Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (25)

Search Parameters:
Keywords = intraplate volcanism

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
43 pages, 20293 KiB  
Article
Volcanic Stratigraphy, Petrology, Geochemistry and Precise U-Pb Zircon Geochronology of the Late Ediacaran Ouarzazate Group at the Oued Dar’a Caldera: Intracontinental Felsic Super-Eruptions in Association with Continental Flood Basalt Magmatism on the West African Craton (Saghro Massif, Anti-Atlas)
by Rachid Oukhro, Nasrrddine Youbi, Boriana Kalderon-Asael, David A. D. Evans, James Pierce, Jörn-Frederik Wotzlaw, Maria Ovtcharova, João Mata, Mohamed Achraf Mediany, Jihane Ounar, Warda El Moume, Ismail Hadimi, Oussama Moutbir, Moulay Ahmed Boumehdi, Abdelmalek Ouadjou and Andrey Bekker
Minerals 2025, 15(8), 776; https://doi.org/10.3390/min15080776 - 24 Jul 2025
Viewed by 617
Abstract
The Ouarzazate Group in the Anti-Atlas Belt of southern Morocco, part of the West African Craton (WAC), is a significant Proterozoic lithostratigraphic unit formed during the late Ediacaran period. It includes extensive volcanic rocks associated with the early stages of Iapetus Ocean opening. [...] Read more.
The Ouarzazate Group in the Anti-Atlas Belt of southern Morocco, part of the West African Craton (WAC), is a significant Proterozoic lithostratigraphic unit formed during the late Ediacaran period. It includes extensive volcanic rocks associated with the early stages of Iapetus Ocean opening. Zircon U-Pb dating and geochemical analyses of the Oued Dar’a Caldera (ODC) volcanic succession in the Saghro Massif reveal two major eruptive cycles corresponding to the lower and upper Ouarzazate Group. The 1st cycle (588–563 Ma) includes pre- and syn-caldera volcanic succession characterized by basaltic andesite to rhyolitic rocks, formed in a volcanic arc setting through lithospheric mantle-derived mafic magmatism and crustal melting. A major caldera-forming eruption occurred approximately 571–562 Ma, with associated rhyolitic dyke swarms indicating a larger caldera extent than previously known. The 2nd cycle (561–543 Ma) features post-caldera bimodal volcanism, with tholeiitic basalts and intraplate felsic magmas, signaling a shift to continental flood basalts and silicic volcanic systems. The entire volcanic activity spans approximately 23–40 million years. This succession is linked to late Ediacaran intracontinental super-eruptions tied to orogenic collapse and continental extension, likely in association with the Central Iapetus Magmatic Province (CIMP), marking a significant transition in the geodynamic evolution of the WAC. Full article
Show Figures

Figure 1

39 pages, 48972 KiB  
Article
Volcanic Response to Post-Pan-African Orogeny Delamination: Insights from Volcanology, Precise U-Pb Geochronology, Geochemistry, and Petrology of the Ediacaran Ouarzazate Group of the Anti-Atlas, Morocco
by Mohamed Achraf Mediany, Nasrrddine Youbi, Mohamed Ben Chra, Oussama Moutbir, Ismail Hadimi, João Mata, Jörn-Frederik Wotzlaw, José Madeira, Miguel Doblas, Ezz El Din Abdel Hakim Khalaf, Rachid Oukhro, Warda El Moume, Jihane Ounar, Abdelhak Ait Lahna, Moulay Ahmed Boumehdi and Andrey Bekker
Minerals 2025, 15(2), 142; https://doi.org/10.3390/min15020142 - 31 Jan 2025
Cited by 1 | Viewed by 2001
Abstract
Post-collisional volcanism provides valuable insights into mantle dynamics, crustal processes, and mechanisms driving orogen uplift and collapse. This study presents geological, geochemical, and geochronological data for Ediacaran effusive and pyroclastic units from the Taghdout Volcanic Field (TVF) in the Siroua Window, Anti-Atlas Belt. [...] Read more.
Post-collisional volcanism provides valuable insights into mantle dynamics, crustal processes, and mechanisms driving orogen uplift and collapse. This study presents geological, geochemical, and geochronological data for Ediacaran effusive and pyroclastic units from the Taghdout Volcanic Field (TVF) in the Siroua Window, Anti-Atlas Belt. Two eruptive cycles are identified based on volcanological and geochemical signatures. The first cycle comprises a diverse volcanic succession of basalts, basaltic andesites, andesites, dacites, and rhyolitic crystal-rich tuffs and ignimbrites, exhibiting arc calc-alkaline affinities. These mafic magmas were derived from a lithospheric mantle metasomatized by subduction-related fluids and are associated with the gravitational collapse of the Pan-African Orogen. The second cycle is marked by bimodal volcanism, featuring tholeiitic basalts sourced from the asthenospheric mantle and felsic intraplate magmas. These units display volcanological characteristics typical of facies models for continental basaltsuccessions and continental felsic volcanoes. Precise CA-ID-TIMS U-Pb zircon dating constrains the volcanic activity to 575–557 Ma, reflecting an 18-million-year period of lithospheric thinning, delamination, and asthenospheric upwelling. This progression marks the transition from orogen collapse to continental rifting, culminating in the breakup of the Rodinia supercontinent and the opening of the Iapetus Ocean. The TVF exemplifies the dynamic interplay between lithospheric and asthenospheric processes during post-collisional tectonic evolution. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
Show Figures

