Geology, Geophysics and Environment 44, 1, Mineralogia – Special Papers, 47, Acta Mineralogica-Petrographica 32, Mineralogia – Special Papers, 45, Wyzwania polskiej geologii, 3. Polski Kongres Geologiczny, Mineralogia — Special Papers, 44, Na activity in the fluid. Geologia Sudetica 42,
It provides precise and accurate chemical composition for elements Be to U at the micron-scale of a large variety of solid materials such as minerals, glasses, alloys, and ceramics. The primary advantage of EMP analysis is the non-destructive and in-situ character of the analysis. All you need is a well-polished, flat sample, such as a regular petrographic thin section or an epoxy mount.
EMP is the ideal technique for analyzing chemically zoned crystals, for testing a material’s homogeneity, for sampling delicately intermixed phases, or for identifying and characterizing phases chemistry, size, shape. As it is an in-situ technique, information on texture and deformation can be preserved. Acknowledgments The purchase of the JEOL would not have been possible without the help many researchers throughout Colorado and beyond that supported our proposal.
Electron probe microanalysis (EPMA) of accessory minerals such as monazite, xenotime, and thorite for minor- and trace-element concentrations and geochronology, requires consideration of beam irradiation effects (increasing heat and charge) as higher current densities and lengthy counting times.
Dumplin on west, Central Maine and Conant Brook on east of opposing shear sense enclosing the Monson orthogneiss. Research was designed to establish the timing of deformation to test the hypothesis that strain in transpressional systems occurs contemporaneously. An understanding of the timing of deformation in this zone could elucidate the mechanisms that formed the zone and contribute to a greater overall understanding of fabric evolution in transpressional systems.
Plutons that contain all fabrics associated with progressive transpression — lineations ranging from subhorizontal initial to steeply-plunging parallel to dip final — mark the maximum age of deformation. Ages range from Ma in the Hardwick tonalite, Wachusett tonalite, West Warren diorite, Walker Mountain orthogneiss, and Nichewaug diorite, and indicate transpression in the PZoT initiated after ca. Monazite from Rangeley paragneisses and schists selected in the context of petrofabrics and syn-deformational mineral assemblages yield U-Th-Pb EPMA chemical ages that indicate dextral transpression occurred continuously from to Ma.
Monazite chemical ages also indicate that sinistral lateral displacement in the west-bounding Mt. Dumplin high strain zone initiated ca. The data for the Central Maine zone, Conant Brook shear zone, and Greenwich syncline support the idea of contemporaneous deformation across the compartmentalized zones of a transpressive system Ma , while the ages for the Mt.
Dumplin high strain zone indicate sinistral lateral displacement overlapped dextral transpression by about 10 m. Theses and Dissertations–Earth and Environmental Sciences.
Please complete our online readership survey by clicking the button below We appreciate your comments and feedback so we can continue to improve our magazine. Nevertheless, there are only scarce geochronological data on the timing of formation for the majority of Australian uranium deposits. Because uraninite is commonly a major ore constituent of many primary uranium deposits its geochronology has the potential to provide a direct age of mineralisation.
Welcome to NiLeDAM project! NiLeDAM stands for “Monazite Datation for the NiLeDAM team”. It provides facilities for geologists to date monazite using electron microprobe analysis (EPMA).
IP Policies Research Facilities IIT Kharagpur is widely acclaimed for the quality and breadth of its research enterprise, and particularly for its openness to multidisciplinary research. Several highly rated initiatives represent a long IIT Kharagpur tradition of cross-disciplinary research and collaboration. In this continuous quest for excellence in our research endeavours, we recognize the importance of modernization in infrastructure and experimental facilities.
To ensure that we hold on to our position at the cutting edge of innovation, the Institute has set up several state of the art facilities. The lab has established industry standard design and verification flows. More than chips have been designed in this lab, fabricated and successfully tested. Currently more than 60 PhD students and full time MS students work under the ambit of the lab. Each year about papers are published in areas related to VLSI design and CAD by the students and faculty associated with the activities of the Lab.
In recent times several vertical domains are emerging which exploit the expertise of multiple research groups.
It remains a matter of debate whether the formation of domes was related to the well-documented late orogenic extension or to the contractional tectonics that preceded. Migmatization and magmatism are expected to predate extension if the domes are compression-related regional anticlines, but they must both precede and be contemporaneous with extension if they are extensional core complexes.
