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This was found in shallow water (deltaic) deposits of late Cretaceous age - middle Campanian (central Poland, Europe).
On the left there is an imprint of a tree, but the most interesting structures are encircled by red lines. Additionally there are some "double hollows" marked by blue.
Do you have any proposition what is this?
Best, Zbyszek
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Ok. maybe it is a pice po decorticated wood but the question is what is on the left sied of the photo?
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Hi All!
Can anybody clarify, if the weighted mean average of multiple concordant U-Pb ages (A)(considering concordance >95%) in detrital zircon grains is almost similar to the weighted mean of three youngest concordant ages (B) (following Dickinson and Gehrels, 2009), can I take the overall weighted mean (A) as the maximum depositional age of that sedimentary rock? And do I need to consider any cut-off concordance to select the youngest grains?
Any answers or suggestions are highly appreciated.
Many thanks,
Harshita :)
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In case of the chronology of sedimentary rocks hosting zircon I would express a stark warning to mix up ages simply based upon isotope data which are passed through a statistical treatment. I recommend to have the mineralogy and sedimentology involved. The mineralogy (+microchemistry - see EMPA) allows to categorize the zircon grains according to their internal textures, overgrowth, zonation etc. and the trace element content which is a good tool to constrain the environment of formation during a provenance analysis. With the aid of the X morphology and granulometry you get another tool that enables you to constrain the physical-chemical regime which the various populations have been derived from and get an idea of the recycling of zircon. Zircon is the most stable heavy mineral besides rutile and tourmaline and subjected to strong recycling. It has also a good preservation potential in terms of mechanical attrition and supergene alteration.
You can judge from these statements how manifold the impacts are on such a chronological approach you are going to take.
Stick to the classical chain of operation geology-mineralogy-chemistry - isotope analysis. Then you are going to build your home on solid grounds.
HGD
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Hello Everyone, I am working on paleoclimate of northwest Australia. I have been searching for the sediment discharge/sediment load of ''Ord River'', ''Victoria River'' and ''Fitzroy River'' but cannot find it anywhere. Can anyone guide me where can i find the sediment discharge data of the mentioned rivers?
Thank you
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It depends on what sort of data you want - often monitoring of rivers is poor, especially for sediment data. This kind of work might be useful to you:
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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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I have analyzed few marine samples on the Mastersizer software for the grain size analysis. I calculated the mean grain size, and median data from it but i don't know how to calculate the sorting data from it. I would really appreciate it if somebody guide me how to calculate the grain sorting from this data.
Thanks
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Hello Muhammad Sarim - the pag file contains the information for the report, for example the layout. There should be a special folder where there files are stored,, similar to the way this is handled in the Zetasizer software.
If this does not help, reach out to the help desk https://www.materials-talks.com/help-for-my-instrument-one-step-away/
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Sediment is relatively younger than the soil in the depositional environment as the sediments are consequence of the accretion of particles transported either by waters or by winds, whereas, soil profile is stable lacking any sort of movement. Soil profile is developed with time span which is a stable one, but the movement of the sediment particles developed those soil profiles in so many physiographic set up, are they (soils and Sediments) differed chemically, do they possess different chemical environment?
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yes its do it
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Hello, I am currently working on the design of a device that measures thermal conductivity of sediments and I am not sure if i estimated heat losses and heat flux in the correct way. The device is a 0,0034 cubic meters (200 cubic inches aprox) box with a resistor (curved alloy wire) in contact with one face of the sample, connected to a power supply. The resistor is in the middle of one face of the sample and a heavy insulator, like glass wool (i am not sure if this is the proper term for the material).
This is not my work area, i'm a geologist, but given my current research i am in the need to resolve this issue
Please feel free to answer any of this questions, also any comment will be helpful.
My questions are:
  • If it is ok to estimate heat losses considering an estimation of the temperature at a middle point in the box and thickness and the thermal conductivity at the five walls that surround the internal sample considering that one side of the device is in contact with the surrounding air
  • If using a common insulator (say 0,02 to 0,04 W/m.C°) will yield an aproximate heat loss of less than 1W, considering 0,1 m wall thickness (4 inches aprox).
  • If the sample will reach a quasi steady-state heat flux or will be far from it, considering the room temperature stays aproximately constant.
  • How much heat will disipate the wire if the power output of the power supply is, say 6W. In other words what will be the heat flow at the resistor, through the first face of the sample near the resistor, given that supplied power.
Regards
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Hello Matias
Now I think that I understand what you are trying to do.
