Acta Geologica Sinica ‐ English Edition最新文献

{"title":"New Material of the Zalambdalestid Zhangolestes (Mammalia, Zalambdalestidae) from the Late Cretaceous Changchunsaurus Fauna of Jilin, China","authors":"Jun CHEN,&nbsp;Fangyuan MAO,&nbsp;Wenhao WU,&nbsp;Jin MENG","doi":"10.1111/1755-6724.15307","DOIUrl":"https://doi.org/10.1111/1755-6724.15307","url":null,"abstract":"<p>We report new material of the zalambdalestid, <i>Zhangolestes jilinensis</i>, from the Quantou Formation (lower Upper Cretaceous, Cenomanian to Turonian), Gongzhuling City, Jilin Province, NE China. Using micro-CT-scan, the material is shown to include dentocranial and postcranial elements recovered from the same matrix block containing the holotype specimen. The CT-images also show the labial and internal structures of the holotype fragment of the lower jaw of <i>Z. jilinensis</i>. Based on the preservation, relative size, and tooth wear, the new material and the holotype lower jaw likely belong to the same individual animal, whereas the hypodigm mandibular fragment assigned to <i>Z. jilinensis</i> in the original study is thought now to belong to a different individual, potentially representing a different species, which, if true, would increase the eutherian diversity in the Late Cretaceous <i>Changchunsaurus</i> Fauna. Furthermore, the new CT-images show that the incisor morphology is diverse within zalambdalestids and probably evolved independently from the enlarged incisors in placental mammals, such as Glires.</p>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"99 3","pages":"634-645"},"PeriodicalIF":3.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144515124","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":"Variation of Heteroatomic Compounds from the First Member of the Upper Cretaceous Qingshankou Formation in the Sanzhao Sag, Songliao Basin (NE China) using ESI FT-ICR MS and its Shale Oil Geological Significance","authors":"Fei XIAO,&nbsp;Jianguo YANG,&nbsp;Yulai YAO,&nbsp;Shichao LI,&nbsp;Yiming HUANG,&nbsp;Xiaoyong GAO","doi":"10.1111/1755-6724.15299","DOIUrl":"https://doi.org/10.1111/1755-6724.15299","url":null,"abstract":"&lt;p&gt;Organic-rich mudstones and shales, which hold significant potential for shale oil resources, characterize the first member of the Upper Cretaceous Qingshankou Formation (K&lt;sub&gt;2&lt;/sub&gt;&lt;i&gt;qn&lt;/i&gt;&lt;sup&gt;1&lt;/sup&gt;) in the Sanzhao sag of the Songliao Basin, NE China. Focusing on 30 core samples obtained from the first shale oil parameter well, named SYY3 in the study area, we systematically analyzed the composition and stratigraphic distribution of the K&lt;sub&gt;2&lt;/sub&gt;&lt;i&gt;qn&lt;/i&gt;&lt;sup&gt;1&lt;/sup&gt; heteroatomic compounds using electrospray ionization Fourier transform–ion cyclotron resonance mass spectrometry (ESI FT-ICR MS), to assess their geological relevance to shale oil. The findings indicate that in the negative ion mode, the heteroatomic compounds predominantly consist of N&lt;sub&gt;1&lt;/sub&gt;, N&lt;sub&gt;1&lt;/sub&gt;O&lt;sub&gt;1&lt;/sub&gt;–N&lt;sub&gt;1&lt;/sub&gt;O&lt;sub&gt;8&lt;/sub&gt;, O&lt;sub&gt;1&lt;/sub&gt;–O&lt;sub&gt;8&lt;/sub&gt;, O&lt;sub&gt;1&lt;/sub&gt;S&lt;sub&gt;1&lt;/sub&gt;–O&lt;sub&gt;6&lt;/sub&gt;S&lt;sub&gt;1&lt;/sub&gt;; contrastingly, in the positive ion mode, they are primarily composed of N&lt;sub&gt;1&lt;/sub&gt;–N&lt;sub&gt;2&lt;/sub&gt;, N&lt;sub&gt;1&lt;/sub&gt;O&lt;sub&gt;1&lt;/sub&gt;–N&lt;sub&gt;1&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt;, N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;1&lt;/sub&gt;, O&lt;sub&gt;1&lt;/sub&gt;–O&lt;sub&gt;4&lt;/sub&gt;, O&lt;sub&gt;1&lt;/sub&gt;S&lt;sub&gt;1&lt;/sub&gt;–O&lt;sub&gt;2&lt;/sub&gt;S&lt;sub&gt;1&lt;/sub&gt;. Heteroatomic compound distributions vary significantly with depth in the negative