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Hello all,
Is there anyone knows how can I draw the graph like below ?
Do you know any softwares for it ?
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The figure comes from the following paper (Figure 7):
Sechman, H., Góra, A., Twaróg, A., Guzy, P., Górska-Mruk, E., & Górecki, W. (2018). Near-surface geochemical anomalies integrated with seismic and well data over the contact of the Outer Carpathians and the Carpathian Foredeep (SE Poland). Geofluids2018. (see enclosed file).
And here: Henryk Sechman; Marek Dzieniewicz (2011). The example of background determination and mathematical processing of data from surface geochemical survey for the purposes of petroleum exploration. , 78(2), 396–406.doi:10.1016/j.petrol.2011.06.001 (see enclosed file) they described how the statistical analysis is performed (they don’t mentioned any specific/fancy software so I guess you could use something like Excel).
Best regards.
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Which reference would be beneficial for using correlation and matching of surface geochemistry data (Acid Extracted (AE) Gas and GeoPAC Fluorescence analysis) which includes Σn-PC2-C4-ppm, C1/C2, C1/C3, C1/n-C4 and among others, with subsurface geochemical data of the (Rock-Eval analysis) that includes the S1, S2, TMAX, TOC and etc. parameter(s)?
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As a part of my masters thesis I need to accurately measure organic and inorganic carbon and nitrogen. My samples are sandy marine sediment (30-35 ppt) with low total carbon (~0.05% TC and 0.04% TN as % dry weight from initial testing with CHN analysis).
I am using a Flash 2000 elemental analyzer. Initial measurements were collected using 23.272 mg of sediment. The left and right furnaces were set to 950 C and the oven was set to 40 C. I used a carrier gas flow rate of 100 ml/min, and an oxygen flow rate of 25 ml/min. I created a calibration curve using Acetanilide as a standard.
To separate organic and inorganic carbon, I found a Loss on Ignition technique from Kristensen and Andersen (1987), removing organic carbon with ignition at 500 C in a muffle furnace.
The user manual for the Flash 2000 elemental analyzer recommends that you establish how much oxygen is required to completely oxidize a certain type of sample without excess oxygen which would shorten the lifespan of copper catalysts, which can be done adjusting the flow rate. Larger samples require more oxygen to fully oxidize.
I am struggling to find recommended flow levels for this type of experiment. Standard operating procedures from other organizations sometimes reference CHN analysis settings:
World Agroforestry Centrer's "Method for analyzing soil samples for organic carbon and Nitrogen" ( Code: METH 02V01) written by Valentine Karari July 31, 2014 uses the following settings for the Flash 2000 organic elemental analyzer:
  • Right Furnace 950 C, Left Furnace 840 C, Oven 50 C, Carrier gas flow rate 140 ml/min, Oxygen flow rate 250 ml/min
USGS Reston, Virginia Environmental Organic Geochemistry Laboratory "Instrumental Analysis for Total Organic Carbon and Total Nitrogen in Sediments " suggests the following for the Carlo Erba Elemental Analyzer EA 1108:
Oxidation Furnace (left) 1020 C/1040 C, Reduction Furnace (right) 650 °C, Chromatographic column oven 60 °C, Carrier gas flow rate 100 mL/min, O2 dosing loop of 10 mL, flow rate: 20- 25 mL/min.
Has anyone done a similar experiment and does anyone have recommended settings for oxygen flow rates/sample size so that I don't accidentally underestimate sediment carbon content? I also want to try using larger sample sizes to better detect low carbon levels.
References mentioned in question:
Kristensen, E., & Andersen, F. Ø. (1987). Determination of organic carbon in marine sediments: a comparison of two CHN-analyzer methods. Journal of Experimental Marine Biology and Ecology, 109(1), 15-23.
Chicago
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Hi dear Megan,
You can read this paper and download the one inreference
Gustafsson, Ö., Bucheli, T. D., Kukulska, Z., Andersson, M., Largeau, C., Rouzaud, J. N., ... & Eglinton, T. I. (2001). Evaluation of a protocol for the quantification of black carbon in sediments. Global Biogeochemical Cycles, 15(4), 881-890.
