Implications for the geodynamic process of the Wuyi-Yunkai orogen","authors":"Mengyu Tian ,&nbsp;Longming Li ,&nbsp;Xilin Zhao ,&nbsp;Kang Xu ,&nbsp;Yang Liu","doi":"10.1016/j.jseaes.2025.106616","DOIUrl":"10.1016/j.jseaes.2025.106616","url":null,"abstract":"<div><div>The Early Paleozoic igneous rocks are extensively distributed across the Cathaysia Block, documenting the Wuyi-Yunkai orogeny in South China. However, the detailed geodynamic process of this orogen remains unclear. To elucidate this tectonic history, we conducted an in-depth investigation of two significant granitic plutons in northern Wuyi. LA-ICP-MS zircon U-Pb dating reveals that the Huangdun pluton was emplaced during the early Silurian (435 – 434 Ma), whereas the Jiaoxi pluton was formed during the early Devonian (401 – 398 Ma). The Huangdun monzogranites characterized by high silica content, predominantly metaluminous to peraluminous nature, low FeO^T/MgO ratios (2.21 – 2.83) and normative-CIPW corundum values (C = 0.48 – 4.72 wt%), closely resembling I–S transformation-type granites. They show relatively low initial ⁸⁷Sr/⁸⁶Sr ratios (0.7053 – 0.7077), ε_Nd(t) values (−6.6 to − 6.2), and zircon ε_Hf(t) values (−6.6 to − 0.6). These geochemical and isotopic signatures suggest that these granites were formed through partial melting of metasedimentary and <em>meta</em>-mafic rocks. In contrast, the Jiaoxi two-mica granites are rich in silica, peraluminous, with elevated FeO^T/MgO ratios (3.94 – 4.98) and high differentiation index values (88.6 – 93.4), indicating their classification as fractionated S-type granites. They display variable ε_Hf(t) values (−15.1 to + 0.6) and low ε_Nd(t) values (−7.0 to − 5.9). These features suggest that they were derived from partial melting of metasedimentary rocks. Integrating these findings with previous research, including the presence of Early Paleozoic MOR-type ophiolites, we propose that the Wuyi-Yunkai orogen as a subduction-collisional orogen. The Huangdun granites were formed during the <em>syn</em>-collisional stage in the early Silurian, while the Jiaoxi granites were generated during the post-collisional extension stage in the early Devonian.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106616"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genesis and geochronology of the Bayanteeg Li-mineralized pegmatite in the Idermeg terrane, central Mongolia","authors":"Khashbat Dashtseren ,&nbsp;Bolorchimeg N. Tunnell ,&nbsp;Enkhjargal Boldbaatar ,&nbsp;Jargalan Sereenen ,&nbsp;Marek Locmelis ,&nbsp;Yueheng Yang ,&nbsp;Ming Yang ,&nbsp;Willis Hames ,&nbsp;Nobuhiko Nakano ,&nbsp;Tatsuro Adachi","doi":"10.1016/j.jseaes.2025.106615","DOIUrl":"10.1016/j.jseaes.2025.106615","url":null,"abstract":"<div><div>We present the first petrographic, lithogeochemical, and geochronological study of the Bayanteeg LCT pegmatite located in Idermeg terrane, central Mongolia, and interpret the findings within the geodynamic setting. The pegmatite extends over 140 m with a width of 1.3 m and unknown depth within Neoproterozoic gneiss. The pegmatite contains plagioclase, quartz, and lepidolite with minor K-feldspar, spodumene, muscovite, and topaz, and accessory amounts of cassiterite, amblygonite, columbite-tantalite, monazite, zircon, apatite, and fluorite. Locally, minor secondary quartz and lepidolite occur interstitially between plagioclase and quartz and along the edges of primary lepidolite, respectively, implying late-stage hydrothermal influence. Lithogeochemical data show that the pegmatite contains 0.3–1.12 wt% Li, 256–1285 ppm Cs, and 59–522 ppm Ta. Monazite U-Th-Pb geochronology yielded an age of 144.9 ± 2.8 Ma while cassiterite yielded a U-Pb age of 134.8 ± 1.4 Ma. Lepidolite yielded ⁴⁰Ar/³⁹Ar plateau age of 131.25 ± 0.3 Ma. These age results fall during the geodynamic evolution of an intracontinental extension accompanied by the exhumation of metamorphic core complexes and extensive magmatism in the eastern Central Asian Orogenic Belt. These events occurred due to a combination of gravitational collapse resulting from lithospheric delamination and asthenospheric upwelling. The geodynamic setting during the pegmatite emplacement implies abnormally hot conditions, ruling out the possibility of anatectic origin. The pegmatite dike with elevated concentrations of Be, Ga, Rb, Nb, Sn, Cs, Ta, and Tl supports a granitic origin with a hidden parental granite at depth. The fact that the Idermeg terrane contains several LCT pegmatites implies an important exploration target for Li exploration.