• Syed Abbas Jafar added an answer:
    What kind of foraminifera is that?

    Greeting agglutinated salt marsh foram's researchers,

    I have encountered in southern California salt marsh the following live&dead species in surface samples. Test flattened, ovoid in outline, planispirally enrolled and its wall is very coarsely agglutinated. I thought it might be Ammobaculites labvthnangensis (Loeblich and Tappan, 1988) but I'm not sure. I would appreciate your advice on that- see SEM images. Thanks:)

    + 2 more attachments

    Syed Abbas Jafar


    From the beginning your question and the pictures were confusing. The second set of pictures do reveal features of Ammobaculites without specific assignment. Coarse silt on the test of Ammobaculites and fine silt on the tests of Haplo. is misleading - see tests of H. volgensis. In some salt-marsh settings species of both Ammobaculites and Haplo. are common (see link: You need to freshly document and assess your material.



  • Tamar Beridze added an answer:
    Could anyone reccomend me examples of application of ichnology to the interpretation of the rocks hosting VMS deposits ?


    There are many examples of the use of ichnology in hydrocarbon reservoir studies.I'm interested if there are any examles of application of ichnology to theinterpretation of the rocks successions hosting VMS or even other types of metallic deposits (bathymetry,depositional enviroments,relationship of trace fossils development to the sedimentary basins  with volcanic actyvity). I have  one paper of Sainty R.A.(1992)Shallow-Water Stratigraphy at the Mount Chalmers Volcanic-Hosted Massive Sulfide Deposit, Queensland, Australia.  Maybe there is some more recent information?


    Tamar Beridze

    Dear Ashkhan

    Thanks for useful information



  • Hakima Belkhattab added an answer:
    Can anyone help to identify the fossil appearing feature in the photograph?
    It is from Krol Formation, Nainital, India which is considered Terminal Proterozoic sequence
    Hakima Belkhattab

    Dear K.K.Sinha,

    I think that the fossil should be Treptichnus pedum.

    Best Regards

  • Jean-Jacques Châteauneuf added an answer:
    What is the age and stratigraphy of the French Miocene shelly sands "faluns"?

    Can anyone tell me the age and stratigraphy of the Miocene shelly sands of Touraine (Savigne / Lathan) Saumur (Doue la Fontaine, Noyant la Plaine) and of Britain (The Quiou) and their correlation? I found the recent articles of Gagnaisson 2013 and Courville 2003. I work on echinoids fauna.

    Jean-Jacques Châteauneuf

    See message sent to you today with attached papers on "faluns" ages


  • Mohammad Ali Faraji added an answer:
    What is the petroleum system of the Santos Basin, Brazil?

    What is the petroleum system of the Santos Basin, Brazil?

    Mohammad Ali Faraji

    Hi Eugene

    Please see this publication


    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: The Brazilian sector of the south Atlantic margin includes a large number of oil bearing basins. Mærsk Oil is currently involved in the Campos and Santos basins which are two of the most prolific. These basins are characterised by a huge pile of sedimentary rocks with cumulative thickness in the order of 15.000-20.000 m. One of the main features is a thick interval (up to 4000 m) of evaporites located in the lower middle part of the succession, which allows a subdivision into a three large units known as Sub-Salt, Salt and Post-salt sequences. The source rocks for all the oil fields are the lacustrine shales of the Sub-Salt sequence. The organic matter is lipid-rich form algae and bacterial origin. There is a large range of reservoirs, from the basal volcanic rocks, the lacustrine and shallow marine carbonates of the Sub-Salt sequence to the turbiditic sandstones of the post-salt sequence. A common characteristic in all the reservoirs is the high porosity (15-20%) and permeability (1-5 Darcy) which enables high rates of oil recovery. Maturation of the organic matter is related with the progressive increase of geothermal gradient due to burial. The oil generation and migration took place in several pulses. The oil traps are located in the flanks of palaeogeographic highs and salt intrusions. The oil migrated from the lacustrine shales in the basal part of the Sub-Salt sequence trough faults and salt windows, down to the basalts and up the carbonate and sandstones reservoirs. Current challenges are related with the improvement of the seismic definition of facies and with the characterisation of reservoirs internal structure in order to improve the location the horizontal production wells.
      Full-text · Dataset · May 2013
  • Barbora Wouters added an answer:
    What are the relationships and differences between geological and archaeological stratigraphy?

