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What is the speciality of manganese in terms of biogeochemical role that causes this very element to be chiefly concentated into nodues? It is not among top 10 most abundant elements on earth surface, right?
Is it due to some serendipitious redox potential and solubility of manganese, presense of some microbes, or any strongt selective cxhelating agents?
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The Mn/ Fe ratio is not a constant aone nd strongly depends on the origin and source of
ore- forming fluids
Classification of manganese nodules of deepmarine environments
•(1) hydrogenous, i.e., formed due to slow deposition of metals out of sea water and characterized bya high concentration of base metals and varying Mn/Fe rations (from 0.5-5)
•(2) hydrothermal, i.e., rich in iron and depleted of other metals, and turns out to be having an extremely wide range of Mn/Fe rations, near mid-ocean ridges and rift systems
•(3) diagenetic, i.e., characterized byhigh Mn/Fe ratios and relatively low concentration of base metals, halmyrolitic processes
Origin:
•Oceanic nodules may be formed from the ore material of polygenic origin, with a predominant role of hydrothermal sources. Manganese nodules may grow due to a supply from oceanic water and out of host sediments. Ore control strong redox changes
HGD
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Please tell me where oceanic crust is very thick and why? Is it related to the plume? I hope to listen a diffrent answer(one place which has thick oceanic crust, but the reason is uncertain)
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Yes it does. You can read more about crustal thickness beneath 900East ridge (Indian Ocean), Walvis ridge (Atlantic Ocean), Shatsky rise (Pacific Ocean) etc.
Oceanic crust under the influence of plumes may get thickened by magmatic addition at the base of the crust. Processes of such 'underplating' may depend upon prevailing tectonics. I suggest you read more about oceanic plateaus and aseismic ridges to discover more.
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Can hydrate formation occur for a Methane+Carbon dioxide gas system existing at a pressure range of 0.5 MPa - 1 MPa in extremely high salinity environments? If possible, what are the necessary conditions for this process to occur?
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You can use my hydrate dissociation curve calculation module of my EQ-COMP software for calculation of hydrate formation curve between 0.4 bars to 800 bars (0.04 MPa to 80 MPa) for mixture of methane and carbon dioxide. More information and sample results are available at
Results can be requested against a nominal payment through
Sample result file is also attached
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Do Fluoride have any correlation with trace elements other than B and As. Any suggestions will be highly appreciated. 
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hi see this attach can help  you 
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Hello everyone,
Could someone tell me the reasons that why some regions (such as the east coast of Brazil, Caribbean Sea, South Pacific Ocean, and west coast of India) having much higher carbonate saturation state than other tropical areas in present-day oceans? Any introduction or literature supply will be appreciated.
Fei
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As noted earlier, water temperature is a big factor due to the retrograde solubility of CaCO3 minerals (calcite and aragonite). However, calcification decreases the saturations state of water (Ca + 2HCO3 --> CaCO3 + CO2). Photosynthesis (e.g., phytoplankton blooms) will decrease the pCO2 of waters in the euphotic zone, thus increasing the pH and saturation state of the waters with respect to CaCO3.
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Hi! Does anyone have a protocol to determine total phosphorus in marine carbonate sediments? We are having problems as most methods use hydrochloric acid (HCl). In carbonated sediments the HCl dissolves the carbonate, but not the organic phosphorus. I would be very grateful if someone could provide a protocol to analyze it. Thanks in advance.
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Thanks a lot Wokil!
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Can somebody identify this foraminiferan? Marine forams.
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Naoufel:
The outline of microfossil indeed shows affinity with genus Calcarina in possessing blunt spines, which abound in reefoidal facies. Let Joshua furnish asked for details (source and method of preparation including mineral composition etc.) to come closer to the solution.
Best
Syed
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I want to recognize marine sediments from Gondwana sediments.
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Thank you friend.
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I will use various techniques to purify the target compound and i am not sure What should I do after purification and What kind of methods should I use?
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Thanks so much Gemilang. I am gonna look at them and I am sure it will be helpful 
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Can anyone suggest the best method to do Fe-Speciation in the surface sediment..?
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Is there a simple formulation to estimate the composition and amount of salt precipitation (in equilibrium) given the ion concentrations in a brine and the temperature conditions?
