306 Answered Questions for the topic geology

06/25/19

What are the challenges in predicting lithology directly from acoustic impedance?
Seismic inversion methods help to visualize the subsurface layers of the earth in terms of petrophysical properties (e.g. impedance). Still some geophysicists use the final inverted impedance model... more
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06/25/19

Which geological processes will destroy plastic?
The geological record at the end of the Anthropocene will undoubtedly contain large volumes of plastic. However, some geological processes will completely destroy plastic (e.g. magmatic or chemical... more
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06/17/19

Why are minerals found in "large" quantities and not scattered throughout the earth as individual atoms?
Heavier elements are created in stars. After stars die they scatter these heavier elements throughout the universe. These elements eventually gather to form planets. But why do we find "chunks"... more
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06/16/19

What are 'articulate shells'?
I can not really find a definition, not even in a geologic dictionnary: What are articulate (resp. inarticulate) shells?To be more specific, the term is related to tsunami deposits (tsunamite).
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06/16/19

Which geological processes will destroy plastic?
The geological record at the end of the Anthropocene will undoubtedly contain large volumes of plastic. However, some geological processes will completely destroy plastic (e.g. magmatic or... more
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Geology Geophysics

06/15/19

How is the mass of the Earth determined?
According to textbook knowledge, the mass of the Earth is about 242kg. How is this number determined when one cannot just weight the Earth using regular scales?
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06/15/19

Sediment layer chronology?
In the new Cosmos series, Neil DeGrass Tyson in explaining different ways the age of the world has been determined, shows how sedimentary layers at the Grand Canyon are a fossil record of a lot of... more
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06/13/19

What separates the Karakoram Range, the Hindu Kush, and the Himalayan Range?
In Google Maps, I don't see any boundary between the Karakoram (a.k.a. Karakorum) Range, the Hindu Kush, and the Himalayan Range. What separates these ranges?
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06/12/19

Earth's ocean basins?
Was Earth's sea-floor always carved with the numerous geological features that we see today, or was it at some point flat and boring as Mars is today?
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Geology

06/12/19

Is there any correlation between La Nina/El Nino and seismic activity?
I've read in the past that extreme precipitation levels may have an effect on seismic activity, and wondered if anyone has ever analysed the La Nina / El Nino cycles to see if there are any... more
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06/11/19

What was the likely composition of Earth's early crust (how did crustal composition evolve)?
Was the first crust entirely mafic (oceanic) crust which was later distilled via volcanic arcs along subduction zones to make felsic rocks or did the earth start with bits of felsic crust?Are the... more
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06/10/19

What is the current status of geophysical global cooling theory?
Plate tectonics effectively rubbished the theory of geophysical global cooling as a means of explaining many surface features on the Earth. However, [this... more
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Geology

06/10/19

How to distinguish an explosion crater from an impact crater?
(How) Is it possible to tell the difference between a man made explosive crater and an impact crater?
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06/10/19

When metamorphic rocks undergo pressure, how are they changed?
When metamorphic rocks undergo pressure they are changed, but how are they changed? Do they become fragments of rocks? Doesn't that mean that the difference between sedimentary rocks and... more
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Geology Rivers Hydrology

06/10/19

Rocks sparking under water?
I have searched for an answer to this question for years, to verify if it was true.A man that lived on a river in the rugged part of the northern Washington Cascades told me an interesting story.... more
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06/09/19

Methods and Software for Interpolating/Modelling of Stratigraphic Well Data in 2D/3D?
I have some geologic well data. The lithologies have been interpreted, and stratigraphic columns have been drawn. The columns have been adjusted for elevation, and correlation has been done between... more
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Geology Plate Tectonics

06/09/19

How deep are the cracks in the earths crust at fault zones?
I have seen pictures of the cracks in the Earth's crust in Iceland and the San Andreas fault. To my eyes, the crack is relatively wide at the surface than a few meters down seems to be very narrow... more
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06/08/19

Is the magma in one volcano different from the magma in every other volcano?
Is there a significant difference between the magma in different volcanoes? If so, why?Doesn't all magma come from the same place if you go down deep enough?
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06/07/19

Age of fossils found in rocks?
I have heard the claim by creationists that geologists date rocks by the fossils they contain and date fossils by the rocks in which they are found. This supposedly invalidates radiometric ages... more
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06/06/19

Why are alkali basalts found at rifting centres and on top of 'plumes', whereas MORBs are generally tholeiitic?
So I was essentially wondering why it was that the basalts on top of 'plumes' at 'hotspots' (sometimes called OIBs, ocean island basalts) and at continental rifting centres are enriched in alkaline... more
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Geology Science

06/06/19

what takes longer to form, a sedimentary rock or a metamorphic rock
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06/05/19

Why are South African mountains short and flat?
I drove through South Africa from Cape Town to Mozambique and noticed that almost all heights and mountains were no higher than approx 200-400 meters and had a flat top, just like the iconic Table... more
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Geology

06/04/19

Database of geological group or formation exposures?
Is there any sort of database that provides the locations of exposures of certain geologic groups or formations?I ask because I have read that halite occurs in the Michigan Basin, and specifically... more
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06/02/19

Were all of Earth's minerals created before Earth's formation, during, or after?
I've heard that during the accretion of proto-planets that formed the earth, 60 minerals were created through the reactions of atoms and molecules in the nebula.Do these first minerals still make... more
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Geology Geobiology

06/02/19

How can the 'abiogenic oil' hypothesis be disproven?
We do know that complex hydrocarbons (e.g., tholins) exist in the outer Solar System. Some geologists maintain that at least some oil on Earth is of non-biological origin. The mainstream, though,... more
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