Geology

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Answer added to:
2 What is the current opinion about origin of petroleum?
By Morteza Momenzadeh · Zarneh Research Group

Ahmed Al-Ahmed · Al-Nahrain University

Biogenic source (Algaes,Higher plants and Bacteria ) and bacterial activity that causes to decay the particulate organic matter and convert it to am... [more]

Biogenic source (Algaes,Higher plants and Bacteria ) and bacterial activity that causes to decay the particulate organic matter and convert it to amorphous type within aquatic reducing environment ; it consist of light yellow to brownish gel containing sometimes abundant yellow bodies which were finally recognized as being derived from algae

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19 Which is formed first, in structural geology theory, if the tectonic force gives an effect in some area: Fold then fault or fault then fold?
By Ryandi Adlan · Universitas Padjadjaran

Franck Audemard · Fundación Venezolana de Investigaciones Sismológicas

Both ways, in perfect association!!!! First fold and then fault, or viceversa. Or even simultaneously!!!!! Also at the same time, but not physically c... [more]

Both ways, in perfect association!!!! First fold and then fault, or viceversa. Or even simultaneously!!!!! Also at the same time, but not physically connected but related to a single ongoing stress tensor......

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2 Why the quantitative analysis of oxygen cannot be done in XRF?
By Mues Huang · National Cheng Kung University

Martin Menzies · Royal Holloway, University of London

See also McGuire et al (1992) Am Mineralogist 77 on electron microprobe analysis of oxygen - link is to a course in the USA http://www.geology.wisc.ed... [more]

See also McGuire et al (1992) Am Mineralogist 77 on electron microprobe analysis of oxygen - link is to a course in the USA http://www.geology.wisc.edu/courses/g777/AmMin/McGuire-1992.pdf

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27 What is the most effective way at explaining scientific papers and results to a broader audience?
By Owen Fenton · TEAGASC - The Agriculture and Food Development Authority

Susan Kirk ·

I recently worked with a toxicologist to try and explain not only toxicology but the changing science of toxicology.(see www.susankirk.com.au to see i... [more]

I recently worked with a toxicologist to try and explain not only toxicology but the changing science of toxicology.(see www.susankirk.com.au to see if you think I managed to succeed) Here are some of the background processes for what I did. I used the internet (medium) to get the message across. I believe this is the best medium for science communication. Why? Think info graphics: think hyperlinks, including full text bibliography, think video: think podcasts: think word count, science is complex can't always be summed up in a few hundred words. (beware: there are also issues and downsides to lengthy word count): think accessibility. Most of all think back to when you started to learn about science. Get out your old text books if you still have them. Give the journalist links to basic articles about the subject matter. THINK 101. Be prepared to spend a lot of time explaining and helping journalists with the draft (if they will allow you!). This is particularly true for non science journalist like me. And yes use your PR people if you have them. Don't ask them to write a media release (this is causing a lot of sensational science and we don't want that, well newspaper journalists may want it, but it does nothing for the credibility of science) See if they will write you a brief backgrounder and give this to the journalist. Seek out journalists with your news. Think Margaret Gees.

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2 What (if any) is the difference between crushing, pulverising and powdering a rock?
By Liam Harris · University of Leicester

Jonathan Webb

PS I have done sediment-size analyses. Simply put the sample in a test tube full of water, shake vigorously and centrifuge, or wait. Examine the co... [more]

PS I have done sediment-size analyses. Simply put the sample in a test tube full of water, shake vigorously and centrifuge, or wait. Examine the columns, the heaviest will be at the bottom - but you knew that of course

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9 How to decide whether the distribution is unimodal or bimodal in grain size distribution?
By Praveen Mishra · Deutsches GeoForschungsZentrum GFZ

Praveen Mishra · Deutsches GeoForschungsZentrum GFZ

Dear Peter and Charles, Thanks for your suggestions. I'll try to plot log normal plot of cumulative weight vs size in phi units and also go through t... [more]

Dear Peter and Charles, Thanks for your suggestions. I'll try to plot log normal plot of cumulative weight vs size in phi units and also go through the paper.

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Question:
New High sinusoidal meandering river and straight rivers TOGETHER?
Where on Earth can I find high sinusoidal meandering river and straight rivers together? Any idea? Thanks.

Where on Earth can I find high sinusoidal meandering river and straight rivers together? Any idea? Thanks.

By Simon Khor · University of Malaya

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7 How to calculate percentile (50th, 16th, etc.) values in grain size distribution.
By Praveen Mishra · Deutsches GeoForschungsZentrum GFZ

Praveen Mishra · Deutsches GeoForschungsZentrum GFZ

Dear Alexander, thanks ...for clarifications .....now I will follow your method.

