Mineralogy - Science topic

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

You can use Qmin for some EPMA data

Good luck!

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?

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

Tushar Kumar

I suggest reading these papers:

1. https://www.diva-portal.org/smash/get/diva2:1515573/FULLTEXT01.pdf

2.

The images above are from "sun et al." Mine are not so pretty. Same process I believe.

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.

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

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

Origin pro 8.5.1

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

I have not seen yet it but it is too interesting case

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.

With Mac Diff I visualize and interpret diffractograms applied to clay mineralogy and crystalline substances.

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

Biotite as a petrogenetic discriminator: Chemical insights from igneous, meta-igneous and meta-sedimentary rocks in Iran

DOI: 10.1016/j.lithos.2021.106016

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.

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

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.

https://cran.r-project.org/web/packages/CHNOSZ/vignettes/anintro.html

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.

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

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.

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?

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.

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.

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.

Here, I think the degree of alteration, contamination and/or the oxidation has major impact on the obtained percentage.

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

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

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

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.

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.

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.

I wish you much success H.G.Dill

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

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?

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!

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

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

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

Respected Ali sir,

Thank your for your response. Is there any other reasons to increasing noise level during rock drilling.

Regards

Ch.Vijaya Kumar

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

@ 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.

turbidites sediments are mainly consist of quartz, plagioclase, K-feldspar, lithic and accessory minerals , in addition to the clay minerals.

With best regards

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.

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

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

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.

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).

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

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

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.

Thank you for your answer

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

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.

I do not understand your question. Any combination is recommended

Norm (Rittmann, Niggli) calculation is always an artificial composition and different from the modal content.

It depends on your experience but I would not work with decimal figures and exaggerate the accuracy

With kind regards

H.G.Dill

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:

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.

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

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

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).

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.

I think the following paper will be useful

Best Regards Sudip Saha

Recommend Harald G. Dill answer

Please have a look at( Mincomp - a program to calculate a likely mineralogical bulk composition from XRD and XRF results) :

Phase diagrams for ceramists , American Ceramic Society , now exists also as a database of the different volumes.

Interesting point,following

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.

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.

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

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

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.

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

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!

I think it is not clear what your question is.