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greetings dear community,
I am looking for the ASTM D7708 - 14 standard for vitrinite reflectance measurement on dispersed organic matter.
I have the standard for coals, which is not entirely applicable to DOM.
Could anyone provide me with a PDF version?
Thank you,
Best regards,
Yacine
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Dear Mr. Mokri,
I, happy to share ASTM D7708 - 14 standard with you. I sure it will help you.
Please find the attached pdf file.
Regards
Alok
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To calculate CIA and also plot the data on A-CN-K ternary diagram, I need to know the CaO in silicate minerals only, so reliable correcting method.
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The Formula provided by Fedo et al., 1995 to estimate the amount of CaO* that is present as Ca in silicate -bearing minerals only is CaO*=mol CaO - mol CO2 (calcite) - (0.5 x mol CO2) (dolomite) - [(10/3) x mol P2O5] (apatite)
for me it is not clear however where does the factor 10/3 for apatite come from.
Similarly, the factor 0.5 for dolomite.
any ideas?
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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).
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Thank you so much. Will check that.
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In order to estimate the sources of particulate organic matter in a large freshwater lake. I measure the C/N ratio and C13 and also the n-alkanes as the biomarker to eluciate the potential sources of POM.
However, the results is very confusing. Because most of the POM have appraent peaks at c27 or c29 of alkanes profile (terrestrial signal), which have low C/N ratio as 3 to 5 (phytoplankton signal). I can understand that sometimes the clay particles from terrestial soil will have lower C/N, which are already reported by many references.
But these particles are also have low POC/chla ratio (<100), and a very good linear relationship of POC and chla was observed(R2>0.8).
Can anyone give some clue or suggestion? Thanks a lot.
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Yes, I am totally agree your comments. As the sampling area is a big shallow urbanized lake, many sources was generally mixed and biodegraded. I have already tried to apply the proxy as your recommend, and I got a higher contribution of terrestrial and sometimes petroleum contribution. But what I am confusing is that the particles have lower C/N ratios and relative low POC/chla (<100 microgram per Litter) as I said in my questions. And actually I am not expecting the higher contribution of terrestrial, because the lake is highly eutrophication, and cyanobacteria bloom (I thought they are main contributors to C17 in my case) is serious issues in this lake. So I am wondering if the alkanes indicators are still robust in my case, since I saw some articles showed the diagenesis effect could cause higher contribution of long chain n-alkanes in sediments, even though the allochthonous inputs is few.
And I am very grateful for your suggestion, I will try to test them. Could you tell me the approximate retention time of these compounds basing my TIC graphs, it will be helpful for quickly locating them.
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I have about 56 analyzed ditch samples (Rock-Eval Pyrolysis and TOC), I want to write potential paper about Quantity, Quality and Thermal Maturation of a shallow marine shale source rock. Is It enough or I need more data and If yes, what are the types of this data?
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Yes and no, it all depends on the depth of your question and the scope. If it is a classic source rock evaluation integrated into a larger program that includes petrophysical and basin modelling components , you might get away with it for an initial assesment. However, if your main focus is the holistic evaluation of the source rock potential, you MUST include Organic Petrography (using both transmitted and reflected white light and UV light), as well as sulfur speciation work (the Rock-Eval 7S can now do that and you get differentiation between S2-sulfur and S4 sulfur from that coming from sulfides and sulfates), Pyrolysis-Gas Chromatography (if possible). In addition, if you samples are thermally mature, you need to use a modified pyrolysis program (Shale Play, MHR, Reservoir, etc.), the basic temperature program might not be adequate.
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Shale Gas: Is it just a Technically Recoverable Resource (TRR) OR An Economically Recoverable Resource (ERR)?
Shale Gas Plays: Which are the dominant and Sensitive parameters?
Porosity - Mineralogy - Thermal Maturity (1 - 1.5%) - Organic Geochemistry - Depositional Environment - Basin Type - Reservoir Thickness - Depth - Age - Larger TOC (greater than 2%) - Low Clay Content - In-situ Stress Regime - Reservoir Stress History.
How difficult is to deduce the Estimated Ultimate Recovery (EUR) for wells associated with Shale Gas Plays?
