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Mineralogy - Science topic

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Questions related to Mineralogy
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What salts differ in the mineralogical composition of the soil in the prevention of primary or secondary salinization of the soil?
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The salts that differ in the mineralogical composition of the soil in the prevention of primary or secondary salinization of the soil are:
1. Calcium carbonate
2. Magnesium carbonate
3. Calcium sulphate
4. Magnesium sulphate
5. Potassium sulphate
6. Sodium sulphate
7. Potassium chloride
8. Sodium chloride
9. Calcium chloride
10. Magnesium chloride
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Minpet——( a software for Mineralogical and Petrological data processing system), it can run under the Windows system XP or Windows 7. However, it can't run under the circumstance of Windows 8.1. 
Does anyone have the lastest version?
Please contact with me, thank you!
My e-mail is xiegen@cugb.edu.cn.
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You can use Qmin for some EPMA data
Good luck!
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Dear Researchers,
I am working on a petrographic analysis, and I have a thin-section database, referred to partially metamorphic rocks such as meta-basalt, meta-andesite, meta-gabbro and so on.
In the thin-section results, I have got the percentage of several main minerals such as Quartz, Epidote, Feldspar, Chlorite and some other minerals which are significantly varying among samples from one to another. For example, Quartz is fluctuating between 0 and 59 percent in various samples.
In my research, I need to categorize the mineral percentages in three ranges: Low range, Middle range and High range. For example, when we say that there is a high quantity of Quartz in a metamorphosed rock, what exact percent we are dealing with?
I would appreciate if you could share your ideas about this question.
Best,
Behzad
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That is a strange question. As Ioan Pintea suggested, 100% is a high quartz value for a quartzite, but 59% is a high value for your meta-basic rocks, but 59% might be a low value for a quartzite. The categories low, medium and high will be different for each different rock. You need to understand the purpose for making these categories. Is there any purpose? If not, why are you doing it?
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I noticed that there was some sandstone interval contains some considerable amount of Siderite. I know that this is diagenetic. Could we attribute some specific depositional environment to these sandstones with some initial specific mineralogical &/or chemical composition that led to the transformation to siderite in time. ???
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The best known Fe carbonate is siderite (the stochiometric Fe content
is 48.2% Fe). This amount will rarely be attained in an ore deposit because
Fe carbonates tend to have a wide range of substitution of Mn, Mg, Ca for
bivalent Fe. Spherosiderite is microcrystalline siderite found in claystones
and coaly sandstones associated with coal seams (claybands and
blackbands). Ankerite (26% Fe) is ferroan dolomite which forms part of vein and replacement deposits, but occurs seldom in the above strongly reducing environments.
There exist a classical transformation with increasing Eh: Vivianite (blue iron Fe phosphate) – siderite (white iron) -goethite (brown iron ore). In SEDEX deposits there exists a facies differentiation dependent
mainly on the Eh and pH conditions occurring within the basin changing from calcareous hematite, magnetite, siderite to siliceous Fe ore or even pyrite (melnikovite) ore.
One should keep always in mind whether it is true sedimentary environment like the clay- and black bands which reflect lacustrine, paludal (swamp) or marsh-like (paralic) environments or a volcanic or hydrothermal influence is identified. In the latter case the situation may be a bit more complicated.
HGD
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Spectroscopy is said be easier and cheaper for soil chemical property analysis. how well does it perform in mineralogical studies? also how well does the data set calibration and validation tests yields any relevant results through machine learning and artificial neural network in this field?
I basically belong to non programming background, I do know moderate application of R-Studio in PLRS and basic training set and validation set preparation.
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To date, it is highly recognized the association between alkaline/calc-alkaline potassic rocks and gold and copper-gold deposits (Muller & Grooves, 2016; Muller, 2001; Jensen & Barton, 2001). Although not yet perfectly clear in some. I am now focusing on the Roman Magmatic Province (Italy), and I was wondering why, although in some districts (especially Sabatini and Vulsini) the whole rock composition and partially the mineralogy resemble those of some high-k rocks of gold-related deposits (Cripple Creek, for instance, where phonotephrites crop out ), this Magmatic Province didn't develop any precious metal mineralization. Obviously, whole-rock and mineralogical characteristics do not define the chance to develop or not a deposit, but they make comparable these rocks with other ones associated to dep worldwide.
I reach out just to open a discussion about this topic because I think it is very interesting and might lead to distinguishing, in some cases, the limit of the accepted model.
Food for thought! :)
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The images above are from "sun et al." Mine are not so pretty. Same process I believe.
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I am trying to find out XRD (Phases present) with Match3 software from XRD data of sand powder, but whenever quartz sands are nearly pure, these two phases are also shown to be present. Is it due to their XRD patterns being very close, or is it due to material contamination?
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Berlinite has a crystal structure which resembles the one of a-quartz (formally replacing one Si by 1/2 Al and 1/2 P). As the lattice parameters of both phases are very similar as well, berlinite always appears when you have quartz and allow Al and P in your search/match routine.
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These two images are 1.15 mm wide. Both types of magnetic particles have been extracted from river sand- the rounded ones from construction sites and more irregular ones from dried-up riverbeds. The rounded-grained samples have been subject to mechanical smoothing action pre- and post-extraction, while more irregular-shaped magnetic particles have not undergone any severe mechanical erosion. Both sand samples are need not be chemically the same. The rounded magnetic particle samples are likely to be magnetite as they are strongly magnetic. But the more irregular-shaped grains are weakly but certainly magnetic. What they can be - chromite, ilmenite, zircon, garnet, amphibole, pyroxene, or any other mineral?
Even if the exact mineral name cannot be said, can the mineral family be identified by observing its fracture and cleavage?
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You have two options to use, field or laboratory methods.
In the field there are only handmagnets (Type Wilke) for different field strength values with adjustible working distances (for separation of Fe oxides, Fe-(Mg) silicates) , etching with HCl and and alkaline solutions such as (KOH) mainly for alteration zones and a couple of pycnometer and balance to determine the specific gravity of minerals which covers a rather wide range. These field method which needs some experience are good for grouping of mineral groups (ferromagnetic-diamagnetic..), solubilities and density. I have a so-called "Emergency kit for applied geosciences" which contains all these items and more, e.g., (hand) lenses of larger magnification Moh´s hardness set, UV lamp, diamond tester (useful also for topaz, corundum varieties etc,). I have built up the kit over a long period of time along with increasing practical experience gathered in the field mainly for heavy mineral exploration and soft rocks.
It may be enough for exploration but it is insufficient for a precise identification which can only been done in the lab using polished sections - see Dr. Grundmann´s suggestions-, XRD, SEM-EDX/WDX, and EMPA.
HGD
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NASICON's and their common analogues use Na, K,Li or other alkali metals, Si, P and some other relatively common metals like Al, Ti, (Fe?) etc. NASICONs are with the formula Na1+xZr2SixP3-xO12with 0<x<3 . NA, Zr, Si are replaceable with isovalent elements and beyond. For example, LiTi2(PO4)3 is also considered a NASICON analogue, so is Li1+xAlxTi2-x(PO4)3. Both Sol-gel and Ball-milling then sintering techniques an be used for NASICONs.
While there are many common minerals like ZIrconia or Moissanite that shows fast ion conductivity, they act at quite high temperature. Silica is extremely common mineral, so is alumina, and apatites are quite common in sedimentary as well as some igneous environment. While complex silicates like Zeolites can exist in nature, why not NASICONs or their some sort of analogues? Does all of them react with moisture and Carbon dioxide relatively rapidly in geological scale? If they do exist, then what kind of geological environment would be conducive to their existence?