ion mode, with minor variations in the positive ion mode. These distributions are categorized into three types based on the negative ion ratio ((N&lt;sub&gt;1&lt;/sub&gt; + N&lt;sub&gt;1&lt;/sub&gt;O&lt;sub&gt;x&lt;/sub&gt;)/O&lt;sub&gt;x&lt;/sub&gt;): Type I (&gt;1.5), Type II (0.8–1.5), and Type III (&lt;0.8); types I and II generally exhibit a broader range of carbon numbers compared to Type III. The distribution of double bond equivalent (DBE) values across various sample types exhibits minimal variance, whereas that of carbon numbers shows substantial differences. Variations in heteroatomic compound compositions among the samples might have resulted from vertical sedimentary heterogeneity and differing biotic contributions. Type III samples show a decrease in total organic carbon (TOC) and free oil content (&lt;i&gt;S&lt;/i&gt;&lt;sub&gt;1&lt;/sub&gt;) compared to types I and II, but an increased oil saturation index (OSI), indicating a lower content of free oil but a higher proportion of movable oil. The reduced content of N-containing compounds implies lower paleolake productivity during deposition, leading to a reduction in TOC and &lt;i&gt;S&lt;/i&gt;&lt;sub&gt;1&lt;/sub&gt;. A lower TOC can enhance oil movability due to reduced oil adsorption, and the decreased presence of polar nitrogenous macromolecules with fewer high-C-number heteroatomic compounds further promote shale oil movability. Additionally, the negative ion ratios of N&lt;sub&gt;1&lt;/sub&gt;/N&lt;sub&gt;1&lt;/sub&gt;O&lt;sub&gt;1&lt;/sub&gt; and O&lt;sub&gt;2&lt;/sub&gt;/O&lt;sub&gt;1&lt;/sub&gt; exhibit positive and negative correlations with the values of TOC, &lt;i&gt;S&lt;/i&gt;&lt;sub&gt;1&lt;/sub&gt;, and extractable organic matter (EOM), respectively, indicating that the salinity and redox conditions of the depositional water body are the primary controlling factors for both organic matter en","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"99 3","pages":"840-861"},"PeriodicalIF":3.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514990","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":"Lithofacies Assemblages, Source-Reservoir Characteristics, and Gas Enrichment Mechanisms of the Permian Longtan Formation Shale in Central Hunan Province, South China","authors":"Jingqiang TAN,&nbsp;Shihao HUA,&nbsp;Xinyao MA,&nbsp;Xiao MA,&nbsp;Yaohua WANG,&nbsp;Baomin ZHANG,&nbsp;Wei TIAN,&nbsp;Bohao WANG","doi":"10.1111/1755-6724.15308","DOIUrl":"https://doi.org/10.1111/1755-6724.15308","url":null,"abstract":"<p>The marine-continental transitional shale of the Upper Permian Longtan Formation is widely distributed in Hunan and shows significant exploration potential. Frequent changes in lithofacies have however notably influenced the shale gas enrichment. The strata of the Longtan Formation in the Shaoyang Depression, central Hunan, were taken as the study object for this project. Three lithofacies assemblages were identified: shale interbedded with sandstone layer (SAL), sandstone interbedded with shale layer (ASL) and laminated shale layer (LSL). The SAL shale shows significant variability in hydrocarbon generation potential, which leads to shale gas characterized by ‘hydrocarbon generation in high total organic carbon (TOC) shale, retention in low TOC shale and accumulation in sandstone’. The ASL shale, influenced by the redox conditions of the depositional environment, shows a lower concentration of organic matter. This results in an enrichment model of ‘hydrocarbon generation and accumulation in shale, with sealing by sandstone’. The laminar structure of LSL shale causes both quartz and clay minerals to control the reservoir. Shale gas is characterized by ‘hydrocarbon generation in mud laminae, retention and accumulation in silty laminae, with multiple intra-source migration paths’. In the marine-continental transitional shale gas system, the enrichment intervals of different types of shale gas reservoirs exhibit significant variability.