Article
Geosciences, Multidisciplinary
Andreas Petersson, Ulf Soderlund, Anders Schersten, Tod Waight, Mimmi K. M. Nilsson, Jeff Vervoort
Summary: While it is now common to use Hf isotope analysis of accessory zircon in intermediate to silicic rocks, analysis of whole-rock Lu-Hf isotope remains necessary for obtaining the initial Hf isotope signatures of old mafic rocks. However, whole-rock analysis is particularly important for Si-poor rocks with a metamorphic imprint due to the sensitivity of baddeleyite, commonly used for U-Pb age analyses of mafic rocks, to alteration and metamorphism. This study demonstrates the feasibility of using whole-rock analysis for determining initial Nd and Hf values in (meta-)mafic rocks despite deformation and metamorphism under hydrated amphibolite-grade conditions.
PRECAMBRIAN RESEARCH
(2023)
Article
Geochemistry & Geophysics
Adam R. Nordsvan, Silvia Volante, William J. Collins, Amaury Pourteau, Jiangyu Li, Ian W. Withnall, Simon Beams, Zheng-Xiang Li
Summary: The study examines the magmatic activity in NE Australia during the late stages of Nuna amalgamation, revealing an increase in mantle input towards the west and suggesting progressive lithospheric thinning of the crust.
Article
Geochemistry & Geophysics
Alanielson Ferreira, Gary Stevens, Elton L. Dantas, Reinhardt A. Fuck, Ticiano J. S. dos Santos, Marcel V. S. Leandro
Summary: Eclogites provide important evidence for understanding the geological processes during high-pressure to ultra-high-pressure metamorphism. The different groups of retrogressed eclogites studied in this article have distinct origins and mineral compositions, highlighting the complex geological history of the deep crust.
Article
Geochemistry & Geophysics
Elizabeth M. Bollen, Harold H. Stowell, Ruth F. Aronoff, Sara Stotter, Christopher G. Daniel, Christopher R. M. McFarlane, Jeffrey D. Vervoort
Summary: In this study, garnet compositional zoning and monazite U-Pb ages were used to explain the differences in garnet Sm-Nd and Lu-Hf ages for low- to mid-amphibolite facies rocks from the Picuris and Tusas Mountains, New Mexico. It was found that most garnets preserve primary compositions and have indistinguishable ages of around 1400 Ma, but some samples show discrepancies between Lu-Hf and Sm-Nd ages, which may be caused by primary zoning in garnet, diffusion modification, or disequilibrium. The study also redefines the youngest extent of amphibolite facies metamorphism during the Picuris orogeny.
JOURNAL OF PETROLOGY
(2022)
Article
Geosciences, Multidisciplinary
K. P. Osei, C. L. Kirkland, D. R. Mole
Summary: The study utilizes Nd and Hf isotopes to image the crustal structure of the Yilgam Craton and finds spatial relationships between gold, nickel-copper, base metals, and iron ore deposits and isotopic signatures. Different metals show varying degrees of enrichment in areas with different crustal ages. The research proposes models regarding the distribution trends of various metal deposits in regions of young and old crust.
Article
Multidisciplinary Sciences
Meng Guo, Jun Korenaga
Summary: Based on a theoretical analysis of Hf and Nd isotopic data, we have demonstrated that the formation of continents must have started in the early Hadean. Our modeling considers the effect of a finite mixing time, which delays the appearance of depleted mantle signatures in continental crust. Our results suggest that Hadean growth of continental crust is required, with a minimum of 50% of today's continental volume existing by the end of Hadean.
Article
Geology
Cem Yucel, Emre Aydincakir, Abdullah Kaygusuz, Mehmet Arslan, Keewook Yi, Youn-Joong Jeong, Derya Cicerali
Summary: The Late Cretaceous magmatic activity in the Eastern Pontides Orogenic Belt of NE Turkey was characterized by the intrusion of I-type and A-type plutons. A-type plutons from the Sebinkarahisar area, with ages of approximately 77.36 +/- 0.96 Ma, display characteristics of enrichment in K2O and Na2O, Ga, Zr, and strong negative Eu anomalies. These plutons were formed in an extensional tectonic environment and were sourced from a metasomatized lithospheric mantle and juvenile crust.