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I work as a mineralogist and I am not a specialist in NASICON phases, but the reason that these substances have not yet been found in nature will most likely be the strong hydrating ability and oxygen affinity of Ti and Zr. In even slightly hydrothermal environment there is anatase, resp. zircon (resp. hydrated zircon phases, gelzircon etc.) strongly stable. It is necessary to assess under what conditions, from which input components NASICON are synthesized and whether it is at least a little realistic for a similar synthesis to take place in nature. However, some Zr and Ti phases with PO4 or SiO2 have been found in nature. It is possible to use the search at: https://www.mindat.org/chemsearch.php
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I am currently working on XRD results composite materials which need to be analyzed for mineralogical compositions
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Origin pro 8.5.1
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I found quite huge idiomorphic apatite crystals (up to 0,5 mm) in the Anisian shallow water limestones and they look pretty much like porphyroblasts with pressure shadows. Limestones are highly recrystallized with mylonitic texture.
Whether an increase in temperature can cause the growth of apatites from phosphorus rich limestones?
What is the origin of phosphorus?
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Francolite synonymous with carbonate fluorapatite or
called collophane when microcrystalline
is the principal component of many sedimentary
phosphate rocks (“phosphorite”). Brushite (41.24 wt.% P2O5 ) and
monetite (52.16 wt.% P2O5) are only widespread in guano deposits,
where locally rather exotic phosphate minerals accommodating N, O
and H bridge the gap between organo-mineralic chemical compounds
and inorganic chemical compounds (coastal region in Chile). They can be the source of your apatite when recrystallized.
Marine upwelling along the shelf edge is responsible for the formation of carbonate-hosted phosphates and phosphorites. Some phosphorites accumulated within high energy — nearshore zones. Some formed in the outer shelf deposits. The common minerals besides francolite are smectite, illite, opal, sepiolite, clinoptilolite, quartz , siderite, smectite and palygorskite.
When they undergo physical-chemical alteration, e.g., an increase in T apatite may recrystallize and form XX of different X shape from elongated to stubby XX (pisms). You should investigate your apatite s.s.s. and determine how much carbon dioxide, F , Cl and OH is still in the XX. The OH- and CO3- anion complex should decrease along with increasing T. Also have a look at the minerals associated with the phosphate. The minerals mentioned above only occur in diagenetically overprinted phosphate-bearing limestones.
There are many phosphate deposits hosted by calcareous rocks.
See: DILL, H.G. and KANTOR, W. (1997) Depositional environment, chemical facies and a tentative classification of some selected phosphate accumulations.- Geologisches Jahrbuch, D 105: 3-43.
HGD
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Microscopic examination of a sample of low cretaceous igneous rock (alkaline bazaltoid or monchiquite?) revealed this foaming in the older generation of apatite (see photo). The central parts of apatite crystals are highly crowded with gas-liquid inclusions, the surfaces of crystals, just as younger generations are without them. Do you happen to know what that indicates? My timid guess is that it could be the release and decay of a supercritical fluid during crystallization, perhaps. I can't find anything like that in the literature.
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I have not seen yet it but it is too interesting case
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Can we judge the crystallization sequence by the degree of euhedral of different minerals? For example, if plagioclase phenocryst is more euhedral than pyroxene, can we say surely that the plagioclase began to crystallize before pyroxene? Is it certain that the earlier the crystallization of phenocryst minerals, the more euhedral?
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Hello,
Tracking success relationships can be difficult. In general, it is probably true that successively older minerals have a higher degree of restriction than younger ones, but there are many complications. For example, cases of crystal melting are known from igneous rocks. Then it is necessary to pay attention to possible pseudomorphic transformations and to the presence of several generations of the same mineral. In addition to the degree of idiomorphy, it is necessary to monitor which mineral is overgrown by which mineral.
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A free Simple windows based computer program software for XRD data interpretation with a complete mineral peak library ?
please let me inform about same programs.
Thanks so much every body.
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With Mac Diff I visualize and interpret diffractograms applied to clay mineralogy and crystalline substances.
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Is there any software or excel sheet to calculate the mineral proportions (modal % of minerals) based on bulk-rock analysis. Your kind help is highly appreciated.
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You can use the GCDkit software for normative calculations (no modal % of minerals). You can download it free. It works under the R program and you can use an excel file. It is very easy to use.
Good luck
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Is it recommended for granitoids?
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Biotite as a petrogenetic discriminator: Chemical insights from igneous, meta-igneous and meta-sedimentary rocks in Iran
DOI: 10.1016/j.lithos.2021.106016
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How can we distinguish a Charnockite and a Pyroxene granulites mineralogically?
what are the protoliths of both?
as Charnockite is Hypersthene bearing granulite, is it considered as a pyroxene granulite?
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The major difference between these rocks is their nature, charnockites are igneous while granulites are metamorphic. Le Maitre (1989, 2002); Frost and Frost (2008) and Fettes and Desmons, (2007) consider charnockite as being orthopyroxene-bearing granitoids (sensu lato). Furthermore, Frost and Frost (2008) suggested use of the term charnockite only to igneous rocks, since metamorphic rocks with quartz, feldspar and orthopyroxene already known as granulites.
Usually, granulite's texture is granoblastic and present metamorphic reactions compatible with high metamorphic phases (i.g. granulite). While charnockites have a preserved igneous texture, and very commonly show hydration parageneses caused by magmatic fluids in the late magmatic stages (deuteric alteration). We can also use combined techniques, such as geological background, petrography, mineral chemistry and isotopic data to help distinguish between these two types of rocks.
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I read contradicting reports on Great Salt Lake ooids: Were/are these ooids originally aragonitic or calcitic? Could you cite any relevant and trusted bibliographic reference!?...
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Here is an interesting paper (with color photographs) in Facies 1997:
"Organic matter in Great Salt Lake ooids (Utah, USA) - First approach to a formation via organic matrices" @Gernot Arp and colleagues
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I need to calculate solubility constants for some minerals, I intend to use them for geochemical modeling. I've searched for these contants in EQ3/6, Thermoddem and SUPRCTBL, however some minerals are missing on the databases, for example Andesine, which is one of the key minerals on my simulation.
I have seen that in some papers, the the log K values are derived using SUPCRT or EQ3/6. The authors use the mineralogical characterization (from microprobe data for example) and theoretical formulas, either using a solid solution approach or directly, however the detailed methodologies are not explained. The available information in this regard is also scarce. I am able to calculate log K values for defined minerals (in the databases) in SUPRCTBL but I do not know how to calculate the values for new minerals.
Any advice in this regard is warmly received, bibliography, tutorial......
Thanks in advance.
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Hi! I'm an alumni of the GEOPIG group at ASU and might have some useful info for your search. The database in the SUPCRT92 url posted cannot be edited and also has the drawback of occasionally spitting back the wrong output if other users happen to be running a calculation at the same time (it's not super common, but it can happen).
One suggestion I would make is to use CHNOSZ, the R-package tool developed by Dr. Jeff Dick.
If you can find the thermodynamic properties for your minerals of interest, you can include them during your session (imported as a CSV file) while running CHNOSZ and then perform a SUPCRT92 calculation. You will need to find literature that lists the thermodynamic properties for your minerals of interest so that they can be estimated by the HKF equation used in SUPCRT. I've helped Jeff run workshops on CHNOSZ and am planning to create modules from those materials at some point, but the progress is slow for now. He has included very thorough documentation through the website above though, so you should be able to find the info.
Also, the GEOPIG group are starting a series of workshops on using various thermodynamic tools and databases. Again, that will take a little time, but it is in development.
In addition, there are ways to use these tools through the ENKI portal.
The ENKI project allows easier access to a variety of different database tools through a JUPYTER notebook interface, so if you know python, that is another place you should check out.
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Hi, everyone.
I'm looking for a paper of Kuzel in 1969 entitled "Über die orientierte Entwässerung von Tricalciumaluminathexahydrat 3CaO⋅Al2O3⋅6H2O", published in Neues Jahrbuch für Mineralogie - Monatshefte.
Many authors cite this work, and I need it to check some information, but I can't find the full-text on the journal webpage or anywhere.
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Dear Dr. Pacheco,
contact my colleague Prof. Dr. Dr. Herbert Poellmann from Halle University / Germany. You will find his E-mail address under Institut für Geowissenschaften & Geographie FG Mineralogie/Geochemie in the Internet (HERBERT.POELLMANN@GEO.UNI-HALLE.DE). He is a scholar of the late Prof. Kuzel at Erlangen University. He should be the prime source for his papers and more on cement research. Give him best regards from Harald. I guess you can write in Portuguese because of his close cooperation with Belem University (?).
