Questions tagged [mass-extinction]

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

The KT boundary was first discovered in North America at South Table Mountain near Golden, Colorado in 1943. Supposedly, it is a dark layer 1-3 cm deep sandwiched between lighter clay. I would like ...
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4 votes
1 answer
75 views

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

In the past, the Earth's ecosystem has experienced catastrophic mass extinctions as a result of large-scale volcanic eruptions. One example is the event known as the "Great Dying", 252 ...
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How much increase in the atmospheric pressure when the global temperature is elevated by 10 C?

In this paper Temperature-dependent hypoxia explains biogeography and severity of end-Permian marine mass extinction is established a link between an increase of the global temperature by $10^\circ ...
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1 vote
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"Great Dying" reduction in biomass

In "The Great Dying" About 250 million years ago, at the end of the Permian period, something killed some 90 percent of the planet's species. Less than 5 percent of the animal species in the seas ...
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4 votes
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Did the Azolla Event 49 Million Years Ago Result in an Extinction Event?

55 million years ago, the world was literally a jungle. With such high temperatures, rainfall and humidity, life could proliferate. But 49 million years ago, something drastic happened: The Azolla ...
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7 votes
2 answers
328 views

Unwarranted claim of higher degree of accuracy in zircon geochronology

The uncertainty in the half life of uranium-238 is stated at 0.05% [1]. The same paper gives the date 251.941 myr ± 31 kyr. 251.941 $\times$ 0.05% = 125 kyr. How are the authors justified in ...
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3 votes
0 answers
46 views

Recovery of terrestrial ecosystems after the end-Permian mass extinction?

Paleontologist Michael J. Benton of the University of Bristol wrote: “​The aftermath of the great end-Permian period mass extinction 252 Myr ago shows how life can recover from the loss of >90% ...
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1 vote
0 answers
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Did low $\small\sf{CO_2}$ levels affected Permo-Triassic mass extinction?

After answering this question: How did plants adapt to $\small\sf{CO_2}$ levels past 400k years? Why won't they do it again? I know Permo-Triassic mass extinction is associated to a catastrophic ...
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7 votes
1 answer
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Signatures of acid rain at KT boundary

I read in Walter Alvarez' book T. Rex and the Crater of Doom that the Earth's collision with the large meteor leading to the K-T extinction catalyzed the reaction of atmospheric oxygen and nitrogen ...
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-4 votes
2 answers
235 views

Variations in Gravity over Time

Is there any consensus about the conjecture that gravitational force on Earth may have changed significantly over geological time; and in particular in periodic increase associated with mass ...
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8 votes
3 answers
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Could the current climate change events cause long-term problems in the viability of Earth to sustain life?

There are a lot of reports on the consequences of climate change for the relative short term. From what I understand, in the next 100 years or so, we will face: global floods of coastal areas, ...
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Why are pole reversals not more detrimental to life?

This question is linked to the following question, and has two parts. Mars interdicts approximately 40% of the radiation (per square meter) of the sun that Earth does. It has been claimed that Mars ...
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What if we detonated the entire worlds nuclear supply in the center of the earth? [closed]

What would the effects of detonating every single nuclear bomb currently in existence at once in the center of the earth? Would the earth simply explode into bits? Would the heat have some sort of ...
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11 votes
2 answers
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Is it possible that the geomagnetic field reversal led to the extinction of Dinosaurs?

Is it possible that the geomagnetic field reversal with a weakened geomagnetic field over centuries if not thousands of years (according to the Pittsburgh simulation: https://www.psc.edu/science/...
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2 votes
1 answer
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Permian-Triassic mass extinction. Consequences on Earth's system

Coming from this post: Causes of fluctuations in atmospheric oxygen in past 300 Mya I believe there are a lot of questions still unanswered about Permian-Triassic mass extinction, but I ask only ...
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-3 votes
1 answer
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Safest spots when an asteroid hits? [closed]

I am breaking this question and no longer making an effort in refining it with the exception of adding an associated link with the scenarios. I always wondered if a devastating asteroid was ...
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How does extinction caused by human activity compare to extinction caused by glaciation?

