scholarly journals Heterogeneity in lunar anorthosite meteorites: implications for the lunar magma ocean model

2014 ◽  
Vol 372 (2024) ◽  
pp. 20130241 ◽  
Author(s):  
Sara S. Russell ◽  
Katherine H. Joy ◽  
Teresa E. Jeffries ◽  
Guy J. Consolmagno ◽  
Anton Kearsley
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Ocean Model ◽  
Magma Source ◽  
The Moon ◽  
Magma Ocean ◽  
Element Abundances ◽  
Wide Range ◽  
Lunar Meteorites

The lunar magma ocean model is a well-established theory of the early evolution of the Moon. By this model, the Moon was initially largely molten and the anorthositic crust that now covers much of the lunar surface directly crystallized from this enormous magma source. We are undertaking a study of the geochemical characteristics of anorthosites from lunar meteorites to test this model. Rare earth and other element abundances have been measured in situ in relict anorthosite clasts from two feldspathic lunar meteorites: Dhofar 908 and Dhofar 081. The rare earth elements were present in abundances of approximately 0.1 to approximately 10× chondritic (CI) abundance. Every plagioclase exhibited a positive Eu-anomaly, with Eu abundances of up to approximately 20×CI. Calculations of the melt in equilibrium with anorthite show that it apparently crystallized from a magma that was unfractionated with respect to rare earth elements and ranged in abundance from 8 to 80×CI. Comparisons of our data with other lunar meteorites and Apollo samples suggest that there is notable heterogeneity in the trace element abundances of lunar anorthosites, suggesting these samples did not all crystallize from a common magma source. Compositional and isotopic data from other authors also suggest that lunar anorthosites are chemically heterogeneous and have a wide range of ages. These observations may support other models of crust formation on the Moon or suggest that there are complexities in the lunar magma ocean scenario to allow for multiple generations of anorthosite formation.

scholarly journals Rare Earth Elements in Planetary Crusts: Insights from Chemically Evolved Igneous Suites on Earth and the Moon

Minerals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 455 ◽  
Author(s):  
Claire McLeod ◽  
Barry Shaulis
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Lunar Surface ◽  
Ore Deposits ◽  
Global Distribution ◽  
Igneous Rocks ◽  
The Moon ◽  
Magma Ocean ◽  
Chemical Signature ◽  
Global Demand

The abundance of the rare earth elements (REEs) in Earth’s crust has become the intense focus of study in recent years due to the increasing societal demand for REEs, their increasing utilization in modern-day technology, and the geopolitics associated with their global distribution. Within the context of chemically evolved igneous suites, 122 REE deposits have been identified as being associated with intrusive dike, granitic pegmatites, carbonatites, and alkaline igneous rocks, including A-type granites and undersaturated rocks. These REE resource minerals are not unlimited and with a 5–10% growth in global demand for REEs per annum, consideration of other potential REE sources and their geological and chemical associations is warranted. The Earth’s moon is a planetary object that underwent silicate-metal differentiation early during its history. Following ~99% solidification of a primordial lunar magma ocean, residual liquids were enriched in potassium, REE, and phosphorus (KREEP). While this reservoir has not been directly sampled, its chemical signature has been identified in several lunar lithologies and the Procellarum KREEP Terrane (PKT) on the lunar nearside has an estimated volume of KREEP-rich lithologies at depth of 2.2 × 108 km3. This reservoir therefore offers a prospective location for future lunar REE exploration. Within the context of chemically evolved lithologies, lunar granites are rare with only 22 samples currently classified as granitic. However, these extraterrestrial granites exhibit chemical affinities to terrestrial A-type granites. On Earth, these anorogenic magmatic systems are hosts to U-Th-REE-ore deposits and while to date only U-Th regions of enrichment on the lunar surface have been identified, future exploration of the lunar surface and interior may yet reveal U-Th-REE regions associated with the distribution of these chemically distinct, evolved lithologies.