Figure 1

51 pages, 13757 KiB  
Article
Coastal Hazard and Vulnerability Assessment in Cameroon
by Mesmin Tchindjang, Philippes Mbevo Fendoung and Casimir Kamgho
J. Mar. Sci. Eng. 2025, 13(1), 65; https://doi.org/10.3390/jmse13010065 - 2 Jan 2025
Cited by 2 | Viewed by 2357
Abstract
The coast is the most dynamic part of the Earth’s surface due to its strategic position at the interface of the land and the sea. It is, therefore, exposed to hazards and specific risks because of the geography as well as the geological [...] Read more.
The coast is the most dynamic part of the Earth’s surface due to its strategic position at the interface of the land and the sea. It is, therefore, exposed to hazards and specific risks because of the geography as well as the geological and environmental characteristics of different countries. The coastal environment is essentially dynamic and evolving in time and space, marked by waves, tides, and seasons; moreover, it is subjected to many marine and continental processes (forcing). This succession of events significantly influences the frequency and severity of coastal hazards. The present paper aims at describing and characterizing the hazards and vulnerabilities on the Cameroonian coast. Cameroon possesses 400 km of coastline, which is exposed to various hazards. It is important to determine the probabilities of these hazards, the associated effects, and the related vulnerabilities. In this study, in this stable intraplate setting, the methodology used was diverse and combined techniques for the study of the shore and methods for the treatment of climatic data. Also, historical data were collected during field observations and from the CRED website for all the natural hazards recorded in Cameroon. In addition, documents on climate change were consulted. Remotely sensed data, combined with GIS tools, helped to determine and assess the associated risks. A critical grid combining a severity and frequency analysis was used to better understand these hazards and the coastal vulnerabilities of Cameroon. The results show that Cameroon’s coastal margins are subject to natural processes that cause shoreline changes, including inundation, erosion, and accretion. This study identified seven primary hazard types (earthquakes, volcanism, landslides, floods, erosion, sea level rise, and black tides) affecting the Cameroonian coastline, with the erosion rate exceeding 1.15 m/year at Cape Cameroon. Coastal populations are continuously threatened by these natural or man-induced hazards, and they are periodically subjected to catastrophic disasters such as floods and landslides, as experienced in Cameroon. In addition, despite the existence of the National Contingency Plan devised by the Directorate of Civil Protection, National Risk, and Climate Change Observatories, the implementation of disaster risk reduction and mitigation strategies is suboptimal. Full article
(This article belongs to the Special Issue Monitoring and Analysis of Coastal Hazard Risks)
Show Figures

