• Starting today August 7th, 2024, in order to post in the Married Couples, Courting Couples, or Singles forums, you will not be allowed to post if you have your Marital status designated as private. Announcements will be made in the respective forums as well but please note that if yours is currently listed as Private, you will need to submit a ticket in the Support Area to have yours changed.

Antipodal Hotspot Impact Hypothesis explaining Permian Mass Extinction.

sjastro

Newbie
May 14, 2014
5,740
4,672
✟345,863.00
Faith
Christian
Marital Status
Single
This is a hypothesis and probably fits more into the ‘Non-Mainstream Science and Controversial Science’ forum but given some of the outrageous threads there this is far more mainstream like by comparison.

First of all some preliminaries, when a seismic event occurs such as an earthquake seismic waves are produced.
Seismic waves which travel through the earth’s interior are called body waves and can either be P- waves (Primary waves) or S-waves (Secondary waves) which travel in different trajectories in the interior.

1.png

Seismic events can also be triggered by impact events, the most well known is the Chicxulub crater caused by an asteroid impact which led to the Cretaceous mass extinction 66 million years ago.
The Permian mass extinction which occurred nearly 200 million years earlier was far worse, the scientific consensus is the extinction was caused by extensive volcanism that formed the Siberian Traps which released large volumes of sulfur dioxide and carbon dioxide into the atmosphere resulting in oxygen starvation, elevating global temperatures, and acidification of the oceans.

Volcanism is easily explained when it occurs at tectonic plate boundaries but the Siberian Traps are nowhere near a plate boundary, volcanism must have been triggered by some interior hotspot but what caused this hotspot in the first place?
There is evidence of an enormous impact crater in Wilkes Land Antarctica, direct evidence is difficult to obtain as the crater lies beneath the ice sheet.
If it is a crater the impactor is 4-5 times wider than the asteroid which created the Chicxulub crater.

Wilkes.png

The location of this suspect crater puts the Siberian Traps antipodal to the crater.
This supports the hypothesis seismic energy from a major meteorite impact would disrupt the surface on the opposite side of the Earth. The different types of wave phases are shown below. In a perfectly spherically symmetrical structure, waves arrive simultaneously from all directions and focus exactly at the antipode.

3.png

The disruption would cause the formation of a mantle plume hotspot and resulting volcanism.

4.png

A further consequence of the impact event was the separation of Australia from Antarctica.
The paper for antipodal hotspots is found here.

A criticism of this hypothesis is whether it is even possible to focus enough energy at the antipode to form hotspots.
 

Ophiolite

Recalcitrant Procrastinating Ape
Nov 12, 2008
9,184
10,080
✟280,628.00
Country
United Kingdom
Faith
Agnostic
Marital Status
Private
I make these provisional remarks without having read your links.

Mantle plumes originate from the core-mantle boundary. I see zero reason that the simultaneous arrival of seismic waves at a zone within the outer couple of percent of the Earths's diameter should generate a mantle plume from that boundary. Moreover, given the time that a plume takes to rise from the boundary to the asthenosphere, the synchornicity of impact and volcanic activity is destroyed.

Of course, these points may be addressed by the authors. I shall see.

(Time passes.)

The author (singular), questions the existence, or at least the nature, of mantle plumes. If his questioning is valid that makes my objection wholly redundant. So, I think the important message of this paper is not that volcanic activity might be generated by antipodal bolide strikes, but that here is further evidence to question the existence, or character, of mantle plumes. I have been nervous for some years about the mantle plume hypothesis. I think the jury is still out and this paper makes an interesting contribution to their deliberations.
 
Last edited:
Upvote 0

Hans Blaster

Hood was a loser.
Mar 11, 2017
21,438
16,193
55
USA
✟407,232.00
Country
United States
Gender
Male
Faith
Atheist
Marital Status
Private
This is a hypothesis and probably fits more into the ‘Non-Mainstream Science and Controversial Science’ forum but given some of the outrageous threads there this is far more mainstream like by comparison.

First of all some preliminaries, when a seismic event occurs such as an earthquake seismic waves are produced.
Seismic waves which travel through the earth’s interior are called body waves and can either be P- waves (Primary waves) or S-waves (Secondary waves) which travel in different trajectories in the interior.


Seismic events can also be triggered by impact events, the most well known is the Chicxulub crater caused by an asteroid impact which led to the Cretaceous mass extinction 66 million years ago.
The Permian mass extinction which occurred nearly 200 million years earlier was far worse, the scientific consensus is the extinction was caused by extensive volcanism that formed the Siberian Traps which released large volumes of sulfur dioxide and carbon dioxide into the atmosphere resulting in oxygen starvation, elevating global temperatures, and acidification of the oceans.

