Solid Earth Sciences最新文献

{"title":"Reappraising the eruptive history of the Alchichica Maar Volcano (Mexico) based on Sr–Nd isotopes: Understanding the role of the magma source region on the growth of small-volume volcanoes","authors":"Boris Chako-Tchamabé ,&nbsp;Bodo Weber ,&nbsp;Merlin Gountié Dedzo ,&nbsp;Jules Tamen ,&nbsp;Jhoanna Silis-Esquivel ,&nbsp;Karoly Nemeth","doi":"10.1016/j.sesci.2024.100214","DOIUrl":"10.1016/j.sesci.2024.100214","url":null,"abstract":"<div><div>Alchichica Maar is in the eastern sector of the Trans-Mexican Volcanic Belt, where volcanics range from basalts to rhyolites, with ⁸⁷Sr/⁸⁶Sr and ¹⁴³Nd/¹⁴⁴Nd values between 0.70293 to 0.70447 (εSr = −21.1 to −4.5) and 0.512733 to 0.512949 (εNd = +3.4 to +6.2), respectively. In this study, Nd and Sr isotopic data and new major and trace elements compositions are provided for the lava flow, the scoria cone, and the phreatomagmatic deposits composing Alchichica Maar Volcano. These results are used in combination with published data to reexamine its eruptive history, though to be formed by more than one eruptive event. The cogeneticy of the magmas that fed the eruptions of these deposits is examined to infer the role of the deep magma source region and post-magmatic alterations on the construction of the Alchichica Maar magmatic system. Alchichica samples present ⁸⁷Sr/⁸⁶Sr values between 0.70387 and 0.70447 (εSr = −9.0 to −0.4) and ¹⁴³Nd/¹⁴⁴Nd values from 0.512749 to 0.512773 (εNd = +2.0 to +2.8). While the ⁸⁷Sr/⁸⁶Sr values suggest a slight increment in radiogenic ⁸⁷Sr from the pre-maar lower lava flow to the upper maar eruptions indicative of magma contamination within the upper crust and by hydrodynamic mingling during the phreatomagmatic phases, the slight variation in Nd isotopes suggest an overall homogeneous source where small batches of magmas formed episodically to feed monogenetic eruptions, which subsequently yielded the pre-maar lava flow, the pre-maar surge, the scoria cone, and the maar units. This study reinforces the idea that an already “tapped” source region of a monogenetic volcano may become fertile again, and new eruptions can occur from near or old vent sites. It also highlights the hazardous potential of small-volume volcanoes.</div></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"9 4","pages":"Article 100214"},"PeriodicalIF":2.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"ECO: A new reference model of dry olivine electrical conductivity","authors":"Xiaozhi Yang","doi":"10.1016/j.sesci.2024.100193","DOIUrl":"10.1016/j.sesci.2024.100193","url":null,"abstract":"<div><p>Electrically Conductive Olivine, ECO, is presented as a new reference model for the electrical conductivity of dry olivine. The model takes into account the prevailing redox state, temperature and pressure in the upper mantle, as well as their effects on the conductivity, and is based on conductivity analyses of dry single crystal olivine at high pressures. The model demonstrates higher conductivity of olivine than those previously proposed standard olivine models, which rely on the conductivity of olivine measured at room pressure. Accepting that the bulk electrical structure is in general dominated by olivine, the upper mantle is more conductive than the estimates of the previous models. The olivine conductivity is in fact high at the oxidizing conditions of the shallow mantle, but drops at greater depths where the mantle portion is reducing. The model provides a new reference basis for understanding the electrical structure of the upper mantle, and is important for invoking any other conductive candidates to explain enhanced mantle conductivity.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"9 4","pages":"Article 100193"},"PeriodicalIF":2.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2451912X2400031X/pdfft?md5=ffdfa2e9386bbd8f182c93bdd0f4c146&pid=1-s2.0-S2451912X2400031X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142271889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Late Ordovician amphibolites in the Taoxinghu area of central Qiangtang, northern Tibet, and their tectonic significance","authors":"Shuangfei Han ,&nbsp;Xijun Liu ,&nbsp;Haodong Wei ,&nbsp;Yaoming Wei ,&nbsp;Yao Xiao ,&nbsp;Zhiguo Zhang","doi":"10.1016/j.sesci.2024.100216","DOIUrl":"10.1016/j.sesci.2024.100216","url":null,"abstract":"<div><div>The early Paleozoic tectonic evolution of the Qinghai-Tibetan Plateau remains not fully understood. The Longmu Co-Shuanghu Suture Zone within the Qiangtang block of northern Qinghai-Tibetan Plateau, records important evidence of the early Paleozoic evolutionary history of the plateau. In this study, we investigated early Paleozoic amphibolites exposed in the Taoxinghu area of central Qiangtang, using zircon U–Pb dating, mineral chemistry, whole-rock geochemistry, and zircon Hf–O isotopes. The objective was to identify the characteristics of the protoliths and the metamorphic processes. Two types of zircons with different characteristics occur in the amphibolites, yielding zircon U–Pb ages of 490 and 440 Ma attained using kernel density estimation, which represent the ages of the protolith and subsequent metamorphism, respectively. The amphibolites have SiO₂ (42.4–55.7 wt.