I think you can obtain a quasi-steady-state in your sample but you must wait some time to obtain it. As you have an insulator (your box) under the resistor you may have a problem with increasing temperature in that wall of the box and an increase of heat flowing in your sample.
You can obtain the heat lost through the walls of the box measuring temperature differences between inner and outer surfaces of the box P(lost) = (0,04) (Tin - Tout)/ 0,1. You can also have an idea about the heat lost through lateral sides using several termocouples in the upper surface of your sample located from the center to the lateral part of the samle.
The values obtained will depend on the sample you want to study. In principle if you are studying rock sediments you will obtain low thermal conductivity values (compared with common rock values ) but higher values than 0,04 and you will have heat flowing predominantely in the vertical direction.
Try to not use high temperature values in your experiment. Thermocouples are very good to use in this type of experiments because its volume is very small and they have a rapid answer.
As I said in my first message you are using Joule's effect in your experiment and the power dissipated is P= R I2 . The value o I depends on the value of R. You must know the ddp (voltage) at the ends of your resistor ((V=RI).
I think I unswer to your questions but if you have some question more you can contact me.
Best regards
Maria Rosa Duque
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In a delta front context, How can we discriminate between sands deposited by river floods & sands deposited in wave dominated deltas
esp when we don't have any sedimentary structures observed except few horizontal lamination, no bioturbation. 4 to 5 meters of structurless/massive fine sandstone with abundance of mud clasts and few convoluted bedding (attached some core photos)?
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The question whether it is a fluvial-dominated or wave-dominated delta cannot be decided based upon the data available and should be done by investigating the vertical/ lithologs and also in plain view (e.g. "birdfoot delta" = fluvial) .
Often it is not a true end-member type but a mixture of wave- and fluvial-dominated processes. That is why I tried to convince you to look at this transitional landform between land and sea in a 3-D view to get a full-blown and true picture. It is certainly not an easy task.
H.G.Dill
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In deltaic system; Very fine to fine grained compact sandstones with planar laminations and no bioturbation. could we consider this a wave or fluvial dominated delta front?
* some intervals of fluid mud (Non bioturbated shales)are observed within the prodelta facies
* only a half HCS observed
* sand intervals are very clean and can form 4 to 5 meters of sandtones
* Some sediment gravity flow and dewatering structures were also observed
Wave dominated or River dominated delta front ???
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Dear Colleagues,
to distinguish the three end-member types of deltas (wave-. fluvial-.tide-dominated) should not be done based upon the description of some textures and structures. The delta front is the subaqueous part of the delta which is mainly built up under the influence of marine high energy processes, such as longhshore drift, wave and tidal actions. There may be discordant beds which have derived from fluvial reworking but they have not been mentioned in your record. You excluded a strong tidal impact which could have been indentified by the overall stacking of bedsets. So I assume you are studying currently a wave-dominated part. My general recommendation is try and investigate the entire delta (I do not know how much of it you have insight into ?) plot it and collect all data. The risk to over-interpret one part while others are ignored is high.
With kind regards
H.G.Dill
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I want to know the ideal tectonic setting with example on which sediments experienced very little transportational history with no signature of deformation and post depositional metasomatism.
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I agree with Ramon and Ahmed. The conditions Ahmed describes occur less disturbed along passive margins such as the Gulf of Mexico, the Santos and Campos Basins offshore Brazil, the offshore basins of West Africa, and many others. In tectonically active margins, the sedimentary record can be disturbed by earthquakes, overturned in folding events caused by compression, strike-slip faulting, or active volcanoes.
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I would like to know the fast and easiest way to differentiate aeolian and fluvial silt by looking at the samples itself.
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- Aeolian silt and sand grains have frosted surfaces due to the the abrasion that they suffered when impacted to each other's.
- Aeolian silt might be better sorted than fluvial silts, while fluvial silts tend to be mixed with fine sand and clays and often have organic matter content.
-In a fluvial system, silts and finer sediments are related to flooding plains, so when the river level grows up and cover the plains around the river, after the energy decreases, the silts, clays and organic matter particles deposit on the flooding plain. Silts also occur in abandoned channels in meandering river systems.
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These photos taken at Sandstone layer . Please can somebody help me in the identification of these concentric and parralel laminations ? And which is the origin of this process ? NB : outcrops located on the coast influenced by marrine erosion.
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Dear Dr. Idries
These fine-grained sandstones show a rock parting on a different scale and intensity which allows the infiltration of (meteoric) fluids to a different extent and leave behind a residue of Fe-oxide hydrates (“limonite”). The latter “mineral” gives rise to the concentric structures resembling the contour lines of topographic map which reflect the different altitudes. It is a near-surface (supergene) process.
