Zirconolite, aeschynite-(Ce), titanite and apatite have been found as minor or accessory minerals in a Ti-rich (TiO2=2.1 4.5 wt.%) hydrothermal vein occurring in dolomite marbles at the contact with a tonalite intrusion of the Tertiary Adamello batholith (northern Italy). The vein consists of four distinct mineral ...

Natural spinel, perovskite and zirconolite rank among the most leach resistant of mineral forms. They also have a strong affinity for a large number of other elements and including actinides. Specimens of natural perovskite and zirconolite were radioisoto...

Results are presented for leach testing at 95/sup 0/C and 200/sup 0/C of SYNROC containing 9% and 20% simulated high level radioactive waste, synthetic hollandite and pervoskite samples, and natural zirconolite and pervoskite samples. Single phase synthetic minerals show much higher leach rates than natural mineral samples and ...

Experimental studies show that the accessory minerals of comatiites and intrusive ultramafic greenstone structures of the Kursk magnetic anomaly differ significantly in terms of mineral type and composition. This finding indicates that accessory minerals can be considered an important ...

Plagioclase-Olivine Inclusions (POIs) are an abundant group of chondrule-like objects with igneous textures found in carbonaceous chondrites. POIs consist of plagioclase, olivine, pyroxene, and spinel, and cover a wide range of compositions between Type C Ca-Al-rich Inclusions (CAIs) and ferromagnesian chondrules. POIs are distinguished from CAIs by the absence of melilite, lack of refractory ...

The saturation of impurity-rich accessory phases in a Ce-analog baseline ceramic formulation for the immobilization of excess plutonium has been tested by synthesizing an impurity-rich baseline compositions at 1300 C, 1350 C, and 1400 C in air. Impurity oxides are added at the 10 wt% level. The resulting phases assemblages are typically rich in pyrochlore, ...

This "Accessory mineral behaviour during partial melting in the crust - improving the geochronology of granulite terrains." is licensed under a Creative ...

Accessory mineral behaviour during partial melting in the crust - improving the geochronology of granulite terrains (ASAC_2690) ...

The iron-enriched basalt (IEB) waste form, developed at the Idaho National Engineering Laboratory a decade ago, was modified to IEB4 by adding sufficient ZrO{sub 2} and TiO{sub 2} to develop crystals of zirconolite upon cooling, in addition to the crystals that normally form in a cooling basalt. Zirconolite (CaZrTi{sub 2}O{sub 7}) is an extremely ...

Between 8 and 50 metric tonnes of excess plutonium are currently planned to be immobilized in a glass or ceramic waste form in the US. The immobilized Pu would then be encased in HLW glass (the can-in-canister alternative), which would provide a radiation barrier to enhance the proliferation resistance of the material. Associated with the plutonium are about 15 metric tonnes of uranium primarily ...

... Their mineral content, as determined by ... calcite, and accessory minerals: zircon, disthene ... sphene, corundum, hydromica, chlorite and amphibole. ...

Transmission electron microscopy (TEM) has been used to determine the microstructure of crystalline phases present in zirconium- and titanium-bearing glass crystalline composite (GCC) waste forms. The GCC materials were found to contain spinels (maghemite), zirconolites, perovskites (CaTiO{sub 3}) and plagiociase feldspar (anorthite) mineral phases. The ...

Synroc-D is a polyphase nuclear waste ceramic optimally consisting of zirconolite, perovskite, an ulvospinel-rich solid solution, a hercynitic spinel solid solution, and nepheline. A continuous intergranular glass phase is also present, which may aid in densification, but decreases the waste form's durability in aqueous environments, as does the presence of nepheline. ...

The uranium content of the Susamyr batholith was determined in various intrusion phases. The mineral compound was measured in a large thin section. Uranium was found in every mineral with about 40 to 50% in the rock forming minerals and 50 to 60% in the accessory minerals. It was shown ...

Relating ages, determined using the decay of radioactive elements in minerals, to geological events is central to understanding mountain building and ...

Chemical extraction techniques and scanning electron microscopy were used to study the distribution and behavior of actinides and rare earth elements (REE) in hydrothermal veins at Adamello (Italy). The six samples discussed in this paper were from the phlogopite zone, which is one of the major vein zones. The samples were similar in their bulk chemical composition, mineralogy, and leaching ...

Samples of primarily-monoclinic /sup 238/Pu-doped zirconolite were stored at ambient temperature to allow accumulation of alpha decay self-damage to a dose of 1 x 10/sup 24/ ..cap alpha../m/sup 3/ (equivalent to a SYNROC age of approx. 10/sup 3/y). Bulk swelling reached 2.3 vol% with no tendency toward saturation, a damage response similar to that observed for cubic Pu-doped ...