%), and Al₂O₃ (14.4–18.7 wt.%) and MgO (3.62–8.80 wt.%) contents. Their geochemical characteristics show large ion lithophile elements enriched and high field strength elements depleted. The zircon U–Pb age and rock geochemical data suggest the protoliths of the amphibolites were late Cambrian supra-subduction zone-type ophiolites that organized in association with Proto-Tethyan subduction. The subsequent Late Ordovician metamorphic event might be associated with the collision between continental blocks after oceanic closure. We favor that amphibolites provide essential constraints on the early Paleozoic tectonic evolutionary history of the Qinghai-Tibetan Plateau.</div></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"9 4","pages":"Article 100216"},"PeriodicalIF":2.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Petrology of the Pan-African high-K alkali-calcic Bocaranga plutonic complex in the Adamawa-Yadé domain (Central African Republic): Nature, origin and contribution to geodynamic reconstruction of the Central African fold belt","authors":"Rodrigue Martial Topien ,&nbsp;Jules Tcheumenak Kouémo ,&nbsp;José Kpéou ,&nbsp;Gaetan Moloto-A-Kenguemba ,&nbsp;Maurice Kwékam","doi":"10.1016/j.sesci.2024.100211","DOIUrl":"10.1016/j.sesci.2024.100211","url":null,"abstract":"<div><div>The Bocaranga plutonic complex belongs to the northwestern extension Adamawa-Yadé Domain of the Central African Fold Belt (CAFB) in the Central African Republic (CAR). Six petrographical units are recorded in the Bocaranga plutonic complex: (i) a coarse-grained biotite granite, (ii) hornblende-biotite granite, (iii) fine-grained biotite granite, and (iv) two micas granite emplaced in Pan-African metamorphic basement rocks composed of (v) gneisses and (vi) amphibolites. Their chemical compositions are similar to quartz monzonites, monzogranite, syenogranite and alkali granite, respectively. The pluton rocks are metaluminous to weakly peraluminous I-type granitoids, hornblende-biotite granite are magnesian and high-K alkaline, while grained biotite granite and fine-grained biotite granite are ferroan, alkalic-calcic and shoshonitic, whereas the two micas granite are weakly to strongly peraluminous and calc-alkaline. The evolution of the major elements (Al₂O₃ and CaO) and some trace elements (Sr) suggest that fractional crystallization controlled by plagioclase is the main magma differenciation process which influenced the magmatic evolution in this plutonic complex. However, the presence of gneiss xenoliths and mafic enclaves within the plutonic complex, combined to the geochemical data, indicate that the Bocaranga plutonic complex is most likely the result of mixing between mantle- and crust-derived magmas, with high crustal implication for coarse-grained biotite granite, fine-grained biotite granite and two micas granite and high mantle one for hornblende-biotite granite. High U–Th content displays by two-mica granite the high REE content display by all the plutonic rocks indicate that these rocks appear to be respectively favourable for mineralisation in the aforemention elements, thus indicating that the Bocaranga area may represents a potential exploration target for U–Th and REE deposits. The Bocaranga plutonic complex is a synkinematic pluton whose emplacement is synchronuous to the D₂ ductile deformation phase related to linear lithospheric delamination along the MBéré Shear Zone around 620-550 Ma during the late-to post-collisional history the Pan-African orogeny. Such granitic plutons are common in the Orogenic Belt of Central Africa and the Brasiliano Belt.</div></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"9 4","pages":"Article 100211"},"PeriodicalIF":2.