Article
Geochemistry & Geophysics
B. Chiasera, T. O. Rooney, I. D. Bastow, G. Yirgu, E. B. Grosfils, D. Ayalew, P. Mohr, J. Zimbelman, M. Ramsey
Summary: The study of magmatic activity in the Galema range in the northern Main Ethiopian Rift reveals evidence of magma ponding during ascent, indicating relatively thick lithosphere during the early magmatic rifting. Contrasting modeling approaches show different melting conditions and temperatures, suggesting a thermo-mechanical boundary to ascent. These results have important implications for late-stage decompression melting prior to the onset of seafloor spreading.
Article
Geosciences, Multidisciplinary
Valentin Rime, Anneleen Foubert, Joel Ruch, Tesfaye Kidane
Summary: The Afar Depression is a unique location where active rift processes are observed, and this study provides a comprehensive review of its geology and tectonostratigraphic evolution. The region can be divided into Central Afar and the Danakil Depression, with differing geological events and characteristics.
EARTH-SCIENCE REVIEWS
(2023)
Article
Geochemistry & Geophysics
Josua J. Pakulla, Mike W. Jansen, Raymond A. Duraiswami, Purva Gadpallu, Jonas Tusch, Carsten Jentzsch, Ninja Braukmueller, Frank Wombacher, Carsten Muenker
Summary: The Deccan Volcanic Province (DVP) in India, which covers a large area, has recorded about five million years of volcanic activity. Previous studies have shown that DVP basalt has a common isotopic signature, which is best explained by a mixture of early Reunion plume-related melts and depleted upper mantle melts. This new study provides further insight into the DVP's magma-plumbing system and suggests that it may be more complex than previously thought.
Article
Geosciences, Multidisciplinary
Rhiannon Rees, Thomas M. Gernon, Derek Keir, Rex N. Taylor, Carolina Pagli
Summary: This study reports on a region located between the Northern Main Ethiopian Rift and Southern Afar, which is a key link between two important sectors of the East African Rift System. The volcanic activity in this area occurs along a NNE-SSW trending chain of Quaternary volcanoes and volcanic fields, segmented by WNW-ESE trending right-steps. The three volcanoes in the Adda'do Magmatic Segment (AMS) exhibit similar evolutionary patterns, including older lavas at the base, followed by large-volume evolved magmatism, and recent basaltic-intermediate eruptions.
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
(2023)
Article
Geochemistry & Geophysics
Quanshu Yan, Luke Milan, J. Edward Saunders, Xuefa Shi
Summary: This study reports new major and trace element, isotopic compositions and ages for basaltic lavas from seven poorly studied seamounts/guyots in the Western Pacific Seamount Province. The isotopic data of these samples identify four mantle end-members in the source region, supporting the existence of multiple contemporaneous plumelets and a heterogeneous upper mantle reservoir in the region. A proposed model suggests the formation of relict fragments of enriched mantle and their influence on the depleted mantle.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geosciences, Multidisciplinary
Haotian Yang, Debin Yang, Wenliang Xu, Anqi Wang, Maosong Mu
Summary: This study reports new data on the Funiushan pluton of the southern North China Craton, including zircon U-Pb ages, whole-rock geochemistry, and isotopic compositions. The data reveal the late Mesozoic continental recycling and geodynamic processes within the region, with early Early Cretaceous and late Early Cretaceous granites showing distinct characteristics suggesting different origins and formation processes. The differences observed between the early and late Cretaceous granites reflect variations in tectonic regimes, likely influenced by the subduction of the Paleo-Pacific Plate.
Article
Geochemistry & Geophysics
Peng-Fei Lu, Ping-Ping Liu
Summary: In the Emeishan large igneous province (ELIP) of the Yangtze Block in SW China, there are abundant high-Ti and low-Ti basalts as well as plutonic complexes composed of gabbroic and A-type granitoid units. The study of these granitoids indicates that some were produced by fractional crystallization of high-Ti basaltic melts, while others were derived from partial melting of the mantle plume with variable amounts of high temperature-altered oceanic crust. These findings highlight the importance of the interaction of mantle plume with subducted slab, juvenile lower crust, and ancient crust in the generation of diverse igneous rocks in the large igneous provinces (LIPs).