Figure 1

20 pages, 13649 KiB  
Article
Zircon U-Pb Dating, Geochemistry, Lu-Hf Isotope Characteristics, and Geological Significance of Volcanic Rocks in Zhenghe Fozi Mountain National Geopark, Fujian, China
by Nan Chen, Dunpeng Li, Yanna Huang, Yihang Fu, Xiaomin Yang and Hanbin Wang
Minerals 2024, 14(6), 616; https://doi.org/10.3390/min14060616 - 17 Jun 2024
Viewed by 1753
Abstract
Fozi Mountain National Geopark is located in Zhenghe County in the northern region of Fujian Province, where the volcanic rocks of the Zhaixia Formation of the Shimaoshan Group are exposed. Zircon U-Pb dating and geochemical analysis were carried out to constrain its age [...] Read more.
Fozi Mountain National Geopark is located in Zhenghe County in the northern region of Fujian Province, where the volcanic rocks of the Zhaixia Formation of the Shimaoshan Group are exposed. Zircon U-Pb dating and geochemical analysis were carried out to constrain its age and tectonic environment. The results show that three zircon U-Pb dating samples have attained ages of 99.2 ± 1.0 Ma, 99.6 ± 0.8 Ma, and 99.7 ± 2.0 Ma. Volcanic rocks in the core scenic area of Fozi Mountain were formed during the Late Cretaceous period. Elemental analysis showed that these volcanic rocks were dominated by the shoshonite series. They include gray dacite porphyry, grayish-white breccia tuff, volcanic agglomerate, and gray tuffaceous sandstone. These rocks were characterized by high silicon, high alkali content, and rich potassium levels. Lu-Hf isotope analysis of zircons revealed that their εHf(t) values varied from −8.7 to −6.8. The corresponding TDM2 values were primarily distributed in the range of 1.71 Ga to 1.59 Ga. These findings indicated that the magma primarily originated from the partial melting of the Mesoproterozoic crystalline basement, accompanied by a small number of mantle-derived materials. Tectonic environment analysis indicated that these rocks were formed in the post-orogenic intraplate extensional environment, which was associated with the back-arc extension or lithospheric thinning caused by the subduction of the paleo-Pacific plate beneath the Eurasian plate. The formation of these volcanic rocks was attributed to post-orogenic magmatism. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
Show Figures

Figure 1

23 pages, 8624 KiB  
Article
Tracing the Origin and Magmatic Evolution of the Rejuvenated Volcanism in Santa Clara Island, Juan Fernández Ridge, SE Pacific
by Javier Reyes, Luis E. Lara, Vanessa Sutherland, Nicolás Aguirre, Carlos Orellana, Folkmar Hauff and Kaj Hoernle
Minerals 2024, 14(5), 524; https://doi.org/10.3390/min14050524 - 19 May 2024
Viewed by 1554
Abstract
Oceanic intraplate volcanoes sometimes experience late-stage eruptive activity known as rejuvenated volcanism, and contrasting interpretations for its petrogenesis depend on the compositional characteristics. In the Juan Fernández Ridge (JFR), a volcanic chain approximately 800 km in length emplaced on the Nazca Plate, some [...] Read more.
Oceanic intraplate volcanoes sometimes experience late-stage eruptive activity known as rejuvenated volcanism, and contrasting interpretations for its petrogenesis depend on the compositional characteristics. In the Juan Fernández Ridge (JFR), a volcanic chain approximately 800 km in length emplaced on the Nazca Plate, some subaerial occurrences of rejuvenated volcanism have been recognized on the Robinson Crusoe and Santa Clara Islands, both part of the same deeply eroded shield volcano complex. This study aims to understand the origin and magmatic evolution of rejuvenated volcanism on Santa Clara Island, emplaced after ~2.15 Ma of quiescence above the shield sequence, mainly via the analysis of unpublished geochemical and isotopic data. Field reconnaissance identified two nearly coeval rejuvenated sequences on Santa Clara Island: Bahía W (BW) and Morro Spartan (MS), both formed by basanitic and picro-basaltic lava flows with brecciated levels and local intercalations of sedimentary and pyroclastic deposits. In comparison to the chemical signature of the preceding shield-building stage (comprised mainly of basalts and picrites), the two rejuvenated sequences exhibit a notable enrichment in incompatible elements, but the Sr, Nd, and Pb isotopes are very similar to the FOZO mantle endmember, with an apparent additional contribution of HIMU and EM1 components. The geochemistry of lavas revealed the involvement of various processes, including contamination by ultramafic xenoliths, high-pressure fractional crystallization of olivine and clinopyroxene, and potential partial assimilation of oceanic lithospheric components. While the oceanic lithosphere has been considered as a potential source, the isotopic data from Santa Clara lies outside of the mixing curve between depleted mantle (DM, here represented by the North Chile Rise and the East Pacific Rise) and the previous shield stage, suggesting that a lithospheric mantle is not the primary source for the rejuvenated stage volcanism. Therefore, we favor an origin of the rejuvenated volcanism from the mantle plume forming the JFR, supported by similarities in isotopic signatures with the shield stage and high values of 208Pb/204Pb (only comparable to San Félix—San Ambrosio in the vicinity of JFR), implying the presence of a regional source with radiogenic 208Pb/204Pb isotope ratios. In addition, isotopic variations are subparallel to the mixing line between HIMU and EM1 components, whose participation in different proportions might explain the observed trends. In conclusion, we propose that the source of the rejuvenated volcanism on Santa Clara Island is a heterogeneous mantle plume, the same one that fed the shield stage. The rejuvenated volcanism is derived from a secondary melting zone away from the main axis of the plume. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
Show Figures

