Questions tagged [sedimentology]

Sedimentology encompasses the study of modern sediments such as sand, mud, and clay, and the processes that result in their deposition.

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194 views

Does the existence of limestone nodules in a clay soil horizon indicate a limestone bedrock?

A profile (clay soil) was excavated to a depth of 100 cm in the north of Tunisia. We have found limestone nodules, colluvium and alluvium. What I would like to know is the nature of the bedrock of ...
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362 views

What are the mechanisms maintaining the Dune of Pilat?

The Dune of Pilat (Dune du Pilat) is the tallest dune in Europe. The dune has been around for at least centuries. Where is the sediment coming from? Why is the dune so tall?
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The grains of the parabolic dunes

My text book says that parabolic dunes consist of consolidated limestone grains, but I wondered if they have sand grains too, so I googled this issue and found that they consist of sands, but I am ...
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164 views

Deposition in epioceanic areas

I found allochthonous (I don´t know the 2 locations) fined grained carbonate sediment in Ammonitico Rosso, which is possibly mudstone in the South Iberian Peninsule, specifically in Carcabuey (Córdoba)...
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727 views

What are the differences in terms of appearance between sandstone and limestone?

On the field, I find it very difficult to differentiate the two types of rocks just by looking at them.I know that you should do some analysis of the sample before any conclusions. But, for example in ...
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185 views

Why pro-gradation occurs along coastal environments?

I am currently studying the deposition process in coastal environments and I came across a point which I do not understand concerning grading of grain size. According to "Petroleum Geology by North F....
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143 views

When sediments are deposited, do they sink into the earth?

I was listening to a geology podcast describing how sedimentary rock forms and later turns into metamorphic rock. As a river lays down sediment, the lower layers can eventually be several kilometers ...
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1answer
130 views

Do any rivers deposit sediment in their deltas fast enough to counteract sea level rise?

Assume a 1m per century sea level rise. Looking at a topographic map it quicly becomes clear that Bengal, the Netherlands, the lower Mississippi, South American Mesopotamia, etc will all soon be ...
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Is there any significance of lacustrine gastropoda fossils regarding paleoenviroment interpretation?

How to interpret lots of gastropoda fossils seen in lacustrine marls? Do they indicate any paleoenvironment conditions? Depth, temperature, chemistry, ph?
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1answer
48 views

What is the best way to mount white mica separates?

I have detrital mica separates that I would like to mount in EpoThin resin for microprobe analysis and I would simply like to know the best method for mounting them. With zircons you can mount on ...
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67 views

How do we detect floods?

How do we know that there was a flood at a certain place at a certain time. For example if there was a flood in place A 200 years ago. How could we detect it?
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Mass budget of coastal erosion and ocean deposion

This question made me wonder: how much mass (or volume) of material is eroded by the sea each year? Of this mass, how much is deposited in the oceans? (As Michael pointed out in his answer, part of ...
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120 views

Can a braided fluvial create thick relatively continuous siltstone beds?

I am attempting to interpret an outcrop I went to. I suggested it was created by a braided fluvial. The one thing I cannot explain are prominent alternating siltstone beds with the sandstone beds. ...
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Presence of cross stratified conglomerates in fan deltas

Why are cross stratified conglomerates found in deposits of fan deltas? I know that fan deltas are alluvial fans that deposit directly into the sea, hence they are poorly sorted.But could not ...
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How can we estimate the amount of sediment that traveled downstream during the California flood?

It's amazing how much water traveled down the slopes of California during the first two months of rain/flooding of 2017. Since the amount of water was far greater than anything in recent history, ...
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Is Desert Sandstone a chemical sedimentary rock?

I gather that chemical sedimentary rocks are formed when minerals in solution are supersaturated and therefore they precipitate out. I also understand that desert sandstone is formed as Iron Oxide ...
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Dolomite in deep-water environment

Is it possible that dolomitization occur in deep-water environment? If it possible, how?
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460 views

Inorganic Limestone and Inorganic Gypsum

I read that limestone is made from the compaction of marine animals' bones. But, I am unable to find out why limestone could not have been produced from calcium occurring naturally (5th most abundant ...
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Sedimentology (Particle size distribution parameters)

The Inclusive graphic standard deviation (sorting) value of this claystone sample is negative (-1.29). Is this right to be considered as very well sorting ? However, the bivariate plots of ...
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What kind of soil is being worked in this video? [closed]

I have recently stumbled across this video on Youtube, where quite a magnificient building is carved into the soil with simple tools like a shovel and hoe. The location is somewhere in South America, ...
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1answer
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Can we separate a sandy, clayey & salt layer on basis of their rheological properties?