    Has anyone published on the relationships and differences between geological and archaeological stratigraphic recording and analysis?

    Barbora Wouters

    Hey Keith,

    Just a quick answer to your previous post where you mentioned the graph from Rue de Dinant. 

    "Does the order, overlap, or duration of when these activities/events happen effect the nature of the resulting Dark Earth?

    How do people record those temporal relationships such as sequence, overlap or duration?

    Is there a sequence in how these activity/event processes happen?

    Does one event take place some time before the others?

    Do they 'meet in time' end to end?

    Do some of them occur at the same time? i.e. Do they 'overlap in time'

    Can we record the start and end point for each, or any, of them?

    What do the arrows in this diagram actually represent? where (if anywhere) are such relationships recorded in the data?"

    For some sites, it is easier to answer these questions than for others. For instance, I recently did the micromorph of a urban site called Lier (not yet published, but should come out in QI sometime next year) where three different dark earths are superimposed, in one case separated by a different, non-dark earth unit. In that particular case it was possible to pure out the relative order of some of the processes quite well, and we have very distinct interpretations for each of the dark earths that give a good biography of that particular place. Dating was also a bit more precise where the remains of a microstratigraphy could be distinguished within one dark earth and could be linked to the excavator's findings.

    We have been trying to think of a way to answer some of these questions (especially about the sequence and overlap of the activities/processes) in a single graph, but unfortunately, for dark earths we have to this date not found an adequate way of expressing these all at once. With the risk of stating the obvious, a big problem is the complexity of the mutual interaction between, and influence of these processes. Additionally, a few of them may occur more than once, or continue in interaction with other processes, if this makes sense. For instance, bioturbation and mixing will take place throughout the entire formation period, and afterwards as well, and may be strengthened or weakened by the amount of organic matter (still present), water table, C/N-ratio, ...; oxido-reduction and leaching of elements affecting soil fertility can have an influence on subsequent management/use by humans, etc. The arrows in this particular diagram represent the mutual interaction between some of these processes, and also that some of them reoccur.

    So far, the only (slightly disappointing) way we have been able to explain these complex relationships, dating of start/end time of certain processes where possible, duration of formation processes and their relative order, overlap and mutual interaction has been in the text (and I fear that this usually means the entire results and discussion section of a paper) that goes with the graph. Since dark earths are still not well understood among all archaeologists in the region where we work, it has mainly been an instrument to illustrate the number and complexity of processes that have led to dark earth formation, and why 'dark earth' can never be used as an interpretive term. Each situation is different and can be represented by a different graph. It's almost like a  summary or an index of processes. I still think there should be a way of refining these graphs, or connecting them to Harris matrices in some way, but am having trouble imagining how exactly. Perhaps a network model, where you link all the processes that influence a certain layer, could be a step in the right direction, but I'm unsure how one could add chronological data to this if they do not apply to the entire layer.

    More questions than answers from my end I'm afraid, but I hope I could at least illustrate some of the aspects of the type of graphs Yannick has introduced and we are trying to experiment with and implement further.

    I also completely agree with Rusty, archaeologists in Belgium would also benefit greatly from a better understanding of pedology, geomorphology and geoarchaeology in general. On the other hand, this type of graph may not have emerged if this was the case :).

  • M. F. Quamar added an answer:
    Which perspective of age-depth modeling is better, regression analysis or interpolation?
    Two perspectives of age-depth modeling prevail: (1) regression analysis, which represents a statistical expression of the data; (2) Interpolation, which reveals a deterministic relationship of the data. Which one is better?
    M. F. Quamar

    I wish I could also get a copy from prof (Dr.) Martin H. Trauth on the very interesting topic.

    Thanking you!