Dear Alexander, thanks ...for clarifications .....now I will follow your method.

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5 Does anyone know a laboratory (preferably in EU) to perform U-Pb datings on carbonates?
By Carlo Bertok · Università degli Studi di Torino

V. Podkovyrov · Russian Academy of Sciences

Hi Carlo This is quite a chore, but the bulk process, has long tested in our laboratory isotope chemostratigraphy by GV Ovchinnikova (IPGG RAS). Among... [more]

Hi Carlo This is quite a chore, but the bulk process, has long tested in our laboratory isotope chemostratigraphy by GV Ovchinnikova (IPGG RAS). Among recent works here this G. V. Ovchinnikova, A. B. Kuznetsov, et al. 2012. U-Pb age and Sr isotope signature of cap limestones from the Neoproterozoic Tsagaan Oloom Formation, Dzabkhan River Basin, Western Mongolia // Stratigraphy and Geological Correlation November, V. 20, Iss 6, 516-527 or http://www.authormapper.com/search.aspx?val=journal%3AStratigraphy+and+Geological+Correlation&val=name%3AOvchinnikova%2C+G.+V. or old references in http://serials.unibo.it/cgi-ser/start/it/spogli/ds-s.tcl?authors=%22OVCHINNIKOVA+GV%22&language=ITALIANO Best Victor Podkovyrov

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4 Does anybody know how to triangulate a raster image (geol. map)?
By Emilio Pueyo · Instituto Geológico y Minero de España

Emilio Pueyo · Instituto Geológico y Minero de España

Yes, JL, we should post it here!

Yes, JL, we should post it here!

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Question:
Open Please help testing lithologs, a new online tool to describe outcrops and create lithology logs
I have recently published a first alpha version of this tool which is available at http://www.lithologs.net. Basically it allows you to enter some inf... [more]

I have recently published a first alpha version of this tool which is available at http://www.lithologs.net. Basically it allows you to enter some info on e.g. the location etc of your outcrop and a nice online tool to create lithologs which can be viewed and exported as SVG. You will need a modern browser to use it.. I would like to ask you for some feedback which would help to improve the tool so volunteers are welcome to play with it. Please provide your feedback at http://lithologs.net/index.php?action=feedback

http://www.lithologs.net ×
LithoLogs - Outcrops, Boreholes & Profiles, Online Log Plotting

By Robert Huber · Universität Bremen

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Answer added to:
4 Can you explain how Arsenic is formed?
By Ryandi Adlan · Universitas Padjadjaran

Olaf Cirpka · Eberhard-Karls-Universität Tübingen

The question is posed wrong. Arsenic is a chemical element. On earth, it is not "formed"; heavy elements in the solar system are all remnants of forme... [more]

The question is posed wrong. Arsenic is a chemical element. On earth, it is not "formed"; heavy elements in the solar system are all remnants of former star systems gone nova. I guess the question is how mobile arsenic (relevant for groundwater quality) is formed. Arsenic in groundwater is released from cristalline rock (such as granites) at significant but comparably low concentrations. The original arsenic bearing minerals are often pyrite and other sulfides. In these environments, oxidation of the sulfides is needed for mobilization. The highest geogenic arsenic concentrations in groundwater on large scales are found in holocenic sediments of river deltas in south-east Asia (Bangladesh, Vietnam, Combodia). The release of dissolved arsenic is strongly related to reducing conditions which are common in these aquifers. Under oxic conditions, the arsenic is sorbed onto ferric iron-oxides/-hydroxides. The exact mechanisms of arsenic release under reducing conditions are still debated but a clear relationship between redox and arsenic concentration has been established (brown, oxidized sediments = low dissolved arsenic; gray, reduced sediments = high dissolved arsenic). In the older, pleistocenic sediments, arsenic has already been washed out. Thus, the probable process chain is: (1) erosion of arsenic-bearing rocks (granites) in the Himalayas, (2) sedimentation in the river delta, (3) oxidation of the sulfide and sorption onto ferric iron hydroxides, (4) release of the arsenic under reducing conditions. The Swiss Federal Institute of Aquqatic Science and Technology - Eawag has developed methods to predict the worldwide risk of arsenic groundwater contamination (see http://www.eawag.ch/forschung/qp/wrq)

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19 Can anyone help me with this mineral (Reflected Light Microscope)?
By Andrei Ionut Apopei · Universitatea Alexandru Ioan Cuza

Andrei Ionut Apopei · Universitatea Alexandru Ioan Cuza

Thank you for the answer and for your kindness, the sample was sent for an EMPA analysis.