</p>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"99 3","pages":"862-878"},"PeriodicalIF":3.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514818","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":"Tourmaline and Mica Chemistry of the Wangxianling Granitoids, South China: Implications for Petrogenesis of Highly Fractionated Granite","authors":"Xiaoxia DUAN,&nbsp;Ziyi WANG,&nbsp;Bin CHEN,&nbsp;Lingli ZHOU,&nbsp;Zhiqiang WANG,&nbsp;Yanjiao CHEN","doi":"10.1111/1755-6724.15311","DOIUrl":"https://doi.org/10.1111/1755-6724.15311","url":null,"abstract":"<p>Both fractional crystallization and fluid-melt-crystal interaction are involved in the formation of highly fractionated granites. This paper assessed those two processes using geochemistry of muscovite and tourmaline and bulk-rock chemistry of multi-phase Wangxianling granitoids, South China. Compositional variations suggest the coarse-grained muscovite granite is produced from fractional crystallization of the two-mica granite whereas the fine-grained muscovite granite represents a distinct magma pulse. Progressive fractionation of quartz, feldspar and biotite leads to elevated boron and aluminum content in melt which promoted muscovite and tourmaline to crystallize, which promotes two-mica granite evolving towards tourmaline-bearing muscovite granite. Fluid-melt-crystal interaction occurred at the magmatic-hydrothermal transitional stage and resulted in the textural and chemical zonings of tourmaline and muscovite in finegrained muscovite granite. The rims of both tourmaline and muscovite are characterized by the enrichment of fluid mobile elements such as Li, Mn, Cs and Zn and heavier <i>δ</i>¹¹B values of the tourmaline rims (–15.0‰ to –13.6‰) compared to cores (–15.7‰ to –14.3‰). Meanwhile, significant M-type REE tetrad effects (TE_1,3 = 1.07–1.18) and low K/Rb ratios (48–52) also correspond to fluid-melt-crystal interaction. This study shows zoned muscovite and tourmaline can be excellent tracers of fractional crystallization and late-stage fluid-melt-crystal interaction in highly evolved magmatic systems.</p>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"99 3","pages":"789-805"},"PeriodicalIF":3.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514826","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":"Intra-oceanic Subduction in the Eastern Paleo-Asian Ocean: Constraints from Late Carboniferous High-Mg Diorites in Suprasubduction Zone Ophiolites, Central Inner Mongolia, North China","authors":"Peipei DONG,&nbsp;Yingjie LI,&nbsp;Shuai WANG,&nbsp;Xiawei ZHANG,&nbsp;Zhibin LIU,&nbsp;Jinfang WANG,&nbsp;Jinzhao ZHAO,&nbsp;Likao WANG","doi":"10.1111/1755-6724.15306","DOIUrl":"https://doi.org/10.1111/1755-6724.15306","url":null,"abstract":"<p>High-Mg andesite/diorite (HMA) is useful for identifying subduction-related processes in orogenic belts, including the identification of ophiolites formed in suprasubduction zone (SSZ) environments. The E'rentaolegai high-Mg diorite from the Diyanmiao ophiolite in central Inner Mongolia, North China, has been investigated revealing low-K tholeiitic–calc-alkaline characteristics and have SiO₂ contents of 53.44–54.92 wt%, MgO contents of 8.44–9.54 wt%, and Mg^# of 54.35–57.60, with variable Fe₂O₃ (7.51–8.61 wt%), Al₂O₃ (11.95–15.09 wt%), and Na₂O (3.42–3.94 wt%) contents, low K₂O (0.34–0.97 wt%), TiO₂ (0.35–0.67 wt%), and P₂O₅ (0.12–0.15 wt%) contents, and high Ni (43–193 ppm) and Cr (189–556 ppm) contents. Samples collected have low total rare earth element (REE) contents (30.58–77.80 ppm), with flat or slightly right-dipping REE patterns (La_N/Yb_N = 2.19–3.11) and a lack of pronounced Eu anomalies. The samples