19 votes
Accepted

Is it possible that the geomagnetic field reversal led to the extinction of Dinosaurs?

Mark's answer is correct, but in my opinion is not clear enough. Let's make it a bit simpler: Is it possible that the geomagnetic field reversal led to the extinction of Dinosaurs? NO, DEFINITELY ...
Gimelist's user avatar
  • 23.1k
13 votes

Is it possible that the geomagnetic field reversal led to the extinction of Dinosaurs?

It's a commonly-proposed theory that geomagnetic reversals cause extinction events, but there's no evidence for it. There aren't enough mass extinction events for any sort of statistical analysis, ...
Mark's user avatar
  • 1,261
11 votes

Variations in Gravity over Time

Is there any consensus about the conjecture that gravitational force on Earth may have changed significantly over geological time; No, Earth's gravity did not change significantly over time. Yes, ...
Gimelist's user avatar
  • 23.1k
10 votes
Accepted

Unwarranted claim of higher degree of accuracy in zircon geochronology

I can't be entirely sure but I'll make an informed guess: That value doesn't come for a single measurement. Therefore, if the error in the age of a single sample is $\pm125$ kyr, you just need to ...
Camilo Rada's user avatar
  • 17.7k
8 votes
Accepted

What if we detonated the entire worlds nuclear supply in the center of the earth?

I'll ignore the complete impossibility of getting the world's nuclear arsenal to the center of the Earth and the impossibility of exploding them all at once. The total number of nuclear weapons, ...
David Hammen's user avatar
  • 23.6k
6 votes

Why are pole reversals not more detrimental to life?

There are several factors to consider. The main one is the atmosphere (especially if you want to compare Mars with the Earth's during magnetic reversals). Earth's atmosphere is a formidable shield ...
Camilo Rada's user avatar
  • 17.7k
5 votes
Accepted

Safest spots when an asteroid hits?

Being in a submarine in the ocean is not a good idea because if a large asteroid hits the ocean the shock wave created, and its energy, would be very large. If the submarine survives intact its ...
Fred's user avatar
  • 24.7k
4 votes
Accepted

Could the current climate change events cause long-term problems in the viability of Earth to sustain life?

There is one scenario in which climate change could render the Earth inhospitable to life in general, which would be a runaway greenhouse effect. In a runaway greenhouse effect, the Earth would get ...
gerrit's user avatar
  • 11.7k
3 votes

How long does earth take to recover from mass extinctions? What is "normal"?

Mass extinctions are selective: not all living organisms will be affected by it to the same extent. Meaning also that various groups will recover from it at various speed: a group from which half of ...
plannapus's user avatar
  • 5,348
3 votes
Accepted

gamma ray burst, extinction-level event

As bon noted in the comments, that it the time it would take the gamma rays to reach Earth. Gamme rays travel at the same speed as all other forms of electromagnetic radiation, including visible light,...
Gimelist's user avatar
  • 23.1k
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 ...
Earth Science Expatriate's user avatar
3 votes

Unwarranted claim of higher degree of accuracy in zircon geochronology

The uncertainty on the decay constant / half life is systematic. This means that, if the "used" value would be off the "true" value by 0.05%, then it would affect all the ages in ...
Geochron's user avatar
  • 851
3 votes

What if we detonated the entire worlds nuclear supply in the center of the earth?

To add to David Hammen's answer. Earth is big. I hate to use the words "really really big" cause there are things much bigger, like the sun, but Earth is quite large. Imagine what would happen if ...
userLTK's user avatar
  • 5,857
2 votes

Where can I see/photograph the KT boundary on South Table Mountain?

According to Cretaceous-Paleogene Boundary the coordinates are: 39.7488 deg N, -105.1633 deg E The linked page has some photographs with this descriptive text: The Cretaceous-Paleogene (K-Pg) ...
GrapefruitIsAwesome's user avatar
2 votes
Accepted

Has Earth's geological activity calmed down in the past 250 million years?

The large-scale volcanic eruptions you mention are called Large Igneous Provinces (LIPs) and are probably linked to mantle plumes. They have been investigated for quite some time now. Ernst & ...
Jean-Marie Prival's user avatar
2 votes
Accepted

Signatures of acid rain at KT boundary

Estimated sulfur release 325 gigatonnes = 325,000 teragrams. The numbers in this diagram are in teragrams Sulfur Cycle so the release is $\approx 1000\times $ today's annual sulfur cycle. I think ...
Keith McClary's user avatar
2 votes

Could the current climate change events cause long-term problems in the viability of Earth to sustain life?

100 years is not very long-term at all. The added CO2 will not miraculously disappear after a century, but will go on warming the planet. (And that's just assuming that humans stop burning fossil ...
jamesqf's user avatar
  • 1,758
2 votes

Could the current climate change events cause long-term problems in the viability of Earth to sustain life?

Depends on the further actions humanity takes. If we keep on pumping green house gases into the atmosphere, survival will become significantly harder. Sure, we most likely wont be able to create a ...
Erik's user avatar
  • 756
2 votes

Why are pole reversals not more detrimental to life?

National Geographic published an article about this in January 2018 - No, We're Not All Doomed by Earth's Magnetic Field Flip. Yes, the flipping of the magnetic poles does take a long time - ...
Fred's user avatar
  • 24.7k
2 votes

Percentage of Oxgen left after burning all the available biomass

Estimates of earth's total biomass vary widely, from 0.5 to 4 trillion tons C, so instead of citing a source, I'll just go with an assumption of $1\times10^{15} \text{kg C}$. Measuring biomass in ...
kingledion's user avatar
  • 3,376
2 votes

Are there any metal anomalies other than iridium in the K-Pg boundary?

Another good historical perspective from this blog: http://lablemminglounge.blogspot.com/2006/09/iridium-anomaly-as-historical-artifact.html Iridium anomaly as historical artifact Everybody knows ...
Gimelist's user avatar
  • 23.1k
1 vote
Accepted

Permian-Triassic mass extinction. Consequences on Earth's system

Wow, I just finished watching this it seems we know, or can guess, quite a bit about the level of Carbon, particularly Methane that were released at the end of the Permian and what they did to the ...
Ash's user avatar
  • 4,260
1 vote

Recovery From the Great Dying

Let me propose that if an anoxia event were a cause of the P-T marine extinction; then it wouldn't be Pangaea that would slow recovery, but Panthalassa; the global ocean counterpart to Pangaea. Here ...
kingledion's user avatar
  • 3,376

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