Article
Geochemistry & Geophysics
Remco C. Hin, Kate E. J. Hibbert, Shuo Chen, Matthias Willbold, Morten B. Andersen, Ekaterina S. Kiseeva, Bernard J. Wood, Yaoling Niu, Kenneth W. W. Sims, Tim Elliott
Summary: Several studies have shown that the Earth's upper mantle is slightly enriched in light molybdenum isotopes compared to the bulk Earth. This study provides further evidence of this sub-chondritic signature in the upper mantle through the analysis of depleted mid-ocean ridge basalts from various ocean basins. The findings suggest that this feature may be a result of molybdenum isotope fractionation during the recycling of oceanic crust.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Dmitri A. Ionov, Kun Wang
Summary: Recent studies have shown wide ranges of K content and K-41 values in mantle materials from different tectonic settings, suggesting significant variations in K isotopes in the lithospheric mantle possibly due to diverse sources of K-bearing fluids and isotope fractionation during fluid-rock interaction.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Multidisciplinary Sciences
Alexandra Kunert, Brian Kendall
Summary: Mesozoic oceanic anoxic events are widespread deposits of marine organic-rich mudrocks associated with mass extinctions and large igneous province emplacement. The Toarcian Oceanic Anoxic Event is an example of expanded ocean anoxia due to environmental perturbations linked to the Karoo-Ferrar igneous province. However, the global extent and nature of anoxia during the Toarcian Oceanic Anoxic Event remain poorly understood. This study estimates the global anoxic and euxinic seafloor areas before and during the event using rhenium and molybdenum enrichments in organic-rich mudrocks of the Fernie Formation in Canada. The results show an expansion of seafloor anoxia dominated by euxinia at the onset of the event, followed by a contraction, and the ocean redox trends align with patterns of biodiversity collapse and recovery.
NATURE COMMUNICATIONS
(2023)
Article
Environmental Sciences
Seyedeh Atefeh Moafi Madani, Seyed Reza Mosavi Harami, Payman Rezaee, Abolfazl Naji
Summary: This study assessed the distribution, ecological risk assessment, and source identification of trace metals in surface sediments and soil samples from the Babolsar region of the Caspian Sea. The results indicated high levels of Cd and Cr contamination, moderate levels of Pb contamination, and low levels of contamination for other trace metals. The river, wetland, and farmland sites showed higher contamination compared to the Caspian Sea samples.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Geochemistry & Geophysics
Xianquan Ping, Xiangli Wang, Jianping Zheng, Yongsheng Liu, Yuping Su, Haihong Chen, Ying Wei, Hongkun Dai, Lei Ai
Summary: The stable chromium isotope composition of Earth's mantle is heterogeneous, with peridotites and basalts being similar to the Bulk Silicate Earth, while pyroxenites and chromitites have lighter and heavier isotopic compositions, respectively. This suggests the presence of a complementary light chromium isotope reservoir in the mantle.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geochemistry & Geophysics
A. W. Hofmann, C. Class, S. L. Goldstein
Summary: Efforts to characterize the mantle have led to conflicting conclusions about the composition and size of different reservoirs within it. While past models assumed that the depleted MORB reservoir is limited to the upper part of the mantle, new findings suggest it exceeds 60% of the total mantle. This conflict has invalidated the classical 3-reservoir Earth model and led to the proposal of an additional enriched reservoir to reconcile discrepancies in mass balance calculations.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Multidisciplinary Sciences
Nevin P. Kozik, Seth A. Young, Sean M. Newby, Mu Liu, Daizhao Chen, Emma U. Hammarlund, David P. G. Bond, Theodore R. Them II, Jeremy D. Owens
Summary: This study explores previously unexplored thallium isotope records from two paleobasins, revealing two distinct and rapid excursions in global marine redox conditions during the Late Ordovician. The strong temporal link between these perturbations and extinctions suggests that dynamic marine oxygen fluctuations played a major role in the mass extinction, which has important implications for modern deoxygenation and biodiversity declines.
Editorial Material
Geochemistry & Geophysics
N. V. Vladykin
Summary: After disagreements with Dr. Mitchell's comments, the article was published following necessary corrections. Despite initial dissatisfaction from Professor Roger H. Mitchell, the editors made their decision based on reviewers' feedback.
Article
Geochemistry & Geophysics
Robert B. Emo, Balz S. Kamber
Summary: The composition of the lower continental crust was estimated through analysis of granulite xenoliths, granulite terrains, and geophysical properties, with new data from central Queensland presented. The enrichment of potassium and highly incompatible elements in granulite networks and fractures was revealed, potentially skewing chemical composition estimates.
Article
Geosciences, Multidisciplinary
Tais W. Dahl, Emma U. Hammarlund, Christian Mac Orum Rasmussen, David P. G. Bond, Donald E. Canfield
Summary: The Late Ordovician Mass Extinction happened in two phases, primarily due to marine anoxia and deteriorating climate. Globally expansive ocean anoxia was most prominent during LOME2, while periodic sulfidic anoxia developed during LOME1.
EARTH-SCIENCE REVIEWS
(2021)
Article
Geochemistry & Geophysics
Helen Gall, Tanya Furman, Barry Hanan, Biltan Kurkcuoglu, Kaan Sayit, Tekin Yurur, Megan Pickard Sjoblom, Erdal Sen, Pinar Alici Sen
Summary: Quaternary mafic lavas in Central Anatolia provide geochemical insights into melt generation processes following regional delamination of the subducted Tethyan slabs. The new geochemical data indicate contributions from subduction-modified lithospheric and sub-lithospheric source domains, suggesting significant contribution from metasomatic phases and input from a spatially heterogeneous mantle with contributions from depleted MORB-like and recycled sediment sources. The geochemical similarities to Miocene alkali basalts from other regions in Anatolia imply a regional scale geological process following Tethys subduction.
Article
Geochemistry & Geophysics
Marc C. Halfar, Bradley J. Peters, James M. D. Day, Maria Schonbachler
Summary: The Mascarene Islands in the western Indian Ocean are surface expressions of the Reunion hotspot. The lavas from these islands have uniform isotopic composition and may have contributions from different sources. The lavas from Rodrigues Island may contain a unique component that is not found in other islands.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geochemistry & Geophysics
Nikolay. V. Vladykin, Franco Pirajno
Summary: Three types of carbonatites have been identified based on geological, petrological, and geochemical data analysis. The differentiation between these types is based on alkalinity type and timing of separation of carbonatite component from silicate melts. The geochemistry of C, O, Sr, and Nd isotopes reveals three potential mantle sources for carbonatite complexes depending on their geotectonic setting.
Article
Geochemistry & Geophysics
Alican Aktag, Kaan Sayit, Bradley J. Peters, Tanya Furman, Jorg Rickli
Summary: Quaternary Elazig mafic alkaline volcanism provides crucial insights into the chemical nature of the mantle source domains beneath eastern Turkey, revealing compositional similarities to global OIBs and MORBs.
Article
Geography, Physical
Federico Di Rita, Matthieu Ghilardi, Nathalie Fagel, Matteo Vacchi, Francois Warichet, Doriane Delanghe, Jean Sicurani, Lauriane Martinet, Sebastien Robresco
Summary: This study provides new insights into the coastal evolution of northwestern Corsica over the past 6000 years, highlighting the influences of climate change and human activities. The findings suggest that fires, both anthropogenic and climate-induced, played a significant role in the development of Mediterranean maquis vegetation. The study also reveals earlier evidence of agriculture in the Late Neolithic period and a subsequent degradation of the maquis due to human impact.
QUATERNARY SCIENCE REVIEWS
(2022)