In the Montagne Noire area southern French Massif Central , where migmatization, magmatism and the deformation framework are well documented, the age of the extensional event was unequivocally constrained to — Ma. Therefore, dating migmatization in this area is a key point for discriminating between the two hypotheses and understanding the Late Palaeozoic evolution of this part of the Variscan belt. Although zircon did not record any Variscan age unequivocally related to compression Ma , two age groups were identified from the monazite crystals.
U-Pb zircon and U-Th-Pb monazite ages indicated metamorphism at ca. Ma and Ma and inherited ages of – Ma, suggesting possible provenance to granitoids comparable to those in the Altai Mountains, China.
The terrane is underlain by heterogeneous isobarically cooled orthogneisses termed the Mary batholith. A transect across the batholith documents early, penetrative subhorizontal to gently dipping gneissic foliation S1. L1 coincides with garnet aggregates, elongate mafic enclaves, and core-and-mantle structure in feldspar porphyroclasts. Lineations are coaxial with hinges of isoclinally folded layering F1.
L1 is interpreted as a composite mineral lineation with intersection and stretching components. Kinematics are uniformly top-to-the-ESE. Metamorphic reactions accompanying D1 strain were synkinematic, with preferential nucleation of high-Ca garnet and amphibole in the Na-rich mantles of recrystallized plagioclase porphyroclasts.
Subhorizontal tectonites in the Mary batholith may represent an important field-based analog for lower crustal flow during orogenesis or large magnitude extension. The results illustrate the evolving strength of continental lower crust. Neoarchean subhorizontal flow of weak lower crust was followed by near-isobaric cooling and strengthening. Paleoproterozoic deformation events produced steep fabrics S2 , steeply dipping shear zones, and reactivation of S1, a record of strain localization and strain hardening in an isobarically cooled anisotropic medium.
The Chadormalu magnetite-apatite deposit in Bafq metallogenic province, Central Iran, is hosted in the late Precambrian-lower Cambrian volcano-sedimentary rocks with sodic, calcic, and potassic alterations characteristic of iron oxide copper-gold IOCG and iron oxide-apatite IOA ore systems. Apatite occurs as scattered irregular veinlets and disseminated grains, respectively, within and in the marginal parts of the main ore-body, as well as apatite-magnetite veins in altered wall rocks.
Our data suggest that hydrothermal magmatic fluids contributed to formation of the primary fluorapatite, and sodic and calcic alterations. The primary apatite reequilibrated with basinal brines in at least two regional extensions and basin developments in Silurian and Triassic in Central Iran. Introduction The formation of apatite-bearing iron deposits is a current topic of debate.
In addition to performing high quality micro-beam chemical analyses, the facility has pioneered within the country in the development of specialized protocols for U-Th-Pbtotal dating of geological events using monazite, uraninite, xenotime and produced trained manpower in using EPMA.
Monazite TS-Mnz is reddish brown with initial weight of The TS-Mnz in high-contrast BSE-imaging demonstrates homogeneous, clear domains, and domains including numerous inclusions. The TS-Mnz contains 4. Monazite ANK-Mnz is significantly larger, with an initial weight of g. The crystal reveals gem quality, crystal-clear domains up to several hundred microns-sized , homogeneous in high contrast BSE-imaging; and domains with inclusions.
The rim is porous, easy to be recognized and neglected for the standard. The ANK-Mnz contains 5. Monazite in nature is compositionally heterogeneous and commonly registers multiple geological processes that occasionally may affect its Th-U-Pb system.
Mineralogical, geochronological, and geochemical characterization of Early Devonian aquamarine-bearing dykes of the Zealand Station beryl and molybdenite deposit, west central New Brunswick Kristy-Lee Beal, a David R. Lentz, a Douglas C. Paper handled by associate editor Victor Owen Published on the web 28 June
EPMA Th-U-Pb dating of monazite for two samples of mozogranitic rocks from Yongji and Henglingguan intrusions in the Zhongtiao Precambrian complex reveal two peak age ranges of 1 Ma and 1 Ma.