H.G.Dill
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There are numerous databases for geochemical analyses for rocks like georoc and the National Geochemical Database of the USGS or purely mineralogical databases like mineralienatlas, mindat or webmineral. But is there a database for quantification of minerals in rocks?
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To sum up:
The recommendations of Guenter Grundmann , Harald G. Dill and Patricia Roeser provide the best results for my question.
The British Geological Survey shares its deposites data on their homepage:
If you want to search for the quantitative mineralogical composition of rock use the phrase "X-ray Diffraction" in the text search and the rock you search for.
In the pangaea-data warehouse the mineral composition of rocks are sourced from publications. The search for locations is also possible. The raw data can be downloaded or can be viewed as html.
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Suppose one needs to find out room-temperature stable silicates chemical composition of a particular cation, suppose magnesium. Is there any rule to estimate which stoichiometric values of metal oxide: silica ratio would stabilize the binary silicate at room temperature? (i.e. in this example, how would I find out only Forsterite and Enstatite are of stable ratio, without empirically studying MgO-SiO2 phase diagram?)
At a first glance, the ratio seems to be consisting of any possible prime(and 1) numbers. Since its crystal structure is not known, Pauling's Rules also cannot be applied step-by-step to find out where silica tetrahedra are sharing corners, edges or faces.
Theoretical Computational and numerical simulation of phase diagram obviously can find out the stable ratios, but this is not what I ask for. I ask for tolerably simple chemistry rules like those provided by Hume-Rothery, Pauling or Goldschmidt, understandable with freshmen/sophomore chemistry/materials science/mineralogy knowledge.
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Dear Frank T. Edelmann
It is sad, but it is true. Your valuable suggestion was not recommended. In contradistinction, the banal response -- Good question --- got one recommendation. I have already seen that such a banal and unjustified response gets 7 or more recommendations. It is happened to me on several occasions Someone says that my post brings very good points. This someone gets 7 or more recommendations, whereas my post gets none. There will be "recommendation teams" ? To put things right, in name of justice and intellectual probity, I decided to recommended your post, not because of you, but because of what it contains.
Could you please not to recommend this my post?
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Can someone suggest me a software or method for easily plotting compositional data (especially from chromite) in the spinel prism? I would like to show the raw material and its chemical evolution in this type of plot.
Thank you so much in advance!
ORL
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This article popped up on my ResearchGate feed some time ago, I will take a look at it the next time I will plot Cr-spinel.
Antonini, A. S., Ganuza, M. L., Ferracutti, G., Gargiulo, M. F., Matković, K., Gröller, E., ... & Castro, S. M. (2020). Spinel web: an interactive web application for visualizing the chemical composition of spinel group minerals. Earth Science Informatics, 1-8.
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Anyone knowing metamorphic geology would know the sequence of mudrock to gneiss transformation and its intermediate steps, including mica formation and growth (slate, phyllite, schist) and breakdown (gneiss) as metamorphic change intensifies. One may also refer to any standard petrogenetic grid to locate P-T curve for that transformation, since composition of gneiss lighter bands (plagioclase,...) and darker bands (pyroxene, amphibole...) are also commonly known. My questions are-
  • Mica being phyllosilicates with layered structure, gain what kind of free-energy lowering advantage by growing normal to direction of maximum compression instead of being growing, say, in scattered or parallel to maximum compression direction? what are the chemical factors that affect the layer spacing?
  • Similar question for generation of lamellar lighter and darker bands in Gneiss by decomposition of mica into feldspar and mafics (why layer instead of scattered blobs?). Why the free energy (magnitude and hence stability) of phyllosilicates drop at higher P/T and what is the molecular-level mechanism of this exsolution? how this transformation is different from and similar to eutectoid phase transition seen in metals? What are the factors that affect spacing of the layers (quantitatively?)
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If heterogeneities existed in the protolith, tectonic transposition can be a major factor. e.g.
Myers, J., 1978. Formation of banded gneisses by deformation of igneous rocks. Precambrian Res. 6, 43–64. doi:10.1016/0301-9268(78)90054-2.
And illustration in
Ramsay, J.G., Graham, R.H., 1970. Strain variation in shear belt. Can. J. Earth Sci. 7, 786–813. doi:10.1139/e70-078.
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I have come through a few literature,were the presence of particular clay mineral has been validated through the Si:Al ratio obtained from EDAX analysis. But, I would like to understand the basic principle behind these classification based on Si:Al ratio. Is there any article that explicitly talks about such classification?
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It is a crude method, but it works. Try and use an EXCEL spreadsheet, take your atomic weight contents form SEM/EDX of O, Si, Na, K, Al, Mg, and Fe (can be supplemented). Calculate some element ratios such as O/Si, Si/Al, Si(Fe+Mg+(Ca)), Na/Al, K/Al and normalize them to an ideal kaolinite, biotite, muscovite etc. by means of the “data sorting” command and you will obtain some kind of a “best fit”. It will not be suitable if you want to publish your data in “Clay minerals” or anything like that but to get an idea of the predominating clay mineral in a sandstone or any other sediments it works. Complex chlorite and smectite s.s.s. are hard to distinguish as it is the case with mixed-layers. But it is better than nothing. It is a geologist´s if you have no access to XRD.
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EPMA analysis
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Here, I think the degree of alteration, contamination and/or the oxidation has major impact on the obtained percentage.
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  • for example: if you consider the d-spacing of plagioclase's main peak in XRD which is at the d-spacing value 4.02, is it possible that this value may be reported as 4.021 or 4.0222, 4.017 (possible to round off to 4.02 in all three cases) as reported by an XRD analysis software (using Highscore)
  • Please find attached my XRD file (refer to T1 sample) where I am trying to calculate the semi-quantity of each mineral using "height of main peak=count of mineral".
  • To calculate the ''count" of each mineral, I need to choose the correct d-spacing for each mineral in my data according to the literature's suggested d-spacing (using handbook of mineralogy)
  • Question: but the problem is I am NOT sure which d-spacing value fits which mineral in my data because it is not the EXACT d-spacing value as in literature, so how do I choose the correct one?
  • Note: my data is sulphide copper tailings XRD
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One thing that quickly came to my attention is that you suspect you've found various sulphate and sulphide minerals, but you haven't analysed for S by XRF. If you've got the actual XRF spectra, have a look at them and see what you can mae of them: remember that WD-XRF gives better dispersion for low-energy lines (light elements), while ED-XRF gives better dispersion for high-energy lines (heavy elements). Also remember that peak identification software is rarely infallible when there are overlaps and/or relatively unusual elements.
I'm curious about your possible identification of bassanite. This is not the form of calcium sulphate I would expect to see: bassanite is better know as Plaster of Paris, so it picks up water and converts to Gypsum quite easily. If you've dried your sample at a little over 100 °C this could explain how you've produced bassanite, always assuming that it hasn't had a chance to regain its water of crystallisation from the atmosphere.
Good luck!
David
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I am in search of the minerals that have magnetic susceptibility and also minerals that show response to electrical conductivity... Will be so nice if someone can guide me in this regard as to search minerals one by one take time.
Thanking you in anticipation
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Dear Mr. Saeed,
from the succeeding tripartite subdivsion you will see that apart from the ferrimagnetic minerals it makes not very much sense to list all diamagnetic minerals.
The majority of minerals which do not accommodate iron in their lattice are diamagnetic yielding a negative moderate susceptibility, e.g., calcite and quartz. By contrast, Fe-bearing paramagnetic minerals give a positive read-out. Siderite, ankerite and some Fe-bearing phyllosilicates pertain to these minerals. Only a fraction of these minerals are ferrimagnetic, the most well-known of which are magnetite [Fe3O4], maghemite [γ-Fe2O3], ferroxyhyte [δ-FeOOH] and pyrrhotite [Fe7S8] which can also appear in sedimentary rocks. Another group of Fe-bearing minerals also quite common to sedimentary rocks differ from the afore-mentioned oxidic Fe minerals by their antiferromagnetic order such as hematite [α-Fe2O3], ilmenite [FeTiO3] and goethite [α-FeOOH].