INTERNATIONAL GEOLOGY REVIEW
(2023)
Article
Geosciences, Multidisciplinary
Alf Andre Orvik, Trond Slagstad, Bjorn Eske Sorensen, Ian Millar, Harald Hansen
Summary: This study presents new mineralogical, geochronological, and isotopic data for the Gallojavri ultramafic intrusion in the Karasjok Greenstone Belt. The study suggests that the intrusion was formed around 2.05 billion years ago and experienced incomplete magma mixing and crustal interaction.
PRECAMBRIAN RESEARCH
(2022)
Article
Geochemistry & Geophysics
Ryoga Maeda, Steven Goderis, Vinciane Debaille, Hamed Pourkhorsandi, Genevieve Hublet, Philippe Claeys
Summary: Long-lived radioactive isotope systems like Sm-Nd and Lu-Hf are important for dating and tracing chemical processes. The effects of Antarctic alteration on the Sm-Nd and Lu-Hf systems in chondrites seem to be limited, except in cases of severe alteration. The distribution of elements between minerals in ordinary chondrites may control the heterogeneity observed for bulk Sm-Nd and Lu-Hf data.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geology
Roland Maas, Olga B. Apukhtina, Vadim S. Kamenetsky, Kathy Ehrig, Peter Sprung, Carsten Muenker
Summary: The Olympic Dam deposit in South Australia exhibits complex mineralization history with multiple stage brecciation and mineralization from 1.59 to 0.5-0.4 billion years ago. The diverse carbonate mineral suite associated with the ore minerals provides insight into the protracted formation process of the deposit. This study highlights the importance of detailed radiometric dating in understanding the formation of sulfide and gangue minerals in ore deposits.
ORE GEOLOGY REVIEWS
(2022)
Article
Geochemistry & Geophysics
David Murphy, Hanika Rizo, Jonathan O'Neil, Robert Hepple, Daniel Wiemer, Anthony Kemp, Jeffrey Vervoort
Summary: The study examines the evolution of the Earth through ancient rocks, analyzing basaltic rocks from Western Australia to gain insights into mantle composition and geodynamic models. The research reveals important information about the mixing and evolution of the Paleoarchean mantle.
Article
Geosciences, Multidisciplinary
Armin Zeh, Maria Kirchenbaur
Summary: There are ongoing debates about the nature and timing of Kaapvaal-Zimbabwe Craton accretion. In this study, the authors present new results of combined U-Th-Pb and Lu-Hf isotope analyses of zircon grains from different lithologies in the Central Zone (CZ) of the Limpopo Belt. The data indicate that the CZ hosts a composite terrane with relics of Zimbabwe Craton-related crust and a south-to-north developing accretionary system of granite-greenstone terranes younger than 3.1 Ga.
PRECAMBRIAN RESEARCH
(2022)
Article
Geochemistry & Geophysics
Afanga Archelaus Emmanuel Basua, Changqian Ma, Kanouo Sylvestre Nguo, Lian-Xun Wang, David R. Lentz, Soumyajit Mukherjee, Siggy Signe Nformidah-Ndah, Bovari Syprien Yomeun
Summary: A study on biotite granite and hornblende-biotite massifs at the Cameroon-Chad border revealed that these rocks are calc-alkaline with specific petrological and geochemical characteristics.
Article
Geosciences, Multidisciplinary
Ankita Nandi, Shreya Mukherjee, Nilanjana Sorcar, Ravikant Vadlamani
Summary: The Pale-oarchean felsic crust in the Bastar craton, central India, contains remnants of the oldest Archean terrestrial sedimentary rocks. The metamorphic events in these rocks were studied using garnet Lu-Hf and Sm-Nd geochronology and Th-U-total Pb dating. The metamorphism occurred in two distinct stages, with the later stage being the widespread garnet-breakdown to cordierite-anthophyllite symplectite. Late Neoarchean tectonothermal events also occurred, indicating crustal thickening and the amalgamation of Paleoarchean crustal fragments.
PRECAMBRIAN RESEARCH
(2023)
Article
Geosciences, Multidisciplinary
Zhongwu Lan, S. K. Pandey, Shujing Zhang, Mukund Sharma, Yuya Gao, Shitou Wu
Summary: Integrated detrital zircon U-Pb and Lu-Hf isotope analyses in sedimentary rocks from central India reveal different age groupings of zircon grains, which match well with exposed magmatic and metamorphic rock components in the Northern India Block, providing crucial insights into crustal growth and plate tectonics evolution.
