Article
Geochemistry & Geophysics
Nicholas Arndt, Carole Cordier, Anne-Marie Boullier, Valentina Batanova, Valerie Magnin, Nathaniel Findling
Summary: Kimberlites contain olivine nodules with a wide range of Fo content. These nodules, regardless of their Fo content, have similar sizes, internal textures, and habits. They are believed to have a common origin with olivines in the megacryst suite, formed through interactions between mantle peridotite and CO2-rich fluid. This interaction occurred near the base of the lithosphere, not during kimberlite ascent.
JOURNAL OF PETROLOGY
(2022)
Article
Geosciences, Multidisciplinary
Sinan Ozaydin, Kate Selway, William L. Griffin
Summary: The study shows that water content decreases with depth in the southwestern Kaapvaal Craton, broadly matching the distribution of metasomatism. While most water content measurements from xenolith samples agree with the models, discrepancies suggest a local metasomatic control over xenolith water contents.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
Christian Veglio, Bruce A. A. Kjarsgaard, Duane C. C. Petts, Simon E. E. Jackson, Christopher J. M. Lawley, D. Graham Pearson
Summary: This study analyzed mantle samples from the northern Slave craton in Canada and found significant variations in element concentrations and mineral compositions in harzburgite xenoliths and olivine xenocrysts, which may be attributed to the interaction with carbonatitic and ultramafic silicate melts. With the exception of a few elements, most trace elements in olivine do not vary systematically with depth and are more likely influenced by fluid, sulphides, and mineral inclusions.
Article
Geochemistry & Geophysics
Stephanie Greene, Dorrit E. Jacob, Suzanne Y. O'Reilly
Summary: In this study, the chemical composition of 86 olivines from the Jericho kimberlite in Canada was analyzed, and three main olivine populations were identified. The results indicate a major change in the properties and composition of the kimberlite magma at the 150 km interface between the shallow and deep lithospheric mantle layers, likely due to assimilation of carbonate at this depth.
Review
Geosciences, Multidisciplinary
Aleksey E. Melnik, Nester M. Korolev, Sergey G. Skublov, Dirk Mueller, Qiu-Li Li, Xian-Hua Li
Summary: This study constrains the characteristics of zircon from mantle eclogite xenoliths through analyzing data from zircons in different geological settings, suggesting zircons within the xenoliths may have magmatic, metamorphic, and xenogenic origins. The origins of zircon in mantle eclogites can vary, including inheritance from mafic oceanic crust, direct crystallization from mantle-derived melts, and metasomatism related to kimberlite magmatism. The study also demonstrates a possible method for identifying inherited and xenogenic zircons within mantle eclogites, using zircon grains from kimberlite-hosted eclogite xenoliths.
GEOLOGICAL MAGAZINE
(2021)
Article
Geochemistry & Geophysics
Yuval Boneh, Emily J. Chin, Greg Hirth
Summary: By studying a sheared peridotite xenolith deformed under comparable strain rates to laboratory shearing time scales, variations in microstructure between monophase and multiphase bands were observed, shedding light on the rheological properties of the upper mantle. The microstructure analysis revealed a dominant and secondary activated crystallographic preferred orientation in olivine grains, along with deformation mechanisms involving dislocation creep and dynamic recrystallization. The reduction of grain size in orthopyroxene was found to promote activation of diffusion creep, indicating a high activation volume for wet orthopyroxene dislocation creep.
Article
Geochemistry & Geophysics
Geoffrey H. Howarth, Andrea Giuliani, Ashton Soltys, Yannick Bussweiler
Summary: Olivines are the dominant phase in kimberlites, displaying compositional zoning with xenocrystic cores surrounded by magmatic rims. Previous studies have shown variations in major and minor element compositions of both core and rim in kimberlites globally, which can be attributed to entrainment and assimilation of sub-continental lithospheric mantle material. However, there is limited knowledge of trace element variations in olivine from kimberlites and the effect of mantle assimilation on the trace element composition of kimberlite melts is unclear. To address this, a global survey of olivine trace element compositions, along with major and minor element compositions, was conducted for samples representing the full spectrum of olivine variations in kimberlites. The results indicate that lithospheric mantle assimilation has a major influence on the trace element composition of kimberlite magmas, which has been overlooked in previous studies.