Thank you for the answer and for your kindness, the sample was sent for an EMPA analysis.

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Answer added to:
9 Are these Tetrahedrite twins (using a reflected light microscope)?
By Andrei Ionut Apopei · Universitatea Alexandru Ioan Cuza

Tark Hamilton · Government of Canada

They appear to be too broad and too irregular along their boundaries for normal thermal cooling induced twinning. The morphology looks like exsolution... [more]

They appear to be too broad and too irregular along their boundaries for normal thermal cooling induced twinning. The morphology looks like exsolution or growth zonation. I'd recommend looking at eds spectra on both sides to see what compositional variation exists. It could still be growth related contact twinning but the common twins are still on (111) or parallel to the [111] pole as a zone axis. In that the series is 4 3bar m and isometric, it should not have any bireflectance in reflected polarized light if it is just a twin and not an exsolution of another bireflectant phase. Substitutions and related phases may involve: Ag, Fe, Zn in the cation sites and Bi, As in the Anion sites.

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5 Is the gas compression ratio higher in the Tertiary or Cretaceous?
By Rakesh Gosain · Wadia Institute of Himalayan Geology

Michael Clark · New Mexico State University

Rakesh Is there a shallow basin that runs semi-parallel to the Himalayan Mountain Range that the Ganges River occupies. ???

Rakesh Is there a shallow basin that runs semi-parallel to the Himalayan Mountain Range that the Ganges River occupies. ???

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18 On hitting dolomite with a hammer, it produces a typical pungent smell of H2S where as on powdering, it is not so? Is there any explanation?
By Harshita Joshi · Wadia Institute of Himalayan Geology

Thomas Oberthür · Bundesanstalt für Geowissenschaften und Rohstoffe

Most probably - organic material. Known from many limestones ("Stinkkalk").

Most probably - organic material. Known from many limestones ("Stinkkalk").

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13 I wonder has anybody seen similar structures before (domical fractures, please see attached photo)?
By Joanna Roszkowska-Remin · Państwowy Instytut Geologiczny

Sandeep Singh · Indian Institute of Technology Roorkee

To me all three photographs could be pseudonodules or cycloids similar to the flame type structure of Dzulynski and Walton (1965), and ball-and-pillo... [more]

To me all three photographs could be pseudonodules or cycloids similar to the flame type structure of Dzulynski and Walton (1965), and ball-and-pillow structure of Potter and Pettijohn (1963), or pseudonodules of Hempton and Dewey (1983). Maybe these references can help Dzulynski, S.,Walton, E.K., 1965. Sedimentary Features in Flysch and Greywackes. Developments in Sedimentology, vol. 7. Elsevier, Amsterdam. 274 pp. Potter, P.E., Pettijohn, F.J., 1963. Palaeocurrents and Basin Analysis. Springer, Berlin. 296 pp. Hempton, M.R., Dewey, J.F., 1983. Earthquake induced deformational structure in young lacustrine sediments: East Anatolian Fault, Southeast Turkey. Tectonophysics 98, T7–T14. Singh, S. and Jain, A.K., 2007. Liquefaction and fluidization of lacustrine deposits from Lahaul-Spiti and Ladakh Himalaya: geological evidences of paleoseismicity along active fault zone. Sedimentary Geology, 196, 47-57. I am not suggesting that they are Earthquake induced structure rather they are sedimentary structures.

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8 How possible is it to have several forced regression surfaces below and immediately above major sequence boundary?
By Muhammad Abubakar · Abubakar Tafawa Balewa University

Muhammad Abubakar · Abubakar Tafawa Balewa University

Thank you very much all for your well informed contributions and assistance. As a fall out from Prof. H. W. Posamentier's contribution/observations, ... [more]

Thank you very much all for your well informed contributions and assistance. As a fall out from Prof. H. W. Posamentier's contribution/observations, I have attached some facies evaluation of the sections of study. We are at the moment working on outcrops.

Microsoft PowerPoint - Facies association of sections of study.pdf ×

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1 What is the meaning of D(4,3) and D(0,5) values in grain size analysis and how is it calculated?
By Praveen Mishra · Deutsches GeoForschungsZentrum GFZ

Ioan Tanţău · Babeş-Bolyai University

You can find some explanations in attachments

You can find some explanations in attachments

Basic_principles_of_particle_size_analysis_MRK034.pdf ×

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Answer added to:
14 Is it possible to have a La and Gd negative anomaly in any of the hard rocks with Eu positive anomaly?
By Resmy K J · Indian Institute of Technology Roorkee

Michael Bau · Jacobs University

Resmy, do you see fractionated (i.e. non-chondritic) Y/Ho ratios? if what you see is related to the lanthanide tetrad effect, you should also see fra... [more]

Resmy, do you see fractionated (i.e. non-chondritic) Y/Ho ratios? if what you see is related to the lanthanide tetrad effect, you should also see fractionation of the geochemical twins Y and Ho. cheers - Michael

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5 I did a strain analysis from a deformed conglomerate, what should I do next to generate a regional tectonic model of the area?
By Ketan Chourasia · Dr. Harisingh Gour University

Ketan Chourasia · Dr. Harisingh Gour University

Thanks Hossam, thats the only book i am following for microtectonics.