Are we successfully managing the Hydraulic Fracturing process?
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Please see the following article
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Greetings dear community,
It yas been quite a while since I have come to ask for your guidance.
Here's today's question:
What method do you use to estimate, or compute organic porosity?
Are there any good papers talking about this subject?
Personally, I teamed up with my colleague to get some SEM pictures of some source rock samples cut vertically to the bedding.
We then used two approaches (both with image analysis using photoshop's pixel count):
1- we tried estimating the organic porosity on a large section (something like X250 magnification).
2- we estimated the porosity on single kerogen particles ( identifying each particle as amorphous, phytoclast or palynomorphs). And then upscaling this estimation using a precise palynofacies analysis (aom, palyno, phyto ratios with minimum 1000 particles) to get an estimation of organic porosity for whole samples.
Our research is a work in progress, but we observed so far that in our particular SR, the organic porosity is about 3% when translated to the whole sample, and it seems like organic porosity is not entirely correlated to TOC.
I would very much appreciate you advice on this subject. And if you have any references, it would be even better.
Best regards,
Yacine
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Porosity calculation from images is a hard task. There are some issues:
1) only ex-situ porosity you can determine. you can interpolate the pores inside the material, but not a recommended one. Solution: you can use gas adsorption techniques to get an estimation.
2) Detecting pores is also challenging. If the pores are irregular than complexity arises. I have used Atomic force microscopy images (AFM), where I used height data based images to detect pores.
3) SEM requires vacuum condition to operate. To take image in ambient condition you might take AFM images. I know this is not a big issue, sometimes image taken in ambient condition might provide some extra information.
You can see my paper:@Yacine Mokri
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I want to know what is the difference of nitrogen composition between the part could be extracted by organic solvent and the part could not be extracted (but not the inorganic nitrogen in minerals ) when we do the extraction from sediments/coals.
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Thank you for your answers! Jai Ghosh Bayan Hussien Steven L Larson
Ali Alwaeli
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I need to make a burial history on petrel for a borehole.
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Thank you for your help
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Organic Geochemistry
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I agree with Matthieu. Cycling in this context means the movement of elements within soil, from soil to plants as they take up nutrients, to animals who eat the plants, back to soil or into air/water when plants and animals die, , back into plants as they grow etc.. It is a cycle because the elements are continuously moving around in the environment in repeating "cycles". There are some very well-known and well identified cycles such as the carbon cycle (see https://en.wikipedia.org/wiki/Carbon_cycle), or the nitrogen cycle (https://en.wikipedia.org/wiki/Nitrogen_cycle).
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Organic Geochemistry
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Dear Mr. Hamed,
even if English is not my mother tongue I do not see any difference between material, matter, substance and “stuff” as has been underscored by Dr. Towe. Maybe there are more serious linguistic connotations in geosciences which should be subjected to a semantic debate. The important dictionaries used in geosciences do not discuss this issue of matter or material.
We should not do it either and do not create artificially differences and rifts H.G.Dill
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Dear Friends: Is there any peer-reviewed research papers/publications regarding influence of oxidation-reduction conditions upon distribution of geochemical elements in coaly sediments? I’ve conducted several downhole ICP-MS analysis followed by systematic well logging operations within a thermal coal mine. Geochemical data processing of the resulted data indicates considerable amounts of trace elements in the coal bearing argillite-shales. I’m now thinking about further studies to answer my doubts regarding the concentration mechanism of the elements and the corresponding mineralization evolution. Hence, the hypothesis is that: Redox condition might effect on the element partitioning process in this sedimentary basin. Any Ideas? Thanks.
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Pleased to meet you!
You're welcome @ Pezhman Rasekh
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Greetings dear community,
Today, I have a question about reworked organic matter. In fact, I am actually working on a project in Frasnian hot shales with cutting/core samples in which I have to determine the maturity through microscopic observation.
We analysed samples of cores and cuttings from very close depths in the same well. These show show a similar trend, but with a clear contamination in the cutting samples coming most likely from cavings or poor cleaning prior to sampling. The Tmax in cuttings averages 439 in contrast to the 458-460°C in core samples.