Advanced Search Abstract Ages of detrital monazite and zircon from alluvium collected from the French Broad River drainage basin, an orogen-crossing main trunk river, and alluvium in first-order tributary streams, provide an unconventional perspective for examining the regional tectonic and metamorphic history of the southern Appalachian orogen eastern United States. The French Broad River system samples migmatitic Ashe—Tallulah Falls suite paragneisses with inferred Neoproterozoic clastic protoliths of the Eastern Blue Ridge and western Inner Piedmont, Mesoproterozoic basement orthogneisses, numerous Paleozoic metaplutonic gneisses, and tectonite equivalents of these lithologies in the Brevard fault zone.
Middle Ordovician ages dominate the monazite age spectrum. Monazite from tributaries has a dominant Pb Th age peak ca. Electron microprobe total Th-U-Pb chemical ages for selected tributary monazite grains also analyzed by ion microprobe reveal additional monazite growth events i. Tributary and French Broad River zircon age spectra are dominated by Mesoproterozoic and Ordovician grains.
Rare Neoproterozoic ages of — Ma and — Ma are present in all zircon data sets. Ordovician monazite ages and zircon rim ages correspond to Taconian metamorphism in the Eastern Blue Ridge province. The dominant monazite age mode Ma from tributaries is slightly older than the Ordovician metamorphic zircon age mode Ma , which is accounted for by monazite growth primarily via prograde metamorphic reactions, and zircon growth by melt-forming reactions in migmatites at the thermal peak.
The scattered middle to late Paleozoic zircon and monazite ages attest to the lack of significant thermotectonic and magmatic events of that age in the Southern Blue Ridge providing sediment to the French Broad River drainage system. This dearth of ages is consistent with the pattern of nonpenetrative late Paleozoic deformation, retrograde metamorphism, and scattered plutonism northwest of the Brevard fault zone.
A reasonable source of Neoproterozoic zircon in alluvium or in Ashe—Tallulah Falls paragneisses is Neoproterozoic rift-related magmatic rocks. The rarity of Mesoproterozoic monazite compared to zircon contrasts with the marked abundance of monazite in Ashe—Tallulah Falls paragneisses, and emphasizes the responsiveness of monazite compared to zircon in regional metamorphism.
Advanced Search Abstract The growth and dissolution behaviour of detrital, metamorphic and magmatic monazite and zircon during granulite-facies anatexis in pelitic and psammo-pelitic granulites and in garnetiferous granite from the southern margin of the Central Indian Tectonic Zone CITZ have been investigated using reconstructed metamorphic reaction history, monazite electron microprobe dating and sensitive high-resolution ion microprobe SHRIMP U—Pb zircon geochronology.
The meta-psammite additionally records two stages of granulite-facies recrystallization BM2 and BM3. Irrespective of variations in the bulk-rock compositions and peak metamorphic conditions, monazite is highly reactive during the BM1 event, producing complex, chemically zoned crystals. Textural, compositional and chemical ages of these grains indicate the stability of six compositional domains CD1 to CD6 in the paragenetic sequence , of which CD1 represents pre-metamorphic detrital cores of Paleoproterozoic age.
These zircon dates are correlated with the timing of the following: These chronological constraints from monazite and zircon, when integrated with the metamorphic reaction history and published geochronological data, allow recognition of three episodes of granulite-facies metamorphism in the CITZ at Ma pre-BM1 event , between and Ma BM1 event , and between and Ma combined BM2 and BM3 events , as part of a latest Paleoproterozoic to Early Mesoproterozoic orogenic event.
Comparison of EPMA correction procedures in CHIME dating, 19th General meeting of the International Mineralogical Association, , Poster Presentation. 5． Effect of gold caoting in quantitative EPMA: A MC study of monazite, International Symposium on Radiometric Dating Studies, , Oral Presentation. 6．.
Detail of the specifications of EPMA is as follows: Up to 10 uA Beam Stability: Up to 1 uA Beam Stability: Because the wavelengths of these X-rays are characteristic of the emitting species, the sample composition can be easily identified by recording WDS spectra Wavelength Dispersive Spectroscopy. WDS spectrometers are based on the Bragg’s law and use various moveable, shaped monocrystals as monochromators. EPMA is a fully qualitative and quantitative method of non-destructive elemental analysis of micron-sized volumes at the surface of materials, with sensitivity at the level of ppm.
It is the most precise and accurate micro-analysis technique available and all elements from B to U and above can be analyzed. EPMA is fully compatible with routine analysis sessions, with easy and direct interpretation of the results.