With kind regards
H.G.Dill
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What are the main reasons when HI values are more than 100 but Oxygen index values are equal nil ?
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Dear Dr. Darko Spahić
Many thanks for your help.
Regards
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What is the best method for measuring the age of clastic rocks which has no fossils ? Your advice is highly appreciated.
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As I understood you have clastic rocks. The clastic rocks have mineral constituents derived from more than one source, each mineral gives the age of its source rock " assuming a state or radioactive secular equilibrium exists". So, it is impossible to have a true age dating for clastic rocks by simple method of dating as we do for hard rocks. You will then have mixed ages. You can use 87Sr/86Sr stratigraphy if you have chemically formed sediments such as limestone but since you have clastic sediments you will have minerals with different 87Sr/86Sr ratios. People try to use Thermoluminescence dating (TL dating) for clastics and age of sedimentation but with high uncertainty.
TL dating is the determination, by means of measuring the accumulated radiation dose, of the time elapsed since material containing minerals was either heated (lava, ceramics) or exposed to sunlight (sediments).
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This facies belong to upper Cretaceous in the Azarbailan, NW Iran. this is a lime sandstone or sandy limestone that deposited in marine environments. I need more discusstons about this facies with references .
Photos take by 4 and 10 lens of microscope.
Tanks
Mobin
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Dear Mr. Nejad,
your attempt to interpret the carbonate (micro) facies is very ambitious and is in my opinion not the correct way because the term facies is a far-reaching one to discuss the origin of a rock unit, in this case a sedimentary one where all available features of different scales need to be considered. The late Professor Walliser from Göttingen University once showed us a hand specimen and said: “ You should not create a new orogeny using only one hand specimen”. With kind regards H.G.Dill
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I was reading a past question (https://www.researchgate.net/post/how_to_calculate_the_degree_of_discordance_of_zircon_ages) where people were debating the cutoff age for switching between calculation of discordance/concordance based on either 206/238/207/206 or 206/238/207/235 and the related cutoff age applied when reporting detrital zircon ages. I decided to ask this question to start a debate on the pros and cons of using concordia ages (Ludwig, 1998) which removes the necessity for a cutoff and filters data by probability and MSWD of concordance. The issue has recently been raised by Zimmermann et al (2017) who recommend the latter approach and has been applied as far back as 2004 (perhaps before) by Peter Cawood. The concordia age approach seems to be the most sensible one but I cannot understand why it is not becoming widely adopted by the 'detrital zircon community'. All opinions welcome.
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Hello Jorge,
Thank you for your contribution. I am aware of how ages are determined using the U-Pb isotopic system in zircon. I think, perhaps, you have misinterpreted my question or my question was misleading as it referred to a question about calculation of concordance/discordance. I refer to the concordia age as defined by Ludwig (1998), not specifically concordant ages and how they are calculated. I take the following quote from the Isoplot 3.75 manual (Ludwig, 2012) which provides a concise description of the corcordia age:
"In addition to the usual 206Pb/238U, 207Pb/235U, 207Pb/206Pb ages, you can use any pair of 206Pb/238U - 207Pb/235U or 238U/206Pb - 207Pb/206Pb ratios to calculate a single “Concordia Age” (Ludwig, 1998). A Concordia Age is the most-probable age for a data-point (or weighted-mean data-point) on a concordia-diagram, where the true location of the data point is assumed to fall precisely on the concordia curve."
Most detrital zircon studies will use the 'usual' ages, particularly utilising 206Pb/238U for ages younger than a certain cutoff (e.g. 1.0 Ga) and 207Pb/206Pb for ages older than the cutoff because the latter age tends to be more precise for older ages. However, using the concordia age removes the necessity for a cutoff.
I refer you to the papers referenced in the question and to:
Spencer et al 2016. Strategies towards statistically robust interpretations of in situ U-Pb zircon geochronology. Geoscience Frontiers 7, 581-589.
The above paper provides a discussion on the cutoff age used to switch from 206/238 ages to 207/206 ages.
My question is aimed at starting a discussion on the pros and cons of the adoption of the concordia age method for detrital zircon studies rather than using the more traditional 206/238 and 207/206 method.
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This sand body is located on the southern edge of the Pannonian Basin, on the southern slopes of the Papuk Mountain, and the age is Pleistocene, approximately 1.6 million years. The sand is medium to coarse grained with 2-31% of gravel. It contains a lot of fossil remains (fish bones, dolphin bones) from a nearby older sediments (Pliocene and Badenian). No structures were found on site that would help us to determine sedimentary environment.
Could it be a quick slope movement of sediment triggered by earthquake?