Volcanism is easily explained when it occurs at tectonic plate boundaries but the Siberian Traps are nowhere near a plate boundary, volcanism must have been triggered by some interior hotspot but what caused this hotspot in the first place?
There is evidence of an enormous impact crater in Wilkes Land Antarctica, direct evidence is difficult to obtain as the crater lies beneath the ice sheet.
If it is a crater the impactor is 4-5 times wider than the asteroid which created the Chicxulub crater.


The location of this suspect crater puts the Siberian Traps antipodal to the crater.
This supports the hypothesis seismic energy from a major meteorite impact would disrupt the surface on the opposite side of the Earth. The different types of wave phases are shown below. In a perfectly spherically symmetrical structure, waves arrive simultaneously from all directions and focus exactly at the antipode.


The disruption would cause the formation of a mantle plume hotspot and resulting volcanism.


A further consequence of the impact event was the separation of Australia from Antarctica.
The paper for antipodal hotspots is found here.

A criticism of this hypothesis is whether it is even possible to focus enough energy at the antipode to form hotspots.
Interesting. Something to look at later, but I always knew the anti-podians were going to doom us all. :)
 
Upvote 0

sjastro

Newbie
May 14, 2014
5,740
4,672
✟345,863.00
Faith
Christian
Marital Status
Single
I'm not a fan of AI giving complex mathematical and scientific descriptions but ChatGPT-3 gave a surprisingly good simplified explanation of the antipodal impact hypothesis.

The antipodal impact hypothesis suggests that the effects of a large planet can cause geological and volcanic activity on the directly opposite (antipodal) side. This concept is often discussed in the context of the Cretaceous-Paleogene (K-Pg) extinction event and its potential connection to the Deccan Traps volcanic activity. The mathematics behind this hypothesis involves several aspects of geophysics, wave propagation, and energy transfer.

Here’s a simplified breakdown of the key concepts.

1. Impact Energy and Wave Propagation.

When a large meteor impacts a planet, it releases a tremendous amount of energy. This energy propagates through the planet in the form of seismic waves.
The energy E of the impact can be estimated using the kinetic energy formula.

E = ½mv²

where:
  • m is the mass of the meteor.
  • v is the velocity of the meteor at impact.
2. Seismic Wave Propagation.

Seismic waves travel through the Earth’s interior and can be divided into primary (P) waves and secondary (S) waves. The speed of these waves depends on the material properties of the Earth’s layers.
The travel time t of the wave for the impact point to the antipodal point can be calculated using the wave speed v and Earth’s radius R.

t = 2R/v

3. Focusing of Seismic Energy.

At the antipodal point the seismic waves can focus due to spherical symmetry of the planet. The focusing effect can increase the energy density at the antipodal point, potentially causing geological disturbances.

4. Stress and Strain at the Antipodal Point.

The focused seismic energy can create high stress and strain in the Earth’s crust at the antipodal point. The stress σ induced by the seismic waves can be estimated using:

σ = ρv²ε

where:
  • ρ is the density of the Earth’s material.
  • ε is the strain.
The strain ε is related to the displacement u and wavelength λ of the seismic waves:

ε = u/λ

5. Volcanic Activity.

If the stress and strain at the antipodal point are sufficient to fracture the crust, it can lead to volcanic activity. The critical stress required to initiate fracturing can be estimated using the materials yield strength σy:

σ ≥ σy

Simplified Numerical Example.

Let’s consider a hypothetical meteor with:
  • Mass m = 1 X 10¹⁵ kg (a large asteroid)
  • Velocity v = 20,000 m/s (a typical impact velocity)
1. Impact Energy.

E = ½ X 1 X 10¹⁵ x (20,000)²
E = 2 X 10²³ J

2. Seismic Wave Speed.

Assume a seismic wave speed of 8,000 m/s and Earth’s radius R = 6,371 km.

t = 2x 6,6371x10³/8,000
t ≈ 1,5593s ≈ 26.5 minutes.

3. Focusing and Stress.

Assume a density of ρ = 3,000 kg/m³ and strain ε = 0.001.

σ = 3,000 X (8,000)² X 0.001
σ = 192 X 10⁶ Pa:

If the yield strength σy of the Earth’s crust is around 100 X 10⁶ Pa:

σ ≥ σy

This indicates that the focused seismic energy could exceed the yield strength of the crust, potentially causing volcanic activity.

Conclusion.

The antipodal impact hypothesis involves complex interactions of impact energy, seismic wave propagation, and geological responses. While this simplified model provides a basic understanding, detailed simulations and geological evidence are required to fully validate the hypothesis.
 
  • Informative
Reactions: Astrophile
Upvote 0