JOURNAL OF PETROLOGY
(2022)
Article
Geochemistry & Geophysics
Z. J. Sudholz, G. M. Yaxley, A. L. Jaques, J. Chen
Summary: The study presents new synthesis experiments conducted in the temperature-dependent exchange of Ni and Mg between garnet and olivine, resulting in an updated Ni-in-garnet geothermometer for more reliable temperature estimates in the upper mantle and kimberlite diamond potential. The calibration can be applied to garnet peridotite xenoliths or monomineralic garnet xenocrysts, offering a more accurate understanding of mantle temperatures and geological processes related to diamond formation.
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
(2021)
Article
Geosciences, Multidisciplinary
Yu-Sheng Zhu, Jin-Hui Yang, Qiu-Li Li, Hao Wang, Ya-Dong Wu, Fu-Yuan Wu
Summary: Our research on the Trans-North China orogen has revealed the presence of a thick and refractory lithospheric mantle at approximately 1.54 Ga. This lithospheric mantle, which exhibits craton-like properties, may have been formed due to a large volume melt extraction caused by a major igneous event around 1.78 Ga. These findings are significant for understanding the evolution and stability of the Trans-North China orogen.
Article
Geochemistry & Geophysics
Federico Casetta, Rene Asenbaum, Igor Ashchepkov, Olga Ageeva, Rainer Abart, Theodoros Ntaflos
Summary: Kimberlite melts are low volume, volatile-rich melts formed in the asthenosphere at depth >150-250 km. They rise rapidly through the lithosphere due to their buoyancy and exsolution of CO2 triggered by their interaction with the sub-cratonic mantle. The ascent rate of kimberlite melts can vary between 0.1 and 30 m/s, and the overall average ascent rates are comparable to those of typical alkali basalts, suggesting that kimberlite melts start with moderate ascent rates and increase their speed later on.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
M. G. Kopylova, F. Ma, E. Tso
Summary: The study reveals significant metasomatic alteration and carbonation freezing effects on Chidliak peridotites, highlighting the importance of these processes in magma interactions.
Article
Geochemistry & Geophysics
Jing Wang, Ben-Xun Su, Paul T. Robinson, Yan Xiao, Yang Bai, Xia Liu, Patrick Asamoah Sakyi, Jie-Jun Jing, Chen Chen, Zi Liang, Zhi-An Bao
Summary: The study examined the trace elements in olivine and found differences in trace element contents and ratios among different types of mafic-ultramafic rocks, which can be used as chemical proxies to distinguish the origin and evolution processes of the rocks.
Article
Geology
M. G. Pamato, D. Novella, D. E. Jacob, B. Oliveira, D. G. Pearson, S. Greene, J. C. Afonso, M. Favero, T. Stachel, M. Alvaro, F. Nestola
Summary: Sulfides are the most abundant inclusions in diamonds and can be used to date diamond formation via Re-Os isotopic analyses. The study found that Re-Os isotope equilibration in sulfide inclusions is sufficiently fast at mantle temperatures to be reset by the diamond-forming event, confirming that the Re-Os isochrons likely reflect the ages of diamond formation.
Article
Geology
Soumendu Sarkar, Andrea Giuliani, David Phillips, Geoffrey H. Howarth, Sujoy Ghosh, Hayden Dalton
Summary: Cratonic lamproites, diamondiferous ultrapotassic rocks, may originate from convective mantle rather than subcontinental lithospheric mantle, with melts interacting with metasomatized subcontinental lithospheric mantle en route to the surface.
Article
Geochemistry & Geophysics
Lingzhi Sun, Paul G. Lucey
Summary: In this study, a mantle boulder candidate search algorithm was applied around the Imbrium basin using radiative transfer modeling and datasets from Moon Mineralogy Mapper and Multiband Imager. Two boulders consisting of olivine and possible mantle dunite were found on Copernicus central peaks, excavated by Imbrium basin or Copernicus crater. The algorithm presented in this work has the potential to be used for a global search for mantle candidate boulders in lunar basins.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
N. M. Sushchevskaya, A. Sobolev, G. L. Leitchenkov, V. G. Batanova, B. Belyatsky, A. Zhilkina
Summary: The study of basalts and dolerites in East Antarctica suggests the presence of high-Mg ferropicrites related to a unique pyroxenite mantle source, likely the earliest eruptions associated with the Karoo plume impact. The dolerites show relatively smooth lithophile element patterns, low content of compatible elements, and a moderately radiogenic neodymium composition, indicating a potentially old age of the pyroxenite component.