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Dear Dr. Banak,
You may be on the right track but for an in-depth analysis I would like to know some more information, e.g.:
1. Where is this rock positioned along the paleoslope? What rocks are up- and down-slope?
2. What is its upper and lower contact like?
3. How did it debouch and what is its aerial distribution like?
4. What is its extension downslope?
5. You did not see any structural and textural variation.
Are there any lateral facies changes? Currently I am speculating on massing wasting processes in an alluvial to colluvial regime.
With kind regards
H.G.Dill
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Hello,
I deal with detrital heavy minerals. I found quite numerous topaz grains in several samples. I wonder if this is possible to distinguish between different source rocks (e.g., various pegmatites and skarns from the Bohemian Massif, Central Europe) using chemical composition of the topaz grains/crystals (major and minor elements using electron microprobe, and/or trace elements using laser ablation). This subject is completely new for me, I will be grateful for any tips.
Monika
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Considering the limited variability of topaz in terms of major elements, studying trace elements, both of your heavy minerals and suspected source areas, might be the most fruitful approach. Perhaps cathodoluminescence imaging may also give some information (e.g. Agangi et al., 2016. Relation between cathodoluminescence and trace-element distribution of magmatic topaz from the Ary-Bulak massif, Russia. Mineralogical Magazine, 80(5): 881-899.
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Dear all,
I have done XRD analyses of modern fluvial unconsolidated sediments (soil- clay, silt and sand) to identify the mineralogy and their proportions. I require to select the best minerals to interpret the provenance & paleoclimate of the modern fluvial sediments. Do I need to select different mineral group for provenance & Paleoclimatic interpretation? I would be extremely grateful if you kindly help me in this regard.
Best regards,
Ashok
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heavy and clay minerals are good indicators...
For example
Chemical analysis of sediment and ratios like Ca/Fe, Sr values, K/Al will give provinances
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while we drill we face hard formation sandstone plenty of mica.
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Micaseous sand is deposited now on the pointbar of meandering river within Tigris River channel in Baghdad, Iraq.
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There is a significant variation in gamma counts of borehole sediments collected in fluvial environments. The sediments belong to clayey Flood Plain deposits without any sandy sediments. This may not be related to the organic matters since most of the sediments are yellowish brown in appearance. The lower value is concentrated in a particular zone only. Does it relate to drainage condition of the area? If yes, well drained sediments should have lower gamma value relative to poorly drained one. Is it correct ? What would be the possible reasons for such a variation in terms of depositional environment?
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Dear Ashok,
At the Geological Survey of the Netherlands we routinely use spectral gamma ray logs in a number of our deeper boreholes (20-500 m) for the purpose of geological mapping and characterisation of Tertiary and Quaternary deposits. These consist mainly of sandy and clayey marine and fluvial sediments, not just clay as in your case. Moreover, in the Dutch lowlands, the groundwater table is in general very close to the surface, so I cannot comment on the influence of drainage conditions on gamma ray values. However, I do not think that groundwater will be the most important factor influencing the gamma ray values, although one might assume that water decreases gamma ray transmission and thus cause (slightly?) lower values. Other and more important factors explaining variations in gamma ray values are a.o.:
1.       Physical characteristics of the borehole itself: diameter (inc. variations like cavities made during drilling) and presence and thickness of casings. Everything else being equal, larger diameter boreholes and greater thickness of casings will decrease gamma ray values. Often boreholes are wider and/or have thicker or more casings in the uppermost part (~tens of meters), and thus will register a lower gamma ray value in that zone. Thus, this is not to be confused with a ‘groundwater’ or drainage effect in the upper part below the surface! In our experience, the physical features of boreholes are often difficult to reconstruct, especially for older ‘archived’ boreholes, as this kind of data is frequently overlooked and not recorded. If you make your own drillings, this is very important primary information that should be recorded in detail for the proper interpretation of a.o. gamma ray logs.
2.       Grain size and the presence of clay: the smaller the grain size and the higher the clay content, the higher the gamma ray values. This is self-evident, as mapping/correlating fine-grained/clayey layers is one of the main goals of gamma ray logging.
3.       Organic matter content: in general, the more organic matter, the higher the gamma ray values. In spectral gamma logs, this will best be seen in the much higher U gamma ray values.
4.       Mineralogy and geochemistry: These are often influenced by the provenance of the sediments. E.g. everything else being equal we see that sediments originating from deeply weathered Tertiairy deposits have much lower gamma ray values than those from more freshly eroded material from the Alpine region, due to the presence of a.o. micas in the latter, which can also be seen visually in sediment samples. The presence of glauconite also increases gamma values. As glauconite occurs only in marine to coastal/estuarine deposits, this will probably not be relevant for your ‘fluvial-only’ environments. Using spectral gamma logs, different minerals can often be determined by their K-U-Th ratios, and there is a lot of information on this subject in textbooks, papers and the Internet (see below).