For example: if we know the concentrations of Cl−, Na+, Mg2+, SO2−, Ca2+, K+ of a sea-water brine at a known temperature T,
what salt(s) and how much of them will precipitate if there is time enough to reach equilibrium?
Can you refer to a concise text-book?
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Please see attached figure. How to plot the evolution cross-spectral phase of the single period? Is there a special software? I often use the CWT tool in matlab, but I can not expot the data of the single period evolution cross-spectral phase. Thank you very much. 
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Mr. Ma,
Let me see if I missunderstood your problem. What you need is to export that information?
If that is the case, consider using the "wcoher" function, this returns the numerical values, and when you plot your results, you can save the graphics in EPS or other formats.
I hope this helps.
Best regards,
Luis M. Gato
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Please look at the attached figure (Heiko Palike et al., 2012, nature). At ~34 Ma, we can find the CCD deepening, carbonate accumulation, pCO2 decreasing,  ice-sheet expansion, and Antarcitic cooling. Mybe the trigger was  ice-sheet expansion induced by  low insolation. If the decrease of the pCO2 was uptaked by ocean, will be not good for carbonate accumulation. Isn't that a bit of a contradiction? How about the relationship between these variations? Thank you very much!
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Additional references that will be helpful:
Coxall, H.K., Wilson, P.A., Pälike, H., Lear, C.H., and Backman, J., 2005, Rapid stepwise onset of Antarctic glaciation and deeper calcite compensation in the Pacifi c Ocean: Nature, v. 433, p. 53–57, doi: 10.1038/nature03135.
Coxall, H. K., and P. A. Wilson (2011), Early Oligocene glaciation and productivity in the eastern equatorial Pacific: Insights into global carbon cycling, Paleoceanography, 26, PA2221, doi:10.1029/2010PA002021.
Lear, C.H. et al., 2008, Cooling and ice growth across the Eocene-Oligocene transition: Geology, v. 36(3), p. 251-254.
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I want to estimate the concentration of CO2, Carbonic acid ,Bicarbonate and carbonate in seawater, please suggest any new techniques using sensors 
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As Niko Finke said, you need to know two of the following parameters to completely describe the inorganic C system: alkalinity, total DIC, partial pressure of CO2, and/or pH. Once you have those measurements, you can use a variety of computing platforms to make all the calculations:
• as an application on your computer (http://pubs.usgs.gov/of/2010/1280/), or
On the other hand, if your question is about how to measure (in the field or lab) the concentrations of the various species in the carbonate system, I suggest consulting the "Guide to best practices for ocean CO2 measurements" (http://cdiac.ornl.gov/oceans/Handbook_2007.html).
Hope this helps.
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We are trying to see the effect of sedimentation on wildlife in Tanzania and we can't seem to find any effective but yet inexpensive way of measuring sedimentation. any advice would be much appreciated. 
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We have done some experiments to understand the sedimentation process in our seaweed cultivation farm. We have used small glass bottles with round bottom and placed them for 24 hr in  the field. The samples were collected and data was expressed over area of the bottle. The only precaution which you need to take is the bottles remained in the same plain as the topography of the sea bed.
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Carbonate deposits resulting from a microbial process in a solution containing required nutrients for bacterial growth, 0.1M CaCl2, 0.78M urea and 50% seawater (composed of 0.055M Mg2+, no Sr) were examined using XRD and FTIR (the precipitates were earlier filtered, rinsed with water, dried at 50C). the results are attached.
Looking at XRD, calcite and aragonite phases can be identified, as expected to occure; BUT the IR spectra represents hydromagensite (http://rruff.info/Hydromagnesite) which is in contrary with the XRD result and not expected (as [Ca2+]>>[Mg2+]). Excluding the peaks at 798cm-1 and 590cm-1, we can conclude a mixture of Mg-incorporated calcite (considering a shift in major peaks of calcite to higher frequency due to smaller atomic radius of magnesium ion) and aragonite; but what can we say about these two peaks, why are they appeared? can they be attributed to the other carbonates precipitated in the solution?