Geochemical evolution of the Chatham–Grenville stock, Quebec

1985 ◽  
Vol 22 (6) ◽  
pp. 872-880 ◽  
Author(s):  
Michael Denis Higgins
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Mass Balance ◽  
Major Element ◽  
Parental Magma ◽  
Alkali Feldspar ◽  
Geochemical Evolution ◽  
Wide Range ◽  
The Mean

The Chatham–Grenville stock is an anorogenic multiple intrusion that shows a complete gradation from early cumulate and noncumulate syenites to slightly peralkaline granites. It can be divided into four units. Unit 1, the first unit, is a noncumulate syenite with modal quartz less than 5%. Unit 2 has a wide range in composition from cumulate syenites (no modal quartz) to noncumulate syenites and quartz syenites (modal quartz = 20%). Units 3 and 4 are granites with modal quartz up to 25 and 30%, respectively. The parental magma of the whole complex was syenitic. Differentiation occurred as a result of crystal fractionation by filter pressing both at depth and in situ. Ba, Sr, Rb, and Eu abundances and major-element mass-balance calculations show that alkali feldspar, mafic minerals, and apatite were fractionated. At least 79% fractionation is necessary to transform the mean composition of the first unit (1) into the mean composition of the last unit (4). The rare-earth elements, Th, Ta, Hf, and Zr, did not behave in a residual fashion but may have been fractionated in minor accessory phases such as apatite, zircon, monazite, allanite, and xenotime.

Synthetic zircon doped with hafnium and rare earth elements: A reference material for in situ hafnium isotope analysis

2011 ◽  
Vol 286 (1-2) ◽  
pp. 32-47 ◽  
Author(s):  
Christopher M. Fisher ◽  
John M. Hanchar ◽  
Scott D. Samson ◽  
Bruno Dhuime ◽  
Janne Blichert-Toft ◽  
...  
Keyword(s):  
Rare Earth ◽  
Reference Material ◽  
Rare Earth Elements ◽  
Isotope Analysis

Simultaneous determination of Sm–Nd isotopes, trace-element compositions and U–Pb ages of titanite using a laser-ablation split-stream technique with the addition of water vapor

2021 ◽  
Author(s):  
Le Zhang ◽  
Jia-Lin Wu ◽  
Yanqiang Zhang ◽  
Ya-Nan Yang ◽  
Pengli He ◽  
...  
Keyword(s):  
Rare Earth ◽  
Water Vapor ◽  
Laser Ablation ◽  
Rare Earth Elements ◽  
Trace Element ◽  
Simultaneous Determination ◽  
Nd Isotopes ◽  
Trace Element Contents

Titanite is a widespread accessory nesosilicate with high trace-element contents including rare-earth elements, Th, and U, and is thus suitable for in situ isotopic and trace-element analyses and U–Pb dating....

Two phases of post-onset collision adakitic magmatism in the southern Lhasa subterrane, Tibet, and their tectonic implications

2019 ◽  
Vol 132 (7-8) ◽  
pp. 1587-1602
Author(s):  
Tian-Yu Lu ◽  
Zhen-Yu He ◽  
Reiner Klemd
Keyword(s):  
Rare Earth ◽  
Lower Crust ◽  
Tectonic Setting ◽  
Geochemical Data ◽  
Magma Source ◽  
New Mineral ◽  
Element Abundances ◽  
Lhasa Terrane ◽  
Adakitic Rocks ◽  
Two Phases

Abstract Abundant Neogene adakitic magmatism occurred in the southern Lhasa subterrane after the onset of the India–Asia collision while convergence continued. However, the tectonic setting and magmatic evolution of the adakitic rocks are still under discussion. This study includes new mineral chemical and whole-rock geochemical data as well as zircon U-Pb and Lu-Hf isotopes of adakitic intrusive rocks from the Gyaca and Nyemo locations in the southern Lhasa subterrane. Laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) zircon U-Pb dating yielded crystallization ages of ca. 30 Ma for the Gyaca and Nyemo monzogranite and ca. 15 Ma for the Nyemo granodiorite. Both have common chemical signatures such as low MgO and heavy rare earth element contents as well as low compatible element abundances, indicating that these rocks result from partial melting of thickened lower crust with residual eclogite and garnet amphibolite. Furthermore, these rocks are characterized by variable positive zircon εHf(t) values, suggesting a juvenile magma source with variable ancient crustal contributions. Taking previous data into account, the adakitic magmatism concurs with an early late Eocene to Oligocene (ca. 38–25 Ma) and a late Miocene (ca. 20–10 Ma) phase. The adakitic rocks of the two phases are characterized by different fractionation evolutions of light and medium rare earth elements. We propose that the early-phase adakitic rocks were generated by the anatexis of Lhasa terrane lower crust owing to crustal shortening and thickening subsequent to the onset of the India–Asia collision and the upwelling of hot asthenosphere beneath the Lhasa terrane caused by the break-off of the Neo-Tethyan oceanic slab. The latest phase of adakitic rocks, however, relates to upwelling asthenosphere following the delamination and/or break-off of the subducting Indian continental slab.

