43 Questions 134 Answers 0 Followers
Questions related from Christian Ungewitter
We operate a measurement station. We measure for example the soil water content. During the last data checks I realised a sudden increase and decrease in soil water content by up to 10 %. The...
16 January 2024 3,125 6 View
I'm searching for a range or list of values for the stiffness (in MPa or GPa) for highly weathered sandstones. It would be very beneficial if you could give some information on their petrography.
23 November 2023 4,523 3 View
I tried to find a site where I can buy a needle penetrometer for weak rocks/soft rocks. But my search was not successful. Does anybody where I can get a needle penetroemter? Links are welcome.
16 October 2023 663 2 View
Can you say that unconsolidated sediments that deposited in a high energy environment like creeks and rivers possess a higher bulk density and thus a higher stiffness than unconsolidated sediments...
04 October 2023 4,384 2 View
Attached you find some pictures of a fine grained sandstone/siltstone from the Buntsandstein in Germany. What are the bright pinkish, blobby structures? How do they form? They are...
23 June 2023 3,104 9 View
Along the Werra basin in Thuringia (Germany) triassic sediments are very common. What is their minimal and maximum burial depth? Are there publications, thesis etc. on this topic? I have...
10 January 2023 3,098 1 View
I would like to know what the minimum strength of a rock has to be when I want to conduct a point load test. When rocks or indurated soils have a strength below a certain treshold they fail very...
21 November 2022 831 4 View
Is there some kind of empirical formula or some outcrop characteristics you can use to assess the duration a sandstone outcrop was subject to weathering? How big is the influence of the...
04 September 2022 6,288 4 View
Please share the links in your comments.
13 March 2022 6,824 2 View
Below you can see a picture of a sandstone from the lower Buntsandstein group in Thuringia (Germany). The grey dots are sandstone, too. They are free of carbonates.
21 February 2022 1,346 6 View
I stored some clay rock samples in a diluted salt solution (c=2,5 g NaCl/l). The duration of the storage is around two to three months. Is there a possibility that Na+ from the salt solution...
17 April 2021 1,345 4 View
The range of forms and sizes of cavities in rock is very big. Is there a classification scheme for rock cavities regarding their size and shape?
03 March 2021 5,047 3 View
There are numerous databases for geochemical analyses for rocks like georoc and the National Geochemical Database of the USGS or purely mineralogical databases like mineralienatlas, mindat or...
16 February 2021 5,306 9 View
During my PhD studies I was wondering at what point a system becomes complex or even chaotic. I conducted a laboratory study under defined boundary conditions. I conducted my research on fairly...
31 July 2020 8,339 5 View
My question relates to drilling in mudrock. There are numerous types of exploration drilling for rock. In some publications air is used as drilling fluid. But can air cool the drilling bit enough...
28 February 2020 4,709 3 View
I have a rock specimen and a soil specimen. During my mechanical measurements I observed that the rock reacts much faster on stress rate changes (observable by a sharp kink in the deformation...
01 October 2019 3,214 5 View
In the media you can always read that petroleum has an organic source. But I never heard a geologist ruling out a possible inorganic source for petroleum. I have the impression that there is still...
26 September 2019 2,122 22 View
I have two variables for which I want to calculate the correlation coefficient. One variable has an interval level (the values are 200, 400, 600, 800) the other has a ratio level. Is there a...
10 July 2019 8,894 3 View
My question relates to the potential damaging effect (lowering strength and stiffness properties) of thermal expansion on shale. Is this phonemenon important in a tempersture range from 0 to 40 °C...
09 April 2019 623 5 View
Dear researchers, I have two questions: 1. I want to evaluate the maximum burial depth of a Lower Cretaceous mudstone from Germany with the Kübler index. Mostly you can find correlations with...
07 February 2018 3,344 4 View
Are there any standards (ISO, EN, DIN, ASTM etc.) for the mineralogical quantification of rock materials?