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"287 ","pages":"Article 106615"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemical evidence for Late Eocene to Oligocene climate change in the Lühe Basin of the southeastern Tibetan Plateau","authors":"Hao Cui ,&nbsp;He Tang ,&nbsp;Zhifeng Liu ,&nbsp;Jianghao Bai ,&nbsp;Juncai Chen ,&nbsp;Gangjian Wei","doi":"10.1016/j.jseaes.2025.106612","DOIUrl":"10.1016/j.jseaes.2025.106612","url":null,"abstract":"<div><div>The transition from the Eocene to the Oligocene marks a critical phase in Earth’s history, characterized by a shift from greenhouse to icehouse conditions. While global climate changes during this period have been extensively studied, continental geological evidence particularly from landmasses such as the Tibetan Plateau (TP) and its surrounding regions remained limited. Addressing this research gap, our study employs high-resolution trace element geochemical records from the Lühe Basin at the southeastern margin of the Tibetan Plateau (SEMTP) to systematically investiate sediment provenance and weathering processes from the Late Eocene to the Oligocene (35.5–25.5 Ma). The results indicate that the sediment provenance in the Lühe Basin shows limited variation across different scales of provenance analysis, and lithological have little effect on the reconstruction of chemical weathering records. Based on various geochemical proxies, three distinct phases in the evolution of weathering are identified: (1) a phase of progressively intensified weathering during the Late Eocene, (2) a marked decline in weathering intensity during the Eocene-Oligocene Transition (EOT), and (3) a phase of recovery followed by sustained fluctuations in the Oligocene. Furthermore, we discuss the potential global climatic and regional environmental drivers underlying each phase.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106612"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Depositional framework of the Sangkarewang and Sawahlunto Formations, Ombilin Basin, West Sumatra, Indonesia","authors":"J-P. Zonneveld ,&nbsp;V.D. Barreda ,&nbsp;Y. Zaim ,&nbsp;Aswan ,&nbsp;Y. Rizal ,&nbsp;A.T. Hascaryo ,&nbsp;R.L. Ciochon ,&nbsp;J. Head ,&nbsp;A. Murray ,&nbsp;T. Smith ,&nbsp;P. Wilf ,&nbsp;J.I. Bloch","doi":"10.1016/j.jseaes.2025.106611","DOIUrl":"10.1016/j.jseaes.2025.106611","url":null,"abstract":"<div><div>Analyses of rock samples collected during recent fieldwork in the Ombilin Basin of west-central Sumatra, Indonesia yielded pollen data that constrain the age and depositional setting of associated plant macrofossil and vertebrate fossil-bearing units in the Sangkarewang and Sawahlunto formations. Articulated fish and plant fossils were recovered from bedding plane surfaces of fissile, laminated shales in the Sangkarewang Formation that are interpreted to have been deposited in an actively-subsiding, deep, anoxic lake. The overlying Talawi Member of the Sawahlunto Formation records stratigraphy consistent with deposition in a segue to marginal lacustrine marsh and poorly-drained paleosol settings. Interbedded carbonate mudstone / wackestone and lignitic claystone units in the basal Talawi Member preserve scattered, disarticulated fossils of fish, reptiles, an amphibian, and one mammal tooth. These beds grade into a heterolithic succession of fine-grained clastic rock, with coal interbeds likely deposited in a coastal alluvial setting. Marine influences in this interval are indicated by the nature of physical sedimentary structures in several zones, the presence of trace fossils such as <em>Diplocraterion, Cylindrichnus</em> and <em>Teichichnus,</em> and the occurrence of foraminiferal linings, dinocysts and other palynomorphs indicative of mangrove and back-mangrove settings. Palynological analysis indicates that the most probable age of the Sawahlunto Formation ranges from the middle to late Eocene, with a possible extension from the middle Eocene to the early Oligocene.