I have been involved as economic geologist and mineralogist in IP studies and according to my knowledge and experience, there are multifacted properties which impact on the electric field, e.g., grain size, grain moprhology, grain orientation, alignment together with matrix graphite, porosity, grain distribution (massiver vs. disseminated) etc............. I hardly can imagine that such a simple list of minerals exists. It would contradict any experience.
Judging from you other thread I suspect of using ot for placer-type deposits.
In this case I would suggest to pass through case histories described by exploration geophysicists who deal with this type sedimentary deposits.
With kind regards
H.G.Dill
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1:1 mineralogy is easily dispersed under saturated conditions. Is by add organic matter/amendment can stabilize these soil and increase soil bearing
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J. C. Tarafdar yes but from paper 20-30% organic adequate for increase the aggregate but how it works in saturated water. the presence of water may disperse the aggregate soil due to the present H
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During a drillcore logging exercise, not long ago, I noticed how much confusion still exists regarding the use of the term "lamprophyre". This term tends to be somewhat overused in the mining and exploration industry and some mine geologists, including very senior ones, like to call almost every mafic dyke intersecting their deposit a "lamprophyre". This encouraged me to show some characteristic lamprophyre samples here (please see attached):
(1) The first image shows an amphibole-phyric shoshonitic lamprophyre under the polarisation microscope (crossed nicols). Please note the lack of free quartz in this rock and that the feldspars (mainly plagioclase in this case) are restricted to the groundmass.
(2) The second image shows a phlogopite-phyric alkaline lamprophyre with quenched margin at the lithological contact with a metasediment (under crossed nicols).
Lamprophyres are typically porphyritic, but only containing mafic phenocrysts, no free quartz, and their feldspars are generally restricted to the groundmass.
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Dear Rameshchandra Phani: You asked for a photomicrograph of carbonate ocelli in a lamprophyre, here I attach some, and also panoramic views of the whole rock, and inversely zoned hornblende, all from the lamprophyres of Paraguaná Peninsula. Regards, Sebastián.
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Geochemically and mineralogically, the studied granite shares all the characteristics of A-type granites but they contain inherited zircons. The Ti-in-zircon temperature of the granite is from 664 to 770 oC. Could you please share your experience on this question?
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Pre-magmatic zircons, including zircon cores, could either be inheited from the source region of the host igneous rocks (inherited zircon), or captured from the wall rocks during magma ascent (xenocrystic zircon). If you are sure the pre-magmatic zircons from your A-type granite sample are inherited zircons, I would suggest the possiblity of fractionated S- or I-type granite of your sample, considering the not very high Ti-in-zircon temperature.
To my knowledge, it's very hard to determine if a pre-magmatic zircon belongs to inherited or xenocrystic zircon, especially for a felsic igneous host rock sample.
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I am planning to work on the mineralogy of the rock and lateritic soil samples of the Bingo carbonatite complex in order to determine its REE-bearing minerals and determine its REE prospectivity. I would like to know which method I should use to get reliable results. Thanks for your answers.
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Dear Mr. Kasay:
I can offer you a flow sheet to obtain mineralogical results from a combination of mineralogical and chemical analyses
1. Check your bulk samples with a gamma scintillation counter to see if Th or U minerals are to be expected
2. A rock chip is used for thin section examination of the regolith, lateritic crust…. for textural and mineralogical analysis
3. Bulk chemical analysis of the rock sample using XRF (LREE are normally obtained at a reliable level). For more detailed analysis you need e.g. neutron activation….
3. Part of the grinded material used for preparation of samples for XRF is shipped to a laboratory
for screening and to split into the particle range < 63 µm and 63 µm to 300µm.
4. The interval < 63 µm is suitable for XRD (in case of detailed clay mineral analysis the use of settling tubes is recommended)
5. The grain size interval 63 µm to 300µm forms the basis of the separation of heavy minerals and for further investigation see point 6
6. The fraction separated under point 5 can be used for XRD (Rietveld), EMPA, SEM-EDX (+MLA) or (micro) Raman analysis of accessory minerals as they are common in the regolith on top of carbonatites
All data can be plotted into triplots and x-y plots for mineralogical and chemical discrimination.
Dependent upon the availability you can stop and leave this sequence at any point.
Do not expect one method alone as the philosopher´s stone but only the reasonable mixture of techniques will bring you success.
I wish you much success H.G.Dill
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Hi everyone, please, anyone can help me in a issue about the physicochemical stability of the silica? Actualy, I have cryptocrystalline silica veinlets cross cutting some supergene manganese minerals (eg., pyrolusite). So, is possible to precipitate silica under surface conditions?
All the best and stay safe guys!
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Dear Mr. Santos:
It is possible to precipitate silica in nature over the entire pH range and Eh around 0. This is also valid for cryptocrystalline chemical compounds which may uptake U or Cu and subsequently turn into uranyl-silica minerals such as uranophane or chrysocolla, respectively. I studied and dated these silicacretes/ silcretes also in context with Mn, where cryptomelane offers a possibility for chronological constraints.
DILL, H.G. and WEMMER, K. (2012) Origin and K/Ar age of cryptomelane-bearing Sn placers on silcretes, SE Germany.- Sedimentary Geology, 275/276: 70-78.
DILL, H.G., GERDES, A. and WEBER, B. (2010) Age and mineralogy of supergene uranium minerals - tools to unravel geomorphological and palaeohydrological processes in granitic terrains (Bohemian Massif, SE Germany).- Geomorphology, 117: 44-65.
DILL, H.G., WEBER, B. and BOTZ, R. (2013) Metalliferous duricrusts (“orecretes”) - markers of weathering: A mineralogical and climatic-geomorphological approach to supergene Pb-Zn-Cu-Sb-P mineralization on different parent materials.- Neues Jahrbuch für Mineralogie Abhandlungen, 190: 123-195.
DILL, H.G., PÖLLMANN, H. and TECHMER, A. (2013) 500 Million years of rift- and unconformity-related Mn mineralization in the Middle East: A geodynamic and sequence stratigraphical approach to the recycling of Mn.- Ore Geology Review 53: 112-133.
All papers are available for download from the RG server
Kind regards H.G.Dill
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Ladies and gentlemen, I have a favor to ask of you. If you've collected beautiful and back-corrected EBSD patterns of preferably non-cubic phases... could you send them to me along with the information about the projection center (pattern center + detector distance)? If this information is not available, it doesn't matter... It would also be nice to know the diffracting phase, but even that is not necessary if the pattern looks good. The resolution should not be lower than 400x300 pixels. In any case, it doesn't necessarily have to be high resolution patterns. The image format is irrelevant. I want use the patterns for tests regarding crystal lattice description (approximate lattice parameters and crystal symmetry). If I should use the patterns later in publications you can be sure that I will refer to you. Thanks in advance!
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Hi Mehran, actually not since they cannot be processed as three-dimensionally periodic.crystals. I am more intested in mineralogical samples which contain numerous phases so that people should have access to patterns of many different phases.
Which symmetry does the quasicrystal have?
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Charnockite is an opx (usually hypersthene), quartz and feldspar bearing meta-igneous rock, mostly acidic in composition, and metamorphosed under granulite facies conditions. It is commonly found in Gondwana fragments such as in Sri Lanka and India. One of the key characteristic features of chranockite is that minerals of feldspar and quartz in the rock have a greenish appearance. Is there any scientific explanation for the cause of this colour?
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I just discovered this debate and was intrigued by your observation Craig, recalling that HCl treatment of Arendal charnockites caused them to turn grey (reported by the late Dennis Field in one of his papers). I think the green colour is related to deposits from a fluid along grain boundaries, being unrelated to the high grade assemblage. These rocks frequently form with beta-quartz, which upon cooling into alpha qz shrink a bit, making space for minor deposit, and I think some workers have shown that they are the cause of the ‘coloration malgachitique’. Perhaps it is possible to restore in some cases a sort of charnockite colour by chemical weathering where similar components are present? at least rational arguments should not overrule a good observation. In geology observation is always the first step!
