(U-Th)/He Dating of Phosphates: Apatite, Monazite, and Xenotime
Dating xenotime. May also offer opportunities for life? U-Pb dates are enriched in studying the xenotime—garnet relationships provide. Apr 25, andhra pradesh. Precambrian research — Nov 8, in carbonatite dykes at least when you.
Monazite geochronology (EPMA)
Petrology and Geodynamics. Neoproterozoic reworking of the Ubendian Belt crust: Implication for an orogenic cycle between the Tanzania Craton and Bangweulu Block during the assembly of Gondwana. Precambrian Research.
Monazite is a common accessory mineral occurring in a wide variety of rock types (sedimentary, metamorphic and magmatic), therefore allowing the dating of.
Email Address. Sign In. Heterogeneously developed retrograde shear zones S 3 are marked by widespread chloritization, but minor chlorite is present in the studied samples. Monazite is zoned, showing embayments and sharp boundaries between zones, with low Y in the staurolite zone, high-Y cores and low-Y rims in the kyanite zone, and high-Y cores, a low-Y mantle and a high-Y rim in the sillimanite zone. A systematic increase in heavy rare earth element HREE content with decreasing monazite age from to Ma is correlated with growth on the prograde P—T path; the drop in HREE of monazite at — Ma is assigned to recrystallization.
The presence of chlorite even in the least retrogressed samples witnesses limited external fluid availability on the retrograde P—T path. Migration of this fluid was probably responsible for heterogeneous fluid-assisted recrystallization and resetting of original prograde monazite, even where included in garnet, staurolite or kyanite.
Coupling of in-situ Sm-Nd systematics and U-Pb dating of monazite and allanite
Th-U-Pb dating of monazite from the Cretaceous uranium. Manuscript received December 1, ; accepted in revised form June 16, This rock was a protolith for stratiform U-Mo mineralization formed during the Late Permian by ground water. The quartz vein with uranium mineralization in Krompachy is accompanied by albite, rutile, sulphides, xenotime- Y and rare monazite- Ce. Monazite, a REE phosphate commonly occurs in acid mag- matic and metamorphic rocks.
This assumption forms the basis for electron microprobe dating of. monazite, as the method measures the total Pb, rather than each of the separate Pb.
The sample, an osumilite-bearing ultra-high-temperature granulite from Rogaland, Norway, is characterized by complexly patchy zoned monazite crystals. Three chemical domains are distinguished as 1 a sulphate-rich core 0. This study illustrates that it is possible to discriminate different generations of monazite based on their S contents. From the petrological context, we propose that sulphate-rich monazite reflects high-temperature Fe—sulphide breakdown under oxidizing conditions, coeval with biotite dehydration melting.
Monazite may therefore reveal the presence of S in anatectic melts from high-grade terrains at a specific point in time and date S mobilization from a reduced to an oxidized state. This property can be used to investigate the mineralization potential of a given geological event within a larger orogenic framework. This is a preview of subscription content, log in to check access. Rent this article via DeepDyve. J Phys Appl Phys Ore Geol Rev —
Electron Microprobe Dating of Monazite
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previous geologic conditions; (c) the expansion and refinement of techniques for analysis and dating of monazite, particularly in situ analysis;.
Toggle navigation. Have you forgotten your login? Tracing and dating of processes. Conference papers. Tiepolo Gilles Ruffet 2 J. Devidal 1 Details. Philippe Boulvais 2 AuthorId : Author. Pierre Gautier 2 AuthorId : Author. Tiepolo AuthorId : Author. Gilles Ruffet 2 AuthorId : Author. Hide details. However, age perturbations are sometimes documented in monazite grains showing distinct compositional and age domains.
The mechanism by which Pb is lost is not well understood.
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The same monazites selected for U–Th–Pb dating (below) were analysed in situ in polished thin sections for REE concentrations. Laser spots (
Economic Geology ; 3 : — The Jiaodong gold province, the largest gold producer in China, formed in a setting dominated by a m. This study presents new high precision in situ sensitive high-resolution ion microprobe SHRIMP U-Th-Pb and laser ablation-inductively coupled plasma-mass spectrometry LA-ICP-MS U-Pb ages for hydrothermal monazite from the largest of the Jiaodong gold deposits, which were previously dated as indicating ore formation over a few tens of millions of years when applying sericite Ar-Ar, zircon U-Pb, and less robust analytical techniques.
