Sedimentology - Science topic

What is the impact of climate change on stored snow and its significance in the Tibetan Plateau and the Himalayas?

The Himalayan range, which extends over~2400 km, constitutes the largest concentration of snow and ice after the two Polar Regions and is highly sensitive to the ongoing climate changes. The region feeds three major river basins namely: the Indus, the Ganga and the Brahmaputra Basins (Fig. 1) which in turn support a population of more than a billion people. Though there has been a large interest in studying the climatic variability over diferent parts of the cryospheric domain of the Himalaya, there still exists a wide gap in ground-based data as also the uncertainty in data on most aspects (Azam et al. 2021) such as the highly heterogeneous behaviour of glacial melting (Hugonnet et al. 2021). There is a negative balance in the eastern Himalaya, a relatively less negative mass balance in the western Himalaya and a in the Karakoram these are in balasnce. (Amir et al. 2018). Similarly, the estimates of snow cover and rainfall are also highly variable mainly because of an inadequate meteorological observatories in the highly inaccessible mountainous terrain. The decline in the glacier mass balance alters the local and regional hydrological cycle and is a major concern for the agrarian economy of India. Several Indian research institutes, governmental organizations, IITs, and Universities are engaged in conducting research and studying the dynamics of glaciers and their impact on the hydrological cycle natural hazards through remote sensing techniques and ground observations. A brief review of work related to the contemporary dynamics of glaciers in the Himalaya has been articulated in Kulkarni and Shirsat (2020), Sharma et al. (2021), Kulkarni et al. (2021b), Pant et al. (2018), Romshoo (2023), Arora (2018) and several others. A comprehensive data repository on the contemporary as well as paleao glaciers, from Sikkim in the East to Himachal in the West has been reconstructed using techniques ranging from geomorphological mapping, sedimentological analysis, geochemistry, absolute dating of soil and rocks using Infrared Stimulated Luminescence (IRSL), and 10Be Terrestrial Cosmogenic Nuclide (TCN) surface exposure dating (Sharma et al. 2021). Glacial mass balance studies and chronologies, landscape evolution Western Himalaya The topographic analysis of the various glacial valleys in the Western Himalaya (Fig. 1) such as the Sutlej and Bhaga basins indicates a general tendency of loss in smaller glaciers; losing a higher percentage of area as compared to the larger glaciers (Das et al. 2023a, b; Mandal and Sharma 2020). Analysis of a total of 306 glaciers (>0.2 km2 ) with an area of 360.3 ± 4.0 km2 , inventoried between 1971 and 2020, showed accelerated glacier shrinkage (∼8.2±1.5% or 0.16 ± 0.03% year−1) during this period which correlates well with the climatic variability. The signifcant winter temperature increase and year-round precipitation decrease in the Bhaga basin, since the 1990s, have probably augmented ice loss during the early twenty-frst century (Das et al. 2023a, b). Most of the glaciers in this basin have experienced critical thinning and lost huge ice mass in the range from − 6.07 m w.e. to − 9.06 m w.e. during 2008–2018 (Nagajothi et al. 2020). In-depth work in the transitional zone between the monsoon-dominated Pir-Panjal and westerly-dominated TransHimalaya Chandrabhaga basin (Das et al. 2023a); including the Miyar and Thirot watersheds in the Upper Chenab, has been carried out in the recent years (Deswal et al. 2023). The ice mass loss of Gepang Gath Glacier (GGGL) in Chandra basin, western Himalaya was assessed by Kumar et al. (2021a) using multi-year satellite dataset of Landsat series (TM, ETM+and OLI, 1989–2017), indicating~0.28 km3 of ice volume loss between 1989 and 2017. The glacier retreated~846 m with an average rate of 30 m a−1 and lost~0.73±0.05 km2 frontal area from 1989 to 2017. The studies over parts of western Himalaya covering the ranges in the upper Indus Basin (Romshoo 2023; Abdullah et al. 2020) using