Figure 1

25 pages, 8771 KiB  
Article
Relation between Central European Climate Change and Eifel Volcanism during the Last 130,000 Years: The ELSA-23-Tephra-Stack
by Frank Sirocko, Frederik Krebsbach, Johannes Albert, Sarah Britzius, Fiona Schenk and Michael W. Förster
Quaternary 2024, 7(2), 21; https://doi.org/10.3390/quat7020021 - 25 Apr 2024
Cited by 4 | Viewed by 2426
Abstract
The analysis of tephra layers in maar lake sediments of the Eifel shows 14 well-visible tephra during the last glacial cycle from the Holocene to the Eemian (0–130,000 yr b2k). These tephra were analyzed for their petrographic composition, which allows us to connect [...] Read more.
The analysis of tephra layers in maar lake sediments of the Eifel shows 14 well-visible tephra during the last glacial cycle from the Holocene to the Eemian (0–130,000 yr b2k). These tephra were analyzed for their petrographic composition, which allows us to connect several tephra to eruption sites. All tephra were dated by application of the ELSA-20 chronology, developed using the late Pleistocene infilled maar lake of Auel and the Holocene lake Holzmaar (0–60,000 yr b2k). We extend the ELSA-20 chronology with this paper for the millennia of 60,000–130,000 yr b2k (ELSA-23 chronology), which is based on the infilled maar lake records from Dehner, Hoher List, and Jungferweiher. The evaluation of the tephra from the entire last glacial cycle shows that all 14 tephra were close to interstadial warming of the North Atlantic sea surface temperatures. In particular, phreatomagmatic maar eruptions were systematically associated with Heinrich events or C-events. These events represent times of warming of the Southern Hemisphere, global sea level rise, and CO2 increase, which predate the abrupt interstadial warming events of the Northern Hemisphere. This synchroneity indicates a physical relationship between endogenic and exogenic processes. Changes in the lithospheric stress field in response to changes in continental ice loads have already been suggested as a potential candidate to explain the exogenic forcing of endogenic processes. The chronology of volcanic activity in the Eifel demonstrates that intraplate mantle plumes are also affected by the exogenic forcing of endogenic processes. Full article
Show Figures

Figure 1

19 pages, 7120 KiB  
Article
The Magmatic Patterns Formed by the Interaction of the Hainan Mantle Plume and Lei–Qiong Crust Revealed through Seismic Ambient Noise Imaging
by Mohan Pan, Ting Yang, Ba Manh Le, Yuhang Dai and Han Xiao
Geosciences 2024, 14(3), 63; https://doi.org/10.3390/geosciences14030063 - 25 Feb 2024
Cited by 5 | Viewed by 2681
Abstract
Magmatism on continental lithospheres induced by mantle plumes is more complex compared to oceanic intraplate volcanism owing to the heterogeneous nature of continental crustal and lithospheric structures. Substantial evidence points to the deep-oriented Hainan mantle plume beneath the Lei–Qiong region, the southernmost of [...] Read more.
Magmatism on continental lithospheres induced by mantle plumes is more complex compared to oceanic intraplate volcanism owing to the heterogeneous nature of continental crustal and lithospheric structures. Substantial evidence points to the deep-oriented Hainan mantle plume beneath the Lei–Qiong region, the southernmost of the South China block. In this study, we present a detailed shear wave velocity model of the crust and uppermost mantle in the Lei–Qiong volcanic region, derived from 3-year seismic data (2016–2018) from 34 stations and the use of the ambient noise tomography method. An evident columnar low-velocity anomaly was imaged in the crust and uppermost mantle beneath the Wushi Sag (WSS), Beibu Gulf, potentially suggesting that the center of either one branch or the entirety of the Hainan mantle plume impacts the crust here. This low-velocity anomaly is overlaid by a local Moho deepening, indicative of underplating beneath the existing crust. The Maanling–Leihuling Volcanic Field (MLVF) in northern Hainan Island, previously considered the center of the hotspot, does not exhibit such distinct velocity anomalies. Instead, subtle lower crustal anomalies beneath the MLVF are linked with the upper mantle low-velocity zone beneath the WSS. Additionally, the high-conductivity bodies beneath the MLVF indicate lateral magma transport. Earthquake swarms and deep-seated seismic events beneath the WSS further support the presence of magmatic processes. This study indicates that in the Lei–Qiong region, the interaction of the continental crust with the mantle plume centered in the WSS results in magma exhibiting both vertical ascent and lateral migration, leading to a dual low-velocity shear wave pattern in the upper crust, which significantly influences the surface volcanic activity. Full article
(This article belongs to the Section Geophysics)
Show Figures

