hornblende. North Tincroft Lode (New Cook's Kitchen Mine) forms a segment of an ENE-WSW-striking lode structure that can be traced for —2 km along strike and —800 m vertically through the Camborne-Redruth mining district. ..... 19 9: A) BSE images of the leucosome (16TG-143-5) … Monazite identification was facilitated by Ce X-ray mapping of full thin sections and by QEMSCAN mapping. We report here, for the first time, the occurrence of hydrothermal monazite and xenotime in alteration haloes associated with the gold-mineralized zones of the Hutti Gold Deposit in Karnataka, India. The first type appears as small to the monazite location in the thin section in order to evaluate the textural and zoning significance ..... 13 6: Schematic and yttrium x-ray map showing the three compositional zones and associated dates for a monazite grain in the restite.. ..... 17 7: Monazite date results from the restite layer..... 17 8: Restite monazite composition vs calculated date. Although this is a labor-intensive procedure compared to EMP dating, and still cannot be done on very small monazites, an X-ray … The thin sections have been observed using polarization microscopy and two different types of monazite were discovered. Monazite geochronology of one thin section revealed two distinct … This piece is from the same mine for which this material was discovered along the Contacto … Location of monazite in thin-sections is not easy under the optical microscope, because although all the high-relief accessory minerals are readily located, it is difficult to distinguish monazite from zircon or xenotime (Montel, 1993). Three lines of evidence from schists of the Great Smoky Mountains, NC, indicate that isogradic monazite growth occurred at the staurolite-in isograd at ̃600°C: (1) Monazite is virtually absent below the staurolite-in isograd, but is ubiquitous (several hundred grains per thin section) in staurolite- and kyanite-grade rocks. One of the two most important aspect of this work is that (1) monazite selection for isotopic analysis is based on the petrographical setting (i.e. In situ U–Pb dating of monazite and zircon within pet-rographic thin section by LA–MC–ICP-MS has been previously conducted[e.g.,Refs.10,11];however,inbothstudiesthegrains were ablated in ‘raster’ mode with typical sampling volumes of 80 m×18 m×5 m [10] or 60 m×60 m×15 m [11]. Having been deeply eroded during 2020 My of its history, it allows investigation of the impactites at the lowest levels of this large impact structure [1–5]. However, linking monazite U–Pb ages with the PT evolution of the rock is not always straightforward. Twenty-eight grains were mapped at high-spatial resolution (0.3--6.0 mum). Monazite cores are also distinguished by a Th/U ratio below 10, whereas the rims have Th/U of the order of 30–50 (see trace element section, below). However, granophyre (impact melt) dykes in such structures preserve clasts of supracrustal rocks, transported down from the uppermost levels of the initial structure. Monazite in Thin Section. The three minerals are monazite-(Ce), monazite-(La) and monazite-(Nd). Monazite is produced from heavy-mineral concentrates and then separated out by specific gravity, magnetic processes, and other processes. The same oper-ating conditions were used to generate all monazite maps and therefore relative concentrations of Ce, Th and Y are assessable between grains in the same sample and between samples. Colour change from reddish orange in daylight to pinkish brown in tungsten light … Occurrence: An accessory mineral in granites, syenites, and their pegmatites; in carbonatites and volcanoclastic rocks; in fissure veins and high-grade metamorphic rocks; commonly detrital in river and beach sands; rarely authigenic in shales and intense weathering zones. Detection and chemical mapping of monazite was conducted using the JEOL JXA8230 electron microprobe (EMP) at AGH University of Science and Technology (Kraków, Poland) with operating conditions of 100 nA, 15 kV and a dwell time of 100 ms. Monazite grains were … Thin sections were cut with a high-precision diamond saw or … Monazite at low grades Monazite at low grades is often embayed due to either irregularities in growth in different directions, or to 3a, b). Keck Foundation Center for Isotope Geochemistry at the University of California–Los Angeles. Monazite-(Ce) at Ritterpass is rarely such intensely orange coloured, but typically contains reddish flakes - 'Victory crystal group' sitting in 'boxwork' (dissolution cavity) of a large allanite-(Ce). Fergusonite and hingganite are identified in this massif for the first time. A catalogue of minerals & textures in thin section Ruth Siddall, University College London Minerals are listed in the order in which they appear in Deer, Howie & Zussman (1992). Talc in Thin Section. Consequently, concentrations of Ce, Th and Y in monazite are described below as ‘low’, ‘average’ and/or ‘high’. However, on the basis of the BSE information the 15 analyses from SGL5 monazite yielded … Andalusite in Thin Section. Ilmenite - FeTiO 3 Ilmenite is named after the locality of its discovery in the Il'menski Mountains, (Russia). been done on monazite grains, using polished thin sections, to determine the age and to inter­ pret them in conjunction with the textural rela­ tionship of minerals.