the TanDEM-X and SRTM-C Digital Elevation Models (DEMs) from 2000 to 2012 have shown that 12,243 numbers of glaciers of the region have thinned on an average of −0.35±0.33 m a−1 during the observation period. Higher thickness reduction was observed on the glaciers situated at lower altitudes (−1.40±0.53 m a−1) and with shallower slopes (−1.52±0.40 m a−1). The cumulative glacier mass loss of−70.32±66.69 giga tonnes (GT) was observed during the observation period, which, if continued, would signifcantly afect the sustainability of water resources in the basin. Rana et al. (2023) described the morphological and dynamic changes of Parkachik Glacier, Suru River valley, Ladakh Himalaya using satellite images of the period, 1971–2021 supported by feld campaigns between 2015 and 2021. The result reveal that overall, the glacier retreated by − 210.5 ± 80  m with an average rate of 4 ± 1 m a−1 between 1971 and 2021. In contrast, a feld study suggested that the glacier retreat increased to−123±72 m at an average rate of−20±12 m a−1 between 2015 and 2021. Under an integrated Himalayan Cryospheric Observation and Modelling (HiCOM) program, National Centre for Polar and Ocean Research (NCPOR) has been conducting glaciological studies on six benchmark glaciers of Chandra and adjoining basin in Western Himalaya to collecting ground data for estimation of glacial mass balance and energy budget of glaciers. These studies have revealed that the mean annual mass wastage of Chandra basin glaciers was −0.21 m w.e. before 2000 which increased signifcantly to−0.56 m w.e. after 2000 (Patel et al 2021). Chandra basin has lost 3.8 GT (0.62 m w.e a−1) of glacier mass with a mean thing of 5.5 m during the last 9 years (2013–2022). Annual mass loss of monitored glaciers in the Chandra basin varies from+0.71 m w.e. a−1 to −1.65 m w.e. a−1. A model-based study revealed that the Chandra basin glaciers have been losing mass with a mean annual mass balance of−0.59±0.12 m w.e. a−1 during 2013–2019 (Patel et al. 2021). Similarly, other adjoining basins Miyar and Parvati have also been continuously losing a huge mass (0.85 m w.e a−1). Studies related to energy balance in the Chandra basin (Oulkar et al. 2022; Pratap et al. 2019) have highlighted that inward fuxes account for most of the total heat fux over the ablation zone, resulting in strong summertime melting. The study revealed that the net radiation (RN) contributes~75% in total energy (FM) during the melt season while sensible heat (HS), latent heat (Hl ), and ground heat (HG) fuxes shared 15%, 8%, and 2%, respectively. Net short-wave radiation progressively increases during ablation and decreases during winter but net long-wave radiation works as a sink of energy throughout the year. Higher positive sensible and latent heat fux over the ablation zone during summer of the glacier surface enhances the ice ablation and contributes~88% of total ice melt. Geological Survey of India (2020) has been monitoring Neh Nar, Rulung (Jammu & Kashmir); Gara, Gor-Garang, Shaune Garang, Hamtah (Himachal Pradesh) on a long-term basis, for example, the mass balance studies of the Hamtah glacier that started in 2010 are still going on. Based on the geomorphological mapping, Infrared Stimulated Luminescence (IRSL), and 10Be Terrestrial Cosmogenic Nuclide (TCN) surface exposure dating techniques, various stages in the movement of glaciers in the Chandra basin have been dated. The oldest Chandra Glacial Stage is found to be contemporaneous to the late Marine Isotope Stage 6 (MIS 6; 186±30–113±10 ka) and also synchronous with some of the north-western Himalayan established glacial chronologies (Das et al. 2023a). Four local glacial stages in the Upper Chenab basin are: 1. the Chandra, 2. the Batal, 3. Dali, and 4. Mayar; each succeeding advance stood many degrees smaller than the previous episode. A similar corresponding trend exists for the adjoining Beas basin but each episode is many degrees smaller in magnitude. Results indicate that since the presumed Little Ice Age period extensions, glaciers in the region have experienced terminus retreat and area loss (Deswal et al. 2023).

