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The petrography of sandstones integrated with geochemistry is important to infer the provenance, paleoclimate, and tectonic setting. An integrated petrographic and geochemical study of the late Devonian sandstones, Shishtu Formation in central Iran was performed to determine the provenance, tectonic setting, and weathering history. These sandstones …
Kasper-Zubillaga et al.—Petrography of quartz grains, Northland 651 under the extensive kauri forests, which have existed for at least 50 000yr (Isaac 1996). Erosion of these soils during Holocene sea-level rise would have provided the source for the enriched quartzose content of the beach sands. The Mount
Petrography, fluid-inclusion, isotope, and trace-element constraints on the origin of quartz cementation and feldspar dissolution and the associated fluid evolution in arkosic sandstones ... (212°F–239°F) before oil filled the reservoirs. The Q2 quartz was mainly precipitated at 115°C–130°C (239°F–275°F), accompanying or slightly ...
The Oligocene Barail Sandstones of Surma basin from parts of Champhai District of Mizoram, northeast India has been studied for their tectono-provenance setting using petrography and geochemistry. The studied sandstones are poor to moderately sorted, subarkosic to sub-litharenite and show dominance of quartz (avg. 54.46%) …
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The volcanic stratigraphy and petrography of compositionally bimodal volcanic rocks in the Mekane Selam area were characterized by detailed field investigation, spatial and systematic sampling, and petrographic analysis. Three successions of basaltic rocks with rhyolitic and trachytic rock units at the top with a substantial volume of felsic …
1. Introduction. Cathodoluminescence (CL) imaging is a powerful tool in the petrographic study of mineral growth and deformation (e.g., Pagel et al., 2000), and it is often applied to identify the paragenetic setting and relative timing of fluid inclusions in quartz (Behr and Frentzel-Beyme, 1988, Boiron et al., 1992, Graupner et al., 2000, …
and petrography of Permo-Carboniferous sandstones from the Spiti region, Himachal Pradesh, India ... clastic grains dominated by variable amounts of quartz and feldspar accompanied by lithic fragments (mostly metasedimentary, sedimentary, and plutonic grains). ... a steel jaw crusher, and then powdered in an agate mill down to a grain size ...
Economic Geology | 119 | 3 | May 2024. On the cover: Geologic map of the Powell syncline and Powell fault and equal-area, lower-hemisphere stereonet projections of structural measurements from the Powell syncline. Â The geology and ore deposits of this region are described in the paper by Schofield et al. in this issue.
Apparently from the Saxon word querkluftertz, meaning cross-vein ore, which could easily have become condensed to querertz and then to quartz; the idea is supported by the old Cornish name for crystalline silica which means cross-course-spar; in any case the word is from German and of ancient derivation.
Petrography, fluid-inclusion, isotope, and trace-element constraints on the origin of quartz cementation and feldspar dissolution and the associated fluid evolution …
Petrography is one of a series of standard tests used to assess an aggregate's components, mechanical qualities, durability, chemical stability, and alkali reactivity. In this study, aggregate materials were collected …
Qualitative petrography provides important information about the nature and composition of the source area. The high proportion of quartz, along with the dominance of K-feldspar over more mechanically unstable plagioclase, points out to an igneous source.
Petrography is the description and systematic classification of rocks, mainly by the microscopic examination of thin sections. Introduction. Petrographic analysis …
Low grade siliceous manganese ores from the iron ore group of the Bonai-Keonjhar belt, Orissa, India are found mostly in shear zones. The ore characteristics of siliceous manganese ore samples from three different mines, viz. the Shankar (Barbil OMC lease hold area), the Sone-Patuli (Patmunda, OMM lease hold area), and the Musaghar …
The Mercara Shear Zone (MSZ) is an intensely deformed, curvilinear, mylonitised zone juxtaposed between the Western Dharwar Craton (WDC) and the Coorg Block (CB). In the vicinity of Madikeri …
In gold-bearing quartz samples, the concentrations of Cu, As, Ag, and Sb are positively correlated with Au at the degree of shear deformation. ... Field observation and petrography of alteration ...