Quantitative Cathodoluminescence Mapping with Application to a Kalgoorlie Scheelite

2009 ◽  
Vol 15 (3) ◽  
pp. 222-230 ◽  
Author(s):  
Colin M. MacRae ◽  
Nicholas C. Wilson ◽  
Joel Brugger
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Trace Element Level ◽  
Gaussian Peak ◽  
X Ray ◽  
Element Abundances ◽  
Inductively Coupled ◽  
Peak Fitting

AbstractA method for the analysis of cathodoluminescence spectra is described that enables quantitative trace-element-level distributions to be mapped within minerals and materials. Cathodoluminescence intensities for a number of rare earth elements are determined by Gaussian peak fitting, and these intensities show positive correlation with independently measured concentrations down to parts per million levels. The ability to quantify cathodoluminescence spectra provides a powerful tool to determine both trace element abundances and charge state, while major elemental levels can be determined using more traditional X-ray spectrometry. To illustrate the approach, a scheelite from Kalgoorlie, Western Australia, is hyperspectrally mapped and the cathodoluminescence is calibrated against microanalyses collected using a laser ablation inductively coupled plasma mass spectrometer. Trace element maps show micron scale zoning for the rare earth elements Sm3+, Dy3+, Er3+, and Eu3+/Eu2+. The distribution of Eu2+/Eu3+ suggests that both valences of Eu have been preserved in the scheelite since its crystallization 1.63 billion years ago.

Two-stage evolution in an Archean tonalite suite: the Taschereau stock, Abitibi (Quebec, Canada)

1991 ◽  
Vol 28 (2) ◽  
pp. 172-183 ◽  
Author(s):  
Michel Jébrak ◽  
Luc Harnois
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Trace Element ◽  
Greenstone Belt ◽  
Shear Zones ◽  
Granitic Rocks ◽  
Element Abundances ◽  
Abitibi Greenstone Belt ◽  
Rock Types ◽  
End Members

The Taschereau stock occurs north of Timmins and Val-d'Or, Quebec, in the Abitibi greenstone belt of the Superior Province. This late Archean composite pluton is composed mainly of diorite–tonalite–trondhjemite cut by granitic rocks. Gold–molybdenum occurrences are associated with a zone of albite-rich rocks surrounding the granitic rocks. Diabase dykes and shear zones postdate all rock units. Field and geochemical evidence suggests that the Taschereau stock was emplaced diachronously. Trace-element geochemical modelling shows that trace-element abundances (rare-earth elements, Ti, Zr) of Taschereau granitic rocks are consistent with partial melting of preexisting Taschereau tonalitic rocks and implies that these two rock types are not end members of a single magma that evolved through fractional crystallization.

scholarly journals Development of methods for the recovery оf rare-earth elements from the mineral resources of the Arctic

2021 ◽  
Author(s):  
E. P. Lokshin ◽  
◽  
O. A. Tareeva ◽  
◽  
◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Raw Materials ◽  
Mineral Resources ◽  
The Arctic ◽  
Resource Saving ◽  
Apatite Concentrate ◽  
Naturally Occurring ◽  
Wide Range ◽  
Rare Earth Mineral

This paper summarizes the findings of the research aimed at the development of a new method for the integrated processing of naturally occurring and anthropogenic rare-earth raw materials based on the decomposition of rare-earth element (REE) concentrates in the presence of sulfocationite. Sorption and desorption of REE cations on a strongly acidic ion exchanger, sorbent regeneration, and REE recovery from eluates are discussed. A virtually zero-waste integrated process for apatite concentrate is proposed. The generalization of the research findings is aimed at demonstrating the prospects and universality of the proposed resource-saving and environmentally safe approach to the processing of various types of naturally occurring and anthropogenic rare-earth mineral feeds. The new methodology made it possible to develop a number of new hydrochemical processes united by a single approach, providing a qualitative increase in the processing performance of various types of rare-earth mineral feeds. The theoretical foundations of a unified approach to the processing of a wide range of minerals can significantly accelerate and cheapen the implementation of specific process circuits, significantly reduce reagent consumption and waste generation, simplify the separation of rare earth elements and impurities, and the separation of rare earth elements from naturally occurring radionuclides, fluorine, and phosphorus. The study was funded by the Kolarctic CBC 2014-2020 program, Project KO1030 SEESIMA — Supporting Environmental Economic and Social Impacts of Mining Activity.

scholarly journals Sources of Extraterrestrial Rare Earth Elements: To the Moon and Beyond

Resources ◽  
2017 ◽  
Vol 6 (3) ◽  
pp. 40 ◽  
Author(s):  
Claire McLeod ◽  
Mark. Krekeler
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
The Moon
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