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"287 ","pages":"Article 106611"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143843669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tectonic variations in NS-trending rifts, southern Tibetan Plateau: insights from hydrothermal emissions and seismic activities","authors":"Jiao Tian ,&nbsp;Xiaocheng Zhou ,&nbsp;Minghui Liao ,&nbsp;Miao He ,&nbsp;Zhaojun Zeng ,&nbsp;Yucong Yan ,&nbsp;Bingyu Yao ,&nbsp;Yuwen Wang ,&nbsp;Shihan Cui ,&nbsp;Gaoyuan Xing ,&nbsp;Chunhui Cao ,&nbsp;Liwu Li ,&nbsp;Changhui Ju","doi":"10.1016/j.jseaes.2025.106599","DOIUrl":"10.1016/j.jseaes.2025.106599","url":null,"abstract":"<div><div>A series of NS-trending rifts in the Tibetan Plateau interior provide a window for unraveling its rifting properties and geodynamic mechanisms. In this study, we focused on hydrothermal degassing and seismic activities to identify the differential tectonic status of each rift. Analysis of hydrothermal gaseous components reveals that crustal metamorphic products accumulate in the western rifts and the easternmost rift while growing mantle-derived volatiles contribute in the northeast rifting zones. The flow rate of uprising mantle-derived fluids ranges from 0.01 mm/yr to 2972 mm/yr and the total ³He fluxes vary in 1.0 × 10⁻⁷ – 1.2 × 10⁻⁵ mol/km²/yr. The distribution of H₂-enriched hot springs coincides with the young initiation time of the rifts, indicating the young active tectonic setting in the eastern rifts. Spatially discernible characteristics are also observed in seismic activity. Earthquakes occurring in western rifts have relatively shallow focal depths and low frequencies and magnitudes, suggesting that faulting structures are active within the middle-shallow crust. In contrast, more frequent strong and deep-focus earthquakes occurred in the northeastern rifting areas, outlining the large-scale fault planes that dipped into the lower crust or even the bottom of the lithosphere and served as an enhanced conduit for the growing contribution of mantle-derived volatiles at the surface. Our interpretation emphasizes that the underlying Indian slab is unlikely to experience wide tearing beneath Tibet and that eastward-enhanced seismic activity and degassing are likely driven by eastward-propagating lateral slab detachment. These findings have profound implications for the post-collisional evolution of the Tibetan Plateau.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"287 ","pages":"Article 106599"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Organic matter accumulation and carbon sequestration in the Paleocene-Eocene Thermal Maximum: Insights from the Kongdian Formation in Cangdong Sag, Bohai Bay Basin","authors":"Wenwen Li ,&nbsp;Xianfeng Tan ,&nbsp;Wei Jiang ,&nbsp;Xiaowei Dong ,&nbsp;Dunfan Wang ,&nbsp;Long Luo ,&nbsp;Jia Wang ,&nbsp;Jianping Liu ,&nbsp;Xueqi Yan ,&nbsp;Chenlin Huang","doi":"10.1016/j.jseaes.2025.106606","DOIUrl":"10.1016/j.jseaes.2025.106606","url":null,"abstract":"<div><div>The Paleocene-Eocene Thermal Maximum (PETM) has attracted much attention due to resembling the modern climatic change. This study focuses on the organic matter accumulation and carbon sequestration under the PETM by the Kongdian Formation in the Cangdong Sag, Bohai Bay Basin using petrography, geochemistry, and X-ray diffraction (XRD). The PETM happened in the second member of the Kongdian Formation (Ek₂) which experienced a process of warm-dry to hot-humid to warm-dry variations. Hence the Ek₂^1-2 section has been divided into pre-, core-, and post-PETM. During the pre-PETM, a continuous hot climate strengthened the evaporation to induce the lake salinizing which aggravated water stratification and reducing condition. Intense hydrological cycle resulted in rising terrestrial flux and falling salinity, and more oxidic water column at the core-PETM stage. The salinity continuously falls from the highest point at the post-PETM stage, corresponding to the evaporation weakening and terrestrial input increasing. This caused gradually weakening water stratification and oxidic water column. More saline and reducing conditions promoted the boom of aquatic organism and favorable preservation, so more saturated and aromatic hydrocarbons have been formed at the pre- and post-PETM stages. By contrast, the core-PETM section contains more higher plants with unfavorable preservation, generating less asphaltene. Combined with carbonate and TOC contents, the interplay of organic–inorganic carbon sequestration occurred at the pre- and post-PETM stages, distinct from that at the core-PETM. Injection of light oil from the pre- and post-PETM sections leads to high OSI values of the core-PETM which has good shale oil potentials.