Figure 1

36 pages, 18536 KiB  
Article
U-Pb Zircon Geochronology of Detrital and Ash Fall Deposits of the Southern Paraná Basin: A Contribution for Provenance, Tectonic Evolution, and the Paleogeography of the SW Gondwana
by Ruy Paulo Philipp, Ubiratan Ferrucio Faccini, Cesar Leandro Schultz, Gustavo Zvirtes, Matheus Philippe Bruckmann, Ernesto Lavina, Joice Cagliari, Andrea Ritter Jelinek, Renata Guimarães Netto, Adriano Roessler Viana and Miguel Angelo Stipp Basei
Geosciences 2023, 13(8), 225; https://doi.org/10.3390/geosciences13080225 - 27 Jul 2023
Cited by 16 | Viewed by 3309
Abstract
Zircon U-Pb geochronology was applied to investigate the provenance, depositional ages, and paleogeography of the southwestern Gondwana in detrital and ash fall sediments from Carboniferous to Jurassic succession of the southern Paraná Basin. Four detrital age populations suggest provenance from local and distal [...] Read more.
Zircon U-Pb geochronology was applied to investigate the provenance, depositional ages, and paleogeography of the southwestern Gondwana in detrital and ash fall sediments from Carboniferous to Jurassic succession of the southern Paraná Basin. Four detrital age populations suggest provenance from local and distal sources located to the south, southeast, and southwest: (i) Archean to Paleoproterozoic zircons from the Rio de La Plata Craton, Nico Peres and Taquarembó terranes; (ii) Grenvillian zircons from the basement of the Gondwanides and Namaqua–Natal belts; (iii) Neoproterozoic grains from the Don Feliciano Belt; and (iv) Phanerozoic populations from Paleozoic orogenic belts and related foreland systems in Argentina, as well as eroded units of the Paraná Basin. The paleogeographic reconstruction indicates an evolution in three distinct stages: (1) a gulf open to the Panthalassa Ocean during the Carboniferous; (2) an epicontinental sea with the rise of the Gondwanides Orogeny during the Permian; and (3) continental deposits controlled by an intra-plate graben system during the Triassic. Permian–Triassic volcanogenic zircons provide constrained maximum depositional ages and attested persistent volcanism, related to the Choiyoi magmatism and effects of the climate change episodes. During the Triassic, the extensional graben system recorded the uplift of the basement through regional northwest and northeast fault systems, and the recycling of Permian zircons, modifying source-to-sink relationships. Full article
(This article belongs to the Collection Detrital Minerals: Their Application in Palaeo-Reconstruction)
Show Figures

Figure 1

21 pages, 20239 KiB  
Article
New Insights into the Seamount Structure of the Northern Part of the Ninetyeast Ridge (Indian Ocean) through the Integrated Analysis of Geophysical Data
by Vsevolod Yutsis, Oleg Levchenko, Alexander Ivanenko, Ilya Veklich, Nataliya Turko and Yulia Marinova
J. Mar. Sci. Eng. 2023, 11(5), 924; https://doi.org/10.3390/jmse11050924 - 26 Apr 2023
Cited by 3 | Viewed by 2933
Abstract
The linear Ninetyeast Ridge (NER) is the longest oceanic intraplate volcanic edifice and main feature in the Eastern Indian Ocean. Many seamounts are located on the ridge, whose origin and age remain unclear due to the lack of samples of the bedrock of [...] Read more.
The linear Ninetyeast Ridge (NER) is the longest oceanic intraplate volcanic edifice and main feature in the Eastern Indian Ocean. Many seamounts are located on the ridge, whose origin and age remain unclear due to the lack of samples of the bedrock of which they are composed. Carbonate sedimentary caps on these seamounts prevent their direct geological sampling by dredging, therefore indirect geophysical methods are an alternative. Such integrated geophysical studies (the main methods are multibeam bathymetry and magnetic surveys) were carried out in cruise #42 of the R/V Akademik Boris Petrov in 2017 on a large seamount at the base of the NER’s western slope near 0.5° S. The collected data also includes seismic reflection data that reveal morphology, fault tectonics, depth structure, and an assumed origin of this volcanic feature. The Ninetyeast Ridge was formed by the Kerguelen plume magmatism at 50° S in the giant N-S fault. The seamount studied in cruise #42 of the R/V Akademik Boris Petrov was formed mainly to the north as a result of two-stage magmatism in a transverse strike-slip fault. The first stage (47 Ma) formed the main western part of the seamount at 20° S. The second stage (23 Ma) formed its eastern part at 8° S. The time intervals between the formation of the main massif of the Ninetyeast Ridge and the stages of subsequent magmatism that formed the western and eastern parts of the seamount are approximately 31 and 55 Ma, respectively. Full article
(This article belongs to the Special Issue Recent Advances in Geological Oceanography II)
Show Figures