Thanks Hossam, thats the only book i am following for microtectonics.

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Question:
Open Do you know of cases of damage due to expansion by drying magnesium salts? I mean obviously building materials (stone, brick, mortar).
We have a type of rock on which we are looking for damage mechanics which have been caused by magnesium salts in situations of extreme drying (less th... [more]

We have a type of rock on which we are looking for damage mechanics which have been caused by magnesium salts in situations of extreme drying (less than 29% RH).

By Josep Gisbert Aguilar · University of Zaragoza

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11 Can anyone suggest how to effectively present grain size data from core sediments?
By Praveen Mishra · Deutsches GeoForschungsZentrum GFZ

Vahid Tavakoli · University of Tehran

OK. I think that all the answers are perfect. I just want to add the statistical analysis. If you have your size analysis data, you can calculate the ... [more]

OK. I think that all the answers are perfect. I just want to add the statistical analysis. If you have your size analysis data, you can calculate the statistical parameters (such as skewness or kurtosis) from both graphic and moment methods. They are helpful for better understanding of environmental conditions.

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Answer added to:
13 Correct calibration of a Reflected Light Microscope.
By Andrei Ionut Apopei · Universitatea Alexandru Ioan Cuza

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26 Is there only Montmorillonite Minerals in claystone or mudstone whice cause "liquefaction" or subsidence problem? If not, what else?
By Ryandi Adlan · Universitas Padjadjaran

R. Adamcova · Comenius University in Bratislava

Citation from that Rissa .pdf: "For a quick clay, loaded undrained beyond "tau"ef, the pore pressures will increase explosively as the unstable "card ... [more]

Citation from that Rissa .pdf: "For a quick clay, loaded undrained beyond "tau"ef, the pore pressures will increase explosively as the unstable "card house" clay particle structure will start collapsig, resultig in a net decrease in shear strength. Consequently, failure takes place almost instantaneously and long before the angle of internal friction is ully mobilized (Aas, 1981)". It is, in other words, the same card house clay structure collapse as described by Lagaly. As you could see in the Rissa video, addition of salt, i. e. changed type and concentration of ions in the pore solution, accelerated the change from the liquid sensitive clay to the plastic consistency again. I think Lagaly and Prof.Schanz are writing about the same phenomenon, but one from the clay-mineralogical and the other one rather from the mechanical point of view. I stop, sorry, no more time. Nevertheless, the question was not Rissa, but, if another clay minerals can cause similar collapse (I don´t think that Ryandi was asking about the steady state in loading plots).

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Question:
Open Can HF be present in magmatogenic hydrothermal fluids?
HF is highly reactive in contact with silicates and carbonates.

HF is highly reactive in contact with silicates and carbonates.

By Masoud Moslehi · Buali Sina University

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2 Does anyone know where in Germany has wet high intensity magnetic separation?
By Hien Dinh · Universität Freiburg

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2 Any experience with creating SVG graphics for SedLog?
By Matt Burton-Kelly · University of North Dakota

Bhawanisingh Desai · Pandit Deen Dayal Petroleum University

For creating svg graphics for sed log, you can use inkscape, a free software. modify any graphics and then you can import in sedlog or corel draw also... [more]

For creating svg graphics for sed log, you can use inkscape, a free software. modify any graphics and then you can import in sedlog or corel draw also.

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Answer added to:
2 Can anyone provide an article of High-pressure stability of carbonates: quenching of calcite-II, high-pressure poly-morphs of CaCO3?
By Roonak Paktinat · Zanjan University

Roonak Paktinat · Zanjan University

Salam kheyli mamnon az komaketon.ghablan in site rafte bodam chand vaght bod gheyre faal bod. Kolan az khateram rafte bod vali alan tonestam maghala... [more]

Salam kheyli mamnon az komaketon.ghablan in site rafte bodam chand vaght bod gheyre faal bod. Kolan az khateram rafte bod vali alan tonestam maghalam ro sefaresh bedam.kheyli mamnon

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