PRECAMBRIAN RESEARCH
(2021)
Article
Geochemistry & Geophysics
Ann M. Bauer, Jeffrey D. Vervoort, Christopher M. Fisher
GEOCHIMICA ET COSMOCHIMICA ACTA
(2020)
Article
Geochemistry & Geophysics
Asish R. Basu, Puloma Chakrabarty, Dawid Szymanowski, Mauricio Ibanez-Mejia, Blair Schoene, Nilotpal Ghosh, R. Bastian Georg
EARTH AND PLANETARY SCIENCE LETTERS
(2020)
Article
Geochemistry & Geophysics
Merlin Meheut, Mauricio Ibanez-Mejia, Francois L. H. Tissot
Summary: The text discusses conflicting results on the mechanisms of Zr isotope fractionation in igneous systems, suggesting that equilibrium effects driven by vibrational energy or nuclear volume, and diffusion-driven kinetic effects may not fully explain the extreme natural variability in Zr isotope ratios. Instead, diffusion in silicate magmas leading to the development of Zr diffusive boundary layers is proposed as a viable mechanism for producing mass-dependent isotope fractionations similar to those observed in natural systems.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
Arnaud Devoir, Elias Bloch, Othmar Muntener
Summary: This study presents a detailed microchemical study of garnets in a mid-crustal granodiorite from the Ivrea-Zone in Northern Italy. The results reveal that the high-phosphorus cores of the garnets originate from granulite facies country-rock, while low-phosphorus rims indicate magmatic overgrowth in two main episodes. By using zircon saturation thermometry and numerical modeling of diffusion processes, the study quantifies the duration of the overgrowth episodes and suggests that composite garnets in Si-rich magmatic systems have the potential to constrain magma transit rates in the continental crust.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Multidisciplinary Sciences
John A. Tarduno, Rory D. Cottrell, Kristin Lawrence, Richard K. Bono, Wentao Huang, Catherine L. Johnson, Eric G. Blackman, Aleksey Smirnov, Miki Nakajima, Clive R. Neal, Tinghong Zhou, Mauricio Ibanez-Mejia, Hirokuni Oda, Ben Crummins
Summary: Research indicates that the Moon did not possess a long-lived core dynamo, and was therefore not sheltered by a sustained paleomagnetosphere. This implies that the lunar regolith may contain buried He-3, water, and other volatile resources acquired from solar winds and Earth's magnetosphere over the past 4 billion years.
Article
Geochemistry & Geophysics
E. M. Bloch, M. C. Jollands, P. Tollan, F. Plane, A-S Bouvier, R. Hervig, A. J. Berry, C. Zaubitzer, S. Escrig, O. Muntener, M. Ibanez-Mejia, J. Alleon, A. Meibom, L. P. Baumgartner, J. Marin-Carbonne, M. Newville
Summary: Ti-in-zircon diffusion shows strong anisotropy, with diffusion parallel to the c-axis being 4-5 orders of magnitude faster than diffusion perpendicular to the c-axis. This difference increases at lower temperatures. Considering the possible effects of diffusion, temperatures calculated using the Ti-in-zircon thermometer should be evaluated on an individual basis under certain crustal conditions.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
R. Salerno, J. Vervoort, C. Fisher, A. Kemp, N. Roberts
Summary: The initial Hf and Nd isotope compositions of Earth's oldest rocks show that the granites were derived from a chondritic source without a strongly depleted mantle or enriched crustal source. The Lu-Hf and Sm-Nd isotope systems in the Pilbara samples are in full agreement, contrasting with previous records of decoupled Hf and Nd isotope compositions in Eo-Paleoarchean terranes. Integrated age-isotope approach can help assess the integrity of bulk-rock Nd isotope data through examination of Sm-Nd isotope systematics in accessory minerals.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Martijn Klaver, Scott A. MacLennan, Mauricio Ibanez-Mejia, Francois L. H. Tissot, Pieter Z. Vroon, Marc-Alban Millet
Summary: The zircon isotope composition of detrital sediments is minimally affected by hydrodynamic sorting, while titanium isotopes show more pronounced effects of hydrodynamic sorting.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Multidisciplinary Sciences
Tinghong Zhou, John A. Tarduno, Francis Nimmo, Rory D. Cottrell, Richard K. Bono, Mauricio Ibanez-Mejia, Wentao Huang, Matt Hamilton, Kenneth Kodama, Aleksey Smirnov, Ben Crummins, Frank Padgett
Summary: Paleomagnetism is used to understand the origin of inner core structure by determining when crystallization started. The study reveals that inner core nucleation began approximately 550 million years ago, and the growth of the inner core to 50% of its current radius occurred around 450 million years ago. Additionally, the seismic anisotropy of the outermost inner core reflects a global deep mantle structure that has persisted to the present day.
