Questions related to Sedimentology
Can you say that unconsolidated sediments that deposited in a high energy environment like creeks and rivers possess a higher bulk density and thus a higher stiffness than unconsolidated sediments deposited in low energy environments like seas and lakes? This question originated from the geotechnical evaluation of drillings and Dynamic Penetrometer tests.
Hints for papers or other literature are welcome.
I'm studying an upper Aptian carbonate succession of NE Spain which has traditionally been considered to be devoid of rudists due to paleoenvironmental stress. I'm not at all familiar with this group, as indeed I haven't come across a single specimen in 4 years of field research.
However, these pictures of one of my reference outcrops, sent to me by a local, show some strangely shaped fossils which I cannot for the life of me identify. All pics are of the same stratigraphic level, which corresponds to a regional discontinuity surface which could have been subaerially exposed for prolonged amounts of time.
What do you see in these pics?
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?
Rewoquat has been used by numerous authors to free microfossils from tightly-bound shales. I first became aware of the material when reading Jarochowska et al 2013. A virtue of the material is that delicate fossils may be freed without exposure to strong acids or bases. Unfortunately, the material can be difficult to source.
I obtained a sample of the material recently. During a test, I found that Paleozoic shale flakes resistant to disaggregation readily dissolved into a clay slurry when placed in the Rewoquat (see images).
I have found that disorganized demand for the material currently exists, but the up front cost of the material is prohibitive. I was quoted a price of approximately $10.64 per liter (before shipping), but the minimum order size is a 208.2 liter drum. If demand can be organized via a distributor or through geological institutions or museums, the price of the material could be shared amongst prospective buyers. A distributor may also be required for international shipping in order to make export from the United States possible.
I was curious how much interest there is in this particular chemical, and what strategies might be employed to increase it's availability to interested researchers.
Need to correlate the enclosed sediments with their depositional environment and condition either they are in situ or derived in nature.
I am working in the lake sediment system and I have both radiocarbon and osl ages. In order to build a full chronology of the lake is Bayesian age depth model a good option? If not could you please suggest me the alternatives? Thanking in advance.
I am aiming to generate 3D profile of subsurface formation using VES techniques . I have DDR3 Electrical Resistivity meter (http://www.indiamart.com/proddetail/ddr-3-resistivity-meters-3894683488.html) to carry out this studies. Is it possible ?
If it is only software dependent, which software can be suitable for interpretation and 3D profile generation ?
The geological meaning of Cao* seems not to allow the occurrence of negative cases, but in the face of the high content of P2O5 (close to Cao), resulting in caO-P2O5 * 10/3 of the result is negative, how should I deal with this situation, what may be the geological reasons?
Looking forward to your kind suggestions in this regard!
Thanks & regards,
I am working on the Triassic period and particularly sedimentology, petrography, porosity, fracture and Diagenesis.
who worked at this period and has related paper.
I appreciate it.
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.
In the volcanic-sedimentary sequence (teschenite association, Outer Western Carpathians), layers of very fine-grained sediment with an extremely high microcline content (up to 80%, the rest is calcite) were found in shales in close contact with the effusive volcanic (highly altered mygdaloidal trachybasalt?). Feldspar is up to 5 μm in size, hypidiomorphic to idiomorphic. The rock lies clearly outside the volcanic body, but is also finely amygdaloidal.
Is it possible that it is a sediment from hydrothermal activity or what is it about ??? Is there any literature on similar rocks?
As we know, it is a very difficult task to differentiate tsunami deposits from storm deposits. Sedimentological (grain size, grain sorting, sedimentary structure and sedimentary fabric), palaeontological, geochemistry and geophysical analysis are the most common methods to identify and characterise the tsunami deposits. Recently, X-ray computed tomography is being used in grain size, sedimentary structures and fabric analysis. Can we consider X-ray computed tomography as a unique tool that could discriminate between storm and tsunami deposits?
I am studying clays diffraction (air dried, treatment with etilenglycol and heat treatments).
Maybe other mineral association could help? Presence of other minerals (i. e. alunite)? I don´t need to be 100% sure but I would like to know how to predict the predominance of one of them.
Thank you very much
I am looking for papers in the field of sedimentology using the line count method for componentry measurements. The line count consist in using a 1m long tape (or longer sometimes) and measure the intersection length of clasts/particules found along the tape.