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142426070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Stratigraphic correlation and provenance study of exposed Eocene - Oligocene sedimentary sequences in southern Nigeria using high-resolution heavy minerals and garnet geochemical analyses","authors":"Azuka Ocheli ,&nbsp;Ovie Benjamin Ogbe ,&nbsp;Ejiro Newton Omoko ,&nbsp;Godwin Okumagbe Aigbadon","doi":"10.1016/j.sesci.2024.100189","DOIUrl":"10.1016/j.sesci.2024.100189","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Provenance and stratigraphic correlations across the exposed Eocene-Miocene sedimentary sequences of southern Nigeria that exhibit similar lithologies and are biostratigraphically-barren have been carried out. Heavy mineral assemblages in the 63–250 μm sand fractions of 43 sediment samples across the sedimentary sequences were assessed via wet-sieving, centrifugation, and polarizing petrologic microscopic analyses. Opaque, apatite, garnet, kyanite, zircon, rutile, staurolite, tourmaline, and epidote heavy mineral species were identified and point-counted. Electron microprobe analysis was carried out on the garnet-heavy mineral species using a CAMEBAX Cameca electron microprobe with a link four-wavelength energy-dispersive mode spectrometer analyser. This study revealed the existence of three heavy mineral associations and three lithostratigraphic formations. Heavy mineral association A is characterized by assemblages of kyanite, zircon, and rutile grains. The occurrence of kyanite in this association indicates derivation from schist and gneissic rocks. Zircon grains indicate sialic to intermediate igneous rocks derivatives that has sustained several periods of recycling, and redeposition. The occurrence of rutile indicates metamafic and metapelitic rocks with other sources being minor. Heavy mineral association B is characterized by assemblages of staurolite, opaque materials, garnet, and epidote. The presence of opaque grains indicates a shorter distance of transport possibly from proximity. The occurrence of staurolite grains indicates metamorphic and magmatic rock derivatives from schists, slates, and gneisses. Garnets are predominantly derived from high-grade metamorphic rock (granulite-facies) metasediments and charnockites and lower grade (amphibolite-facies) metasedimentary rocks and granitoids. An epidote is a metamorphosed igneous rock derived from the adjoining radix. Heavy mineral association C is characterized by assemblages of tourmaline and apatite. Tourmaline grains indicate pneumatolytic rocks, pegmatite, schist, gneisses, and marble source rocks. Apatite indicates derivation from local outcrops exposed during the Benue Trough uplift. The occurrence of apatite and its assemblages with tourmaline indicate felsic igneous rocks with ultramafic compositions, metamorphic rocks with low to high grades and derivatives of diverse protolith compositions. The exposed Eocene-Miocene sedimentary deposits that exhibit similar lithologies and biodata are relatively lacking. They were differentiated into three different lithostratigraphic formations and correlated. These analyses were performed using heavy mineral characterization, optical property, garnet geochemical composition, and inference supported by multivariate statistical analyses. Variations in the numerical values of unstable heavy minerals reveal dissolution and overgrowth through acidic groundwater, changes in climatic conditions, and relative eustatic sea-level changes. Th","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"9 3","pages":"Article 100189"},"PeriodicalIF":2.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2451912X24000278/pdfft?md5=c16d090ee5ddecd92c488b52381e364f&pid=1-s2.0-S2451912X24000278-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141728752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"High-precision measurement of trace-level Nb, Sn, Ta, and W in rutile using electron probe microanalysis","authors":"Peng-Li He,&nbsp;Xiao-Long Huang,&nbsp;Le Zhang","doi":"10.1016/j.sesci.2024.100197","DOIUrl":"10.1016/j.sesci.2024.100197","url":null,"abstract":"<div><p>The composition of Nb, Sn, Ta, and W in rutile can serve as a highly sensitive indicator for the mineralization of these elements. This information could also be utilized to discriminate different stages of ore deposition or distinct types of deposits. Precise and accurate measurement of trace-level concentrations of these elements in rutile is imperative for such investigations, and can be effectively achieved using electron probe microanalysis (EPMA). In this study, we employed a CAMECA SX5 field emission EPMA to develop an optimal approach for precise and accurate analysis of trace-level Nb, Sn, Ta, and W in rutile. The analytical conditions include an accelerating voltage of 25 kV, a beam current of 200 nA, a beam diameter of 1 μm, optimized background positions for Nb Lα, Sn Lα, Ta Lα, and W Lα, and aggregate intensity counting with a peak counting time of 240 s for each element per spectrometer. The detection limits (3σ) for Nb, Sn, Ta, and W ranged from 22 to 53 ppm. The highest achievable spatial resolution was approximately 4.3 μm. Analytical results obtained from potential rutile standards R10 and R632 were consistent with previous studies within the errors. The precision of these results varied from 1% to 10% (1σ), excluding W in R10 and Nb and Ta in R632, which exceeds the precision achieved in previous EPMA studies. We recommend using R10 as a reference standard for analyses of trace-level Nb, Sn, and Ta, and R632 as an appropriate reference standard for Sn and W when quantifying rutile using EPMA.