are also enriched in large-ion lithophile elements (LILEs, e.g., K, Rb, Ba, U, and Sr) and depleted in high field strength elements (e.g., Ta, Nb, Ti, and P). The E'rentaolegai high-Mg diorite has characteristics typical of HMA, and are similar to those of sanukites from the Setouchi Arc in SW Japan. They also display high positive <i>ε</i>_Nd(<i>t</i>) values (+6.32 to +7.80), comparable to the values of their host rocks. Petrogenetic analyses suggest that the E'rentaolegai HMA was probably formed by the interaction of partial melts and aqueous fluids from subducted sediments with mantle peridotite. Zircon U-Pb dating reveals that the high-Mg diorite crystallized at 313.6 ± 2.4 Ma, i.e., late Carboniferous. Combining our data with the temporal and spatial distribution of the Diyanmiao SSZ-type ophiolite, we propose that the eastern Paleo-Asian Ocean had not closed by the late Carboniferous, but intra-oceanic subduction was ongoing. A new model of the initiation of subduction in the eastern PAO during the late Paleozoic.</p>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"99 3","pages":"693-706"},"PeriodicalIF":3.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514992","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":"Cenozoic Vertically-tearing of Indian Slab Modified the Asian Lithosphere beneath the Eastern Tibetan Plateau","authors":"Zengqian HOU,&nbsp;Bo XU,&nbsp;Tiannan YANG,&nbsp;Haijiang ZHANG,&nbsp;Nian YU,&nbsp;Yi ZHAO,&nbsp;Zhuang MIAO","doi":"10.1111/1755-6724.15313","DOIUrl":"https://doi.org/10.1111/1755-6724.15313","url":null,"abstract":"<p>A subducted continental slab is sometimes torn during collision, yet the exact impact of slab-tearing on the overlying lithosphere remains unclear. Here, we image the structure and architecture of the Asian lithosphere above the Indian slab in the eastern Tibetan Plateau using multiscale seismic tomography models and zircon Hf isotopic mapping, respectively. Our mantle <i>V</i>_p model shows that a large low-velocity anomaly extends laterally beneath the thinned Asian lithosphere above the tear zone roughly along the 26°N. The <i>V</i>_s images, magmatic records and Hf isotopic mapping indicate that this low-velocity anomaly recorded an asthenosphere flow eastward along the tear zone, which thermally eroded and refertilized the overlying Asian lithosphere, leading to the lithospheric melting, thinning and root delaminating. The vertical tear also generated a tectonic weak zone with associated Cenozoic potassic and carbonatitic magma suites. We argue that such a hot lithosphere discontinuity provided a reasonable mechanism for the abrupt change of crust thickness and the transformation of crust-mantle deformation from coupling to decoupling across the tear zone.</p>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"99 3","pages":"627-633"},"PeriodicalIF":3.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1755-6724.15313","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144515123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Origin and Evolution of the Late Middle Pleistocene Trachytes in the Changbaishan Tianchi Volcano (China/North Korea): Insights from Mineralogy, Geochronology and Geochemistry","authors":"Xiqing YE,&nbsp;Zhitao XU,&nbsp;Guido VENTURA,&nbsp;Liying SUN,&nbsp;Zhongwei LI","doi":"10.1111/1755-6724.15301","DOIUrl":"https://doi.org/10.1111/1755-6724.15301","url":null,"abstract":"<p>Cenozoic trachytes are characteristic of some active volcanic fields in China. In particular, the origin and mechanisms of the evolution of trachytes from the Tianchi (Changbaishan) volcano (TV, China/North Korea) are poorly known. Here, we present new geochronological, geochemical and isotopic data on two trachytic suites outcropping on the northern and southern upper slopes of TV. Detailed zircon laser