  • Mohammed Et-Touhami added an answer:
    How to correlate marine and continental Lower Triassic beds?
    A topic on problems of correlation with using of biostratigraphy and paleomagnetic data.
    Mohammed Et-Touhami

    Dear Vladlen Lozovsky,

    For pre-Jurassic time, the geomagnetic polarity reference scale is much less well developed than that for the Jurassic to Recent because of the absence of the sea floor and hence marine magnetic anomalies. Nevetheless, there is a published astronomically calibrated Geomagnetic Polarity Timescale (GPTS) for Late Triassic and Early Jurassic based on scientific coring of the Newark basin (NY, NJ, PA; USA) [1]. There are attempts to correlate marines sections to this geomagnetic polarity record which provides a well-dated chronostratigraphic framework [2] [3]. Furthermore, preliminary data from Morocco, suggests the possibility to extend this timescale down into the Middle Triassic [4]. So I think, it would be interesting if your Lower Triassic nonmarine magnetostratigraphic sections are continuous and have some chronostratigraphic control and lacustrine intervals for cyclostratigraphy to calibrate in time the relative spacing of polarity intervals.


    [1] Kent, D.V. and Olsen, P.E., 1999, Astronomically tuned geomagnetic polarity time scale for the Late Triassic, Journal of Geophysical Research, v. 104, p. 12,831-12,841.[2] Kent, D. V., Olsen, P. E., and Witte, W. K., 1995, Late Triassic-Early Jurassic geomagnetic polarity and paleolatitudes from drill cores in the Newark rift basin (Eastern North America). Journal of Geophysical Research, v. 100 (B8), p. 14,965-14,998.[3] Muttoni, G., Kent, D.V., Olsen, P.E., DiStefano, P., Lowrie, W., Bernasconi, S., Hernandez, F.M., 2004, Tethyan magnetostratigraphy from Pizzo Mondello (Sicily) and correlation to the Late Triassic Newark astrochronological polarity time scale, Geological Society of America Bulletin, v. 116; no. 9/10; p. 1043–1058[4] Olsen, P. E., Kent, D. V, LeTourneau, P. M., Et-Touhami, M., 2002, Astronomically calibrated GPTS for the Late Triassic and Early Jurassic based on the Newark Hartford and Taylorsville basins of Eastern North America. in McRoberts, C. A. and Olsen, P. E., (eds.), Triassic-Jurassic Non-marine Boundary Events in the Newark, and Hartford basins (New Jersey, Pennsylvania, Connecticut, and Massachusetts), Eastern United States, 2nd Field Workshop, June 7th-12th, 2002, Abstracts with Programs, p. 13.

  • Giuseppe Aiello added an answer:
    Can anyone give me any suggestions of why there is not any Ostracods in a marine formation dated of Miocene?

    I am working on a marine sediment dated as Miocene, from the northwestern of Madagascar (Ramihangihajason et al., 2014. « Miocene benthic foraminifera from Nosy Makamby and Amparafaka, Mahajanga Basin, northwestern Madagascar, Journal of African Earth Sciences 100, 409-417)

    Last month, I processed those samples in order to check the diatoms into them, but I didn't find even one specimen. So, I wonder if there is any explanation for that. Thank you

    Giuseppe Aiello

    Dear Aina,

    it is possible that the reason is oxygen. When the bottom oxygen is high ostracods and foraminifers are present. When the bottom waters are anoxic neither ostracods nor foraminifers occur. When the oxygen is low (not too low) you can record foraminifers and no ostracods, less resistent to environmental stress (except for salinity). For example:


    best regards,


    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: An integrated micropaleontological, geochemical and mineralogical study has been performed across the mid-Pleistocene sapropel 19 (i-cycle 90) from the Montalbano Jonico land section (southern Italy), to reconstruct the paleoenvironmental conditions at time of its formation. The sapropel interval is characterized by two oxygen depletion phases (phase A and C) interrupted by a temporary re-oxygenation interval (phase B). The beginning and the end of sapropel deposition are dated at 957 ± 0.81 kyr and 950 ±0.86 kyr respectively. The duration of the interruption is estimated to 0.350 ± 0.32 kyr. The multiproxy approach highlights that deposition of sapropel 19 reflects a period of enhanced freshwater runoff induced by a wetter climate. As a consequence of a more efficient fluvial erosion, a higher terrigenous input, mostly ascribable to a southern Apennines source, and an increased turbidity of surface waters accompanied most of sapropel deposition. Biotic and abiotic proxies document that different paleoenvironmental conditions occur through phases A–C. The beginning of phase A is characterized by warm on-land paleoclimate as well as warm and oligotrophic surface water conditions. During the upper part of phase A temperature starts decreasing and surface waters appear more productive. This change probably represents the prelude to cooler and drier conditions characterizing phase B, which displays a river supply reduction and an eolian input increase (Sahara dust). During phase C the restored depleted oxygen environment at the bottom sediments is clearly coupled with the re-establishment of humid conditions and increased river supply. At the same time, enhanced mixing of water column, a cooler paleoclimate, and increased productivity of surface waters are recorded, the latter likely favored by the enhanced mixing of water column and also increased delivery of land-derived nutrients. The end of phase C is marked by a restored “normal” run-off. Enhanced productivity in surface waters and low oxygen conditions at the bottom sediments persist slightly above phase C. The overall results suggest that the onset of sapropel deposition is related to water stratification that caused low oxygen exchanges with the sea-bottom. Although enhanced productivity characterizes most of the sapropel deposition it was not the primary factor triggering sapropel deposition.
      Full-text · Article · Dec 2008 · Palaeogeography Palaeoclimatology Palaeoecology
  • Asheesh Kumar added an answer:
    Can someone help me about the formation of gas hydrate ?

    hi, can you helpe me about the formation of gaz hydrate ? 

    • [Show abstract] [Hide abstract]
      ABSTRACT: Gas hydrate exploration technology has developed from an interpretation of Bottom Simulating Reflections (BSRs) on seismic data to more advanced target oriented acquisition of seismic and other geophysical data. The rock physics modeling also developed in parallel to keep up with a demand for interpreting the observed anomalies and also the joint inversion of geophysical data such as controlled source electromagnetic and seismic. The simplest models of using empirical methods have given way to more sophisticated methods of incorporating rock microstructure into the inversion to minimize the uncertainties involved in predicting gas and gas hydrate saturations associated with gas hydrate prospects. Models combining rock property measurements and host medium grain to grain interactions gave good control on background rock properties about the host medium and hydrate microstructure. Self consistent approximation - differential effective medium (SCA/DEM) approach gave an opportunity to incorporate the microstructure through statistical assumptions. Visco-elastic effects of fluid flow within the gas hydrate microstructure and frequency related interface properties on seismic attenuation is incorporated into a new rock physics model which can explain contrasting acoustic observations from gas hydrate zones from different geological settings.
      No preview · Conference Paper · Jun 2013
    Asheesh Kumar

    Find the attached ppt. it will help you to understand the gas hydrates.

  • Roger Spurr added an answer:
    Does anyone know locations of Arnheim Fm outcrops along the Nashville Dome, TN?

    I am looking to measure and correlate as many Arnheim Fm outcrops along the Nashville Dome as possible however the literature is scarce. The few papers I do have with location data are on the older side and the locations don't all appear to exist anymore when checked on Google Earth.


    Roger Spurr

    I cannot help with locations but may I ask what you are looking for in the outcrops?

    Could it be concentrates, I have been studying intrusions and chemical concentration patterns. I could use some stratigraphy help and may be able to help you as well.  The story is long but these things have a direct relation to my other work...mud fossils. I would like your thoughts on these videos of giant primate CT scans. If interested in a little collaboration rspurr@gmail please contact me.

    + 1 more attachment

  • Bhawanisingh G Desai added an answer:
    Can anyone help me with this bioturbation?