Hello!

I'm carrying out a sediment grain size analysis to build a grain size distribution for several lagoon site samples to get a sense of sediment heterogeneity at my sites, and I've had some issues analyzing raw data due to combined methodologies. If any folks well-versed in granulometry or sediment grain size analyses can help, would be greatly appreciated!

I have been using USGS grain size analysis practices on my samples with EMAP (Strobel, 1995), namely standard coarse sieving for any grains larger than 63 µm, and the pipette method for fine particle analysis on anything smaller. However, I am having issues with delineating between coarse and fine grain size due to an additional procedure step with my samples. I used standard coarse grain sieves as a first filter on my samples, then vacuum filtered remaining sample liquid through a fine mesh filter of 43µm. After this, I carried out standard pipetting procedure on samples of less than 43 µm in size. I believed vacuum filtering in between coarse and fine filtering would give me more accurate direct data on sediment weight because mesh filters of a smaller size than 63 µmwere on hand and used for other sediment analyses. I'm now having issues with building % for each sediment size, because while I have weight of coarse grain and weight of fine grain through the pipette grain settlement method, I now have an in-between metric that falls between <63µm and >32µm, between sand and silt in the coarse silt in-between of what I assume is categorized as Phi 4.5. I am primarily confused as to whether I can count this vacuumed sample because it falls at that 4-5 and is the raw weight of any sediment of that size range, while the pipetting protocol bases the entire fine sample weight on the first aliquot of a 1000mL sample of essentially sediment grain of Phi = 4, much of which I assume I filtered during vacuuming. Can I still use standard pipetting calculations? What can I do to make use of relative grain size data?

Any help or suggestions would be so appreciated, thank y'all!

Hello, I am a PhD student in sedimentology and biostratigraphy, and I have a fossil leaf specimen from a Jurassic-Cretaceous deposit. I would like to receive recommendations on fossil plants used in stratigraphy, especially the upper jurrasic and lower cretaceous. Additionally, if possible, could someone help me find specialists or relevant articles on Jurassic and Cretaceous fossil plants?

Thank you very much for your assistance!

Research collaboration welcome, Earth Science ?

Dear Geology Community,

I am currently researching the dating of detrital zircon in metasediments. Due to the small size of my samples, traditional mineral separation methods may not yield a sufficient number of zircons. However, I have observed numerous zircons in thin sections, with at least 20 visible in each.

I am thinking of making multiple thin sections for each sample, to directly date the detrital zircon present in the matrix and as inclusions. My question is: Could this method potentially influence the representativeness of the dates obtained? Are there any published studies that have employed this method?

Thank you in advance for your insights!

Hi everyone.

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?

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.

These organic walled microfossils are from Late Cretaceous intertrappean sediments.

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

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 ? 

Dear all,

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,

Yanhua Xu

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.

Thanks

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

During an examination of outcrops around Wadi Halfa North Sudan we found a discoidal shape grain of Barite Concretions or Sand Barite.

Dear collegues,

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.

Thanks,

Ben

Dear colleagues,

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,

Luca

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

Sedimentology, Geology 

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:

Regards

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?

Thank you!

Does anybody know a free software to draw a sedimentological log with comments and sample locations? I tried installing Sedlog but does not work on my PC. Thanks

Palynological/ Sedimentological/ Facies interpretations

We want to model shoreline change and morphological changes there.

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.

Thanks

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

Dear Sedimentologists/Geologists

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.

Regards

Ijaz

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.

Please, i'm looking for a copy of a Book : "Principles of Alluvial Fan Morphology ( Dan Bowman )", can you help me to find it ??

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

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

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?

These microfacies belang to Cretaceous plagic limeston in the Azerbaijan (NW Iran). I cant identify plancton microfossils.

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.

These deposits were from mud caps of sediment gravity flow deposits. These mud caps are homogenous and no trace fossils can be identified. Can any one help me identify these aggregates? Thank you very much! The SEM images are attached.

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,

Damien

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.

Thanks.

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?.

Dear all,

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.

Thanks you.

Ashok

Slump structure

such as homogeneity particle size index.

Especially for sandstone and limestone.

And how they can be calculated (With math calculations).

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

Dear all,

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,

Ashok

Dear Colleague,

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.

Sincerely

Massimo

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?

carbonate sedimentology - petroleum geology- diagenesis- sequence stratigraphy

I am studying facies sequence of Tertiary rock in Bengal basin.

I'm going to be coring in a terrestrial environment (ravines near a river). This area has experienced erosion from logging, then agriculture and now construction. I want to be able to tell which layers of sediment are from logging/agriculture/construction to gauge their impacts over time. I'm a grad student and the budget for this project won't be enough to send the samples to another lab for processing, so I'm trying to find out if our facilities will be adequate.