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The order of crystal lization within a magmatic series allows us to deduce mineralogical evolution and also the initial composition of the magmatic fluid. Within plutonic rocks, this method is relatively easy where we based on the relationships between minerals. However, in pyroclastic rocks, the procedure is more complicated where minerals are broken. My question is, how can I deduce crystallization order within pyroclastic rocks?
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You got good suggestions from Guenter Grundmann and the Great Harald G. Dill.
You may also go through: DA Jerram et al., 2018. Petrogenesis of Magmatic Systems: Using Igneous Textures to Understand Magmatic Processes. Chapter 8 in: Steffi Burchardt (Ed), Volcanic and Igneous Plumbing Systems--Elsevier.
All best for 2020
Qasim
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I am a materials science (and metallurgy) student and geology enthusiast. Comparing these two subjects side by side, I have found out some interesting pattern.
Ironmaking slag has 40-45% CaO, 30-40% SiO2 , 10-15% Al2O3 , about 5% MgO and 1-2% FeO. Steelmaking slag can have 40-60% CaO, 10-25% SiO2, 2-10% MgO, 5-35% FeO and 0-25% P2O5.
Ironmaking slag can have, among many other minerals, Akermanite, Monticellite, Gehlenite ,Anorthite, Pyroxene etc, along with some spinels. In my opinion , it matches with some feldspathoids with slightly mafic character. Steelmaking slag is more close to alkaline earth mafic rocks and peridotites. It has a good amount of spinels, monticellite, merwinite, silicocarnite, periclase etc.
Answers from metallurgists and Geologists are welcome
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Dear Mr. Bhowmick,
Slags are artificial products representing Fe ore which is made up of the Fe ore mineral and a wide range of gangue from carbonate to silicate minerals (rock) and the slag-producing additives e.g. limestone. The entire process in blast furnace takes place at low pressure and high temperatures. As a consequence of that the natural analogue is a combination of rocks forming at high T and low P which is the mafic volcanic clan (different types of basalt, see e.g. the major mineraloids in slags are Fe-enriched olivine s.s.s., pyroxenoids, wuestite and native elements plus Ca-Mg components). As far as the metamorphic part is concerned the natural equivalent well presenting these conditions is the so-called sanidinite hornfels facies (contact metamorphic reactions of carbonates at low pressure and very high temperature). These processes result in the formation of monticellite, akermanite, melilite, tilleyite, spurrite , rankinite , merwinite and larnite. The pressure conditions are below 1 kbar and the temperature greater than 700°C.
Kind regards
H.G.Dill
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Many geological descriptions of porphyry Cu-Au deposits use the term "potassic alteration". However, this is actually a rather unspecific umbrella term for three different secondary mineral assemblages: (1) biotite-magnetite, (2) phlogopite-magnetite, and (3) orthoclase alteration, respectively. The orthoclase alteration seems to be most common in the central parts of alkaline porphyry systems such as Cadia, Northparkes and Skouries, while the previous potassic alteration types are well documented in calc-alkaline porphyry systems throughout North and South America and the SW-Pacific. However, when you conduct more detailed studies, the biotite-magnetite alteration recorded at many calc-alkaline porphyry systems actually turns out to be a phlogopite-magnetite alteration assemblage (with a brownish rather than black colour).
Dear collegues, I look forward to your comments! Many thanks.
PS: Please find a sample from Grasberg attached.
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I advocate no longer using these simple summary terms, largely developed during the 1960s in the infancy of porphyry study. Rather, simply report the mineral assemblage, as analytical capability has improved markedly over the last 5-6 decades (from hand lens and thin section plus XRD to microprobe and SEM, then SWIR as well as Qemscan and MLA); still, start with a hand lens. One problem is that different people use some terms differently (e.g., argillic and intermediate argillic). In the case of "advanced argillic", there are 5 distinct environments of formation of minerals that Meyer and Hemley (1967; based on Hemley and Jones work in 1964) included in this term. Just using this term misses all of the information to be gathered from mineralogy, texture, morphology, etc. Please, determine and describe the mineralogy of various assemblages, and the variation between different deposit styles and types. Jeff
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Hi,
I want to know the scientific cause/reasons to increasing the noise levels during drilling with increasing drill bit diameters, penetration rate, drill bit speed, except rock properties and mineralogical composition of rocks. In my investigations I came to know that the reason for increasing sound levels due rock properties and mineralogical composition of rocks. Apart from this, Is there any scientific cause/reasons?.
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Respected Ali sir,
Thank your for your response. Is there any other reasons to increasing noise level during rock drilling.
Regards
Ch.Vijaya Kumar
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Recently, I have just started learning basic mineralogy and I found that it is quite difficult to master. It would help me a lot if you can share some tips on this field of study so that I can easily identify and describe accurately the minerals that is being observed using plane polarised light and cross polarised light.
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Dear Mr. Hanafi,
unless collecting rocks and minerals was one of the launch pads to study mineralogy creating a reference collection of both rock and mineral specimens is recommended. Do no start with the most exotic minerals and rocks but try find common rock types and minerals but different in their outward appearance.
In combination with this practical approach which helps you improve your visual inspection and the use of the classical tools from hardness to crystal morphology read textbooks where simplex chemical systems relevant for litho genesis and mineral formation are discussed.
Get acquainted with the chemical systems and the periodical chart of elements.
The best way to enter classical crystallography is in combination with optical mineralogy. It helps you train your imagination which is the key to successfully master the petrography microscope.
During this incipient stage you will realized where your interests are located in genetic mineralogy, petrology, crystallography or economic geology, applied geochemistry with material sciences which can be an outlet into one of the neighboring disciplines. Be very open-minded and try and get information of adjacent disciplines as much as possible to find your way. If you feel that space and time are more attractive than compositional changes and varying physical-chemical conditions you need not give up mineralogy as you decide to pass over into geology. I did it the other way round without cutting my geological roots.
There is more than one way to head for Rome.
I wish you much success
H.G.Dill
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Is there any (real) advantage of a hexagonal grid used during orientation mapping? And if yes, is there any paper which discusses and proves this in comparison to a regular map? And why all other companies do not use this (inclusive other mapping software like ASTAR in TEM) ?
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@ Bogdan: there is mainly one reason what irritates me: except of EDAX no other company does not care about this obviously irrelevant advantage. Theoretically, benefits might exist, but why standard grain size analysis in microscopy does not use a hexagonal grid as well. And even if this would be disadvantageousl isn't it counterproductive, if EBSD uses a hexagonal grid which might be better, but which is then also not comparable to other techniques? Standard procedures do not have to be "correct" or deliver the "true" wvalue(who knows what is true?) but a universally accepted value.
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Recent turbidite sediments are composed of sandy rhythmites and clayey rhythmites that alternate mainly with silt sized particles. I am interested to know the mineralogy of these types of sediments.
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turbidites sediments are mainly consist of quartz, plagioclase, K-feldspar, lithic and accessory minerals , in addition to the clay minerals.
With best regards
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Hello, after the analysis of volcanic deposits from South-East Asia by DRIFT Spectroscopy, some peaks occur around 1300-1250 cm-1 (please see the attached image). Do you know to which mineralogical compounds they could be associated? How can we interpreted it from a mineralogical point of view? Also this shifting between the spectra (around 1300-1250 cm-1) seems like a slight variations in the crystalline structures. Do you agree?
Thank you in advance for you answers and contributions.
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Have you examined the particles of the volcanic deposits using polarised light microscopy to get an idea about mineral type (or types) are present? I would imagine that the assemblage of minerals in the deposits from a known volcanic source are well-documented (e.g., acidic with lots of silica - granitic, or basic with less silica - basaltic). The presence of coloured (possibly pleochroic) minerals would indicate pyroxenes or amphiboles or if the minerals are colourless then that would suggest silicates such as quartz, feldspar, etc. When using analytical techniques, such as vibrational spectroscopy, don't forget that a quick look down a microscope at your sample can give you lots of valuable information about its composition and if it is a mixture, how many phases, etc.