Figure 1

21 pages, 8636 KiB  
Article
Magma Chemistry and Tectonic Controls of Volcanic Activity in the Southern Ural Area during Early Carboniferous Time
by Natalia V. Pravikova, Petr L. Tikhomirov, Alexander V. Tevelev, Irina A. Kosheleva and Timofey N. Surin
Minerals 2023, 13(2), 258; https://doi.org/10.3390/min13020258 - 11 Feb 2023
Cited by 1 | Viewed by 2244
Abstract
Early Carboniferous (359.3–323.4 Ma) volcanic complexes are widespread in the Southern Ural tectonic province, a fragment of the western (in present-day coordinates) segment of the Central Asian Orogenic Belt. Here, the Lower Carboniferous sequences crop out within the following N–S-trending tectonic zones (from [...] Read more.
Early Carboniferous (359.3–323.4 Ma) volcanic complexes are widespread in the Southern Ural tectonic province, a fragment of the western (in present-day coordinates) segment of the Central Asian Orogenic Belt. Here, the Lower Carboniferous sequences crop out within the following N–S-trending tectonic zones (from west to east): Magnitogorsk, Ui River, East Ural, Transural, and Valeryanovka. We describe and discuss the geology and geochemistry of the Early Carboniferous volcanic complexes on the basis of published and newly obtained data, with implications for paleo-tectonic models. The western zones are dominated by bimodal rhyolite-basalt series, with the basalts relatively enriched in Ti and Zr but depleted in Nb. The volcanics of the Valeryanovka zone belong to the typically evolved calc-alkaline series, with the derivatives depleted in Ti and Nb. Almost all of the selected groups of volcanics bear geochemical signatures transitional between those of subduction-related and intraplate igneous rocks. The relative enrichment of the volcanics of the East Ural and Transural Zones may be interpreted as a result of a contribution from asthenospheric mantle and/or from subcontinental lithospheric mantle. The volcanics of the Valeryanovka zone reveal features common to subduction-related series of the Andean type. The data obtained allow us to compare the Early Carboniferous geodynamic settings in the western zones with the modern setting of the Northeastern Pacific, whereas the geodynamic setting of the Valeryanovka zone resembles that at the western margin of South America. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
Show Figures

Figure 1

20 pages, 16510 KiB  
Article
Crustal Structure Beneath the Arabian Shield Based on the Receiver Function Method
by Saleh Ismail Qaysi, Andrei Ivanov, Ivan Koulakov, Nassir Al Arifi, Sami El Khrepy and Andrey Jakovlev
Geosciences 2022, 12(11), 399; https://doi.org/10.3390/geosciences12110399 - 27 Oct 2022
Cited by 5 | Viewed by 3780
Abstract
Arabian Shield occupying the western part of the Arabian Peninsula is an area where strong heterogeneities in crustal structures are associated with several factors, such as an ongoing rifting process in the Red Sea basin, massive recent effusive volcanism in several large basaltic [...] Read more.
Arabian Shield occupying the western part of the Arabian Peninsula is an area where strong heterogeneities in crustal structures are associated with several factors, such as an ongoing rifting process in the Red Sea basin, massive recent effusive volcanism in several large basaltic fields (harrats), as well as traces of complex tectonic evolution of this area in Precambrian due to the accretion of several terrains. Geophysical studies of the crust give important information to identify the roles of these and other factors. Receiver function is one of the most robust and relatively inexpensive tools to derive the depths of the major interfaces, of which Moho is the most important, as well as mean velocity parameters in the crust. Based on the H-k stacking method, we have determined the Moho depths and the mean Vp/Vs ratios below a number of seismic stations distributed on the Arabian Shield. As in most of previous studies, we have identified a gradual increase of the crustal thickness from 25 km in the coastal areas of the Red Sea to ~40 km in the eastern margin of the shield. The crustal thickness distribution appears to be consistent with seismic velocity anomalies derived at 30 km depth in the tomography model by (El Khrepy, 2021). For the Vp/Vs ratio, we observe strong variations over the entire study area, and in some cases even between stations located close to each other. This is especially clear in areas of recent magmatism, such as in Harrats Lunayyir and Rahat, where stations with high Vp/Vs ratios correspond to zones with fresh monogenic cones and historical magmatic activity. Full article
(This article belongs to the Section Geophysics)
Show Figures

