TY - JOUR AU - Nche, Linus Anye AU - Hasegawa, Takeshi AU - Aka, Festus Tongwa AU - Ohba, Takeshi AU - Mafany, George Teke AU - Németh, Károly AU - Miyabuchi, Yasuo AU - Kaneda, Yasuaki AU - Asaah, Asobo Nkengmatia Elvis AU - Wajiba, Patrick Mendi AU - Ngwa, Caroline Neh AU - Tchop, Joseph Legrand AU - Nguet, Pauline Wokwenmendam AU - Nfomou, Ntepe AU - Suh, Cheo Emmanuel AU - Fantong, Wilson Yetoh AU - Mouncherou, Farouk Oumar TI - Volcanic history and magma systems of Lake Monoun Polygenetic Maar, Noun Plain, Western part of the Cameroon Volcanic Line: Constraints from stratigraphy, chronology and geochemistry JF - JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH J2 - J VOLCANOL GEOTH RES PY - 2025 SP - 108265 SN - 0377-0273 DO - 10.1016/j.jvolgeores.2025.108265 UR - https://m2.mtmt.hu/api/publication/35680471 ID - 35680471 AB - Lake Monoun (LM) is a maar volcano located on the Cameroon Volcanic Line in West-Central Africa. In 1984, a limnic eruption occurred at LM, releasing large amounts of magmatic CO2 gas that had accumulated in the lake. The CO2 gas asphyxiated 37 people in the surrounding area. Despite this hazard, the volcanic history of LM maar remains unknown. This study presents the first comprehensive results of lithostratigraphy, physical volcanology, 14C dating and petrology of LM eruptive products. The lake has a WSW-ENE-aligned morphology with three main craters, the walls of which expose tephra and lava that can be divided into 5 stratigraphic units (A, B, C, D, and E from bottom to top). Unit A, a pyroclastic surge deposit in the NW, was produced by a phreatomagmatic eruption and deposited on a thick (ca.170 cm) paleosol developed on granitic basement. The paleosol yields a 14C age of ca 1.3 cal. ka. Units B (weathered scoria fall) and C (lava flow) in the NW part of the lake were respectively produced by strombolian and effusive eruptive activities. The SE side consists of unit D (scoria fall) a product of violent strombolian activity and unit E (voluminous surge) deposited by phreatomagmatic activity. The surge deposits of units A and E are rich in lithic fragments such as granite and lava, indicating subterranean excavation of country (accidental) and volcanic (accessory) rocks. A short time break represented by thin (ca. 15 cm, 0.1–0.3 cal. ka) paleosol can be recognized between units A and E in the distal facies. Based on the temporal and spatial distribution of these deposits, the eruption history of LM can be grouped into two stages. The first stage led to the development of the western and central craters and is recorded by units A to C in the NE section. The second stage proceeded after a short hiatus represented by the thin paleosol and a shift of the eruptive locus to the SE part of the lake. This gave rise to the largest eastern crater characterized by well-preserved units D and E. The LM case study reveals a potential time-space evolutionary pathway for crater formation, implying a polygenetic origin. Juvenile materials from the units are basanitic in composition with narrow chemical variation, suggesting a common magma system through the two stages. Silica content gradually increases from units A to E (SiO2 = 43.4 to 45.8 wt%), suggesting that the magma was differentiated with time (from units A to E) and tapped from the whole part of the chamber at unit E. Accessory lava fragments in units A and E display three distinct geochemical trends, composed of alkali and subalkaline basalts, implying the presence of diverse magma systems around the area prior to the maar formation. LA - English DB - MTMT ER - TY - CONF AU - Hencz, Mátyás AU - Németh, Károly AU - Spránitz, Tamás AU - Biró, Tamás AU - Karátson, Dávid AU - Berkesi, Márta TI - Evolution and polycyclic nature of a maar-diatreme volcano as constrained by changing external factors T2 - 14. Kőzettani és Geokémiai Vándorgyűlés absztrakt kötet PY - 2024 SP - 49 EP - 49 PG - 1 UR - https://m2.mtmt.hu/api/publication/35742522 ID - 35742522 LA - English DB - MTMT ER - TY - CONF AU - Hencz, Mátyás AU - Németh, Károly AU - Spránitz, Tamás AU - Biró, Tamás AU - Karátson, Dávid AU - Berkesi, Márta TI - Evolution of a maar-diatreme volcano within a sedimentary basin characterized by combined aquifer system T2 - Krzywiec P et al. Book of Abstracts, 18th Workshop