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Hello Professors and colleagues
I am studying Neoproterozoic meta-sediments can i apply the indices of alteration on it or it has to be on sedimentary rocks only ?
Thanks in advance
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Dear Mr. Morad,
Unless you have carried out a geological survey and studied the mineralogical association of your rocks the chemical studies and the use of any index based upon chemical data is meaningless. It is a repetive critics of mine.
It is good for riding the “paper-tiger” but in practice these figures are of no use. Because what it is all about, is the futile attempt to circumnavigate experience and knowledge in geology and mineralogy. To gather experience needs time and to pile up knowledge even more in combination with a series of physical and mental endowments.
We cannot delegate geosciences to the technicians in the chemical lab.
Sorry for this harsh critics which is a general statement rather a reference to your question.
Sincerely yours
Harald G. Dill
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Dear all,
I have a good quality x-ray powder diffraction pattern. For indexing, I tried different software, However, I am sure it can also be done more easily with TOPAS academic version. I know how to search peak with Le bail but I could not apply any indexing algorithms such as ITO etc. in TOPAS. I also use Jedit interface.
I could not find any good material or example on internet. I would be really appreciate if any one can help me or send me a tutorial link.
#XRD #Indexing #TOPAS #crystallography #mineralogy
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Hi Mehdi,
Why don't you look up the textbook "Rietveld Refinement: Practical Powder Diffraction Pattern Analysis using TOPAS" by R. Dinnebier, A. Leineweber, and J.S.O. Evans? There are also somee tutorials on the internet.
Good luck,
Andrzej
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spreading of oil on grains of oil reservoir rock at reservoir conditions (high pressure and high temperature) is undesirable phenomena, petroleum engineers try to free oil from frocks surface and alter rocks wettability to be water wet rather than oil wet, but before that we need to understand relation between rocks wettability and rocks mineralogy.
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Yes mineralogy plays a role in wettability. In general carbonate reservoirs become oil-wet whereas sandstone reservoirs have mixed wettability (some minerals tend to be water wet and others oil wet under the same conditions). If you look at a question posted here in Aug 8 2015 by Parisa POURHAJI (Why are carbonate reservoirs oil-wet?) you can find a wealth of discussion and links focussing minly on carbonate reservoirs.
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I am working on the chemistry and mineralogy of a weathered sandstone in South Africa and I have received some XRD results that don't seem to match the profile of the sandstone. The results of the XRD show that there is a much more frequent occurrence of muscovite as opposed to clay minerals such as kaolinite or some type of illite or smectite. Which I find strange because as I understand it, muscovite mica would only appear in highly weathered sedimentary rock if it is detrital muscovite. It would've broken down into clay minerals a long time ago had it been deposited there during the sedimentation phase of the rock.
Is it plausible to question the XRD analysis and it's interpretation? The quartz peaks on the XRD are very prominent which means that many of the other peaks in the patterns are relatively flat and poorly defined and therefore are quite difficult to interpret accurately. Is it possible that the muscovite has been incorrectly assigned? Is it possible that the peaks that have been assigned to 'muscovite' may actually be the peaks associated with kaolinite or montmorillonite? Any help would be greatly appreciated!
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There is little chance to misdiagnose kaolinite as muscovite, but is quite possible to misinterpret it as chlorite in complex mixtures, or it's other polymorphs (i.e. dickite, halloysite).
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I collected zeolite samples in Ethiopia and analyzed through XRF and XRD. threfore how can I identify what type of the zeolite I collected.
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Dear Adeda,
I don't know what you are after, is it the chemical composition or crystal structure of the zeolite type?
I suggets you first do a thin section & identify textural characteristics of zeolites & any associated minerals.
After that you can go ahead with XRD, EMPA, SEM & XRF depending on what you primary objective is.
Regards
Shad
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In a transition of mixed-layer illite-smectite from R0 to R1 with depth, can the process go the other way around? I guess there were always discussion about this. But what is the most updated conclusion?
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The minerals are the result of changes in the chemical systems; they try and get adjusted to the existing physical-chemical regime (P, T, chemical composition of soluble compounds). As such processes are reversible through time and space. It is, however, a question of the reactivity of the compounds involved if the reaction works its way swiftly or is retarded.
With kind regards
H.G.Dill
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I need to know what clay minerals is exist from raw XRF data?it is used in acidizing design
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One cannot get very much from chemical analyses alone, orientatively the Al:Si ratio equals 1 for kandites (kaolinite) > illite > smectites (montmorillonite). Illite typically contains K, while smectites contain Na and Ca. For reliable diagnostic purposes, as suggested above, XRD is the recommended method, using bulk and treated (heated, glycolated) material.
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X-ray
define mineralogical phases
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Thank you for your answer
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Invite a discussion on quantification of minerals in thin section and their correlation with XRD quantification using Rietveld Method for Quantitative Phase Analysis.
1. Different Approaches for quantification of minerals in thin section
2. Can we compare mineral quantification in thin sections with XRD quantification?
3. How to approach these techniques combined?
4. Or what is the relevance of other geo-chemical procedure such as Rittmann’s norm for stable mineral assemblage (or any other).
5. Accuracy of other mineral quantification techniques (when compare to thin section analyses) !
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1. Different Approaches for quantification of minerals in thin section
It depends on the grain size and the orientation of your thin section relative to the texture, especially in metamorphic and sedimentary rocks showing any cleavage or bedding, respectively
2. Can we compare mineral quantification in thin sections with XRD quantification?
Only if the grain size is suitable for microscopic studies and no anisotropic systems are involved. On the other hand for the Rietveld Method you need precise crystallographic data, particularly for phyllosilicates.
3. How to approach these techniques combined?
I do not understand your question. Any combination is recommended
4. Or what is the relevance of other geo-chemical procedure such as Rittmann’s norm for stable mineral assemblage (or any other).
Norm (Rittmann, Niggli) calculation is always an artificial composition and different from the modal content.
5. Accuracy of other mineral quantification techniques (when compare to thin section analyses) !
It depends on your experience but I would not work with decimal figures and exaggerate the accuracy
With kind regards
H.G.Dill
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Rock: basaltic dykes
Problem: I only have one clinopyroxene phase (augite) and the olivine is not in equilibrium with the melt (whole rock composition). The models of Putirka 2003/2008 do not give reasonable results, most likely because there is not enough Al to stabilize a jadeite (aegerine instead) component which seems to be needed for the models. Any suggestions to solve this problem?
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Clinopyroxene is common in most mantle rock-types including peridotites, eclogites, Cr-diopside and augite-bearing pyroxenites as well as in most metasomatic associations formed by interactions with plume- or subduction-related melts. Not all mantle rocks have the correct mineralogy to work with garnet–orthopyroxene barometry (Nickel and Green, 1985, Brey and Kohler, 1990) or orthopyroxene barometry (McGregor, 1974) which is thought to be the most reliable methods (Taylor, 1998, Wu and Zhao, 2011). However, monomineral single-grain clinopyroxene thermobarometry of Cr-bearing associations (Nimis and Taylor, 2000), based on the Cr-tschermakite has a broad range of applications in mantle petrology. Examples include studies of mantle metasomatism in orthopyroxene- and garnet-free associations (Nimis et al., 2009; Ziberna et al., 2013) in cratonic lithosphere and processes of refertillization in oceanic mantle. But this thermobarometer has some restrictions because it works only in Cr-rich rocks and is worse when applied to Fe-enriched and Al-Na-rich rock-types and is sensitive to Fe3+.
for complete information refer to this link:
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I have recently discussed with Zeiss about the existence of an online forum where automated mineralogy users (specifically in this case Mineralogic) can share ideas about applications and recipes. Do any Research Gate members know of any relevant fora/blogs/websites? A series of introductory posts by Petrolab are the closest I could find.