Thanks in advance,
update 1-------05.21.2015   9:00am
the XRD peaks of the sample: 2theta= 23.03, 25.99, 26.26, 27.26, 29.34, 36.1, 39.45, 43.27, 47.47, 48.50, 57.46
the IR peaks of the sample: 1480, 1417, 1117, 884, 852, 798, 745, 713, 700, 666, 590 cm-1
considering the peaks and the following references, 
Q1- does the XRD spectrum represent a mixture of aragonite and calcite? (if so, answer Q2; if not, what does it show?)
Q2- is the IR spectrum confirms XRD result? (if yes, what are the other appeared peaks (specially 798cm-1 and 590cm-1)?; if not, which compound does it represent? hydromagnesite? if hydromegnesite, answer Q3)
Q3- if the IR spectrum corresponds to hydromegnesite, why the XRD does not show its characteristic peaks? and can we expect to have hydromagnesite in the solution with [Ca2+]>>[Mg2+] ?
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OK. I am usually working in NIR in an aqueous sample. You work immediately on a solid sample, isn't? So, my question doesn't apply. Sorry. But the question of the sample preparation remains. Can you better eliminate what you don't need to mesure?
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For example 950 micro atm pCO2 in seawater and then what will be the  ppm of pCO2.
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Dear Gnanamoorthy and Vinod,
that is in principle true, but the mixing ratio (in ppm) is defined as 'mixing ratio in dry air', i.e. in going from partial pressure you have first to substract out the water vapor pressure. The conversion is
pCO2 = xCO2 * ( p(air) - p(H2O) )
where pCO2 is the partial pressure of CO2, xCO2 is the mixing ratio, p(air) is the air pressure and p(H2O) is the water vapor partial pressure. Because of that, the number for pCO2 is somewhat lower than that for xCO2. How much depends in temperature and relative humidity, but for an xCO2 of 360 ppm you get typically numbers of pCO2 around 350 microatm.
Cheers, Christoph
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Barium in marine sediments controlled by terrigenous supply and diatom production. But what controls Gallium in marine sediments? Is it only by terrigenous?
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Dear Mr. Balaji,
barium is primarily controlled in marine environments by magmatic processes, being, in places, instrumental for the emplacement of Kuroko-type (VMS) and Rammelsbergy-type (SMS) base metal mineralization, dependant upon the geodynamic setting. It goes  along with the precipiation of baryte. Ba can substitute for K in all K-bearing silicates and as such increases along with the detrital input into the basin. Gallium can replace to some degree aluminium in its host minerals and as such will also act as a marker of the detrital input.
Best regards
H.G.Dill
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I would like to stack different deep sea curves. Different genera were used to generate the curve, so I need to correct the data to the Cibicidoides standard. I have found different correction factors and I don't know which one to use. I am a terrestrial geochemist, so I do not know what is the latest standards used. I would be grateful if someone usually working with deep sea sediments could indicate me the latest used references for these standards.
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Actually, most researchers working with oxygen isotopes in different genera of benthic foraminifera use the so-called 'uvigerina' scale, so all genera are corrected to the uvigerina values. For carbon there are more discrepancies as uvigerina is an infaunal species and the measured carbon deviates from bottom seawater values. You can check this reference for a comprehensive comparison:
Shackleton, N. J., & Hall, M. A. (1997). The Late Miocene Stable Isotope Record, Site 926. Proceedings of the Ocean Drilling Program, Scientific Results, 154, 367–373.
Hope this helps.
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I aim on freezing the core then splitting it with a saw. However, freezing the core means that I may disrupt the sediment. So, I'm assuming it must be frozen quickly so water crystals don't grow large enough to disrupt the core. What is the correct temperature to do this, have you any advice/experience in this? Is -40'C enough?
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Hi, I have CT and X-ray. I have already split the core using a technique which was emailed to me. I froze the core and cut it with a diamond tipped saw. The end product was a split core with a polished surface and no apparent sediment disturbance. Thank you. 
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Does anyone know of a database that exists for all currently known and mapped submarine landslides that could then be applied for use in the development of a GIS map?
Or alternatively, where regional information/ databases could be acquired in order to develop a global database for the development of a GIS to map global submarine landslides?
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Last year Roger Urgeles published this pretty extensive database of landslides in the Mediterranean:
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I have analysed marine sediments for grain size distribution. How can I come to a final conclusion for the same?