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106606"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New insights into the middle Eocene environmental conditions and biogeographic setting of the Fergana Basin (Central Asia): Micropaleontological approaches","authors":"Yaroslav S. Trubin ,&nbsp;Alina Winkler ,&nbsp;Ilja Kogan ,&nbsp;Andreas Brosig ,&nbsp;Jingwen Zhang ,&nbsp;Moriaki Yasuhara ,&nbsp;Skye Yunshu Tian ,&nbsp;Vladimir A. Marinov ,&nbsp;Martin R. Langer","doi":"10.1016/j.jseaes.2025.106613","DOIUrl":"10.1016/j.jseaes.2025.106613","url":null,"abstract":"<div><div>The middle Eocene transformation of the Fergana Basin, one of the largest basins in Central Asia situated between the Peri-Tethys and the Asian continent, plays a key role in understanding the transition to regional aridification of Central Asia. The basin’s transformation not only contributed to regional aridification but also affected global ocean circulation and climate. This study examines the micropaleontological communities, especially foraminifera and ostracoda assemblages as proxies, within the Turkestan and Rishtan formations, which corresponding to the Lutetian and Bartonian stages of the middle Eocene, respectively. Statistical analyses were performed to estimate species diversity, structure, and composition of the microfauna, shedding new light on their distribution across facies and stratigraphic profiles, and contributing to a paleoecological reconstruction. The environment is interpreted as a nearshore coastal intertidal or high subtidal zone with a substrate consisting of low-oxygen subsurface sediments and well-oxygenated benthic zone surface habitats. The results of this research provide a deeper understanding of the area, proposing that the middle Eocene of Fergana Basin was a complex configurated realm rather than a gulf, as previously recognized.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106613"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143822388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Middle to Late Mississippian and Early Pennsylvanian foraminifers from the Dianzishang section, South China: Constraints on the Visean-Serpukhovian boundary and implications for biostratigraphic correlation across the Paleo-Tethys Ocean","authors":"Qingyi Sheng ,&nbsp;Jitao Chen ,&nbsp;Xiangdong Wang","doi":"10.1016/j.jseaes.2025.106601","DOIUrl":"10.1016/j.jseaes.2025.106601","url":null,"abstract":"<div><div>A high-resolution, integrative stratigraphic framework is critical for better understanding of the co-evolution of marine biodiversity and paleo-environments during the middle Mississippian to early Pennsylvanian. There are, however, inconsistencies regarding the use of conodonts as index fossils for the stratigraphic correlation of this period, partly due to their facies-dependent occurrence. Foraminifera, widely present in both shallow-water carbonate platforms and deep-water slope sequences, offer a more globally applicable tool as auxiliary index fossil. In this study, we present a high-resolution foraminiferal biostratigraphy from the Dianzishang carbonate slope succession in the South China Block. The foraminifers can be identified into four zones: the <em>Paraarchaediscus koktjubensis</em> Zone, <em>Bradyina modica</em> Zone, <em>Globivalvulina moderata</em> Zone, and <em>Postmonotaxinoides</em> Zone, which are correlated with zonations of Iran, the East Europe Platform, and West Europe. The combined foraminiferal and conodont data in the Dianzishang section suggest the FOD of <em>Lochriea ziegleri</em> here is likely younger than the base of the Serpukhovian and the presence of a stratigraphic hiatus around the Visean-Serpukhovian boundary.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"287 ","pages":"Article 106601"},"PeriodicalIF":2.