This is further proven with HI values. For these samples, which are around 90% AOM and thus considered as type I organic matter (marine environment), the HI values for the cuttings (which are early mature) are quite low (150-170) whereas the values in the core samples (mature samples with a long due oil phase generation and close to dry gas) average 25-30 (type I OM produces its essential potential in the oil phase).
After determining that cutting samples are contaminated, my problem now is that I have reworked OM in my core samples. I can see it in my slides, but I lack some knowledge to do some quality identification and quantification of this reworked OM. for the plus side, this observation of mine correlates well with pyrolysis results (TOCs = 4-4.5% for S2s = 1.2-1.5 mg/g).
I need some references to read more about this subject. If anyone has some information on this, be it articles or books (or their own experience!!), it would be really helpful to me.
Best regards,
Yacine
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Most shales are formed in a non-oxygen medium. In the zone of serozarazheniya. This affects all chemical and physical processes of formation and transformation of petroleum matter. We study this in detail on the shales of Tatarstan. This has its own criteria.
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I need a reliable chart for thermal alteration index assesment. It must have references for at least spores, algae and acritarches.
Your help would be appreciated.
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Thank you for your comment Yacine Mokri, and your previous comments Mr Bencini and Mr Idan. It shows the problem with this topic, there is a lot of personal believe and interpretation involved, leading to very different schemes. Just comparing the schemes submitted by you both, Bencini & Idan, we see significant differences. So who is right???
And you are fully right, Yacine Mokri, that different palynomorphs show different colours at the same maturation levels. Pollen are different from spores, which are different from algae, or dicocysts or acritarchs. And even within each group we see clear differences, depending on wall thickness, density and thickness of ornament, preservation (chemical & microbial alteration). So you have to use very similar types of palynomorphs to have good colour correlation. And because the kerogen we study is from sedimentary rocks, which are mostly recycled to some degree, you can have similar types of palynomorphs in different colours in one sample, due to recycling of higher mature material in your less mature sample. So you see, it's pretty complex.
Unfortunately also the documenting of our results brings additional uncertainty, because the colour of our photoplates depend on the specific of microscope, magnification, lightning system and so on. Therefore the same sample will show three different pictures in three microscopes. And if you take paper, the colours in ptinted papers are effected by printing, in digital documents colours are effected by your system, programs or the settings of your screen.
Working with Vitrinite reflectance and palynomorph colours for several years now, I realized also an age dependence of palynomorph colours. So stratigraphy is another point making it more complex.
So it's even more complicating. And the dream of a simple TAI chart working for everything is finally gone, I guess. Sorry Cristiana.
On the other hand palynomorph colours are just a fast initial tool to determine maturation on a relative rough scale (immature, low/medium/upper oil or gas) and for this we can ignore a lot of the difficulties above.
As one solution, I would like to encourage you to work with the palynomorph darkness index (PDI) from Goodhue & Clayton, which might be a good way out of the troubles with the previous colour analysis schemes.
cheers
Hartmut
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Hey there, I'd like to ask if anybody knows how can evaluate total percentages of macerals in comparision with trace element content in coal. The idea is that I would like to evaluate if trace elements are most bound onto macerals or sulphur content. Can you give me any recommedation. Which method would you perform on it? Any publication has been released? Thank you in advance!
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Some authors say it represent marine environment while other say terrestrial environment of deposition.
kindly guide me in this regards. Thanks
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I wonder what is the solubility of any EPS? Does it contributes to alkalinity/acidity of a medium? What is the pKa/pKb? Does it really depends on the functional groups of the EPS?
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The solubility of EPS varies greatly, depending on its composition. Even within a single organism, such as certain Lactobacilli, homopolymers can vary greatly, depending on their structure. For example, Streptococcus spp. produce two types of glucose polymers: water-soluble dextran and water-insoluble mutan, as well as intermediate combination forms of both.
Regarding the pKa and acidity, that also depends on the EPS structure. In the case of neutral polysaccharides, composed of neutral sugars like glucose or mannose, it's not much of an issue. In the instance of acidic polysaccharides like bacterial alginate, it MAY be an issue. However, these usually exist in the salt form at physiological pH, rather than in the protonated, acidic form. The presence of acidic carboxylate groups will definitely affect the buffering capacity and metal-binding capacity of such biofilms. So, yes, it can depend on the functional groups within the EPS.