Our U-Pb dating on monazite from the Jiaojia and Linglong deposits in western Jiaodong yielded consistent ages at ca. In eastern Jiaodong, the much smaller resource may have formed about 5 m. The postsubduction opening of a slab gap at ca. The gap induced a local and rapid devolatilization of the hydrated mantle wedge at submelt temperatures. The transient event included release of a major volume of gold-transporting aqueous-carbonic fluid that was stored in the wedge into major NNE-trending structures in the overlying lithosphere.
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Electron microprobe monazite crystallization ages are presented for selected granite and metamorphic rock samples from the Socorro and Guaxupe Nappes.
The Granulite Terrane of southern India GTSI is believed to be a microcontinental block which was bounded to the west by Madagascar and East African and to the east by Sri Lanka and Antarctica before it collided with the Indian subcontinent during the amalgamation of Gondwana. The Terrane is divided into different crustal units based on the difference in their evolution history: 1 Salem Block 2 Madurai Block 3 Trivandrum Block 4 Nagercoil Block Santosh et al.
However interpretations from different studies are very controversial based on PCSS being the suture zone. Therefore, this study is wholly directed to a region in the eastern Madurai domain which lies west of Madurai city near the town Usilampatti. Previous geochronological study is done and yielded ages of Neoarchaean to Palaeoproterozoic crust formation age and Pan-African high-grade metamorphism. However, a detailed characterization of the high-grade metamorphism and correlation with metamorphic ages from the same rocks using in-situ dating techniques was lacking.
This is the first study for texturally-controlled in-situ monazite dating of a UHT metapelite from the EMD and we could establish three distinct stages of metamorphism. There is a correlation of the metamorphic textures and assemblage with the in-situ metamorphic ages to understand the metamorphic history. Therefore this study will help in redefining the UHT belt in this terrane. Petrology and in-situ monazite geochronology of ultra-high temperature granulites from the Eastern Madurai Domain, Granulite Terrane of Southern India.
More information and software credits. Login Create Account. Petrology and in-situ monazite geochronology of ultra-high temperature granulites from the Eastern Madurai Domain, Granulite Terrane of Southern India Kharkongor, Melissa Bok Kharmujai Petrology and in-situ monazite geochronology of ultra-high temperature granulites from the Eastern Madurai Domain, Granulite Terrane of Southern India.
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Fissure monazite-(Ce) along the western limit of the dome reports younger ages of 13–7 Ma. A younger age group around 8–5 Ma is limited to fissures and clefts.
Type Journal Article. Metadata Show full item record. Citation Fougerouse, D.
Sulphate incorporation in monazite lattice and dating the cycle of sulphur in metamorphic belts
Jercinovic University of Massachusetts. Assumption: No non-radiogenic lead in monazite or at least very little. If you can precisely measure U, Th, and Pb in ppm , you can solve this equation iteratively for lead to obtain an age.
In-situ monazite Th–U–total Pb dating and zircon LA–ICP–MS depth-profiling was applied to metasedimentary rocks from the Vaimok Len.
Symposium on Geol. Resources of Madagascar – A good example of the usefulness of the in-situ dating method. Madagascar displays a huge portion of the lower crust and its study is fundamental for the understanding of the evolution of this part of the crust. Unfortunately, our knowledge of this domain is limited. At this time, numerous works structural, geochemical, petrological are in progress in Madagascar, but there are only a few geochronological data.
In this context, the fast, non-expensive, reliable electron microprobe monazite dating method, using the Th-U-Pb system, is particularly efficient to obtain many ages see Montel et al. We applied this method in Madagascar. In the granulitic basement Southern Madagascar, three large areas can be distinguished, from East to West : the Androyan, the Bekily and the Vohibory blocks, separated by transcurrent shear zones : the Bongolava-Ranotsara, the Beraketa and the Ampanihy shear zones.
This geometry is interpreted as the result of crustal extrusion towards the S-SE of the South of the island during the Mozambican collision. Martelat et al.
E-mails: marapita1 yahoo. E-mails: mapabarros yahoo. E-mail: orestes.
Petrology and monazite dating of the Fe-rich gneisses from Kokava (Veporic Unit, Western Carpathians, Slovakia): Devonian sediments supplied from.