NATURE COMMUNICATIONS
(2022)
Article
Geochemistry & Geophysics
Anthony I. S. Kemp, Jeffrey D. Vervoort, Andreas Petersson, R. Hugh Smithies, Yongjun Lu
Summary: This study analyzes samples from the Pilbara Craton in Western Australia and finds a connection between mantle and crustal processes throughout the craton's history. The evolution of the craton was mainly driven by the transformation of juvenile mantle materials into felsic igneous rocks, indicating sustained continental growth over the past 4 billion years. The collision of the East and West Pilbara terranes at 3.1 billion years ago increased the involvement of older crust in magma generation. This study highlights the importance of comparing mantle and crustal isotope records to understand crustal growth rates in ancient terranes.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Multidisciplinary Sciences
John A. Tarduno, Rory D. Cottrell, Richard K. Bono, Nicole Rayner, William J. Davis, Tinghong Zhou, Francis Nimmo, Axel Hofmann, Jaganmoy Jodder, Mauricio Ibanez-Mejia, Michael K. Watkeys, Hirokuni Oda, Gautam Mitra
Summary: The researchers report paleointensity data from ancient single detrital zircons containing primary magnetite inclusions, which indicate a nearly identical pattern of paleointensities from about 3.9 billion years ago to about 3.3 billion years ago. This suggests that there was a period of unvarying latitudes on Earth during this time, which is distinct from plate tectonics in the past 600 million years but consistent with predictions of stagnant-lid convection.
Article
Geochemistry & Geophysics
Heather M. Kirkpatrick, T. Mark Harrison, Mauricio Ibanez-Mejia, Francois L. H. Tissot, Scott A. MacLennan, Elizabeth A. Bell
Summary: We conducted Zr isotope measurements on various minerals and rocks from the La Posta pluton in southern California to investigate the factors affecting Zr isotope fractionation in igneous rocks. We observed significant Zr isotope fractionation between titanite and zircon, which suggests that the relative order of phase appearance on the liquidus plays a role in Zr isotope evolution. However, factors such as crystallization order, temperature, and co-crystallizing phases do not fully explain the intracrystalline Zr isotopic distribution in zircons or the wide range of Zr isotopic values among zircons.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geochemistry & Geophysics
Mauricio Ibanez-Mejia, Francois L. H. Tissot
Summary: Isotopic variability in our planet and Solar System is the result of complex processes, including variable production of isotopes in stars and selective incorporation of isotopes into solids, liquids, or gases based on mass and nuclear volume. Understanding the isotopic imprints left by planetary formation and evolution requires precise measurements and knowledge of the factors driving isotopic variability. This article introduces key concepts for interpreting the isotopic code, focusing on heavy stable isotope systems.
Article
Geochemistry & Geophysics
Francois L. H. Tissot, Mauricio Ibanez-Mejia
Summary: Stable isotopes provide insights into processes across various scales. Advances in mass-spectrometry have enabled the analysis of smaller and smaller samples, bringing heavy stable isotope geochemistry to the single-crystal scale. Isotopes of heavy elements can be used to reconstruct magma thermal histories, crystal growth timescales, and possibly magma redox conditions at the single-crystal and subcrystal scales.
Article
Chemistry, Analytical
Hannah G. D. Tompkins, Lisa J. Zieman, Mauricio Ibanez-Mejia, Francois L. H. Tissot
JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY
(2020)
Article
Geochemistry & Geophysics
Xinze Lu, Geoffrey J. Gilleaudeau, Brian Kendall
Summary: The Late Ordovician mass extinction is the first major extinction event in the Phanerozoic, but the reasons for the decline in global biodiversity before the extinction are not well understood.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2024)
Article
Geochemistry & Geophysics
Junyao Kang, Daniel D. Gregory, Benjamin Gill, Shiqiang Huang, Changxin Lai, Zhaoshan Chang, Huan Cui, Ivan Belousov, Shuhai Xiao
Summary: Sedimentary pyrite is an important geological archive, but it can be altered by diagenetic and hydrothermal processes. This study successfully trained machine learning algorithms to distinguish pyrite origins using trace element data. The approach was validated and applied to identify the origins of pyrite in two sedimentary successions in South China.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2024)