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"9 3","pages":"Article 100197"},"PeriodicalIF":2.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2451912X24000357/pdfft?md5=0a0022e566dedf25b48b78b1a087febe&pid=1-s2.0-S2451912X24000357-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Assessment of groundwater resources through hydrogeochemical investigation and multivariate chemometric statistics in Bagerhat district, Bangladesh","authors":"Sujan Mallik ,&nbsp;Sukhen Goswami ,&nbsp;Dhiman Kumer Roy ,&nbsp;Md Jakir Hossain ,&nbsp;Afroz Jahan ,&nbsp;Ayon Saha ,&nbsp;Abu Reza Md Towfiqul Islam","doi":"10.1016/j.sesci.2024.100200","DOIUrl":"10.1016/j.sesci.2024.100200","url":null,"abstract":"<div><p>Groundwater, a primary freshwater source for potable and agricultural uses, is increasingly threatened in southern coastal areas of Bangladesh because of rapid urbanization, industrialization, and climate change. Bagerhat, one of the coastal districts, faces not only frequent tropical cyclones, inundation of low-lying areas, and saline water intrusion but also rapid urbanization, population growth, and pollution from prawn culture and seafood processing industries. The study aims to assess the hydrogeochemistry and the suitability of groundwater based on its significance for potable and irrigation purposes in Bagerhat District. This research includes an integrated approach of hydrogeochemical, geospatial, and multivariate statistical methods to investigate the hydrogeochemical processes and groundwater quality using ninety groundwater samples from existing deep tube wells (around 350 m depth). The hydrogeochemical analysis determined the concentrations of major cations and anions were Na⁺&gt;Mg²⁺&gt; Ca²⁺&gt; K⁺ and Cl⁻ &gt; HCO₃^- &gt; SO₄²⁻ &gt; NO₃^-, correspondingly. Electrical Conductivity (EC) values ranged from 16,260 μS/cm in the southern Mongla Upazila to a minimum of 560 μS/cm in Chitalmari Upazila. The evaporation–crystallization processes were found to be the primary mechanism influencing groundwater chemistry in the study area. Multivariate statistics, including Pearson correlation matrix, principal component analysis (PCA), and cluster analysis, indicated that geogenic processes govern groundwater chemistry. The spatial distribution of the water quality index (WQI) map demonstrated that only 15% of groundwater samples are suitable for drinking in the central and eastern parts, while 85% are unsuitable in the study area. Furthermore, evaluation of irrigation water quality parameters, such as sodium percentage (Na%), sodium adsorption ratio (SAR), Kelly ratio (KR), permeability index (PI), magnesium hazard (MH), and salinity hazard, indicated that most wells are unsuitable for irrigation. The results provide insights into aquifer hydrogeochemistry, groundwater quality status, vulnerable areas of pollution, and sustainable, safe water options for groundwater management in the Bagerhat district.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"9 3","pages":"Article 100200"},"PeriodicalIF":2.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2451912X24000382/pdfft?md5=32e49ae6b1693a3c13c54f7bb6f61b99&pid=1-s2.0-S2451912X24000382-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142149380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 of continental red beds: Warming from above or heating from below?","authors":"Lianting Jiang ,&nbsp;Chun'an Tang ,&nbsp;Bin Gong ,&nbsp;Zhen Chen ,&nbsp;Tiantian Chen ,&nbsp;Zhanjie Qin ,&nbsp;Guoneng Chen","doi":"10.1016/j.sesci.2024.100187","DOIUrl":"https://doi.org/10.1016/j.sesci.2024.100187","url":null,"abstract":"<div><p>The formation of continental red beds is generally considered to be related to an arid climate. Heating experiments (performed by L.J. and G.C.) using dried black mud sediment also demonstrate that the reddening may be caused by the transformation of goethite to haematite that begins at approximately 150 °C under anhydrous conditions, and increasing the temperature to 450 °C is positively correlated with the red colour and peak value of haematite. If this process applies to continental red