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We are currently using Supleco LC-NH2 columns. I found an article in Organic Geochemistry where they observed the same contamination of the free fatty acid fractions with palmitate and stearate from the plastic columns (Russell & Werne, 2007, The use of solid phase extraction columns in fatty acid purification, Organic Geochemistry). They solved this issue by packing their own glass columns, or using a fluorinated polymer coating on the inside of their plastic columns. I am trying to find if there are any commercially available SPE products that solve this problem.
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You can use the LC-NH2 powder to pack into the glass pipette as the NH2 column, it's very easy way to make your own column. And you can download the specific procedure from the Yongsong's lab procedure in Brown University.
Good luck!
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Hello to everyone. I'd like to distinguish maceral subgroups of vitrinite (telovitrinite, gelovitrinite, detrovitrinite). Can you advice me if there is some good website or representative photos of them? Thank you. Regards.
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prezentácia od luis pedra z uniovi neviem, či pomôže, ale pod obrázkami je väčšinou zdroj a teda možno v tých zdrojoch nájdeš, čo potrebuješ.
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Is there any reference or criteria have been published for how to use Rock-Eval data to determine whether the musstone sample have been stained or contaminated
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Dear Dr. Peng,
I routinely use a cross plot of  PI versus Tmax to identify samples containing migrated (non-indigenous hydrocarbons) - see attached word document.  This cross plot is based on comments from Peters et al (1986) Guidelines for Evaluating Petroleum Source Rock Using Programmed Pyrolysis. AAPG Bull. 70, p. 318-329
The following quotes from that reference are of specific relevance here"Oilbased mud contamination or migrated oil is likely for immature rocks (Tmax less than about 435°0 where PI or Sl/TOC is greater than 0.2 or 0.3, respectively"
"Pyrograms of contaminated or reservoir rocks, such as that from 2,090 ft (637 m) in Table 4 (Figure 13), commonly show an SI peak greater than 2 mg HC/g rock, an anomalously high PI and low Tmax (compared to adjacent samples), and a bimodal S2 peak."
Best Regards,
James Collister
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The non-porphyrin N and V complexes in the crude oils form may be primary or secondary. The metal complexes released from kerogen during categenesis and formation of metal-organic complexes represents primary origin, whilst secondary includes the metallic complexes derived via the interaction of oils with sediments or waters during migration, maturation; biodegradation may also affect the concentrations of some trace elements in crude oils. Nickel (Ni) and V occur in oils and bitumen as metallo-porphyrins and non-porphyrin species. Nickel (Ni) and V are usually the most abundant metals with values ranging up to 200 ppm Ni and 2000 ppm V. I'm looking forward to understanding the ideal ratio of V/Ni in the original porphyrin (animals and plant)?
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Thank you Razgar
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I am working on hydrothermal fluorite geochemistry.
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How did you assess REE patterns? Are they normalized to shale, chondrite or to the composition of hydrothermal fluids
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Geochemistry and source Rock
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"The amorphous kerogen components (amorphinite) are subdivided based upon fluorescence properties into fluoramorphinite (fluorescent) and hebamorphinite (non-fluorescent)."
Probably, the non-fluorescent Hebamorphinite is poor in fluorescent components ("live" hydrocarbons).
Therefore, it may represent "spent" source rock (a former source rock that expelled all possible hydrocarbons after reaching very high thermal maturity ).
Alternatively, a totally immature source rock would also contain no hydrocarbons.
It should be easy to establish, from the geological setting of your samples, if you are dealing with totally immature sediments from a thermal viewpoint, or nearly metamorphosed sediments.
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I would like to study sediment cores from Red Sea (Oligotrophic and less productive). Can I expect any signal using organic geochemical proxies??
Please Reply,
Thank you
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Hi Rasiq,
Prior to adding an answer to your question some questions back. are you considering organic or inorganic geochemical proxies? For what purpose would you want to reconstruct paleoproductivity and on what time scales - e.g. Do you want to see changes over glacial/interglacial cycles to see the monsoon intensity or are you interested in the anthropogenic influence on the environment?