When or if the current interglacial ends, what sort of extinction level can we expect, and what sort of organisms and ecosystems are affected ? How does this compare with the current extinction rate, ...
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1 vote
1 answer
135 views

gamma ray burst, extinction-level event

From this subsection in Wikipedia's aricle on extinction event: A nearby gamma-ray burst (less than 6000 light years away) would be powerful enough to destroy the Earth's ozone layer, leaving ...
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9 votes
1 answer
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How is geological time divided into units?

Earth's history is divided into eons, which are divided into eras, which are divided into periods etc. Consecutive time units differ in their geology and/or fossil species. But what events are the ...
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2 votes
0 answers
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Connections between marine and terrestrial ecosystems [closed]

First I would like to note that I have only very basic understanding of ecology, biology and paleontology so I can easily miss something very simple. I can envision certain ways marine and ...
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4 votes
1 answer
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Percentage of Oxgen left after burning all the available biomass

A documentry stated that during the Permian asteroid strike the atmosphere heated up to above 400C, potentially to 600C. As this would ignite most of the biomass, including us, I wondered if this fire ...
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2 votes
2 answers
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Recovery From the Great Dying

252 million years ago, Earth underwent its worst, most violent chapter in the form of the Permian-Triassic extinction event, or "The Great Dying". 70% of the terrestrial species and 95% of the marine ...
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6 votes
1 answer
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How long does earth take to recover from mass extinctions? What is "normal"?

Wikipedia states the following about the P-Tr extinction event: "Because so much biodiversity was lost, the recovery of life on Earth took significantly longer than after any other extinction event,[5]...
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5 votes
1 answer
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Why haven't weeds overtaken the entire planet?

Given how rapidly weed plants spread and grow, choking out all other plant life, how come after millions of years we haven't ended with forests full of thistle or pokeweed, as opposed to pines or oak ...
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1 vote
1 answer
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What is the natural replenishment rate of oil? [duplicate]

What is the natural replenishment rate of oil? Are extinction events connected with higher production?
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9 votes
1 answer
329 views

Why is the concept of "mass extinction" a relatively recent development in geology?

The concept of "mass extinctions", with its catastrophic connotations, is a relatively recent development in the geological sciences. It evolved in the early 1980s, driven by two landmark publications ...
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10 votes
2 answers
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Did a gamma ray burst contribute to the Ordovician mass extinction?

According to the University of California Museum of Palaontology webpage The Ordovician Period, the late Ordovician period witnessed when Gondwana finally settled on the South Pole during the Upper ...
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13 votes
2 answers
201 views

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

The iridium anomaly marks the elevated concentration of iridium in sedimentary deposits of the Cretaceous-Paleogene boundary. The iridium is said to come from the impactor, which is supposed to have ...
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10 votes
1 answer
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Is the Younger Dryas associated with an extinction event?

It's often said that, while warming and cooling have happened before, what is unusual about the current anthropogenic warming is that it's happening so fast, relative to previous warming phases$^1$. ...
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7 votes
2 answers
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Life on Earth previous to us

I've seen in several places that there seems to be an extinction cycle on Earth of approximately 27 million years. I've read this here: http://www.dailymail.co.uk/sciencetech/article-1294372/Life-...
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10 votes
1 answer
400 views

What evidence is there that plant evolutionary history "dances to a different beat" than that of animals?

Floral transformations have been due to gradual replacement and piecemeal, not mass extinction. Plant “geoevents”; have not been synchronous with epochal animal originations/ extinctions and hence ...
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16 votes
2 answers
375 views

Did the impact event that caused the Chicxulub-Crater definitively and single-handedly cause the Cretaceous-Paleogene extinction?

Opinions abound on the web. What is the state of the current science regarding this theory and what is the best evidence? Is the theory gaining or losing traction? If it's losing what's the best of ...
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