I struggle to identify these sediments, which I suspect to be fluvio-glacials deposits alluvial from melting glaciers in Eemian.
The area where this conglomerate is exposed have a bed from recent Riss and located 500 km from the Alps (eastern France)...
I'm not expert, so I would be grateful for anyhelp.
In the geological map, I cercled in violet the light yellow area (Recent Riss).
Thank you !
Hi everybody! Does anyone may suggest me some useful references (papers, books) for the interpretation of the signals emitted from the organic matter preserved in the sediments? Can be great to find a sort of table reporting the different kinds of organic matter (e.g., algal, terrestrial) and their response under specific emission filters.
Thanks in advance,
Hello, i have a sandstone in thin section with 15% matrix from marine deposition and i am confused with this mineral appearance in xpl it has gold colour and in ppl it has brownish yellowish colour but i can't identified it's name. I think it's calcite or lamonite but i doubt it. If you know it please help me
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.
I'm dealing with Upper Cretaceous microfossil association that consists of ostracods and foraminifera. Source material – sandstone and marly limestone – was disintegrated in water with some Hydrogen Peroxide (30%) added to solution. The problem is that microfossils are not totally liberated from the rock and still have pieces of it attached to their carapaces and tests.
Can somebody please give me some hints on how to remove unwanted material?
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)?
The samples were collected from aquifer with the following lithology:
- Conglomerates, calcareous limestones sand red and green clays
- Marls, clays and white limestones
- Clays and gypsum;
In some stratigraphic section, quartzites represents the UNCONFORMITY LEVEL or basement.
Could anyone recommend me some "reference studies/review papers" that explain "why quartzites represent the unconformities"?
I am looking for a master's degree in a good university specializing in sedimentology and diagenesis of carbonate rocks. Could you guide me?
Many time people use HCL before granulometry analysis of sediment and how it affect the overall size of the original material. If we are in deeper environment, then the main source of material is biogenic apart from terrestrial input, because the material derived to this environment is mainly pelagic sources (Benthic, Siliceous, Planktonic forms).
What is the best practice to do the analysis without affecting the originality of the material. Please provide your opinion so that i could clear my understanding about the procedures involved behind it.
I have performed d 13C carbonate in Cenomanian-Turonian core samples and got negative values, I need an explanation from sedimentology and petrology point of view.
the target to detect the positive excursion of OAE2
**you will find plotting to the values attached
Thanks in advance
The classical stratigraphic sequence of the Salt Range contains thin flows of an ultrapotassic rock at its base. Commonly known as Khewra trap, it occurs at the top of the very late Proterozoic to Early Cambrian rocks consisting of marly anhydrite/gypsum, and oil shalis overlying evaporites. The trap is an unusual rock consisting of euhedral to skeletal, spinifex, stellate phenocrysts
in a very fine-grained to cryptocrystalline, locally glassy, matrix. The phenocrysts (up to 3 cm long) are considered to be Mg-rich enstatite now complliely pseudomorphed by a mineral aggregate principally made up of talc with subordinate amoun'ts of Mg-rich clays and, locally, quartz. The matrix is unaltered and almost entirely made up of Na-Ca-poor and
Mg-Fe-rich K-Feldspar (sanidine-orthoclase), with granules, specks and dendroids of Fe-Oxide. Talc, Mg-rich clays, quartz, dolomite, and Fe-oxide constitute the amygdules.
Chemical analyses ofthe rock samples from the trap are remarkably similar in composition except for some variation in iron oxide due, probably, to leaching during alteration. The rocks consist approximately of 60 wt% SiO2, 0.7VoTtOy ll%o Al2O3,2-5% FeO, 10% MgO, 0.4% CaO, O.5% Na2O, 9% K2O, and 0.04% P2O5, Normatively the rocks are eisentially made up of orthoclase and orthofyroxene.
Petrology is a branch of geology concerned with the study of rocks. As we know, that the rocks are of three types, igneous, sedimentary and metamorphic. So, Sedimentary Petrology is the study dealing with sedimentary rocks: their origin, occurrence, composition, texture, etc. Now, another term used for the study of sedimentary rocks is Sedimentology which largely overlaps the former. With no sharp demarcation between the two, they appear to be interchangeable. Are they synonyms?
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 ???
What is the mode of genesis for these ring-like features and deposition environment of these sandstone boulders?
Location: Litra Nala, Taunsa Distt. Dera Ghazi Khan, Eastern Sulaiman Fold-Thrust belt, Pakistan
Thanks for feedback.