The Internet yields a lot of information on the subject. Some interesting links/examples:
Succes with your research!
Patrick Kiden
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The method of Springer-Lilje (1988) is a probabilistic extinction-date determination with the following equation for a confidence interval of 95%: 
Dext = Dmin - ([In(0.05)] / - [(N - 1) / Dmax - Dmin])
where Dext is the extinction date, Dmin the geologically youngest date,  Dmax is the geologically oldest date and N is the number of datings.
However, typically, ASR and EER dates are provided as +/- 20% for the 95% confidence range. Do I have to use for Dmin the youngest date minus 20% (and for Dmax the oldest date plus 20%), OR I ignore this 20%?
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Kenneth is discussing dealing with estimated dates of total extinctions. In fact, for individual species, determining time of extinction is very dependent of the observations at your disposal. In the case of the Mammoth, for many decades, it was thought that they died out at the end of the last major cold event.  Subsequently, it has been found that they persisted in living until 4ka on Wrangell Island in the absence of Man.
There can also be problems using DNA.  Thus the oldest fossil from polar bears is about 1210 Ka.  Whole cell DNA analysis suggests that they died out about 600 ka B.P., whereas  DNA analysis of part of the nucleus suggests 400 ka. Thus there are problems with the choice of your data source that render mathematical estimation rather dependent on the data source rather than computational statistics.
Stuart.
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Dear all,
The fluvial sediments are highly enriched in Carbonates due to the presence of calcrete nodules (Kankars). It is thereby giving higher percentage of CaO in XRF results which in turn is reducing the concentration of other oxides, especially SiO2% (Attached Excel File). Kindly suggest me best and easiest way to remove the carbonates from sediment powder (oven dried) before doing the XRF analysis. The procedure should not be time consuming since I have huge data.
Looking forward to your kind replies ASAP.
Thanks & regards,
Ashok 
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HCl is by far the easiest method if this acid does not alter other mineral phases such as clay minerals. You can also try to use warm formic, acetic or citric acid I presume.  
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I am building a 3D orthomosaic of a Carboniferous coal face and I have projected it in agisoft. However, it has projected with the z-axis coordinates in reverse, I think this may be due to the camera as this is the first time that this has happened. How do you change these coordinates? Does anyone have a link to a tutorial for the coordinate system on agisoft?
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Francois-Xavier
Have you got any further with resolving this problem? I think that it is a case of converting a geographic to mathematic coordinate system, therefore if the coordinates are converted to local datum it might work, it has worked for one of my models so far but failed with a few too!!
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I am studying sandstone with high ferruginous and matrix content, existing schemes do not account high Fe content, any suggestion will be appreciated.  
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Nice thin section photo!
There are two aspects of maturity in sandstones.  One is textural maturity, which is indicated by well sorted, well rounded sand grains.  The other is compositional maturity, which is indicated by a high proportion of quartz and a stable heavy mineral suite dominated by the likes of zircon, magnetitie, etc.  Most of the time, textural and compositional maturity go hand in hand, but not always.  The quartz grains in your thin section are pretty angular still, so this rock is definitely not texturally mature.
Yes, I think that even though this proportion of cement is high, cement is diagenetic, and not part of Dott's classification.  This would be classified as a ferruginous quartz arenite to me, but in the more detailed description (which you have done very well) you would point out the high amount of cement.
I am working on the Jacobsville Sandstone, which is Neoproterozoic in age and found in the Lake Superior area.  In places it is very similar in texture and composition as yours.  My work has been on its age, provenance, and tectonic significance, but folks before me have worked on the sedimentological characteristics.  There are a couple of papers that I have up on ResearchGate that may interest you.  Lots of references in there on the sedimentology.  There is a very high proportion of hematite cement in places and it is difficult to tell whether it is matrix i.e depositional (some is definitely detrital and eroded from the underlying BIFs) or cement i.e.diagenetic in places.  There are some folks who are working on isotopically dating the hematite.  If you like I can send you some hand specimines or heavy mineral splits, just let me know.
Good luck,
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Have you know that the last or/and the best sedimentary basin classification?
Is there a classification for (of) an energy source or  (of) a tectonic evalution source?! 
How do we get source from these classification? 