07 December 2017 9,903 6 View
When performing kriging with anisotropy it can be the case that a very high length-to-width-ratio of my sampling points can pretend an anisotropy which is in reality not existent. So my question...
07 November 2017 4,744 4 View
Does the replacement of potassium by sodium in the illite interlayer increase the spacing between the layers?
06 November 2017 2,579 5 View
Is it possible that K-Na exchange in the crystal lattice of illite enhances its shear strength?
25 September 2017 7,686 1 View
The most suggestions I find in literature are a stepwise increase from about 0.2 MPa up to 400 MPa. Is this the case in general?
23 August 2017 4,926 3 View
I'm new to the topic and I want to have a first and broad overview on questions concerning: What is an artificial neural network? What can they do? How do they work? What types of ANNs do exist?...
27 June 2017 5,440 11 View
I want to dry a mudrock without disturbing the mineralogical composition due to mineralogical changes. The clay fraction in the mudrock is composed of illite, chlorite and kaolinite.
03 March 2017 5,887 6 View
There are numerous corrections for the membrane, the filter plate, the change of specimen diameter and so on during the triaxial test. But is there a correction factor for elasticity modulus and...
02 February 2017 6,728 2 View
I am searching for an overview or list with lattice energies and bonding energies of different minerals (especially clay minerals, carbonate minerals, sulphate minerals, feldpars, quartz and its...
19 October 2016 7,420 0 View
I would like to know if there is a measuring device to measure the lattice enthalpy of a rock or other polycrystalline materials. I know that there are different possibilities to measure the...
07 October 2016 1,342 1 View
Dear reseachers, there is the phenomena that clay particles aggregate and flocculate in salt water. But in fresh water they don't aggregate and develop a laminated structure when deposited. I...
05 September 2016 9,501 7 View
I am searching for a good reference for osmosis from a physico-chemical/thermodynamical point of view. The publication must provide a general introduction to osmosis based on the chemical potential.
30 August 2016 2,646 2 View
Hello, I know that there is a squeezing technique to sample pore water of mudrocks. But this technique is very sophisticated and potentially time consuming. My question if it is possible to...
22 July 2016 3,499 6 View
I would like to know if there are publications on this topic or if there are some rules of thumb.
22 July 2016 10,005 5 View
I want to measure the suction for an unsaturated material in a triaxial testing device. The suction tension for the material should be less than 1 MPa according to a small literature review I...
04 July 2016 1,032 3 View
Hello, are there climate cabinets with an accuracy of +-0,1% relative humidity in the range of 90-99,9% relative humidity? I want to hold the temperature in a steady state so the temperature...
19 May 2016 1,546 0 View
Hello, I want to generate a constant high relative humidity (90-100% in a desiccator) for a research study on mudrocks. There is the possibility to use different saturated salt solutions. But the...
17 May 2016 1,768 10 View
I want to perform a diffential thermal analysis on a mudrock. Is there a preferable heating rate that I do not measure any remnants or effects that disturb the result (e.g. possible destructuring...
18 April 2016 3,342 4 View
Hello, I measured the nickel content in pentlandite in two rocks which are genetically linked (a sheared chromitite and a talc-carbonate-schist). There is a depletion of nickel in the pentlandites...
08 April 2016 2,343 5 View
I want to measure the portion of adsorbed water in a mudrock. There are some references where the adsorbed water is measured in clays, but not in shales or mudrock. So I asked myself if thermal...
04 March 2016 8,458 3 View
Hello, I want to start a discussion about the influence of ChatGPT on the geological business and especially on writing geological/geotechnical reports. Is it possible with the current...
01 January 1970 5,083 13 View
I did my PhD research on slaking rocks or soft sedimentary rocks, respectively. During my literature research in the beginning of my PhD project it was pretty obvious that there is no general...
01 January 1970 7,111 6 View
I read a small blog entry of Jan Merks from the year 2010: https://news.bulk-online.com/general/what-if-our-world-were-free-of-geostatistics.html There he writes (a bit polemically): "All I do...
01 January 1970 4,217 4 View