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143826026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The significance of the high-amplitude magnetic anomaly belt in the seismotectonics of mid-west Taiwan","authors":"Wen-Bin Doo ,&nbsp;Yin-Sheng Huang ,&nbsp;Wen-Nan Wu ,&nbsp;Ching-Yu Cheng ,&nbsp;Chung-Liang Lo ,&nbsp;Hsueh-Fen Wang ,&nbsp;Shiou-Ya Wang ,&nbsp;Yin-Tung Yen","doi":"10.1016/j.jseaes.2025.106598","DOIUrl":"10.1016/j.jseaes.2025.106598","url":null,"abstract":"<div><div>In mid-west Taiwan, there is a unique zone with high crustal magnetization called Lukang Magnetization High (LMH), which is believed to significantly influence earthquake activity in middle Taiwan. According to the magnetic anomaly feature in the Taiwan region, the LMH is the inversion result of the eastern part of the high-amplitude magnetic anomaly zone (NSCSMA) found in the northern South China Sea continental margin. To better understand the connection between this magnetic high (HMAZ) and background tectonic features, this study analyzes the magnetic data in mid-west Taiwan. We used wavelet spectrum analysis and compact inversion techniques to determine its causal source. Wavelet spectrum analysis results show that the wavelength of the major magnetic signal of the HMAZ is 180 km, indicating the source depth of approximately 25 km. The compact inversion results reveal high-susceptibility materials distributed around 20–30 km depth. P-wave velocity models suggest that the causal source of the HMAZ could be located in the lower crust and/or upper mantle and belong to the Eurasia plate. Based on the previous analysis results of the NSCSMA and our observation, we propose that the serpentinized materials may be the causal source of the HMAZ. Moreover, based on the regional seismicity characteristics, our findings indicate that the deformation front plays a more crucial role in the seismotectonic of mid-west Taiwan than the HMAZ.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106598"},"PeriodicalIF":2.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biodiversity and paleoenvironments of vertebrate-rich Eocene marine deposits (Lutetian) of the tropical western Neotethys: New insights from the Arabian Platform","authors":"M. Deville de Periere ,&nbsp;Guillaume Guinot ,&nbsp;Sylvain Adnet ,&nbsp;Sylvia Riechelmann ,&nbsp;Alison Murray ,&nbsp;Didier Merle ,&nbsp;Christian Cesari ,&nbsp;Chris Reid ,&nbsp;Mohammed Sadah","doi":"10.1016/j.jseaes.2025.106604","DOIUrl":"10.1016/j.jseaes.2025.106604","url":null,"abstract":"<div><div>The Eocene deposits of Saudi Arabia (Dammam Formation) are characterized by intertidal to shallow marine carbonate rocks interbedded with meter-scale shale members (Midra and Saila shales). The latter are dated from the middle Eocene and include large numbers of marine vertebrates, dominated by elasmobranch (sharks, skates, and rays) teeth. The rich fossil assemblage comprises at least 13 elasmobranch taxa (including 8 different sharks and 3 batomorph taxa) and at least 7 bony fish taxa. This assemblage is described for the first time from the Arabian Platform (western margin of the Neotethys) and is critically important to understand the changes in circum Tethyan marine biotas during the Eocene. The larger elasmobranchs are dominated by lamniform sharks, such as “<em>Carcharias” koerti</em>, <em>Brachycarcharias</em> cf. <em>lerichei</em> and <em>Striatolamia</em> cf. <em>macrota</em>, along with the tiger shark <em>Galeocerdo eaglesomei</em>, the hammerhead shark <em>Sphyrna</em> sp., and myliobatoids. Teleost fishes appear less diversified in the area and are dominated by <em>Eotrigonodon</em> and <em>Pycnodus</em> species. A low-diversity benthic fauna including bivalves, gastropods, echinoids and corals was found along with the neritic elasmobranch and teleost taxa. The fish assemblage found in the present study is consistent with other middle Eocene faunas worldwide, especially in the tropical Neotethys seaway. Biostratigraphic analyses and strontium isotope ratio measurements from tooth enameloid confirm a Lutetian age (possibly refined to mid-Lutetian). The variety of taxa recovered in Saudi Arabia enables a preliminary reconstruction of the likely interactions between the various fossil groups and their broad paleoenvironments. Apex predators characterized by large lamniform and carcharhiniform sharks probably hunted in shallow near shore waters, where other fish (including eagle rays, carpet sharks, sawfish, and bony fish) were dwelling.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106604"},"PeriodicalIF":2.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}