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Sedimentary basin and sediments  can be classified on the basis of tectonic evolution and tectonic induced sedimentary processes. This can be done by combining the tectonic events with sedimentation. Exactly the figure tell the answer of your question. This explain the relationship of tectonic conditions, basin formation ie classification and mineralogic as well as chemical characteristics of sedimentary rocks.
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One would expect the volume of clastic sedimentary rock to steadily increase from zero in Hadean times. But how much has this been affected by processes like subduction?
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I'm studying a stratigraphic section where clastic sediments are up to 400 meters thick. I have recognized three depositional environments being alluvial fan, fluvial, and marine. In the upper parts of the stratigraphic column where fluvial system turns into marine I was wondering if I've missed to record delta where these two systems intersect. The lithology in the upper part consists of an alternation of large cross-bedded conglomerate and sandy bioclastic limestone which clearly shows the sea-level fluctuation for a fair amount of time before marine conditions dominated. Did I miss recording Deltaic environments or fluvial deposits were transported to the sea with some sort of channels? 
attached photos may be helpful.
Thanks for the comments in advance. 
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Dear Ahmad
 As I said in my previous note, the climate was likely hot and dry and only seasonal flow occurred. Additionally, you most probably are looking at the fanglomerates which were deposited in the alluvial fan(s) in a coastal setting. Resultantly, you may not see typical deltaic sedimentation (delta plain, estuarine etc.) which would be transitional between terrestrial and marine environments.
Nevertheless, you are seeing interbedded fanglomerates and carbonates in the upper part of your section. That likely resulted due to base level rise and resultant transgression. And if your overlying section is only fanglomerates, then within the fanglomerate-carbonate zone lies the maximum flooding surface.
To answer your query, I would say yes; no typical transitional facies development.
Take care.
Saif
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In my project, I have petrograhic data ( SEM, thin section, Core/sw/cutting samples) and calibrated Gamma Ray curves to identify the reservoir's quality.  My target is the arkose sandstones with abundance of granitoid fragments. The sandstones are interbedded with clays. Both granitoid fragments and clays shows high GR values. How can i distinguish them ?
Thanks for your answers
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Dear Mr. Nguyen,
Total counts of gamma radiation are not very helpful and can only be used in combination with other petrophysical methods. If you can discriminate between Th, U and  K the situation turns towards a more positive stand. You have to go to the source of  radioactive elements in clay and granitic fragments.
Th: caused by high contents of heavy minerals such as monazite, zircon, xenotime... They are present in granites but not in a low-energy regime with lots of clay
K: is typical of K-feldspar and mica (mainly illite and muscovite) both may be present in granites as well. Arkoses tend to be strongly kaolinized and thus the K feldspar gets reduced much stronger than the muscovite content. If strongly kaolinized K may be very low and only some Th-bearing heavy minerals survive. Apatite which has a low U content of max. 200 ppm U is going to be decomposed in this acidic environmeent of an arkose, whereas zircon, xenotime and monazite survive. Th is not encountered in shales but U can do so (see next).
U: Given there is no U mineralization (granites used to have when unmineralized between 3 and 15 ppm U, depending upon the degree of fractionation) U is accommodated into the heavy minerals listed for Th, but mainly adsorbed onto clay minerals such as mica
I do not like simple ratios without having any clue of the mineralogy of rocks. Maybe the paper attached may direct your thoughts in a proper direction.
Best regards
H.G.Dill
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The paleocene eocene thermal Maximum Events t associated by several minerological and chemical changes .The Sr 86/87 ratio may clarify that. 
In Dabdaiba section from Eygpt auch phenomena have been cheked. 
In kurdistan region such boundary associated by Incised valley deposits and apperance  of Giant Gastropods. 
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Dear Fadhil
According to Pearce et al., 2012 which show  that changes in the flux of Sr to the oceans during the PETM can be accounted for using the radiogenic Sr isotope system (87Sr/86Sr), enabling variations in δ88/86Sr to be attributed to shifts in the carbonate output flux. New δ88/86Sr, 87Sr/86Sr and Sr/Ca data from the PETM are presented from well-preserved planktonic foraminifera collected from Shatsky Rise in the Pacific Ocean. Foraminiferal calcite has been demonstrated to preserve the δ88/86Sr composition of seawater7, and all samples were handpicked to ensure that only specific species and size fractions were analysed. The new data is compared to previously reported variations in Sr/Ca ratios from the Pacific Ocean, Southern Ocean and Tropical Atlantic 3.
Gleason et al., 2001 suggest comparison of the 87^Sr/86^Sr isotopic ratio of fossil fish teeth (ichthyoliths) with the global seawater Sr curve should provide a highly accurate method for dating pelagic clay cores. This is potentially useful for deep sea red clay cores that are rich in ichthyolith material but barren of other fossils. The strontium component of the fish teeth is assumed to have grown in isotopic equilibrium with seawater.