    I appreciate any help on this vertical-oblique bioturbation (ichnofossil, trackmaker..). Info: Continental setting (alluvial-coastal plan), Cretaceous, located in lutites overlying a sandstone-microconglomerate level. Thanks in advance!!

    Bhawanisingh G Desai

    The Vertically oriented, "Y" shaped trace fossils are usually attributted to Ichnogenus Psilonichnus. This seems more like Psilonichnus rather than Thalassinoides. 

  • Nathan J. Wright added an answer:
    How can I estimate haplotype richness with analytic rarefaction 1.3?

    I will be happy if someone help me to use Analytic Rarefaction for estimate haplotype richness of samples with different sample sizes.

    what input file is needed when I have data; sample size=20,30,50,30, haplotype diversity=0.3, 0.5, 0.5, 0.4 ?

    Or, I should make haplotype frequency table (in text) like;

    10 5 0 0 5

    I would like to see example file, but can not find.

    for each sample?

    Nathan J. Wright

    Here is some more info on PAST

    The website to download the program is the University of Oslo:

    Attached is the pdf manual and a screen shot of the program.

    Across the top (columns) are the different samples if used and down the side (rows) are the categories, in this case species. The data is simple abundance data.

    Hope this helps.

    Cheers Nathan

    + 1 more attachment

  • Mohamed Abdelghany Khalifa added an answer:
    What do you think of this textural relationship of gypsum and anhydrite crystallized in a dolostone?

    Dear Colleagues,

    I am currently working on a problematic evaporite-carbonate sequence. The dominant lithology is dolostone with different but minor siliciclast content. One of the most obvious feature is the overall presence of evaporites; satin spar filled fractures, gypsum rosettes, evaporite cemented dolomitized carbonate framework components (coated grains, bioclasts) and chicken wire structures can be find as well. The whole appearance of the sequence suggests an evaporitic sabkha environment. My question is whether the anhydrite hydrolized to gypsum or gypsum transformed to anhydrite?

    Many thanks for your answer in advance!

    Sincerely yours,


    + 3 more attachments

    Mohamed Abdelghany Khalifa

    The presence of sequence in lithofacies evaporites and dolomite is most probably sabkha environment. The presence of evaporites in between dolomite is normal mode of deposition in sabkha, since the evaporite can be deposited at first consuming the ca ions from saline water, this gave rise to enrichment with Mg ions and hence the dolomite can be formed, you can see the Peritidal to intrashelf basin, facies transition of the Adgham Formation (Late Triassic) Al Qasim Province, Saudi Arabia
    M. A. Khalifa.Carbonates Evaporites (2012) 27:299–319
    DOI 10.1007/s13146-012-0091-8

  • Massih Afghah added an answer:
    What are the best ways to determine paleoclimate in the Pennsylvanian (ex Upper Carboniferous) and Permian?

    These two periods of time were characterized by widespread peat (coal) deposits, great shifts in sea level as observed in cyclothems, and by continental glaciation. What was (were) the driving force (s) behind these great changes.

    Massih Afghah

    Dear Paul

    I recommend to check the Meyer (2007)A Review of Paleotemperature–Lapse Rate Methods for Estimating Paleoelevation from Fossil Floras, Reviews in Mineralogy and Geochemistry,v. 66, p. 155-171



  • Sean Ulm added an answer:
    When calibrating radiocarbon dates taken from marine Cardium edule shells in beach barrier sediments, should we use the Marine13 calibration curve?

    I'm trying to build a Bayesian model for a coastal dune stratigraphy. The oldest date is taken from marine beach barrier sediments, while the other, more recent, dates are taken from gyttja layers (associated with archaeological remains) embedded within dune sediments

    Sean Ulm

    Hi Jos,

    Yes, you should use Marine13 and apply the appropriate local/regional deltaR value (see 14CHRONO Marine Reservoir Database at Although the species appears to be a suspension-feeder, I note that it is densest in in-shore zones ( so may be influences by terrestrial run-off or restricted in-shore/embayment circulation patterns. See the following for an interesting case study of the potential differences in bivalves living in different zones and with different dietary habits:

    Petchey, F., S. Ulm, B. David, I.J. McNiven, B. Asmussen, H. Tomkins, N. Dolby, K. Aplin, T. Richards, C. Rowe, M. Leavesley and H. Mandui 2013 High-resolution radiocarbon dating of marine materials in archaeological contexts: Radiocarbon marine reservoir variability between Anadara, Gafrarium, Batissa, Polymesoda spp. and Echinoidea at Caution Bay, southern coastal Papua New Guinea. Archaeological and Anthropological Sciences 5(1):69-80.