beds, it implies a thermal origin of red beds as a result of high diagenetic temperatures rather than as the cause of their deposition under an arid climate. Namely, subsiding red-bed basins are heated from below rather than warmed from above. Here, we further strengthen this idea by new evidence from borehole cores drilled from red beds in SE China, showing a clear geological section from the surface soil to red beds to bottom granite. The data reveal that the continental red beds formed at least at a temperature within 150–400 °C, and the underlying granite usually formed at temperatures greater than 600 °C. Our results imply a possible relationship between continental red bed events and Earth's thermal cycles.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"9 3","pages":"Article 100187"},"PeriodicalIF":2.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2451912X24000254/pdfft?md5=f90c136f9832d41f2f2e6d84960ec8a4&pid=1-s2.0-S2451912X24000254-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141291374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 origin and tectonic implications of the ca. 406 Ma magmatic activity in the western Yangtze Block, South China","authors":"Chun-Mei Liu ,&nbsp;Hao Zou ,&nbsp;Hai-Feng Chen ,&nbsp;Chen-Wei Li ,&nbsp;Nuru Said ,&nbsp;Chang-Cheng Huang ,&nbsp;Xing-Xing Mao ,&nbsp;Hui-Dong Yu ,&nbsp;Hua-Wen Cao ,&nbsp;Xin-Yu Liu","doi":"10.1016/j.sesci.2024.100198","DOIUrl":"10.1016/j.sesci.2024.100198","url":null,"abstract":"<div><p>In this study, we report for the first time a new gabbro diorite, forming in an intraplate extensional environment during the Early Devonian, in the Shimian of the western margin of the Yangtze Block. Zircon SIMS U–Pb dating indicates that the gabbro diorite formed at ca. 406 Ma. This gabbro diorite belongs to low-K tholeiite and has enriched in Rb, Ba, K, Pb, negative anomalies of Nb, Ta, depletion of flat LREE patterns, negative ε_Hf(t) (−1.1 to −11.7), and high δ¹⁸O (8.83 ± 0.21‰) ratios, showing that the magma formed by partial melting of N-MROB-type mantle and indicating that the magma underwent crustal contamination during emplacement. The magma is formed in the extensional environment, which provides evidence for the extensional environment in the western margin of the Yangtze. The geochemical characteristics and emplacement time of the rocks are similar to those in the early Paleozoic post-orogenic mafic rocks in South China, suggesting that the gabbro diorite may be influenced by the early Paleozoic orogeny in South China.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"9 3","pages":"Article 100198"},"PeriodicalIF":2.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2451912X24000369/pdfft?md5=41c004e24c85a86347e9cc45fb08a037&pid=1-s2.0-S2451912X24000369-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142117344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Polyphase deformation features and extensional detachment faults on the northern and southern edges of the Nigde Massif (Central Anatolia-Turkey)","authors":"Ramazan Demircioğlu","doi":"10.1016/j.sesci.2024.100195","DOIUrl":"10.1016/j.sesci.2024.100195","url":null,"abstract":"<div><p>The polyphase deformation features and detachment faults on the northern (Gumusler) and southern (Camardı) borders of the Nigde Massif rocks, as well as the structures developed as a result of these faults, are investigated in this paper. The Nigde Massif in the studied areas is basement Palaeozoic–Mesozoic metamorphic units. The Late Cretaceous Uckapılı granodiorite and Sineksizyayla meta-gabbro introduced the Nigde massif. These units are overlain unconformably by Late Cretaceous-Quaternary rocks. The metamorphic rocks on the massif's southern edge underwent 5-phase ductile deformation, whereas the metamorphic rocks on the northern margin underwent 3-phase folding. Both the northern and southern edges include post-Middle Eocene extensional detachment features. These are most likely extensional detachment faults related to the massif's uplift. Central Anatolia is still under an extensional tectonic regime today. Therefore, detachment fault activity and occurrence continue. A large portion of the low-angle normal faults shows an extensional detachment feature. The detachment faults identified north and south of the study area are also active today.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"9 3","pages":"Article 100195"},"PeriodicalIF":2.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2451912X24000333/pdfft?md5=efaf1cbb2915e29d87274f0a30b35e70&pid=1-s2.0-S2451912X24000333-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141952902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}