However PETM can correspond with bio-event along Paleocene/Eocene boundary.
Regards
Massih 
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Does anyone know how to use NTG and porosity to know the depositional environment in a clastic environment?
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In order to define a depositional environment from logs, you need to do correlations between the wells (connect certain rock bodies in one well to those exist in another well) in addition to looking at well signature. A well is only one point and you need to link the points together to understand the depositional environment. You can do that by drawing a line from south to north, east to west, ..etc in all directions and link the bodies to one another. Once that is done, start looking at possible environments and possible depositional direction. At the well level, high NTG and thick sand bodies can tell something different from layered/shaly low NTG. I am attaching a picture for GR signature for a certain environment (Serra and et al., 1975.) and a picture for log signature for certain depositional environment (wikipedia). As you can see from the picture and from the fact (as you know) that lower GR represents larger sand bodies, the self, delta, distributary channels (mouth bar) and aeolian have higher NTG in general than submarine fan.
Other things you can try to do:
1. From logs: check for sequences like  Bouma sequence which tells you that you are dealing with turbidite environment. 
2. From cuttings: check for fossils (living organisms ramaning) and try to define the environment in which such organisms live in. For example, bioturbation indicates shallow marine environment. 
3. Benchmark to nearby fields. Other fields might have the same deposition source for your reservoir. 
4. Use your seismic data to define geometries of the sand bodies (this can help you to limit the possible options or at least eliminate some possibilities). For example, you can recognize channels, submarine fan .. etc easily using seismic data.
There are 4 sources that did the same thing you are trying to do, please search for those:
1. Depositional Environment and Petrophysical
Characteristics of “LEPA” Reservoir, Amma Field,
Eastern Niger Delta, Nigeria
2. Characterization of fluvial hydrocarbon
reservoirs and aquifers: problems and solutions
3. Submarine fans and related depositional systems II] variability in
reservoir architecture and wireline log character
4. Interpretation and recognition of depositional systems using seismic data.
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Observe this structure during a geologic mapping of coal.
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Dear Mr. Oluwajana,
I can only support the previous answers to the question which were more a sort of a soft claim of getting more information about the environment of deposition and of the positioning of the image.
It is a clayish matrix and the concentric rings show a slight change in color caused by a variation of the valence state of Fe, due to oxidation. The diameter of the tubular structures lies between that of a tree trunk and a simple root fragment. They are well oriented and as such they might fall into the size range covered by the above floral remains.
Another feature very common in environments abundant in bituminous material belongs to the natural gas seepages which are known from many places such as the Eocene beds of Pobitite Kamani, Bulgaria.
So far there is a lot of uncertainty in my answer due to the lack of information on the internal texture of the tubular or ring-like structures and the host environment. I attach two papers of mine, one from a true coal-bearing environment the other from a transitional environment of the Nepalese Kathmandu Lake, where lignites and bituminous sedimentary rocks occur side-by-side nearshre. Maybe both papers help you to restructure your question and to single out the features you find of assistance in the interpretation of the host environment and the physical-chemical regime.
At the current stage I do not dare to give you a clearer answer.
Best regards
H.G.Dill
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Most of the known successions interpreted as tide-dominated deltas (e.g. Lajas, Tilje Fms.) have recently been reclassified as fluvial-dominated, tide-influenced because of the recognition of typical fluvial-derived features, such as forward-accreting, coarsening-upward mouth-bar deposits, crevasse-mouth-bar deposits, signs of seasonal variations of the fluvial discharge, etc. 
Following this trend, it is arguable that the sand-rich successions that are commonly interpreted as tide-dominated deltas might be more fluvial that what was originally thought  and that ancient tide-dominated delta successions have not been described yet. Does anybody know ancient deltaic successions that are convincingly and extensively tide-dominated? Why? 
Thanks in advance to anyone that will contribute to this discussion.
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Dear Mr. Gugliotta,
the question is, "how ancient" the reference examples should be.There are some classical tide-dominated deltas which date back into the recent past of the geological history such as the Ganges-Brahmaputra , Kiang-Langat ., the Fly River, Yolu and Colorado systems.  There are good publications about the Gironde system, including some sequence stratigraphic approaches. Diessel (1993) also gave an overview of this environment as to the deposition of coal.