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Of course this depends on your research question! But, to get insights to what is possible with grain size data from marine sediments, I suggest: Weltje & Prins (2003):  Muddled or Mixed? Inferring palaeoclimate from size distributions of deep-sea clastics. Sedimentary Geology 162 : 39 - 62
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I have the 222 Rn concentration in lake and well data. Then how should I approach the Radon mass balance method? F advective calculation? and radon inventory means?
Expert suggestions welcome.
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Thank you sir.
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For example: My sample is marine sediment but I used urban dust SRM (both samples were subjected to same digestion technique).
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My personal view is that it's almost impossible to get an SRM/CRM for every matrix in existence, especially one that's certified for the substance for which you're monitoring. The comparability of the physicochemical properties of the two matrices will determine whether the results are comparable. To Neus's point, numerous soil-based matrices exist, and depending on the analysis and extraction method, and the nature of the chemical you're analyzing, the results between two can be considered comparable.
However, there appear to be a couple of SRM's and CRM's for both inorganic and organic components in marine sediment (NIST SRM's 1941b, 1944, 2702, NIES CRM 12, etc). While it would probably be best to use matrices that are closest to your matrix, you could possibly make an argument for the urban dust depending on what you're measuring. Which compound are you looking at?
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I am currently undertaking a desk study on heavy metal distribution in estuaries and other tidal channels and have read a lot of articles on it. However, I am interested in hearing about unpublished studies/ongoing research in this area. I will also like to know more about the dynamics of heavy metal distribution in tidal channels.
Thank you.
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Heavy metals are more likely to attach to organic matter and clays (mud have these) than sand. Clays and organic matter have surface functional groups (net negatively charged) that bind heavy metal (cations; positively charged). Thus, muddy samples will have more heavy metal than sandy sample simply because muddy samples has more clays and organic matter.
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While reading several microbial diversity studies I came across some where certain environmental variables were being correlated with microbial abundances. One of those variables was change in porewater concentration with depth. However, from my understanding, whether it's sulfate reduction or iron reduction, the activity is based on the second derivative of the porewater concentration. So I'm not sure how porewater concentration and microbial abundances can be correlated without taking this into account. Or have I misunderstood something fundamental here?
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This looks like (on a very brief look) a good example of the point I ended on in my previous answer. They conclude not that they have found the physiologies of the groups they have correlated with porewater compounds but that they can now have some real data that allows them to hypothesise about the physiologies of these groups. As these hypotheses may be testable experimentally that is a pretty good outcome form a piece of work! Don't expect correlation to answer questions, but to help you pose better ones!
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I found a data set of 25cm intervals in a 3.5 m core and I want to show the variation of major and trace elements. Is it reasonable ?
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I suggest to have some non-destructive scaning of the core first and use the results as a template for research strategy, including what kinds questions you can ask, and accordingly set up our sampling plan. Recently I have seen a lot of XRF profiles of cores and realized to have a general understaiding of the core is very important, I plotted elemental ratios such as Ca/Fe, Mn/Fe, .... and so on, usually I can recognize major lithologic units, redox front, lamination, turbidite, salphate-methane interface, tephra and so on. Multisensor of physical properties (density, magnetic susceptibility and porosity) as well as color relfectance profiles are also very helpful.
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Some sedimentary columns are oxic, followed by anoxic bottom or intermediate sediments. Is this controlled by marine systems, terrestrial input or both?
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One prerequisite for well developed anoxic conditions is that the bottom-near waters remain stratified preventing oxygenation through overturn. Such a stratification can be due to salinity or temperature stability.
The Baltic Sea is a typical example of a large water body frequently experiencing anoxia in its deep basin due to inflow of more saline North Sea waters through the Danish Straits and further enhanced by lengthy periods of warm climates, e.g. during the Medieval Warm Period with strong algal blooms (high bioproductivity).
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I am using Cl and Ba as a proxy for productivity in sediments in the absence of Organic Carbon data. Can these types of indicators be used in Atlantic, Caribbean and Pacific oceans (e.g. in all marine sediments)?
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Many times, proxies for such studies are location specific due to differences in biodiversity and anthropogenic activities from a region to another region. So approach with several proxies will give reliable information