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I have read in several papers that lighter d13C(org) may be indicative of terrigenous input (landplant) and/or microbial activity (Biodegradation). Some scientists also use d13C(org) value as a proxy for paleoproductivity suggesting that lighter (more 12C) values are indicative of Paleoproductivity and eutrophication. I wonder, to what extent, d13C(org) could be used as a paleoproductivity indicator RELIABLY? Is there any published work on this issue?
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There is a lot of published work - though most of it in the marine environment. These may give you a start - but there are hundreds of papers linking d13C to productivity.
 Kemp A, GSoL Vol 116 1996,
Boyer et al, PPP, 306. 2013,
Goudie & Viles ESR, 113 2012
La Porte et al PPP, 276, 2009.
PPP is probably the best journal to start with some key word searches...
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I am a geologist, not a biologist, but have encountered very old (Archean) rocks with anomalous organic carbon and Os-Ir platinum-group elements. Since the host rock (clay) has high surface area and a possible catalyst, I was wondering of these types of rocks could have served to take simple non-organic carbon compounds and assemble more complex organic molecules. Are there any documented catalytic effects for Os and/or Ir?
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Dear Erik,
The answer is YES. Please read the following publication: 
Properties of Bimetallic Catalysts with Pt, Re, It and Os
ARTICLE in BULLETIN DES SOCIETES CHIMIQUES BELGES 88(7‐8):577 - 597 · SEPTEMBER 2010 with 8 READS
DOI: 10.1002/bscb.19790880711
ABSTRACT
In an attempt to improve our knowledge of bimetallic catalysts usually used in reforming we studied three series of catalysts: Pt-Re, Pt-Ir and Ir-Os.For our Pt-Re catalysts, both metals are reduced to the metallic state and a catalytic effect of platinum on the reduction of rhenium oxide has been evidenced. The infrared spectra of carbon monoxide adsorbed on those catalysts have shown that platinum and rhenium interact together, they are probably alloyed.The catalytic activities of those Pt-Re, Pt-Ir and Ir-Os bimetallic catalysts were determined for various organic reactions. The effect of alloying is different for the various reactions, but the activity of the bimetallic catalysts for a given reaction is never the sum of the activities of the two metals separated. Some important synergistic effects were found. Surprisingly, a marked analogy between the curves activity for given reaction versus the composition of the catalysts has been found for the three series Pt-Re, Pt-Ir and Ir-Os. Some interpretations for those observations are discussed.The use of bimetallic catalysts has been a considerable improvement in catalytic reforming [1–8]. Pt-Re [1–4] and Pt-Ir [5–8] are among the most widely used in this area and the catalytic effects of adding metallic promoters to platinum are multiple. Those promoters act by i)changing the initial selectivityii)decreasing the sintering rateiii)decreasing the coking rate during reaction of hydrocarbonand iv)maintaining the initial selectivity despite coke deposition and activity loss.However little is known on the reasons of those effects and many questions are still pending. For example, what is the degree of interaction between the two metals. Even the oxydation state of rhenium is still a matter of controversy.This is why we started a few years ago a study on bimetallic catalysts containing platinum, rhenium, iridium or osmium in collaboration with a group of research of the Institut de Recherches sur la Catalyse of Villeurbanne.The bimetallic catalysts have been characterized by their physico-chemical properties and their catalytic properties for various organic reactions. 1)The investigation of the reduction by hydrogen by means ofi)differential thermal analysisii)thermogravimetryand iii)volumetry2)The study of the metallic phase after reduction by hydrogen-oxygen titration and IR study of CO chemisorbed3)The study of the activity of the catalysts in the following reactions:-dehydrogenation of cyclohexane and 1,1,3-trimethyl-cyclohexane [9]-hydrogenation of benzene-epimerization of 1,2-dimethyl-cyclohexane [10]-hydrogenolysis of cyclopentane and butane [11,12]-benzene-deuterium exchange.
Hoping this will be helpful,
Rafik
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Presence of n-alkenes in sediments have reasonable maturity is questionable from long time. If anyone have clue about origin/source of even carbon number n-Alkenes from C12 to C22 in sediments.