Article
Geochemistry & Geophysics
Shuang-Shuang Chen, Kaj Hoernle, Rui Gao
Summary: A genetic link between the Georgia-Islas Orcadas and Meteor guyots has been confirmed through geochemical analysis, supporting the model proposed based on seafloor morphology and tectonic reconstructions. The data suggests that these guyots originated from a common mantle plume and formed a continuous hotspot track before being separated by a ridge jump.
Article
Geochemistry & Geophysics
Ren-Zhi Zhu, Shao-Cong Lai, Mike Fowler, Jin-Cheng Xie, Sarah M. Glynn
Summary: Modern continental crust has evolved to a more potassic, granitic composition than early continental crust, with higher concentrations of incompatible elements. The data from the Menglian Batholith exemplify the modern crust formation processes, including subduction-enrichment of the mantle source, mafic magma differentiation, and admixture of crustal melting to felsic magmas. This model suggests a significant role for mafic magmas and juvenile additions in the evolution of mature continental crust.
Article
Geochemistry & Geophysics
V. M. Dekov, B. Gueguen, T. Yamanaka, N. Moussa, T. Okumura, G. Bayon, V Liebetrau, T. Yoshimura, G. Kamenov, D. Araoka, H. Makita, J. Sutton
Summary: The researchers conducted a mineralogical geochemical study of Lake Asal in Africa, and found that it is fed by seafloor-type hydrothermal fluids, making it a typical example of an "oceanic embryo", rather than being supplied by rivers.
Article
Geosciences, Multidisciplinary
Bjorn H. Heyn, Clinton P. Conrad
Summary: This study uses numerical models and analytical relationships to investigate the relationship between surface heat flux anomalies and lithosphere thinning following plume-lithosphere interactions. By observing lithosphere thinning and increased surface heat flux, different-aged plume tracks can be identified even without volcanic activity.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Eric L. Brown, Tyrone O. Rooney, Robert Moucha, Seth Stein, Carol A. Stein
Summary: The study investigates the magma generation factors of the Midcontinent Rift in North America by combining mantle potential temperature and lithospheric thickness constraints. It reveals that the early stage of continental flood basalt magmatism was controlled by deep melting and high mantle potential temperatures, followed by a gradual decrease in temperature. Constraints on mantle potential temperature and lithospheric thickness suggest thinning lithosphere and decreasing mantle potential temperatures during the formation of the continental flood basalts.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Tahiry A. Rajaonarison, D. Sarah Stamps, John Naliboff, Andrew Nyblade, Emmanuel A. Njinju
Summary: Geodynamicists use high-resolution 3D thermomechanical models to investigate the forces driving continental rifting in the East African Rift. They find that the anomalous surface deformation and seismic anisotropy in the rift are primarily driven by northward mantle flow associated with the African Superplume.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geosciences, Multidisciplinary
Adriano Vangone, Carlo Doglioni
Summary: The study reveals significant differences in the gross crustal structure of the Atlantic Ocean passive continental margins between the western and eastern sides, including the continental-ocean transition, MOHO dip angle, and continental crust width. These systematic asymmetries suggest the early stages of continental rifting driven by polarized westward motion of the plates.
GEOSCIENCE FRONTIERS
(2021)
Article
Geosciences, Multidisciplinary
Tilahun Tamirat, Takele Chekol, Daniel Meshesha
Summary: Petrography and geochemical data of basaltic lavas from the north western Ethiopian plateau reveal three distinct groups: Alkali, tholeiitic, and transitional basalts. These groups show significant variations in major and trace element compositions, with the alkali and transitional basalts resembling oceanic island basalts and the tholeiitic basalts showing similarities to enriched mid oceanic ridge basalts. This suggests a complex mantle source involving components from OIB, E-MORB, and SCLM, leading to considerable source heterogeneity within and among the basaltic groups.