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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.
just wondering if there is any published material on how the stereochemistry of environmentally important biomarkers could be affected by the paleo-strain the rocks in a sedimentary basin were subjected to (e.g. folding).
I have an image of a metasedimentary outcrop from a Proterozoic continental rift-fill sequence (attached).
The middle layer has a pelitic composition and contains abundant cordierite porphyroblasts (visible as weathered depressions). The layers above and below this layer are more psammitic. The lower layer appears to display inclined cross bedding, whereas the top layer seems to be more massive. I suspect that this outcrop preserves a 'fining upwards' sequence with the psammitic layers representing the coarser (high-energy) deposition and the cordierite-rich layer representing a finer (low-energy) depositional phase.
What I'm not sure of is which way this outcrop is younging. Are the cross bedded layers deposited on top of the pelitic layer (i.e. the image is 'upside-down')?
Or, was the pelitic layer deposited on top of the cross beds?
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.
Dear colleagues Good day. Can I ask if any one have ever seen such hexagonal cracks (about 1 t0 2 cm in diameter) in marine marlstones. I will be very much grateful if any reference or interpretation is provided. Regards, Sincerely yours Issa Makhlouf Prof. of Sedimentology Hashemite University Jordan
Clay samples are heated at 950 degree centigrade (LOI method) before XRF analysis. Due to which Fe percentage increases in the XRF results. It is due to the oxidation of samples during fusion. Is there any procedure to correct the Fe value within the results?
I am working on the Archean Quartzite rocks from the western Dharwar Craton. I am need to use tectonic discrimination diagram using trace element. I have already used some diagram by major elements. So I am expecting the experts in the field of Sedimentology to suggest me some tectonic discrimination diagram for my manuscript.
I have been searching for some articles which may address the problem mentioned above. I could find some excellent papers dealing with origin of red beds in sand dunes but hardly any dealing with fluvial deposits of Holocene or Late Pleistocene.
Any help in this regard is welcomed.
Works on adhesion warts have shown that these surface features are usually originated by the adhesion of windblown sand on a wet surface. My question is:
Is it possible for wind-blown mud particles to form adhesion warts? Or the different particle size and kinetic energy preclude the formation of these surface structures?
Many thanks for the help!
I am looking for the causes that produce a HREE depletion in sedimentary phosphatic chalks of Late Cretaceous.
Thank you for yours answers,
I wish to do grain size analysis of sand. What experimental set up should I follow for it and how should I analyse the data. Please provide some references on this topic.
Most of papers/researchers regarding cyclicity using Markov Chains are from 1970's to 1990's. However, in the recent literature only a few papers deals with this method. To what extent the use of Markovian processes can control or explain cyclothems or coarsening-, and fining-upward cylces?. Analysis of cyclicity in recent literature is restricted to use astronomical forcing cycles (Milankovitch bands) of known periodicities by using spectral or fourier analysis, so then, we can assume that these are the today-acepted methods for assess cyclicity?, what do you think about it?.
I have calculated Fine content (Silt+Clay), Liquid Limit, Plastic Limit, Plasticity Index, Mean grain size, SPT value for soil samples. I need to obtain Clay % for my study. Kindly suggest a suitable empirical formula to calculate clay % from the above available parameters.
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.
I have collected soil samples up to a depth of 50m from surface during drilling. I need to interpret alternate cycles of dry and wet climate on the basis of soil types. What are the criteria to classify soils into Entisol, Vertisol, Alfisol, Oxisol etc. ? I would like to know the parameters like texture, color, amount of organic matter, presence of particular minerals, cation exchange capacity, and pH values to characterise the soil types. It would be really helpful if you kindly provide me the list or document where the parameters range are given to classify the soils.
Thanks & regards,
this is not a question. I want only share the following paper with you:
In this paper you can find the description of physical features of a S. spinulosa reef in the Mediterrenean area.
I am endeavouring to reassess some Australian palynostratigraphic zones for the Mesozoic, which no one has done (that I know of) since before the release of the latest geologic time scale (2012). Am I correct in saying that palynostratigraphic zones are determined by their stratigraphic placement in the rock record? So if the timing changes (e.g. the Middle-Late Triassic boundary shift from 229 to 237 Ma), the palynozones would become older like the stratigraphy and not remain where they are relative to the chronologic ages?