Best regards
H.G.Dill
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I have 10 microfacies for Permian Mixed-Carbonates as follows: 
Calcareous Sandstone Facies
Crinoid, Bivalve, Brachiopod, Fusulinid, Bryozoanal Calcareous Sandstone Facies
Bryozoan, Bivalve, Fusilinidal Calcareous Sandstone Facies
Fine grained Dolomitic Calcareous Sandstone Facies
Bivalve, Brachiopodal Sandy Packstone
Bryozoan, Bivalve, Brachiopodal Calcareous Sandstone Facies
Crinoid, Bivalve, Brachiopodal Sandy Wackestone Facies
Brachiopod, Bivalve Calcareous Sandstone Facies
Medium grained Dolomitic Calcareous Sandstone Facies
Quartz Wacke Facies
..... Also straight Vertical burrows at places and branching burrows as well. Pic1:Vertical Burrows, Pic2:Dasycladacean(green algae, Pic3:Complex burrowed horizon (may be Thalassinoides, Pic4:Fusulinds, Pic5: Horizontal and vertical branching Burrows, Pic6:Thalassinoides (Skolithos burrows.
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Dear Nisar,
maybe these two papers can help you about the interaction between carbonate and siliciclastic sediments, and the construction of a depositional model.
TOMASSETTI, L., BRANDANO, M. (2013) Sea level changes recorded in mixed siliciclasticcarbonate shallow-water deposits: The cala di labra formation (burdigalian, Corsica)Sedimentary Geology, 294, 58-67;
. BRANDANO M, TOMASSETTI L., BOSELLINI F. & MAZZUCCHI A. (2010). Depositional model and paleodepth reconstruction of a coral-rich, mixed siliciclastic-carbonate system: the Burdigalian of Capo Testa (northern Sardinia, Italy). Facies 56,433–444;
I hope to be helpful.
Demetrio
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My sample is only identified as boulder clay from Marks Tey in Colchester UK. How can I find the predominant clay mineral in it?
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you can refer to one book X-ray diffraction and the identification and analysis of clay minerals 1997
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Hello everyone,
Have any of you used CT scans of sediments to get a density profile/trace? Specifically, I am working with marine and lake sediment cores. I have used CT scans before for their imagery and have exported profiles of their densities based on their grayscale values in ImageJ, Sante DICOM Viewer, and Osirix, but we'd like to move into using our CT scans a bit more quantitatively. I processed the dicom files with the same window and level settings within individual cores, but was not always able to use the same settings from one core to another when I created images (.jpegs, .tiffs, etc.) from the dicoms (sandier cores would be washed out or muddier cores would be too dark to see detail otherwise). Now, though, we'd like to access the actual, or as close to actual, densities as possible. I've read a little bit about calibrating CTs to a known value (I was thinking air that got imaged around the cores, or their PVC/plastic core liners) and about using the Hounslow scale to at least approximate actual densities. I was wondering if a) anyone's got any thoughts on finding good ways to tie CTs to actual densities, and b) if anyone can think of any pitfalls to watch out for while I do this.
Thank you for any help or suggestions you can give!
- Bran
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Hello Mihai and Ferdinand,
Thank you both for responding so quickly! Mihai - looks like you've confirmed some of my concerns about properly calibrating my scale. I think it's going to take some special consideration. Thank you for the link, Ferdinand. I will take a look. 
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I mean how fast will they be disintegrated? How far from the Bryozoan reef will they be in less then a millimeter in size? Do you know any experiment concerning this subject?
Thanks for any news. Zbyszek
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I think hydrodynamic regime and  substrate  along with genus are the key factors rightly pointed by André Klicpera.
I can suggest - Dr. Paul D. Taylor, NHM London and Dr.M.A. Sonar  from Institute of Science, Aurangabad, India may give you the answer.  
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The annual nature of what we now call varves was independently suggested in Sweden and in several places in North America in the late 1800's. We know of these because of the universality of the english language and the pioneering work of the Swede DeGeer in showing the usefulness of varves. HOWEVER, it has always occurred to me that other countries (Germany, Lithuania, Estonia, Russia, etc.) have varved sediments, AND there could have been early geologists that also made the conclusion that they were annual. The rest of the world is not aware of these because these early descriptions are 'locked' in these other languages. Does anyone know of any non-english, non-swedish papers that independently deduce that 'varves' are annual?
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P.S. Albert Heim (1885, in Handbuch der Gletscherkunde) discusses annual changes in the style of meltwater flow but does not really go into a deeper discussion,
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Other major oxide values are within limit of PAAS value.
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Higher Fe2O3 is undoubtedly due to oxidizing environment. For CaO, you need to see its source - detrital feldspar or calcite cement. Calcite cement is generally characteristic of warm and arid climate.