GEOCHEMISTRY INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Alina N. Koshlyakova, Alexander V. Sobolev, Stepan P. Krasheninnikov, Valentina G. Batanova, Alexander A. Borisov
Summary: The study presented the results of experiments focusing on the effects of Na2O and K2O on Ni-Mg partitioning between olivine and highly alkaline melts. The experimental data combined with literature pairs showed that Na2O and K2O have significant effects on the partitioning, with K having a more significant impact than Na. Other elements like Ti and Ca also affect the exchange equilibrium constant value, with Si increasing it.
Article
Geochemistry & Geophysics
Martin Guitreau, Abdelmouhcine Gannoun, Zhengbin Deng, Marc Chaussidon, Frederic Moynier, Bernard Barbarin, Johanna Marin-Carbonne
Summary: This study investigates the silicon isotope signatures of zircon in various granite types to understand their fractionation behavior, which can be useful in studying magma evolution and identifying granite source areas. Silicon isotope ratios in zircon can track changes in magma temperature and composition, revealing complex processes like magma mingling, fractional crystallization, and multiple sources. The study highlights that silicon isotopes in zircon can complement existing techniques in granite studies and should not be used in isolation.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Materials Science, Multidisciplinary
Marie Landeiro Dos Reis, Yvelin Giret, Philippe Carrez, Patrick Cordier
Summary: This study investigates the mechanisms of pipe diffusion and point defect diffusion along dislocation line in MgO. Through numerical calculations and the use of elasticity theory, the migration energies of point defects are determined. The diffusion kinetics near the dislocation is evaluated using an on-lattice atomistic kinetic Monte Carlo algorithm based on atomistic simulations. The study reveals that the edge dislocation in MgO acts as a strong sink for vacancies, leading to enhanced diffusion of point defects near the dislocation.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Hosni Idrissi, Armand Beche, Nicolas Gauquelin, Ihtasham Ul-Haq, Caroline Bollinger, Sylvie Demouchy, Johan Verbeeck, Thomas Pardoen, Dominique Schryvers, Patrick Cordier
Summary: Intragranular amorphization shear lamellae are observed in deformed olivine aggregates, and their formation and propagation are associated with crystal defects and rotational nanodomains. Hence, stress-induced amorphization in olivine is a result of a direct crystal-to-amorphous transformation caused by shear instability, rather than mechanical destabilization.
Article
Geochemistry & Geophysics
B. Tarun Kumar, M. Jayananda, P. Nasipuri, Martin Guitreau, K. R. Aadhiseshan, S. V. Balaji Manasa Rao, T. Tarun Thomas, M. Satyanarayanan
Summary: A widely spaced Neoarchean shear zone network is found in the granite-greenstone terrains of the Western Dharwar craton. The Balehonnur shear zone, trending NNW-SSE, traverses the largest part of the preserved tilted Archean crustal ensemble in the craton. The shearing in this zone is sinistral and affects greenstone sequences, TTG, and Koppa granite.
Article
Geosciences, Multidisciplinary
Jessica Flahaut, Vincent Payet, Frank Fueten, Martin Guitreau, Marie Barthez, Gen Ito, Pascal Allemand
Summary: Plagioclase-bearing rocks have been discovered near impact basins on Mars, with geological evidence indicating they could be excavated plutons or ancient crustal outcrops. These rocks, containing plagioclase feldspar, were previously believed to only exist in anorthositic rocks inherited from a primary flotation crust or granitoids from plutonic activity or ancient continental crust. However, our analysis has found evidence of volcanic rocks with plagioclase VNIR spectral signatures, expanding the understanding of Martian rocks to include multiple lithologies. This discovery has significant implications for Mars' magmatic processes and the nature of its crust.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Multidisciplinary Sciences
Patrick Cordier, Karine Gouriet, Timmo Weidner, James Van Orman, Olivier Castelnau, Jennifer M. Jackson, Philippe Carrez
Summary: Heat transport from Earth's interior drives convection in the mantle, involving solid rock deformation over billions of years. The lower mantle is composed of iron-bearing bridgmanite MgSiO3 and periclase MgO (also with some iron). Recent studies have focused on representing lower mantle assemblages under relevant pressure and temperature conditions. However, the natural strain rates are significantly lower than in the laboratory, making them inaccessible. This study uses numerical modeling to determine the rheological properties of MgO periclase at lower mantle conditions, showing that periclase deformation is much slower than bridgmanite deformation due to slow oxygen diffusion.