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Hi Ben,
I am very happy to provide you with some information about edible minerals. The English translation should be medicinal mineral resources. Chinese medicine practitioners in China use some minerals to cure diseases. They cook boiled minerals and Chinese herbal medicines, and take boiled soup to patients for treatment. Some minerals are even eaten directly to patients. Chinese medicine practitioners use some of the characteristics of minerals to treat some of the corresponding diseases. Common minerals that can be used to treat diseases are: gypsum (which can treat high blood pressure), alum (for eczema, etc.), realgar, and actinolite (Treat male impotence, premature ejaculation, etc..). In traditional Chinese medicine, there are many minerals that can be used in this way. Interested parties can search for relevant materials.
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Could anyone help me to advice the exact name of this rock?The mineralogical composition is: K feldspar~60%, Plagioclase (oligoclase+albite-15%), Quartz-3-4%, Muscovite-5-7%, and 15-20% of isotropic brown colored mass of altered by Fe oxides.
  1. SiO2=57.6-5.26- according different type of analyses
  2. Na2O=5.0-5.11
  3. K2O=6.0-6.89
  4. Al2O3=17.0-17.32
  5. Fe2O3=4.4-3.53
  6. TiO2=0.76-0.76
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Dear Mirian: the rock accordino to the usual Q-A-P classification in is a syenite to quartz-syenite, the isotropic, actually opaque masses of oxides are altered mafics, perhaps hornblende or biotite, or even egirine... maybe you can find other samples with remains of these mafics to make sure. It certainly contains no glass, so it is a plutonic rock.
Regards, Sebastián
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Dear Fellows,
Hope you are having a good day.
I need guidance regarding the interpretation of the smectite mineralogy from XRD Peaks data.
Kindly help me, how I may identify the peak of the smectite from .brml/.asc file of the tested samples.
Regards,
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Dear Mr. Ismail:
Smectite and smectite-mixed layers need a careful preparation under air-dry conditions and glycolated to show the intensity of swelling represented by the 14 Å peak which can expand to as much as 18 Å. The samples bearing swelling phyllosilicates differ with respect to their expandability; some may not fully expand and show, e.g., peaks between 16.5 or 16.8 Å and thereby point to smectite-mica-mixed layer minerals of different ratios. Regular m.l. have superstructures visible in the XRD run. Which type of mixed layer exists depends upon the associated clay minerals such as mica, chlorite, kaolinite-group minerals. It goes beyond a small Q&A process to explain all possibilities you might be faced with in context with this clay minerals. You cannot avoid to consult a textbook of clay mineralogy.
H.G.Dill
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Dupi Tila Formation is extensively exposed in Bangladesh. I am pleased to know the mineralogical composition of DupiTila Formation.
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The heavy mineral assemblages of the Dupi Tila Formation contain in average 0.8% heavy minerals, comprising zircon, garnet, sillimanite, staurolite, kyanite, epidote, rutile, biotite, chlorite, and chloritoid. The opaque fraction includes magnetite, hematite, ilmenite, pyrrhotite, and rarely pyrite. The heavy mineral data suggest a wide range of metamorphic as well as granitoid source areas (Munim et al., 2016).
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I am interested to know about the mineralogical composition of Bhuban shale, Bangladesh.
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Good afternoon, Dr. Saha.
" Clay minerals within the shales, include illite, chlorite, and kaolinite with or without montmorillonite. Other minerals of shales are quartz, feldspar, calcite and dolomite."
The article "Petrography and Mineralogy of the Bhuban Formation, Hari River Section, Jaintiapur, Bangladesh" (Roy et al. 2004) should answer your questions.
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I eager to know the minerological composition of Recent estuarine sediments.
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I think the following paper will be useful
Best Regards Sudip Saha
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A mineral is a naturally occurring chemical compound, usually of crystalline form and abiogenic in origin (not produced by life processes). A mineral has one specific chemical composition, whereas a rock can be an aggregate of different minerals or mineraloids. The study of minerals is called mineralogy.
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Recommend Harald G. Dill answer
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I have elemental composition from XRF results. I need to know what minerals I have?
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Please have a look at( Mincomp - a program to calculate a likely mineralogical bulk composition from XRD and XRF results) :
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I am looking for a reference book to look up phase diagrams of binary mixtures of inorganic salts, for example KNO3-NaNO3, CaF2-MgF2, and so on. Any recommendation will be appreciated!
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Phase diagrams for ceramists , American Ceramic Society , now exists also as a database of the different volumes.
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If we have rock from 9000 - 10000 ft. How reflective is stress memory after taking the core out from the above section?
Thank you
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Interesting point,following
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I've been measuring thermal conductivity of magmatic and metamorphic rocks with the FOX50 heat flow meter in the temperature range 20 - 180 ºC, and I've been noticing that some samples present an increase of thermal conductivity as a function of temperature. My question is, what are the possible causes for this increase? Can it be related with mineralogical composition? The % of feldspar, maybe?
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Dear Mafalda,
Perhaps it is the mineralogical composition, particularly, hydrous minerals. But it is not clear whether you used rocks that represented roughly the same temperature of formation in your experiment. As you know the mineralogy is related to the temperature of formation of the rocks. The samples you used may be fresh but those still may contain hydrous minerals which formed in response to wanning temperatures of formation too. Although the temperatures you are dealing with are not high enough to release OH- from the primary minerals hydrous minerals which formed later may release water vapor with ease. If your samples represent high T metamorphic and magmatic rocks they are likely to contain more secondary hydrous minerals which released water aiding the heat transfer as you heat the rocks during the experiment.
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15 years after the introduction of CCD-based EBSD detectors a new camera technology enters the EBSD world. It is hard to believe, the formerly demonised CMOS chips are now the saviours of the EBSD market. In contradiction to all prevously made statements CMOS are now not only faster but also more sensitive and less noisy. Well, companies are (primarily) not founded to make scientists happy. They need to sell in order to survive (or make their shareholders happy), and if the market does not increase as expected a new technology is very welcome to increase the business ono this way.
In fact, I believe that the spec sheets of the new detectors are credible, but how the detectors really work in practice? Are there some users which have direct comparisons? How profitable is the change if one considers the comparatively huge price?
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The speed might be really one argument... On the other hand, does speed really helps? For drift, 3D measurements (although I am not sure how useful they often really are), sensitive sample etc. However, my impression is that we already now generate too many measurements without analyzing them carefully enough. If something does not look like it should: take another measurement :-)
Anyway, with which detector did you measure before (or still) in your institute? I mean, I wonder when I hear that you still do overnight measurements. We don't do this anymore for a decade. And huge maps only make trouble when you want (re)analyze them. Therefore, my common maps are 640x480 or often simply 400x300. This takes already with an old detector about 30min (if you really squeeze the last accuracy out), i.e. not speed but precision optimized measurements. Otherwise it would take only a few minutes with the previous detector generation.
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GCDkit is one of the most versatile packages for igneous petrology. Writing scripts in 'r' for GCDkit has a steep learning curve. Tutorials may help to facilitate learning with feedback.
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Dear M. Ghoneim,
In GCDkit, you can simply use the menu Plots|Binary plot, and when asked to specify which of the axes should be logarithmic, reply x, y, or xy. See also indication in the relevant dialogue box.
Best wishes, Vojtech Janousek
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Mineralogy Soil Science
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The characteristic bright red color is due to the high pigmenting power of hematite, which masks the coexisting yellow of goethite (Torrent et al., 1983). Ferrihydrite also gives a red color to terra rossa (Durn, 2003).
Best Regards Paolina Santos
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i observed gabbroid rocks many places come like layered gabbro , what is the possible action perform that?
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Layered gabbroids are differentiated intrusions of open and long-lived intermediate chambers through which large volumes of magma passed. Their differentiation is explained by the fact that the velocity of magma in the chamber drops by 5-6 orders of magnitude. The model of dynamic differentiation and crystallization consists of three main axioms and two additional ones (Radko, 1991). 1. The chamber localizing the differentiated intrusion is an intermediate focus that has supply and output channels, that is, it is a hypabyssal subvolcano. 2. Magma passing through the chamber resets part of the solid phase in it. 3. The melt enters the chamber many times, forming various facies.
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Among the clay minerals, which is the most adhesive in nature?