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Your question takes me back 40 years ago, back to my thesis work on organic geochemistry (1973 !). As I can remember, biosynthesis of natural fatty acids is from Acetyl-CoA and produces even number fatty acids. Green leaves contains large amounts of epicuticular waxes to protect them from heat and water (same for insect pupae such as blowfly). These waxes are long chain aliphatic esters (up to C60 and sometimes above) from long chain even numbered fatty acids and even numbered fatty alcohol. Upon burial, bacterial degradation, ...,fatty acids can be released, and together with natural fatty acids, can be decarboxylated, yielding odd numbered alkanes. Further burial and thermal degradation tends to flatten the difference between odd and even numbered alkanes. I guess that there are numerous papers in the literature that have reported this observation, and it is a characteristic difference between recent and ancient sediments.
Note that long chain waxes are often hidden as they do not elute easily from a GC column, and should be first transesterified and derivatized. As for LC, they show no response under UV detection, only by LC/MS under APCI or ESI.
These are just old souvenirs !
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Can anyone suggest a good overview article on what makes Alpine Type serpentinites different from others? I know that plots of Cr# vs Mg# have different fields, but what else is different and why? Mineralogy? Any estimates of P-T conditions, or are they variable?
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Thanks!
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Injection of ferrous sulfate (approx. 3000 mg/L) for a week in anaerobic condition (i.e., iron reducing condition) showed an initial significant decrease in dissolved arsenic for about 7 months, but followed a rebound exceeding baseline. Increasing sulfate did not initiate sulfate reducing condition. DOC did not change over the time, but sulfate came into below detection (background) within 4 weeks after injection. Limited research shows that injection of lanthanum chloride under iron-reducing condition can generate lanthanum hydroxide, a supplement of ferric hydroxide. Lanthanum hydroxide has significant adsorbing capacity for dissolved arsenic and do not undergo reductive dissolution (i.e., rebound) and form stable adsorbent for dissolved arsenic once adsorbed during injection under anaerobic condition. Another research showed the opposite for lanthanum hydroxide as it leaches arsenic from solid lanthanum hydroxide under anaerobic condition. Please advise me.
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Dear Dr Md. Salah
Actually i am working totally in REE species. The REE (e.g., La) less affected by diagenesis when go down to ground profiling even though the iron is REE transporter.  However regarding the lanthanum - As-DOC or anaerobic  condition in  where intention on the role of humic and fulvic of REE in groundwater system. How far the reactive and conservative behavior between thus metal ions also play important role either in dissolve or solid state be considered. The rebound problem should consider of Mn oxide or coated Mn-Fe-Ox-hydroxide complexation between dissolve and particulate before scavenging to surface sediment until certain level of equilibrium. Again according to your research kindly, please refer:
Johan Schifjf, Emily A. Christenson and Robert H. Byrne 2015, YREE scavenging in seawater:  A new look at an model. Marine Chemistry
Robert H.Byrne and Ki-Hyun Kim, 1990. Rare earth element in seawater. Geochemica et Cosmochimica Acta.
Hein de  Baar and Johan Schijf,1991. Solution chemistry of rare earth element in seawater. Europe Journal of Solid state and inorganic Chemistry.
Regard's
Zolhizir Daud
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I think that the calculating method  it's so  faster than experimental
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You can use the Passey method or the CarboLog method. Both methods combine an eletric log and a porosity log (sonic) for calculation. Please take a look for those methods.
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This is a microbial method, originally developed by Phillips Petroleum, which analyzes shallow soil samples for the presence and abundance of hydrocarbon-oxidizing bacteria.
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these two companies have performed such soil surveys for us.
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We measured this Raman spectrum on a secondary mineral speleothem of a lava tube (https://www.researchgate.net/publication/265952424_RAMAN_STUDY_OF_SECONDARY_MINERALS_IN_A_RECENT_LAVA_TUBE). The main body was Thenardite and additionaly this spectrum appears occasionaly. Do you know it ?
Thanks for your help.
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Did you run the pattern through CrystalSleuth against the RRUFF database ? If you send me a copy of the spectrum data in CSV format I can run it against a RRUFF extract that is both cleaner and more extensive than the one released with CrystalSleuth from the RRUFF website.