Article
Geochemistry & Geophysics
Marco A. Lopez-Sanchez, Thomas Chauve, Maurine Montagnat, Andrea Tommasi
Summary: This study examines the relationship between strain localization and microstructural evolution in ice Ih deformed by dislocation creep. The results show that strain concentrates in narrow intracrystalline shear bands and severe dynamic recrystallization occurs at grain boundaries. Additionally, the study reveals that large strains can be accommodated by basal slip without the formation of dislocation substructures. These findings have important implications for the interpretation and modeling of deformation by dislocation creep in rocks.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Sylvie Demouchy, Qin Wang, Andrea Tommasi
Summary: The interior of the Earth is still an unknown territory, and our understanding of mantle deformation relies on analysis of mantle rocks, the consequences of deformation, and geophysical data. Olivine deforms through the motion of defects within its crystalline structure and along grain boundaries, leading to anisotropic propagation of seismic waves, enabling us to probe upper-mantle deformation at scales of tens to hundreds of kilometers.
Article
Geosciences, Multidisciplinary
X. Wang, J. F. Zhang, A. Tommasi, M. A. Lopez-Sanchez, Z. C. Jing, F. Shi, W. L. Liu, F. Barou
Summary: Amphibole-rich rocks are important components of the continental crust in active orogens with thick and hot crusts. However, there is a lack of experimental data on their viscosity. We conducted deformation experiments on synthetic amphibolites under conditions resembling deep sections of overthickened crust. Our results show that calcic-amphibolite is significantly weaker than plagioclase-rich amphibolite, granulite, or gabbro, contrary to common assumptions. This low viscosity deep crust may have implications for the channel flow model in the Tibetan Plateau and the observed high crustal seismic anisotropy in the region.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Xavier Llovet, Maxim Gavrilenko, Valentina G. Batanova, Alexander Sobolev
Summary: Secondary fluorescence (SF) is an overlooked source of error in EPMA, leading to concentration enhancement or decrease near a phase boundary. In this study, Ni profiles in olivine were compared with calculations and simulations of SF, and it was found that the Ni content consistently decreases as distance to the interface or grain radius decreases. This decrease is explained by the lower bremsstrahlung fluorescence emitted from the sample compared to the standard.
MICROSCOPY AND MICROANALYSIS
(2023)
Article
Geochemistry & Geophysics
Lucan Mameri, Andrea Tommasi, Alain Vauchez, Javier Signorelli, Riad Hassani
Summary: Geophysical and geological observations suggest the presence of active and fossil shear zones in the lithospheric mantle. These shear zones affect the behavior of the mantle due to anisotropic viscosity. In this study, 3-D geodynamic finite-element models were used to investigate the strain and viscosity distribution in the lithosphere containing fossil shear zones.
Article
Geochemistry & Geophysics
M. Barthez, J. Flahaut, M. Guitreau, G. Ito, R. Pik
Summary: Plagioclase feldspar, a common mineral in terrestrial rocks, has been detected on Mars using reflectance spectroscopy. The method identifies plagioclase through the presence of an absorption band centered around 1.3 μm on the reflectance spectra, which requires the incorporation of Fe2+ in plagioclase lattice. Previous laboratory studies showed that plagioclase can only be detected if it is present in amounts >90%, as its absorption band can be masked by mafic minerals. In this study, laboratory measurements were performed on different types of feldspar-bearing rocks, and it was found that plagioclase signatures were visible in the spectra of rocks containing between 30% and 80% plagioclase of different compositions (An(25)-An(67)). These findings have important implications for the interpretation of feldspar signatures on Mars, as they can belong to a range of feldspar-bearing rocks and provide information about the formation of Mars' crust.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Mineralogy
Sylvie Demouchy, Manuel Thieme, Fabrice Barou, Benoit Beausir, Vincent Taupin, Patrick Cordier
Summary: In this study, the geometrically necessary dislocation density (rho(c)(alpha)) and disclination density (rho(theta)) in fine-grained polycrystalline olivine were quantified under various deformation conditions. The spatial distribution of both GND and disclination densities were obtained using ATEX software. The results showed that sub-grain boundaries were defined by areas with the highest GND densities, and most olivine sub-grain boundaries had a mixed character. Disclinations were found along grain boundaries, sub-grain boundaries, and at sub-grain boundary tips.
EUROPEAN JOURNAL OF MINERALOGY
(2023)