JOURNAL OF AFRICAN EARTH SCIENCES
(2021)
Article
Geochemistry & Geophysics
David W. Graham, Peter J. Michael
Summary: Basalts erupted within intra-transform spreading centers can be valuable probes of geochemical components in Earth's upper mantle, providing constraints on the proportions of mantle carbon that are juvenile vs. tectonically recycled. Different isotopic compositions of basalts from GTF and EPR suggest they are derived from two different mantle source compositions.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Michael A. Cosca, Mary Reid, Jonathan R. Delphi, Gonca Gencalioglu Kuscu, Janne Blichert-Toft, Wayne Premo, Donna L. Whitney, Christian Teyssier, Bora Rojay
Summary: The study reveals a wide range of ages for the volcanic rocks from Toprakkale and Karasu volcanic fields, ranging from different epochs. Isotopic analysis of basanite samples from Toprakkale volcanic field suggests a depleted mantle source. Melting depths of the volcanic rocks are estimated to reflect partial melting at the base of the lithospheric mantle.
Article
Geochemistry & Geophysics
Jean Milot, Chloe Malod-Dognin, Janne Blichert-Toft, Philippe Telouk, Francis Albarede
Summary: The combination of Pb and Ag isotopes can help identify ancient metal sources and detect alteration in silver coins, artefacts, and ores. New procedures have been proposed for high-precision analysis of lead and silver isotopes in Ag-bearing ores and ancient silver coins, with extraction and purification protocols based on ion-exchange and chromatography. The study used MC-ICP-MS to measure the isotopic compositions of both Pb and Ag in ores and coins, revealing uncorrelated variations in Pb and Ag isotopic compositions and indicating different processes behind isotope variability.
Article
Geochemistry & Geophysics
P. D. Kempton, A. Spence, H. Downes, J. Blichert-Toft, J. G. Bryce, E. Hegner, P. Z. Vroon
Summary: The study analyzed the petrogenesis of alkalic lavas from Mount Etna's prehistoric activity, revealing distinct geochemical variations in different volcanic units over time periods. Isotopic data indicated changes in magma source during the approximately 80,000 years of activity, with the sixth unit exhibiting a unique isotopic signature compared to other prehistoric units.
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
(2021)
Article
Geosciences, Multidisciplinary
Christopher Svoboda, Tyrone O. Rooney, Guillaume Girard, Chad Deering
Summary: Studies show that the diversity of arc lavas is a result of the evolution of mantle-derived magmas through processes like mixing, assimilation, and fractional crystallization within transcrustal magmatic systems. A satellite vent near Ruapehu in New Zealand contains materials that may originate from a hot zone in the middle to lower crust, suggesting that these andesites are products of a hot zone that may appear before products of mature stratovolcanoes.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2022)
Article
Anthropology
Markos Vaxevanopoulos, Janne Blichert-Toft, Gillan Davis, Francis Albarede
Summary: This study combines lead isotopic analysis with geological characteristics to determine the ancient silver ore sources in Greece, identifying several historically significant mining districts. Newly discovered ancient mining areas in Pelion and the Kroussia mountain range are also documented, reshaping our understanding of ancient Greek history.
JOURNAL OF ARCHAEOLOGICAL SCIENCE
(2022)
Article
Multidisciplinary Sciences
Sandrine Peron, Sujoy Mukhopadhyay, Mark D. Kurz, David W. Graham
Summary: Accretion of volatile and refractory elements on Earth occurred simultaneously, with krypton recording concomitant accretion of non-solar volatiles from more than one type of material. The krypton isotopic compositions suggest early accretion of carbonaceous material by proto-Earth and rule out any combination of hydrodynamic loss with outgassing of the deep or shallow mantle to explain atmospheric noble gases. The findings indicate a nucleosynthetic anomaly in the deep-mantle sources, with a deficit in the neutron-rich Kr-86 relative to the average composition of carbonaceous meteorites.
Article
Geochemistry & Geophysics
Tyrone O. Rooney, Jasper G. Konter, Valerie A. Finlayson, Andrew LaVigne, Eric L. Brown, Carol A. Stein, Seth Stein, Robert Moucha
Summary: This study examines the role of the continental lithospheric mantle in continental flood basalts erupted in the 1.1 billion-year-old Keweenawan large igneous province in North America. It reveals that the Mamainse Point lavas are likely to be partially contaminated melts of the Keweenawan plume and ambient upper mantle, with no clear evidence of contributions from an enriched lithospheric mantle.
