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 ...

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) ...

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

Central to our understanding of orogenic processes is an appreciation of the timescales over which these processes operate. An objective is to relate isotopic dating to pressure and temperature conditions so that the significance of the ages can be assessed correctly. A number of studies have focussed on understanding the petrogenesis of the accessory ...

U-Pb isotope analyses on major and accessory minerals from pelitic schists in of southwestern Connecticut are used to date metamorphism and deformation. Most of the major minerals have 206 Pb/ 204 Pb ratios less than 100. However, U-Pb mineral isochron and mineral-whole rock isochrons, ...

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 ...

The extraction of melts from the lower crust and their subsequent emplacement at higher structural levels is an important differentiation mechanism that leads to the transfer of major and trace elements, volatiles and heat through the crust. Residual migmatites and granulites exposed at the Earth�s surface represent former melt-bearing crust and preserve evidence for melt transport on the micro- ...

Accessory chromosomes, also called B-chromosomes, have been reported in more than 1300 species of plants. Accessory chromosomes show numerical polymorphism and when present in high number, are known to negatively affect the growth and vigor of the plants, while in low numbers they may be beneficial...

Zircon is arguably the most studied accessory mineral in geochronological studies and has been lauded for its mechanical and chemical robustness for decades. However, detailed understanding of growth and modification are still emerging from, particularly from in-situ studies combining petrography and internal texture studies with trace ...

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

Continental tectonics and geochronology have had a symbiotic relationship for many decades. A diverse range of chronometers has been applied to tectonic problems and to quantify rates of geological processes. These chronometers include U-Th-Pb, Ar-Ar, ZFTA, U-Th-He, and other systems and fall into geo-chronomters that date geological events (i.e. mineral crystallisation ...

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 ...

1. Detmer's solution and a modified Knop's solution are unfavorable culture media for the growth of Spirodela polyrhiza. 2. When the modified Knop's solution was diluted to 10 times its volume, Spirodela polyrhiza and Lemna valdiviana grew and reproduced for periods of 26 months and 21 months, respectively. 3. Growth in the dilute Knop's solution, which ...

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 ...

... 46 XIII Changes in Accessory Pigments in Comparison With Chlorophyll a as Effected by Growth of Algae in Monochromatic and White Illumination ...

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 ...

Over the past decade, deciphering absolute crystallization ages at micro-scales through in-situ U-series dating has spearheaded conceptual changes in the understanding of how magmas evolve en route to the surface. U-Th and U-Pb zircon geochronology by secondary ionization mass spectrometry (SIMS) now routinely accesses a continuous age spectrum extending well into the Holocene with ka precision ...

For age determination of U and Th minerals an accurate measurement of the Th/U ratio is needed, especially when accessory lead is present. The correction of accessory lead may be made on the basis of the isotope Pb/sup 108/. It is therefore necessary to determine very low contents of Th in U minerals very ...

The market research was undertaken to study the present and potential US share of the market in Japan for automotive maintenance equipment and accessories; to examine growth trends in Japanese end-user industries over the next few years; to identify speci...

The market research was undertaken to study the present and potential US share of the market in Sweden for automotive parts and accessories; to examine growth trends in Swiss end-user industries over the next few years; to identify specific product catego...

The market research was undertaken to study the present and potential US share of the market in Korea for automotive diagnostic and service equipment and accessories; to examine growth trends in Korean end-user industries over the next few years; to ident...

The market research was undertaken to study the present and potential US share of the market in Brazil for plastic and rubber products production machinery, accessories and plastic materials; to examine growth trends in Brazilian end-user industries over ...

The classic "infection stone" struvite is formed as a result of metabolic activity of urease-positive bacteria from alkaline urine with pH-values above 7.5. Due to improved infection diagnostics and antibiotic therapy, the occurrence of infection-related urinary stones in the western industrialized world decreases, despite the generally increasing prevalence rates of urolithiasis in these ...

The Peach Spring Tuff (PST), a large Miocene ignimbrite located in the southwestern USA, is distinctive in its abundance of U, Th, and REE concentrating accessory minerals (zircon, sphene, allanite, chevkinite). We have examined textures and compositions of these accessory minerals and magnetite, as well as ...

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 ...

Zircon and monazite are the most versatile tools for geochronological studies in magmatic, metamorphic and sedimentary rocks. New trace element techniques are now used to link growth and modification to pressure and temperature evolution of magmatic and metamorphic rocks and to coexisting minerals. Studies on the distribution of rare earth elements (REE) ...

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 ...

Perineal lipomas are uncommon congenital anomalies. They mainly develop in male patients with an accessory scrotum, posterior to the original scrotum. However, on rare occasions, these lipomas can occur in female patients with an accessory labioscrotal fold. We report on three such cases, where the lipomas were found in the anterior part of the right side ...

Petrological investigations and monazite dating are carried out on medium-grade metamorphic rocks (micaschist, gneiss and amphibolite) from the Kutjeva?ka Rijeka transect in the Slavonian Mts., Tisia Unit (NE Croatia). Field, mesoscopic and microstructural observations, as well as the preserved mineral chemistry, point to a single metamorphic event during peak assemblage ...