Figure 1

35 pages, 23663 KiB  
Article
Geomorphological Classification of Monogenetic Volcanoes and Its Implication to Tectonic Stress Orientation in the Middle Atlas Volcanic Field (Morocco)
by Mohammed Benamrane, Károly Németh, Mohamed Jadid and El Hassan Talbi
Land 2022, 11(11), 1893; https://doi.org/10.3390/land11111893 - 25 Oct 2022
Cited by 8 | Viewed by 5979
Abstract
The Middle Atlas Volcanic Field (MAVF) covers an area of 1500 km2, with a total erupted volume of solid products (e.g., Dense Rock Equivalent or DRE) estimated to be more than 80 km3. The MAVF comprises 87 monogenetic basaltic [...] Read more.
The Middle Atlas Volcanic Field (MAVF) covers an area of 1500 km2, with a total erupted volume of solid products (e.g., Dense Rock Equivalent or DRE) estimated to be more than 80 km3. The MAVF comprises 87 monogenetic basaltic volcanoes of Tertiary-Quaternary age as scoria cones (71%) and maars (29%). These monogenetic basaltic volcanoes have various morphologies (e.g., circular, semi-elliptic, elliptic in map views). They can be isolated or form clustered monogenetic complexes. They are largely grouped in the Middle Atlas, in an intraplate geotectonic context forming two distinct major alignments (N160–170° and N40–50°), each closely associated with regional structural elements. By the best estimates, the preserved bulk pyroclastic products do not exceed 0.7 km3, and they show large textural and componentry diversity (e.g., bedded/unbedded, coarse/fine, dense/scoriaceous fallout and pyroclastic density current deposit, etc.). Lava flows also demonstrate great variety of preserved surface textures, including pāhoehoe, ‘a’ā, and clastogenic types. Morphostructural features of lava flows linked to lava flow dynamics have also been recognized, and the presence of hornitos, columnar jointed basaltic flow units, lava tubes, tumuli, and clastogenic lava flows have been recognized and mapped. Some half-sectioned dykes expose interior parts of magmatic shallow feeding pipes. The current morphology of the volcanoes of the MAVF reflects various syn- and post-eruptive processes, including (1) erosional features due to weathering, (2) gravitational instability during and after volcanic activity, (3) vegetation impact, and (4) successive burial of lava flows. The documented volcanic features of this typical monogenetic volcanic field form the core of the region’s geoheritage elements and are considered to be unique in the new African geoheritage context. Hence, they will likely form the basis of future geotourism, geoeducation, and geoconservation ventures. Full article
Show Figures

Figure 1

18 pages, 3325 KiB  
Article
Isostatic Adjustment, Vertical Motion Rate Variation and Potential Detection of Past Abrupt Mass Unloading
by Julien Gargani
Geosciences 2022, 12(8), 302; https://doi.org/10.3390/geosciences12080302 - 8 Aug 2022
Cited by 6 | Viewed by 2870
Abstract
Intraplate volcanic islands are often considered as stable relief with constant vertical motion and used for relative sea-level reconstruction. This study shows that large abrupt mass unloading causes non-negligible isostatic adjustment. The vertical motion that occurs after abrupt mass unloading is quantified using [...] Read more.
Intraplate volcanic islands are often considered as stable relief with constant vertical motion and used for relative sea-level reconstruction. This study shows that large abrupt mass unloading causes non-negligible isostatic adjustment. The vertical motion that occurs after abrupt mass unloading is quantified using a modeling approach. We show that a giant landslide causes a coastline uplift of 80–110 m for an elastic thickness of 15 km < Te < 20 km in Tahiti. Theoretical cases also reveal that a coastal motion of 1 m occurs for an abrupt mass unloading involving a displaced volume of 0.2 km3 and influences relative sea-level reconstruction. In Tahiti, a change in the subsidence rate of 0.1 mm/yr (from 0.25 to 0.15 mm/year) occurred during the last 6 kyr and could be explained by an abrupt mass unloading involving a minimum volume of 0.2 km3, 6 ± 1 kyr ago. Full article
Show Figures