In coastal, estuarine and marine sediments, what is the role of clay minerals in the distribution of trace metals?
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Dear Dr. Veerasingam,
The clay mineralogy in marine sediments strongly depends upon the sedimentary facies from shallow marine coastal sediments to deep marine abyssal sediments and whether magmatic or hydrothermal processes are involved in the course of phyllosilicate formation. There is a rule of thumbs or general view that near-shore environments such as estuarine, beach and tidal sediments are richer in kaolinite-group minerals than off-shore ones. Illite and micaceous minerals increase off the coast. Smectite may also increase seaward but may also be concentrated near-shore, e.g., in sabkha environments-see also the accumulation of palygorskite in this nearshore marine macrotidal environment. Kaolinite-group minerals are washed into the sea or form in estuarine environments. Due to the low CEC (cation exchange capacity) the play a minor role than smectite group minerals, which have a high CEC and also can form minerals like Ni smectite (mainly nearshore only). Smectite-group minerals are common in marine sediments, particularly those next to hydrothermal vent systems (nontronite, Fe-saponite) where they are associated with Zn, Cu and Ni concentration. On top of ophiolites alteration and submarine weathering may give rise to bentonites accumulating base metals in ocher derived from the underlying basaltic lavas. Upper Cretaceous basic pyroclastic rocks, which rest on top of the Upper Pillow Lavas Series of the Troodos ophiolitic complex, Cyprus, have been altered to bentonites. Circulation of hydrothermal fluids was facilitated by the high heat flow from the ocean floor. Fe-rich montmorillonite and Fe-rich beidellite both resulted from hydrothermal alteration of basic pyroclastic rocks. In some sites, bentonites are associated also with Si-enriched zeolites, although the parent pyroclastic rocks were basic. Dissolution of radiolarian frustules increased the silica activity of the pore water and thereby triggered replacement of smectite by palygorskite during later stages. One of the most well-known deposits, the Lower Pleistocene bentonite deposits of Eastern Milos, Greece formed from alteration of volcaniclastic rocks under submarine conditions. The major authigenic phases are smectite, K-feldspar, opal-CT and the zeolites mordenite and clinoptilolite. The source of Mg lies within the volcanic parent rocks underneath.
As far as the CEC and trace element contents are concerned you can arrange the clay minerals in order of increasing CEC and trace elements like that:
Kaolinite-group
Mica
Chlorite (+swelling chlorite)
Palygorskite (hormites)
Smectite (bentonites)
DILL, H.G. and KAUFHOLD, S. (2018) The Totumo mud volcano and its near-shore marine sedimentological setting (North Colombia) – From sedimentary volcanism to epithermal mineralization.- Sedimentary Geology 366: 14-31.
DILL, H.G. (2017) Residual clay deposits on basement rocks: The impact of climate and the geological setting on supergene argillitization in the Bohemian Massif (Central Europe) and across the globe.- Earth Sciences Reviews 165: 1-58. DILL, H.G. (2016) Kaolin: soil, rock and ore From the mineral to the magmatic, sedimentary, and metamorphic environments.- Earth Sciences Reviews 161: 16-129
DILL, H.G. , BECHTEL, A., BERNER, Z., BOTZ, R., KUS, J., HEUNISCH, C. and ABU HAMAD, A. M. B. (2012) The evaporite-coal transition: Chemical, mineralogical and organiccomposition of the Late Triassic Abu Ruweis Formation, NW Jordan - reference type of the “Arabian Keuper”.- Chemical Geology, 298-299: 20-40
DILL, H.G., DOHRMANN, R., KAUFHOLD, S. and WEBER, B. (2011) Clay mineralogy and chemistry of fine-grained sediments. Environment analysis around the K/P boundary at Sekarna / Kasserine Island, Tunisia.- Neues Jahrbuch für Mineralogie Abhandlungen, 188: 285-296.
DILL, H.G., KUS J., ABED., A.M., SACHSENHOFER R.F.and ABUL KHAIR H. (2009) Diagenetic and epigenetic alteration of Cretaceous to Paleogene organic-rich sedimentary successions typical of the western margin of the Arabian Plate, northwestern Jordan.- GeoArabia, 14: 101-140.
DILL, H.G., WEHNER, H., KUS, J., BOTZ, R., BERNER, Z., STÜBEN, D. and AL-SAYIGH A. (2007) The Eocene Rusayl Formation, Oman, carbonaceous rocks in calcareous shelf sediments: environment of deposition, alteration and hydrocarbon potential.- International Journal of Coal Geology 72: 89-123.
DILL, H.G., FUESSL, M. and BOTZ, R. (2007) Mineralogy and (economic) geology of zeolite-carbonate mineralization in basic igneous rocks of the Troodos Complex, Cyprus.- Neues Jahrbuch für Mineralogie Abhandlungen, 183: 251-268. DILL, H.G., BOTZ, R. , BERNER, Z., STÜBEN, D., NASIR, S. and AL-SAAD, H. (2005) Sedimentary facies, mineralogy and geochemistry of the sulphate -bearing Miocene Dam Formation in Qatar.- Sedimentary Geology, 174: 63-96. DILL, H.G. and DULTZ, S. (2001) Chemical facies and proximity indicators of continental – marine sediments (Triassic to Liassic, SE Germany).- Neues Jahrbuch für Geologie und Paläontologie Abhandlungen, 221: 289-324.
DILL, H.G., WEHNER, H., BOTZ, R. and DULTZ, S. (2000) Chemical logging of continental-marine depositional systems. A tool to unravel the palaeogeography and diagenetic alteration of fine-grained clastic rocks in a transitional environment of deposition (Triassic -Liassic, Southeastern Germany).- Geochemistry, 60: 129-171.
DILL H.G. SCHEEL M., KÖTHE A., BOTZ R. and HENJES-KUNST F. (1997) An integrated environment analysis-lithofacies, chemofacies, biofacies-of the Oligocene calcareous-siliciclastic shelf deposits in northern Germany.- Palaeogeography, Palaeoclimatology, Palaeoecology, 131: 145-174.
DILL H.G., KÖTHE A., GRAMANN, F. and BOTZ, R. (1996) A palaeoenvironmental and palaeoecological analysis of fine-grained Palaeogene estuarine deposits of North Germany.- Palaeogeography, Palaeoclimatology, Palaeoecology, 124: 273-326.
DILL, H.G., SIEGFANZ, G. and MARCHIG, V. (1994) Mineralogy and chemistry of metalliferous muds forming the topstratum of massive sulfide-metalliferous sediment sequence from East Pacific Rise 18°S: Its origin and implications concerning the formation of ochrous sediments in Cyprus-type deposits.- Marine Georesources and Geotechnology, 12, 159-180.
DILL, H.G., GAUERT, C. HOLLER, G., and MARCHIG, V. (1992) Hydrothermal alteration and mineralisation of basalts from the spreading zone of the East Pacific Rise (7°S-23°S). - Geologische Rundschau/ International Journal of Earth Sciences, 81: 717-728.
I think in these papers you might find some answers to your questions, also in terms of HC exploration.
With kind regards
H.G.Dill
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Based on earthquake data, how we can define the type of rocks and minerals within the earth?
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Lots of earthquake stations today, therefore, lots of data to study using the velocity of the waves. Scientists know a lot more information than previously and there is more to study. The data displayed in the lecture suggested by Dr. @ Borko Bulajic are amazing!
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Kullerud et al. (2018) found that there was an immiscible gap in the Ag2S-Ag2Se system from 60 to 80 mole %, and obtained almost the same result as Pal’yanova et al. (2014). This immiscible gap (70 to 80 mole %) has already been reported by Sugaki et al. (1982) and Kitakaze (2016), both (In ReserchGate of Kitakaze, A).
[Kullerud, K. et al. (2018) Solid solutions in the system acanthite (Ag2S) naumannite(Ag2Se) and the relationships between Ag-sulfoselenides and Se-bearing polybasite from the Kongsberg silver district, Norway, with implications for sulfur–selenium fractionation. Contributions to Mineralogy and Petrology, 173, 1-17].
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I think it is not clear what your question is.