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Thanks in advance for your replies.
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Dear Dr El Nady,
Organic Geochemistry in a simple sense is the study of the chemical components of any organic materials that might have decomposed under certain geological conditions/processes to become hydrocarbons (gas, condensate or oil).
Petroleum Geology again in a simple sense is a Geological Setting (usually basins) on a regional scale where it is most likely to generate & accumulate hydrocarbons. There are at least some critical geological factors (source, maturity, migration, reservoir, seal, trap) that one has to asses for any basins if they worth prospecting for.
Both Petroleum Geology & Organic Geochemistry go hand-in-hand if you want to understand the whole petroleum system of a basin.
Regards
shadrach
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I am investigating the role and effect of OM and its type in the uptake of trace elements in sediment-water interfaces. I would like to know why there are differences in the S4 value (measured in 850 C) of samples with the same kerogen type (I) and homogeneous lithology (marl)? Which factors influence the residual carbon content of samples? Does the S4 or residual carbon content still have potential to generate petroleum (theoretically) or do we consider it as a dead (Type IV) carbon?
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The type of OM which is derived from aquatic environment is already consist mainly from Algae's ,Bacteria ,these particulate OM have bio polymer and mainly content Carbohydrates , Proteins ,Fats and other pigments and so on ..Already determines S1, S2, and S3, promising to generate oil mainly, other wise Higher plants which the mentioned above biopolymer lacking with it, but rich in Lignin (responsible for keeping the plants standing ,is promising to generate gas only .
Regards
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What is the best approach used to extract the organo-halogens (Cl, Br, I) in marine sediments and seawater samples? Should we use a perch and trap system? Or using a flux chamber? Or just collect the gas using a headspace bottles prior to analyzing with a GC-ECD?
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Dear Chin,
Thank you for your question but I have no competence to respond. I am sorry.
All the best,
Nathalie
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Is there any significant characteristic to explain the XRD diagram of asphaltene?
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Dear Professor Connan,
Thankyou for the guidance.
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Chemical analysis is evaluating promising rock units in generating oil and gas, so do you minimize the role of this aspect or there is any alternative method
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Basin modeling based on the burial thermal history ,and determination of lithology for each formation overburied the source rocks and vitrinite reflectance ,and other agents could enable to setup model to indicate transformation ratio that declare the time and extent of oil generation and increasing of tempreature accordingly .
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We'll be visiting manufacturers shortly and have various matrix test samples to run. My lab. will be running soil, plant, earthworm digests and extractions and mainly be analysing for trace elements. Two key questions I'm interested in are:
1. How much of an advantage the dual view nebulisers from manufacturers like Thermo and Perkin Elmer really are over the single view of manufacturers like Agilent given the improvement of sensitivity and detection in modern single view machines
2. If going for a single view what are the merits of axial vs radial view from a practical perspective (i.e. I know about sensitivity and detection limit issues already but in reality is axial really so much more sensitive than radial view for complex extractions for trace element analysis)
I'm also interested to hear from anyone's experiences using the latest suite of Agilent, Thermo and Perkin Elmer machines in an earth science / geology / environmental science lab.
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We have a Thermo iCAP 6300 DV running extracts / digests of soils, rocks, plant and animal tissues, as well as natural waters and experimental solutions. As others have noted, the dual view is a big plus if you are dealing with a wide range of analytes, matrices, or concentrations. I was not involved in the purchase of this instrument but I believe that was the rationale for choosing it.
You will want to consider operating costs including torch lifetime as well as upfront costs. The iCAP eats its torches more rapidly than either of the older instruments I previously used, though their lifetime depends strongly on what matrix we're running. An argon humidifier has helped with this, especially in high dissolved solids and high organic matter matrices (e.g. soil extracts). We have also seen big price increases for high purity N2 and Ar that have put our run costs way up over the last couple of years.
Our instrument is excellent for transition metals and REE at trace levels (mostly ppb), and it is good for metalloids (tens of ppb As and Se in plant / soil digests, probably better if we really spent some time on it). Even alkaline earths are good. For alkalis... I wish we had an AA for the soil fertility people to use, because K is just awful.
Good luck!
Leslie