ablation-multicollector-inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS) U-Pb dating, Rb-Sr isochron dating of plagioclase and hornblende, ⁴⁰Ar/³⁹Ar chronology with mineral chemistry, whole-rock element and Sr-Nd-Pb isotope data are used to explore their origins and evolutionary mechanisms during the late Middle Pleistocene. Our data indicate that the trachytes mainly consist of sanidine, orthoclase and plagioclase, with minor albite, quartz and hornblende. They formed at 0.353–0.346 Ma (lava flow from the northern slope) and 0.383–0.311 Ma (lava flow from the southern slope), respectively. The TV trachytes are characterized by high K₂O/Na₂O and AR values, with low A/CNK and Mg^# values. They are enriched in rare earth elements (REEs; except Eu), depleted in Sr and Ba, crystallizing at 742–858°C. The TV trachytes have high (⁸⁷Sr/⁸⁶Sr)_i values (0.70776–0.71195), positive <i>ε</i>_Nd(<i>t</i>) values (0.61–2.93) and radiogenic ²⁰⁶Pb/²⁰⁴Pb values (17.515–17.806). These values are similar to those of the Pleistocene and Holocene TV trachytes. Geochemical data indicate that they were formed by fractional crystallization from a basaltic melt and assimilated upper crust material. The trace element pattern of the studied trachytes is consistent with an evolution from basaltic melts representative of an enriched mantle source. The vent from which the trachytic magma was erupted probably collapsed inside the caldera during the TV ‘Millennium’ eruption (ME) in 946 AD. The contemporaneous emission of basaltic and trachytic magma during the Middle–Late Pleistocene suggests the coexistence of fissural basaltic volcanism and central-type trachytic volcanism, the latter of which was associated with a magma chamber in the upper crust during the TV cone-construction stage.</p>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"99 3","pages":"774-788"},"PeriodicalIF":3.5,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514746","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":"Rock Magnetic Evidence for the Seismogenic Environment of Large Earthquakes in the Motuo Fault Zone, Eastern Himalayan Syntaxis","authors":"Yong CAO,&nbsp;Zhiming SUN,&nbsp;Yang GAO,&nbsp;Jian LIU,&nbsp;Bin LI,&nbsp;Yuhan YANG,&nbsp;Hao YE,&nbsp;Peng XU","doi":"10.1111/1755-6724.15297","DOIUrl":"https://doi.org/10.1111/1755-6724.15297","url":null,"abstract":"<p>Knowledge of the seismogenic environment of fault zones is critical for understanding the processes and mechanisms of large earthquakes. We conducted a rock magnetic study of the fault rocks and protoliths to investigate the seismogenic environment of earthquakes in the Motuo fault zone, in the eastern Himalayan syntaxis. The results indicate that magnetite is the principal magnetic carrier in the fault rocks and protolith, while the protolith has a higher content of paramagnetic minerals than the fault rocks. The fault rocks are characterized by a high magnetic susceptibility relative to the protolith in the Motuo fault zone. This is likely due to the thermal alteration of paramagnetic minerals to magnetite caused by coseismic frictional heating with concomitant hydrothermal fluid circulation. The high magnetic susceptibility of the fault rocks and neoformed magnetite indicate that large earthquakes with frictional heating temperatures &gt;500°C have occurred in the Motuo fault zone in the past, and that the fault maintained an oxidizing environment with weak fluid action during these earthquakes. Our results reveal the seismogenic environment of the Motuo fault zone, and they are potentially important for the evaluation of the regional stability in the eastern Himalayan syntaxis.