  • Laura Maydagán added an answer:
    Can someone recommend some articles about the influence of oxygen fugacity on arc mamgma and its relation to the formation of porphyry deposits?

    I want to learn about the influence of oxygen fugacity on arc mamgma and its relation to the formation of porphyry deposits. Can someone recommend some articles on this topic to me. Thanks a lot.

    Laura Maydagán

    Also to this paper... Cheers,  Laura

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: Porphyry Cu (+/- Mo +/- Au) and epithermal Au-Ag deposits are major sources of mined metals and are commonly formed by magmatic-hydrothermal fluids derived from hydrous magmas in Phanerozoic convergent margin settings. The igneous rock assemblages associated with porphyry mineral deposits are common in modern convergent margin settings, but while many have produced acidic magmatic fluids, very few, past or present, have produced sufficient metal, chlorine, and sulfur enrichments necessary to engender an ore deposit. The reasons for this remain uncertain. We report SHRIMP-RG ion microprobe analyses of hafnium, titanium and rare earth element (REE) abundances in zircon, a nearly ubiquitous and robust trace mineral in crustal magmas. Comparison of the compositions of zircons in ore-forming and barren granitic plutons indicate that ore-forming granites crystallized at relatively low temperature and have relatively small negative europium anomalies (mostly Eu-N/Eu-N degrees >= 0.4). We interpret these small zircon europium anomalies to indicate oxidizing magmatic conditions and hypothesize that in many cases this reflects oxidation due to SO2 degassing from magmas with a relatively low Fe/S ratio. Oxidation of europium and iron in the melt is produced by reduction of magmatic sulfate (S6+) to SO2 (S4+) upon degassing. This interpretation reinforces the important role of oxidized sulfur-rich fluids in porphyry and epithermal mineral deposit formation. Zircon compositions thus may be used to identify ancient magmas that released significant amounts of SO2-rich gases, and regional surveys of zircon composition are potentially a valuable tool for mineral exploration.
      Full-text · Article · Nov 2014 · Economic Geology
  • Mary Elizabeth Bernardes de Oliveira added an answer:
    Do you know of a multidisciplinary team to carry out studies on stratigraphical sequences reaching at least 20 m deep?

    We are looking for a multidisciplinary team to carry out geological, chronological and environmental studies on stratigraphical sequences reaching at least 20 m deep. Our initial evaluations suggest that the deposits may present a continuous chronostratigraphical sequence dating from around 1.5 Myrs. The two volcanic structures are in a closed depression context linked to soil subsidence at the base of their lava emission centers. This situation is due either to the collapse of the craters under the weight of the lava or to the retraction of the lava during its cooling phase. These depression structures functioned as sediment traps which have yielded archaeological surface remains attributable to the Middle Pleistocene and through to the Holocene. They are located in the south of France, in the Baumes volcanic complex (communes of Caux, Nizas, Pézenas, Lezignan-la-Cebe ...). Exceptional sediment traps, the exhaustive study of these infillings would be a major asset for the paleoenvironmental restitution of the sector and more broadly of Western Europe since 1.5 Ma.
    Please contact me if you are interested and I will be able to provide you with more information.