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
(2022)
Article
Anthropology
Janne Blichert-Toft, Francois de Callatay, Philippe Telouk, Francis Albarede
Summary: The capture of the Achaemenid treasuries by Alexander the Great marked the end of the Persian Empire and the rise of Hellenistic kingdoms. The treasuries contained a significant amount of silver, which was used to produce coins for Alexander and his successors. The source of the silver was traced back to the southern Aegean, Macedonia, and Thrace, with limited contribution from India. The motivations behind the Persian kings' massive hoarding and its economic implications are still not fully understood.
ARCHAEOLOGICAL AND ANTHROPOLOGICAL SCIENCES
(2022)
Article
Geosciences, Multidisciplinary
Tyrone O. Rooney, Paul J. Wallace, James D. Muirhead, Brandon Chiasera, R. Alex Steiner, Guillaume Girard, Jeffery A. Karson
Summary: This study investigates the relationship between magmatic activity and extensional strain in the Turkana Depression. The results show that the magmas at South Island volcano originate from sub-lithospheric sources, similar to the rift's more mature sectors. The study also reveals that the magmatic system in this area resembles modern axial volcanic systems observed in other parts of the East African Rift System. The migration of magmatic and tectonic strain towards the modern zone of focused intrusion is observed at South Island.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2022)
Article
Anthropology
Markos Vaxevanopoulos, Gillan Davis, Jean Milot, Janne Blichert-Toft, Chloe Malod-Dognin, Francis Albarede
Summary: Variations in silver isotopes in silver coins and ores can be used to assess the origin of silver bullion. By analyzing the silver isotopes in ancient mining districts in the Aegean and ancient Greek coins, we found that the silver isotopes in most coins are consistent with literature data, while a smaller group originated from a silver-bearing mineralization in Lavrion, Attica. Sulfur and silver isotopes in Aegean ores do not correlate, and silver isotope compositions can help determine ore provenance within a single mining district.
JOURNAL OF ARCHAEOLOGICAL SCIENCE
(2022)
Article
Geochemistry & Geophysics
A. El Albani, K. O. Konhauser, A. Somogyi, J. Ngwalghoubou Ikouanga, A. Lamboux, J. Blichert-Toft, E. Chi-Fru, C. Fontaine, A. Mazurier, A. Riboulleau, A. -C. Pierson-Wickmann, F. Albarede
Summary: Sediments from the Francevillian Group in Gabon contain pyritized structures that suggest the presence of colonial organisms. Through a comprehensive study, including morphology, mineralogy, and geochemistry, these structures are considered putative biogenic traces, with no association with sulfate reduction. Anomalies in organic carbon and zinc content in the fillings of these structures further indicate their biogenicity.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Tyrone O. Rooney, Eric L. Brown, Ian D. Bastow, J. Ramon Arrowsmith, Christopher J. Campisano
Summary: As continents break apart, the dominant mechanism of extension transitions from faulting and lithospheric stretching to magma intrusion and oceanic crust formation in a new ocean basin. Commonly found in magmatic rifted margins worldwide are large lava flows that erupted near sea level during the latter stages of continent-ocean transition (COT). The mechanisms behind the formation of these lava flows and their significance in COT development are not well understood and difficult to study directly.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
L. B. Kant, K. W. W. Sims, G. M. Yogodzinski, J. M. Garrison, J. Blichert-Toft, M. Reagan, C. L. Waters, T. P. Mathews, S. R. Scott, P. A. Mothes, M. L. Hall, P. Ramon, E. Gaunt, M. Almeida, S. Hidalgo
Summary: Compositions of arc magmas in continental arcs are influenced by assimilation of continental crust in addition to conditions in the mantle wedge and at the slab-mantle interface. This study on Reventador volcano in the Ecuadorian Andes demonstrates the significant role of crustal assimilation in shaping the chemical characteristics of magmas in continental arcs. Understanding crustal processes is crucial in the study of continental arcs.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geochemistry & Geophysics
C. S. Ogden, I. D. Bastow, C. Ebinger, A. Ayele, R. Kounoudis, M. Musila, R. Bendick, N. Mariita, G. Kianji, T. O. Rooney, G. Sullivan, B. Kibret
Summary: Receiver function analysis reveals that the crust beneath the Turkana Depression is thin and lacks lower crustal intrusion and melt. This suggests that modern faulting and plate stretching dominate the tectonic activity in the region, rather than magma intrusion. These observations provide important insights into the tectonic evolution and crustal deformation mechanism of the East African Rift.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)