</p>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"99 3","pages":"896-907"},"PeriodicalIF":3.5,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1755-6724.15297","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Geochronology and Geochemistry of Paleozoic S-type Granites in the Western Segment of the East Kunlun Orogen and its Implications for Tectonic Evolution","authors":"Haidong REN,&nbsp;Tong PAN,&nbsp;Tao WANG,&nbsp;Bingzhang WANG,&nbsp;Xiaoxia WANG,&nbsp;Jianjun ZHANG,&nbsp;Jianguo WANG,&nbsp;Wentao ZHAO","doi":"10.1111/1755-6724.15294","DOIUrl":"https://doi.org/10.1111/1755-6724.15294","url":null,"abstract":"<p>In the western segment of the East Kunlun Orogen (WEKO), muscovite granite and garnet granite from the Hureguole intrusion exhibit zircon U-Pb ages of 435–442 Ma. Geochemically, these rocks contain high concentrations of SiO₂, K₂O and Al₂O₃, with low concentrations of TiO₂ and MgO, indicating a peraluminous high-K calc-alkaline affinity. They are enriched in Rb, Th, U and LREE, depleted in Eu, Ba, Sr and Ti, being classified as S-type granites. Negative whole-rock <i>ε</i>_Nd(<i>t</i>) values (–9.8 to –9.1) and zircon <i>ε</i>_Hf(<i>t</i>) values (–11.6 to –8.2) for those granites indicate that they were derived from partial melting of pelitic rocks in the Paleoproterozoic Baishahe Formation of the Jinshuikou Group. Based on the collected zircon ages, Cambrian–Devonian magmatic activity in the WEKO was divided into three stages: early (446–520 Ma), middle (427–441 Ma) and late (372–424 Ma) stages. Statistically, whole-rock Nd and zircon Hf isotope data (<i>ε</i>_Nd(<i>t</i>)/<i>T</i>_DM^Nd, <i>ε</i>_Hf(<i>t</i>)/<i>T</i>_DMC^Hf) from Paleozoic igneous rocks in the WEKO reveal a magma source that was initially dominated by depleted mantle components in the northward subduction stage of the Proto-Tethyan Ocean plate (446–520 Ma), shifting to predominantly crustal sources during the closure period of the North Qimantagh back-arc basin (427–441 Ma), then to crust-mantle mixed sources in the post-collision stage (372–424 Ma).</p>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"99 3","pages":"743-760"},"PeriodicalIF":3.5,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514709","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":"Stratigraphic Revision of the Selendi, Güre, and Uşak Neogene Basins, Western Anatolia","authors":"Fikret GÖKTAŞ,&nbsp;Serdar MAYDA,&nbsp;Mehmet Cihat ALÇİÇEK","doi":"10.1111/1755-6724.15279","DOIUrl":"https://doi.org/10.1111/1755-6724.15279","url":null,"abstract":"<p>In a re-examination of the Neogene stratigraphy of the Uşak, Güre, and Selendi basins of western Anatolia, western Turkey, the stratigraphic position of the previously defined İnay Group is revised, which was previously considered to be of the Middle Miocene age. Based on mammalian biochronology and stratigraphic relationships, two sequences are identified, separated by conformable/transitional contacts within the former group: the Middle Miocene Güre Group is composed of the Fakılı Formation, characterized by alluvial fan deposits, and the lacustrine Derbent Formation. Radiometric dating of alkaline volcanics laterally associated with Güre Group sediments in the Uşak and Güre basins, and mammalian fossils re-evaluated into the MN5-6 biozones in the Selendi Basin, indicate early Middle Miocene. Considering the stratigraphic relationship with the overlying early Late Miocene İnay Group as redefined, we estimate that the Güre Group was deposited in the Middle Miocene. The İnay Group is characterized by a lateral–vertical transition from alluvial deposits of the Ahmetler Formation to the overlying lacustrine Ulubey Formation. An MN9-10 fauna, containing deinotheres, was found within the latter formation.</p>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"99 2","pages":"332-351"},"PeriodicalIF":3.5,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1755-6724.15279","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}