of the International Lithosphere Program Task Force Sedimentary Basins 07–11 october 2024 Kraków, Poland. (2024) PY - 2024 SP - 30 EP - 30 PG - 1 UR - https://m2.mtmt.hu/api/publication/35740140 ID - 35740140 LA - English DB - MTMT ER - TY - CONF AU - Vladyslav, Zakharovskyi AU - Pál, Márton AU - Németh, Károly TI - Comparison of quantitative and qualitative-quantitative geodiversity assessment-based geosite recognition in the Novohrad-Nógrád UNESCO Global Geopark, Hungary/Slovakia T2 - EGU General Assembly 2024 PB - European Geosciences Union (EGU) C1 - Wien PY - 2024 SP - 1 DO - 10.5194/egusphere-egu24-353, 2024 UR - https://m2.mtmt.hu/api/publication/35723844 ID - 35723844 LA - English DB - MTMT ER - TY - JOUR AU - Chako-Tchamabé, Boris AU - Weber, Bodo AU - Gountié, Dedzo Merlin AU - Tamen, Jules AU - Silis-Esquivel, Jhoanna AU - Németh, Károly TI - 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 JF - SOLID EARTH SCIENCES J2 - SOLID EARTH SCIENCES VL - 9 PY - 2024 IS - 4 SP - 100214 SN - 2451-912X DO - 10.1016/j.sesci.2024.100214 UR - https://m2.mtmt.hu/api/publication/35469284 ID - 35469284 AB - 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. LA - English DB - MTMT ER - TY - CONF AU - Mohammed, Benamrane AU - José, Francisco Santos AU - João, Mata AU - El, Hassan Talbi AU - Németh, Károly AU - Luís, Portela TI - Origin and Evolution of the Middle Atlas Volcanic Field (Morocco) A Volcanological, Petrological, Mineralogical and Geochemical Perspective T2 - Origin and Evolution of the Middle Atlas Volcanic Field (Morocco) A Volcanological, Petrological, Mineralogical and Geochemical Perspective PY - 2024 SP - 10 UR - https://m2.mtmt.hu/api/publication/35201461 ID - 35201461 LA - English DB - MTMT ER - TY - BOOK AU - Mohammed, Benamrane AU - José, Francisco Santos AU - João, Mata AU - El, Hassan Talbi AU - Németh, Károly AU - Luís, Portela TI - Origin and Evolution of the Middle Atlas Volcanic Field (Morocco) A Volcanological, Petrological, Mineralogical and Geochemical Perspective PY - 2024 UR - https://m2.mtmt.hu/api/publication/35201459 ID - 35201459 LA - English DB - MTMT ER - TY - BOOK AU - Mohammed, Benamrane AU - José, Francisco Santos AU - João, Mata AU - El, Hassan Talbi AU - Németh, Károly AU - Luís, Portela TI - Origin and Evolution of the Middle Atlas Volcanic Field (Morocco) A Volcanological, Petrological, Mineralogical and Geochemical Perspective C1 - Aveiro PY - 2024 UR - https://m2.mtmt.hu/api/publication/35201455 ID - 35201455 LA - English DB - MTMT ER - TY - JOUR AU - Hencz, Mátyás AU - Németh, Károly AU - Spránitz, Tamás AU - Biró, Tamás AU - Karátson, Dávid AU - Berkesi, Márta TI - Evolution and polycyclic nature of a maar-diatreme volcano as constrained by changing external factors JF - JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH J2 - J VOLCANOL GEOTH RES VL - 453 PY - 2024 PG - 19 SN - 0377-0273 DO - 10.1016/j.jvolgeores.2024.108158 UR - https://m2.mtmt.hu/api/publication/35164900 ID - 35164900 N1 - MTA-EPSS FluidsByDepth Lendület Research Group, Institute of Earth Physics and Space Science, Hungarian Research Network (HUN-REN), Sopron, Hungary Department of Physical Geography, Institute of Geography and Earth Sciences, ELTE Eötvös Loránd University, Budapest, Hungary National Program for Earthquakes and Volcanoes, Geohazard Research Center, Saudi Geological Survey, Jeddah, Saudi Arabia Istituto Nazionale di Geofisica e Vulcanologia, Bologna, Italy Lithosphere Fluid Research Lab, Eötvös Loránd University, Budapest, Hungary Export Date: 26 August 2024 Correspondence Address: Hencz, M.; MTA-EPSS FluidsByDepth Lendület Research Group, Hungary; email: hencz.matyas@epss.hun-ren.hu LA - English DB - MTMT ER - TY - CHAP AU - Németh, Károly AU - Moufti, Mohammed Rashad H. TI - Synthesis T2 - Geoheritage and Geodiversity of Cenozoic Volcanic Fields in Saudi Arabia PB - Springer Nature Switzerland CY - Cham SN - 9783031612176 T3 - Geoheritage, Geoparks and Geotourism, ISSN 2363-765X PY - 2024 SP - 181 EP - 184 PG - 4 DO - 10.1007/978-3-031-61217-6_7 UR - https://m2.mtmt.hu/api/publication/35139063 ID - 35139063 AB - In this book we provided a detailed summary of the geoheritage aspects of the dispersed Cenozoic (mostly Neogene–Quaternary) volcanic fields of western Saudi Arabia. LA - English DB - MTMT ER -