    Je cherche une équipe pluri-disciplinaire pour l'étude géologique, chronologique et environnementale sur des séquences stratigraphiques de minimum 20 m de profondeur susceptibles de recouvrir une chronologie continue depuis 1,5 Ma. Il s'agit de deux structures volcaniques en dépression fermées dues à l’affaissement de sol à l’aplomb de centres d’émission de lave soit liées à un effondrement des structures du cratère sous le poids de la lave soit à la rétractation de la matière lors du refroidissement de la lave. Ces structures dépressionnaires ont fonctionné comme des pièges sédimentaires et livrent des éléments archéologiques en surface depuis le pléistocène moyen jusqu’à l’holocène. Elles sont localisées dans le sud de la France, dans le complexe volcanique des Baumes (communes de Caux, Nizas, Pézenas, Lézignan-La-Cèbe ...). Pièges sédimentaires exceptionnels, l’étude exhaustive de leur remplissage serait un atout majeur pour la restitution paléo-environnementale de ce secteur et plus largement de l’Europe de l’ouest depuis 1.5 Ma.
    Merci de me contacter pour de plus amples renseignements.

    Mary Elizabeth Bernardes de Oliveira


  • Lionello Morandi added an answer:
    Does anyone have a clue to this Holocene microfossil?

    In polar view it appears circular and strongly resembles HdV-119, whereas in equatorial view it is more similar to a fern spore. It's got a characteristic circular/polygonal rupture pattern (this latter feature is shown also by some smooth dinocysts).

    It is from a coastal fresh/brackish-water alluvial plain.


    + 9 more attachments

    Lionello Morandi

    Dear Gonzalo,

    thanks for your suggestion.

    I think it does look similar to Isoetes in one plane, but it's circular in polar view, and sistematically has a rounded break, features that should not be found on a monolete spore.

    I also have reference slides for Isoetes here and I have checked them today.



  • Rogerio de Lucena Alves added an answer:
    Can anyone provide a reference for papers about rare elements (Ag, Au) in black shales?

    It is known that rare elements (e.g., Ni, Cu, Zn) can be enriched in black shales. Can anyone provide papers on trace element analysis on the Toarcian Posidonia Shale and/or the Middle Jurassic Opalinus Clay (Opalinuston-Formation)? In particular, I'm interested in a possible Ag and Au content in these deposits.

    Rogerio de Lucena Alves


    I beleive that the bigest gold deposit in black shale is the Paracatu mine in Brazil from Kinross. The deposit is formed by deformed quartz veins hosted by black shales. Paracatu is a low grade (around 0.3g/t cutoff) high tonnage deposite. I know that some Ag, Pb and As are also present. There are several papers available on internet about Paracatu, you for sure will find what are you looking for.


    Rogerio Alves

  • Mateen Hafiz added an answer:
    Can anyone provide the information on vindhyan basin and its prospectivity for shale gas exploration?

    I have been looking for the detailed information about the vindhyan basin evolution, its stratigraphy and also its prosectivity for shale gas exploration. I found some links online but are not accessible. Can anyone provide the links from where I can directly download? Thank you in advance.

    Mateen Hafiz

    In Vindhyans, the Rampur and Bijaigarh shales seems to be promising for shale resources exploration. Other formations are organically lean. I have attached few articles which discuss the source quality of different shales of Vindhyan Basin. 

    + 4 more attachments

  • Jooly Jaiswal added an answer:
    What are the main points during Speleothem sampling?

    Can somebody tell me the proper site for speleothem sampling?

    I am little bit confused whether is taken from the location where it is equilibrium with external atmosphere or deep from the cave where humidity is near about 100. Some one told me the sample collected near from the cave entrance are most significant for the climatic study because it records the diurnal variation of the atmosphere. but here the kinetic fractionation also goverened the precipitation process please tell me the exact things.

    Jooly Jaiswal

    Thank you so much Mr. Silviu Costantin for your answer. Now I am understand the point of consideration during the speleothem sampling.

  • Syed Haroon Ali added an answer:
    What is the Sequence Stratigraphy, High Resolution Stratigraphy and Cyclicity of Mixed Carbonate-Clastic Successions?

    Hi all,

    While working with Mixed Carbonate-Clastic successions, how do we mark Sequences and High Resolution Stratigraphy? Any recommendation of reference or research paper will be appreciated.



    Syed Haroon Ali

    Thanks Sir for sharing your experience and research!

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