10
votes
Accepted
Incised valleys and hydrocarbon potential
Sandstone bodies in incised valleys can be good hydrocarbon reservoirs.
Incised valleys form on the coastal plain and/or continental shelf during a fall in relative sea-level by a combination of ...
- 10.9k
9
votes
How accurate is the law of superposition?
The principle does not apply to all materials on earth as observed by us but is primarily concerned with sediments and rocks that form from sediments. Since sedimentation is a process driven by ...
- 4,779
9
votes
How old is Steptoe Butte (WA, USA)?
Without directly knowing anything about WA geology myself, you're dealing with two ages here: the age the rock deposited as a sandstone (protolith age, 1.4-1.5 Ga), and the age of metamorphism (400 Ma)...
- 415
9
votes
Accepted
What are these geological horizontal lines formed on this mountain called and why they are formed?
What you see are bedding surfaces. They formed horizontally in a sedimentary lacustrine environment, the Kailash Formation.
This is a reconstruction of the paleoenvironment:
.
(Source)
As Gimelist ...
8
votes
Are there any geological periods found on top of each other that have dinosaurs of that period with in them?
There are definitely many examples of overlying Mesozoic strata that contain characteristic dinosaur fossils (and ichnofossils – i.e. trace fossils). One of the best examples is the Mesozoic ...
- 263
6
votes
Accepted
What are 'articulate shells'?
If I remember correctly from my intro to paleo class, the terms articulate and inarticulate refer to a classification of brachiopods depending on the nature of their hinge. Articulate brachiopods have ...
- 947
6
votes
Nuclear testing and the Anthropocene, a chemostratigraphic link?
I will try to plainly answer your question about an artificial radionuclide production/diffusion resulting from human activities, without getting into the discussion of deciding if this is ...
- 2,623
6
votes
Accepted
Nuclear testing and the Anthropocene, a chemostratigraphic link?
Certain anthropogenic radionuclides have pragmatic advantages as markers for the start of the anthropocene. The advantage of radionuclides over anthropogenic stable nuclides is that the primordial ...
- 4,359
6
votes
where are the thickest limestone layers on earth ? (CaCO3)
Reading your comments I see that you're asking:
so could we find for example 1km high limestone layers on earth ?
The answer is definitely yes. Here's an example of a stratrigraphic geological ...
- 22.8k
6
votes
Accepted
Predicting rock type from seismic processing
This is a ginormous question; a complete answer is probably worth an MSc in exploration geophysics. But I can try to give some pointers for places to find out more.
Preface: in general, considering ...
- 10.9k
5
votes
How have global sedimentation rates changed over the last billion years?
Big question.
There is not enough data resolution at the moment, neither spatially nor temporally. There are geological periods thought to have undergone higher erosion rates based on the abundance ...
- 1,673
5
votes
Accepted
The youngest and oldest source rock for hydrocarbons in economic quantities
According "The youngest natural oil on earth" Doklady Chemistry vol. 438, pages 144-147:
Prior to this paper, it was known that oil of the Guaymas basin is from young sediments and is 5000 years old.
...
- 5,922
5
votes
Database of geological group or formation exposures?
You may also find localised geological guides, such as the Roadside Geology series.
http://geology.com/store/roadside-geology.shtml has a listing. While I have not used them, I have seen them crop up ...
- 441
5
votes
Nuclear testing and the Anthropocene, a chemostratigraphic link?
The chapter on the Anthropocene (Zalasiewicz et al., 2012) of "The Geological Timescale 2012" quote 3 papers that used artificial radionucleotides as stratigraphic markers: Schwikowski (2004), ...
- 5,298
5
votes
Width of strata in stratigraphic column
At least in Germany, another approach is very common („Verwitterungsprofil“): the width of layers shows their competence (resistance to weathering/erosion). So competent rocks (which don’t weather ...
- 221
5
votes
How accurate is the law of superposition?
Here is another example where the law of superposition breaks. Mind you this is a natural process: meteorite impacts.
A meteorite impact will excavate material from the bottom, and deposit it above ...
- 22.8k
5
votes
How accurate is the law of superposition?
As Peter correctly responds, for sedimentary rocks the principle of superposition is pretty much watertight except where tectonic superposition takes place. The latter can either repeat the ...
- 14.1k
5
votes
What are these geological horizontal lines formed on this mountain called and why they are formed?
Just to add on this point from the comments:
But this mount is the only mouth with this kind of formation in local mountain range
First, the image on the mountain's Wikipedia page clearly shows that ...
- 22.8k
4
votes
Accepted
Relative dating of intrusion
It does seem like it's impossible to know unless you have additional information. However, I think there is a hint in there. See this white halo around the intrusion? My guess (and I could be wrong ...
- 22.8k
4
votes
Accepted
How are stratigraphic limits defined before the Phanerozoic?
The standard stratigraphic nomenclature is a chronostratigraphic system based on palaeontological intervals of time defined by recognised fossil assemblages.
That's wikipedia for you. This is ...
- 22.4k
4
votes
How was the onset of the Cambrian period dated?
Fossils are only in very rare cases dated directly, because they do not contain sufficient radioactive isotopes for dating.
Most geological periods are first and foremost defined by biostratigraphy- ...
- 791
3
votes
What did tunnel digging teach us about the formation of chains of mountains?
Tunnels have provided nothing more than what was learned from conventional geological drilling and surface mapping. Tunnels provide supplemental information. Very rarely do they provide "make or break"...
- 23.1k
3
votes
Accepted
Can we call the Precambrian eons (i.e. Archaic and Proterozoic) eras?
It is and is not an an error depending on how it is used. They are Eons but in older literature they were also, sort of, eras as the Eons were not subdivided as they are now. Especially in literature ...
- 6,679
3
votes
Accepted
Boundary problems in stratigraphy
I believe what is being referred to here is the problem of determining where, in a continuous deposition sequence, a particular geologic time transition occurs. If you have uniform depositional ...
- 822
3
votes
How is geological time divided into units?
The divisions in the geologic time scale have evolved over time.
Its origins can be traced back to Nicolaus Steno in 1669 described two basic geologic principles.
The first stated that sedimentary ...
- 5,909
3
votes
Methods and Software for Interpolating/Modelling of Stratigraphic Well Data in 2D/3D
I believe that Leapfrog 3D will do this. They have academic licenses. I also seem to recall that Intrepid Geomodeller does what you are after. Both of these options are probably overkill though.
- 1,044
3
votes
Methods and Software for Interpolating/Modelling of Stratigraphic Well Data in 2D/3D
OpendTect may do this, however getting to that stage would be a painful experience.
Petrel can do this very easily, however, that is not anywhere near free...
If you're a student, your department ...
- 146
3
votes
Database of geological group or formation exposures?
Macrostrat is (or in fact will be) what you are looking for I think.
This database is still in development and is apparently only available through the website as a beta so far. It only seems to cover ...
- 5,298
Only top scored, non community-wiki answers of a minimum length are eligible