Since, given enough compaction, salt is able to behave like a fluid & buoyant too if it's overlain by a higher density rock (it could be fine grained clay or a sandy sequence). But in another case,...
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Sandstone Layer Question

I have been exploring the sandstone of southern Utah for many years and I have a question about the area around Sidestep Canyon (near Wahweap, near Page, AZ). There are many amazing hoodoos there and ...
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How do I plot Troels-Smith lithological symbols in R?

I'm trying to plot lithological data using the Troels-Smith scheme. I have tried psimpoll but as I only have lithological data I cannot create a main input file which is required. I also do not have ...
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Formation of petrified trees

In my book, I came across this question: Give reason why formation of petrified tress is considered as a degradation and a sedimentation action of the underground water. My book explains that ...
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How should core-rim detrital zircon ages be reported in a sedimentary provenance study?

I understand this might be drifting into the black hole of subjectivity but I would like to know if anyone knows if there is a generally accepted practice. If one has a detrital zircon with a core age ...
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How are natural specimens, such as ‘Moqui Marbles’, distinguished from man-made artifacts?

If a particular type of rock specimen is found throughout Earth and is made entirely of natural minerals, but the individual specimens differ minutely from another in size and shape and look to be ...
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How much does the weight of urban structures (buildings) affect the compaction (permeability, porosity, density) of alluvial sediments below a city?

I live in Van, Turkey. Van City is situated on an alluvial plain beside Lake Van. General geological structure of the area can be seen on pages 43-44 in this conference book. One of the images is ...
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Where can I find papers on the geology of the Wastach Range in Utah

I am looking for papers on the stratigraphy, geochronology and/or compositional make up of the Wastach Range and its formations. I prefer a broad overview paper and I can't seem to find one. Any help ...
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What are the differences between alluvial, eluvial and colluvial deposits? [duplicate]

There's always confusion and disagreement when these terms are mentioned. Need to be sure of their exact meanings.
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What is the difference between Saprolite and Regolith?

Saprolite and Regolith both imply loose material, is one a subset of the other how can I differentiate them ?
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Would you see a correlation between detrital zircon age and grain shape?

If one was to quantify the shape (particularly roundness) of detrital zircon grains, would there be a correlation between the age of the detrital zircon grains and their shape? For example, if the ...
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1answer
107 views

Have we looked for human-like signals in the geological record?

This is somewhat of a follow up to some interesting discussion here about using synthetic radioisotopes to define the start of the anthropocene. It is also sort of related to a question asked here, ...
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What are these basal rip up clasts in North Dakota?

Ther's an graph that appears that the KT asteroid turned the rocks into rubble 3000 km away, else there was a rain of big rocks from the sky. What are the rip up clasts and what is the way they were ...
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Specific Chemical Composition of Nero Marquina Marble

I'm looking to understand the chemical composition of the Spanish Nero Marquina Stone. Specifically, are the white veins of different composition than the black? We are design studio pursuing work in ...
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SC7 and SC10 Lithology Classifications

I am looking for the full names of the lithology classifications SC7 and SC10. According to the FAO's guidelines for soil description SC3 e.g. refers to silt-, mud-, claystone. What do SC7 and SC10 ...
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what kind of rock or mineral is in my pic [closed]

I'm trying to identify this sediment. Any ideas of what its named or how its formed?
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A few questions about the morphology and sediment dynamics of Wissant Bay (France)

Could someone please explain what exactly is shown on the following image? I have a few questions such as: How did the 'Banc à la Ligne' come about? (I know it has something to do with the fact that ...
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How do you interpret Oxygen Isotope changes?

In a paper I am reading, the authors note "large (5-7%) negative shifts in the oxygen isotopic composition of geologic proxy materials" (Davis 2008, pg. 102) in several regional basins. This is then ...
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1answer
204 views

What is meant by Monte-carlo simulation? (would like an elaborated answer with some references) [closed]

I have come up with simulations which involves monte-carlo method that I am not fully aware of. I would be very happy if someone can help me with some references to read and learn.
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453 views

What does a negative value for the inclusive graphic standard deviation mean?

I'm calculating the inclusive graphic standard deviation for sediment from a cumulative frequency graph, with this formula: But when I plug in the numbers, I get a negative value, because my ranges ...
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Are fossil fuels really formed from fossils?

Hydrocarbons have been found in great abundance elsewhere in the solar system where there is unlikely to be evidence for life past or present. No fossils involved. Petroleum and natural gas wells ...
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What is limestone made of?

I know that it is calcium carbonate (CaCO3). I also know that these are the dead bodies of microorganisms. My question is, where do they procure the building material? The limestone seems to cover ...

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