The paste is nearly isotropic, with fine-grained quartz, biotite, and feldspar minerals. Figure 6.6. Polygranular quartz + K-feldspar (microcline) + mafic igneous rock fragments (right …
crushed with a steel jaw crusher and then powdered in an agate mill down to a grain size smaller than 200 mesh. Major oxides were determined by X-ray Fluorescence
Petrography of the quartz euhedra as a tool to provide indications on the geologic history of the Upper Triassic Burano Evaporites (Northern Apennines, Italy) @inproceedings{Lugli1996PetrographyOT, title={Petrography of the quartz euhedra as a tool to provide indications on the geologic history of the Upper Triassic Burano …
The ore petrography and chemistry of the tellurides from the alteration zone of the deposit have been studied in detail using optical microscopy, scanning electron microscopy, electron probe micro-beam and X-ray diffraction facilities. ... Discovered in the 1980s, the Dongping gold deposit is a mesothermal quartz vein and potassic alteration ...
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Cathodoluminescence (CL) petrography provides a unique capability for documenting physical and chemical diagenetic processes in sandstones, particularly those cemented by quartz. Mostdetrital quartz grains display relatively intense CL owing to lattice defects and trace cation inclusions inherited from crystalline source rocks.
Grain-replacive clay cements (kaolinite and illite) are also well developed. Silica cement occurs locally in the form of quartz overgrowth. Occurrence of a thin film-like iron cement, which separates the core from the overgrown rims of quartz, indicates that the iron oxide cement predates silica cement. Coal is present in some sandstones.
This shows a quartz-rich xenolith enclosed in a granitic porphyry. At the time the xenolith became trapped, the magma was undersaturated with respect to quartz. The quartz reacted with the magma to grow a rim of hornblende. Later, the magma became quartz-saturated and grew quartz and hornblende as distinct, separated crystals.
Cathodoluminescence (CL) petrography provides a unique capability for documenting physical and chemical diagenetic processes in sandstones, particularly …
Five schist samples from Igarra and Environs in Akoko Edo area of Southwestern Nigeria were obtained with the aim of determining their geochemical properties using XRF techniques and also for petrographic analysis. Results from the geochemical analysis revealed the presence of SiO2 (54.65-59.01wt.%), Al2O3 (21.98 …
Quartz (SiO 2) is the most abundant mineral in terrigenous sedimentary rocks and is exceedingly durable (surviving multiple generations of weathering and …
THE second volume of Prof. Johannsen's work on petrography is both a descriptive petrography of the quartz-bearing igneous rocks and an illustration of the author's proposed new method of ...
alteration of quartz within the upper impactite sequence of drill core LB-07A, recovered from the annular moat of the crater. These observations include the occurrence and general petrographic properties of shocked quartz within the sequence, the abundance and crystallographic orientations of planar microstructures in quartz based on
The Rb versus Nb + Y diagram (Pearce et al. 1984) was used to determine the tectonic Fig. 5 Representative photomicrographs of the studied rocks, mineral abbreviations used are according to Kretz (1983): a garnet …
Granite-related wolframite-quartz veins are the world's most important tungsten mineralization and production resource. Recent progress in revealing their hydrothermal processes has been greatly facilitated by the use of infrared microscopy and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis of …
Sample locations and melt inclusion petrography. ... Melt inclusions in quartz crystals from sample 1159 and 1160 were homogenised using conventional horizontal cold-seal pressure vessel technique (Fig. B.1). The vessel was pressurised with CO 2 to 3 kbar and moved into a tubular furnace. Different sections of the same sample were heated at …
The source rock provenance determines the sandstone composition. Petrography, the sandstone contains quartz, feldspar, micas (mainly biotite and muscovite).
In this work, petrography, major and trace elements data on fifteen relatively unknown banded and granitic gneiss plutons have been used to address the knowledge gaps in the area of provenance, petrogenetic evolution and tectonic setting, and hope it ... quartz schist an inter-banded in places with iron formations and (iv) syn- tectonic and ...