Figure 1

26 pages, 20005 KiB  
Article
Magnetometric Surveys for the Non-Invasive Surface and Subsurface Interpretation of Volcanic Structures in Planetary Exploration, a Case Study of Several Volcanoes in the Iberian Peninsula
by Marina Díaz Michelena, Rolf Kilian, Miguel Ángel Rivero, Sergio Fernández Romero, Francisco Ríos, José Luis Mesa and Andrés Oyarzún
Remote Sens. 2022, 14(9), 2039; https://doi.org/10.3390/rs14092039 - 24 Apr 2022
Cited by 5 | Viewed by 3012
Abstract
Volcanoes are typical features of the solar system that offer a window into the interior of planets. Thus, their study can improve the understanding of the interiors and evolution of planets. On Earth, volcanoes are monitored by multiple sensors during their dormant and [...] Read more.
Volcanoes are typical features of the solar system that offer a window into the interior of planets. Thus, their study can improve the understanding of the interiors and evolution of planets. On Earth, volcanoes are monitored by multiple sensors during their dormant and active phases. Presently, this is not feasible for other planets’ volcanoes. However, robotic vehicles and the recent technological demonstration of Ingenuity on Mars open up the possibility of using the powerful and non-destructive geophysical tool of magnetic surveys at different heights, for the investigation of surfaces and subsurfaces. We propose a methodology with a view to extract information from planetary volcanoes in the short and medium term, which comprises an analysis of the morphology using images, magnetic field surveys at different heights, in situ measurements of magnetic susceptibility, and simplified models for the interpretation of geological structures. This methodology is applied successfully to the study of different examples of the main volcanic zones of the Iberian Peninsula, representative of the Martian intraplate volcanism and similar to Venus domes, as a preparatory action prior to the exploration of the rocky planets’ surfaces. Full article
Show Figures

Graphical abstract

36 pages, 14401 KiB  
Article
Petrogenesis of Lava from Christmas Island, Northeast Indian Ocean: Implications for the Nature of Recycled Components in Non-Plume Intraplate Settings
by Trevor J. Falloon, Kaj Hoernle, Bruce F. Schaefer, Ilya N. Bindeman, Stanley R. Hart, Dieter Garbe-Schonberg and Robert A. Duncan
Geosciences 2022, 12(3), 118; https://doi.org/10.3390/geosciences12030118 - 3 Mar 2022
Cited by 5 | Viewed by 4211
Abstract
Lava samples from the Christmas Island Seamount Province (CHRISP) record an extreme range in enriched mantle (EM) type Sr-Nd-Pb-Hf isotope signatures. Here we report osmium isotope data obtained on four samples from the youngest, Pliocene petit-spot phase (Upper Volcanic Series, UVS; ~4.4 Ma), [...] Read more.
Lava samples from the Christmas Island Seamount Province (CHRISP) record an extreme range in enriched mantle (EM) type Sr-Nd-Pb-Hf isotope signatures. Here we report osmium isotope data obtained on four samples from the youngest, Pliocene petit-spot phase (Upper Volcanic Series, UVS; ~4.4 Ma), and four samples from the earlier, Eocene (Lower Volcanic Series, LVS; ~40 Ma) shield building phase of Christmas Island. Osmium concentrations are low (5–82 ppt) with initial Os isotopic values (187Os/188Osi) ranging from (0.1230–0.1679). Along with additional new geochemical data (major and trace elements, Sr-Nd-Pb isotopes, olivine δ18O values), we demonstrate the following: (1) The UVS is consistent with melting of shallow Indian mid-ocean ridge basalt (MORB) mantle enriched with both lower continental crust (LCC) and subcontinental lithospheric mantle (SCLM) components; and (2) The LVS is consistent with recycling of SCLM components related to Gondwana break-up. The SCLM component has FOZO or HIMU like characteristics. One of the LVS samples has less radiogenic Os (γOs –3.4) and provides evidence for the presence of ancient SCLM in the source. The geochemistry of the Christmas Island lava series supports the idea that continental breakup causes shallow recycling of lithospheric and lower crustal components into the ambient MORB mantle. Full article
Show Figures

Figure 1

Back to TopTop