The principal objectives of the study are to examine potentially harmful consequences of element redistribution on the environment and to assess the opportunities for economic byproduct recovery of accessory elements. Attention is focused on mining and pr...

The principal objectives of the study are to examine potentially harmful consequences of element redistribution on the environment and to assess the opportunities for economic byproduct recovery of accessory elements. Attention is focused on mining and pr...

Accessory minerals commonly occur attached to or included in the major crystalline phases of felsic and some intermediate igneous rocks. Apatite is particularly common an inclusions, but Fe-Ti oxides, pyrrhotite, zircon, monazite, chevkinite and xenotime are also known from silicic rocks. Accessories may nucleate near the host ...

'The end of the Cold War raised the need for the technical community to be concerned with the disposition of excess nuclear weapon material. The plutonium will either be converted into mixed-oxide fuel for use in nuclear reactors or immobilized in glass or ceramic waste forms and placed in a repository. The stability and behavior of plutonium in the ceramic materials as well as the phase ...

The end of the Cold War raised the need for the technical community to be concerned with the disposition of excess nuclear weapon material. The plutonium will either be converted into mixed-oxide fuel for use in nuclear reactors or immobilized in glass or ceramic waste forms and placed in a repository. The stability and behavior of plutonium in the ceramic materials as well as the phase behavior ...

The characteristics of the accessory minerals in the rock massif are reported. According to the association of the primary accessory minerals the alkali syenites and subalkali granitoids pertain to the sphene-ilmenite-magnetite type with constant presence of zircon and apatite. Zircons, magnetites, and ...

Analyses were made of uranium and thorium in zircon, sphene, apatite, epidote, and monazite separated as accessory minerals from samples of granitic rock from widely scattered localities to indicate the abundance, and the natural distribution of these two components among the five mineral phases. The approximate distribution ...

Naturally occurring mineral analogues to crystalline phases that are constituents of crystalline radioactive waste forms provide a basis for comparison by which the long-term stability of these phases may be estimated. The crystal structures and the crystal chemistry of the following natural analogues are presented: baddeleyite, hematite, nepheline; pollucite, ...

Zirconolite (CaZrTi(sub 2)O(sub 7)) is the major host phase for actinides in Synroc, a promising waste form for the immobilization of high-level radioactive waste. The effect of radiation damage on the structure and durability of zirconolite are important...

This report summarizes work after completion of a three-year project and our current ongoing efforts. Research efforts at UC Davis have focused on establishing the thermodynamic properties of zirconolite and pyrochlore, and the synthesis of other minerals relevant to storage of nuclear material. Heat capacity, entropy, enthalpy of formation, and fkee ...

The distribution of rare earths in accessory minerals of granitoids, apatite, sphene, garnet, epidote, fluorite, zircon, orthite, monazite, and xenotime was studied. The highest contents of rare-earth elements are typical of sphenes and fluorites. The greatest Ce contents were found in sphene and epidotes; Nd, Sm, Cd, and Dy in garnets or ...

Complex and protracted crystallization histories over geologic timescales are recorded in accessory minerals (e.g., zircon, allanite). Although magmatic crystallization was traditionally assumed to occur essentially instantaneously for the purposes of interpreting mineral geochronometers with low absolute time resolution for ancient ...

Uranium in granites has long been known to occur mainly in a few accessory minerals. Examination of a dozen granites with high resolution BSEI, EDS, and neutron induced fission tracks provides new data on the distribution of U and the elements correlated with U. The following features are common. Fresh allanite, monazite, apatite, and zircon grains are ...

Rock 75035 is a medium-grained, holocrystalline, subophitic ilmenite basalt collected from the rim of Camelot Crater, and is believed to represent the subfloor basalts of the Taurus-Littrow valley. The rock consists of the major minerals pyroxene (45%), plagioclase (31%), and ilmenite (17%). Minor minerals include cristobalite (about 5%), troilite, native ...

The uranium distribution in rock minerals (syenites, granosyenites, and alaskite granites) of the Kyzyl-Ompul raassif is studied. Alaskite granites are characterized by the granite type of uranium distribution in minerals, about 50 percent of this element being connected with rockforming and about 50 percent with accessory ...

The structure of a new polytype of zirconolite, zirconolite-4M, has been determined using X-ray and neutron powder diffraction, high resolution transmission electron microscopy, and selected area electron diffraction. Zirconolite-4M occurs when zirconolite is doped with 0.5-0.8 Nd per formula unit. Its structure ...

The report is divided into three sections: morphology, mineralogy and elemental composition. The nodule morphology section defines what is considered a nodule for the study, and details the external characteristics and internal structure. Nodule mineralogy is discussed in three sections: manganese minerals, iron oxide minerals, and ...