Questions tagged [earth-history]

Questions relating to Historical Geology.

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3
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1answer
227 views

Why is Great Oxidation Event associated with Iron oxidation but not Aluminum or Silicon?

Just to build up on my previous success with oxygen origin in the atmosphere, I want to expand the question as was advised in the answers. The official heresy, despite denied in the comments and ...
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2answers
636 views

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 up ...
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1answer
235 views

How does water still exist on the Earth?

Almost all the theories that explain the origin of Earth says, it was way hot back then. That means It was in a lava state in its early days. Then gradually cooled down to the current state. If ...
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1answer
196 views

If we assume the mega impact hypothesis for the formation of Moon, where on Earth is the impact point?

Given that Pangaea had C-shape can we assume that the point of impact was in the center of this C-shape? In modern world it would be under Tibet? Or should we assume the oldest shape of the ...
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What is the age of the earliest traces of life on Earth?

In the article Oldest rocks, earliest life, heaviest impacts, and the Hadean–Archaean transition (Moorbath, 2005), the author states (based on previous referenced research) that the $\ce{^13C}$ ...
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What composition would the early cratons have? [closed]

I am trying to get into early-Earth geochemistry, and the cratons piqued my interest. They would need a very specific density to float, and the right heat resistance to not melt. What composition ...
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3answers
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What is the age of the earth's oil?

Oil in the ground is found under the oceans and seas. It is made of dead fish. But from what period are those fish? I heard they are about 119 million years old. But fish exist much longer than that. ...
6
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1answer
196 views

What caused the earth's climate to stabilise ~10 thousand years ago?

We can see that the last glacial period ended 12-10K years ago. Interestingly enough, this also appears to coincide with the rise of large human civilisations. My question is: What caused the earth'...
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1answer
222 views

Did an impact crater influence the formation of uranium deposits in South Australia?

As a supplementary question Did an impact crater cause the formation of the gas fields in north eastern South Australia . South Australia is a well documented uranium province. Could an impact crater, ...
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2answers
323 views

Change in earth mass since the time of the dinosaurs

Is there a significant difference in the mass of the Earth between now and the time of the dinosaurs (250 - 75 million years ago)? I was just wondering if the force of gravity on dinosaurs would have ...
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270 views

How have global sedimentation rates changed over the last billion years?

Do we have a graph of how sedimentation rates changed over time?
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1answer
118 views

Future super-continent

What will the earth look like when the continents recollide? What will the climate be like? Assume global warming has been taken care of.
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164 views

How did the intensity of Earth's magnetic field change through geological time?

Looking at the wikipedia article on the Earth's magnetic field, I see that its strength varies through time. How did Earth's magnetic field change throughout its history, from the beginning of the ...
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2answers
672 views

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 ...
5
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1answer
143 views

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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363 views

Is this scientific explanation of The Bible flood accurate?

I googled "the flood and freshwater fish" and came up with this question Christianity StackExchange: How did Noah preserve fresh water fish?. The writer makes a lot of claims like how the salinity of ...
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580 views

When was the last time there was a landlocked body of water bigger than the Caspian?

Was it the Mediterranean before it dried into small lakes? What was the biggest one before that?
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1answer
365 views

Did Jupiter really make Earth (in)habitable?

A new study by Batygyin and Laughlin suggest that a Jupiter migration toward the inner region of the Solar System during the early stages of system formation cleared the habitable region (Goldilocks ...
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1answer
245 views

What caused a fall in atmospheric oxygen about 1.9 billion years ago?

Using chromium isotopes geochemistry, Frei et al. 2009, describe in the article Fluctuations in Precambrian atmospheric oxygenation recorded by chromium isotopes that after the Great Oxidation Event (...
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543 views

What is the earliest tropical cyclone in record?

The question is simple: what is the earliest tropical cyclone (hurricane or typhoon) described in the historical record?
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Was volcanic activity more prevalent when the dinosaurs roamed?

Popular film culture often depicts much volcanic activity during the time of the dinosaurs. Assuming "time of the dinosaurs" as the Jurassic (200 million years ago) until the end of the Cretaceous (...
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1answer
130 views

How to measure the cycles of earth moving/rotation?

My knowledge of science is very basic, but after some research I have some knowledge, but I am still not clear with so many things regarding to this earth. I have read Laser's Measure the Earth's ...
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3answers
2k views

Why deep ocean didn't freeze during snowball Earth?

I know that at least twice in its history Earth was totally frozen. I also know that the last time it happened there were already life on Earth, and it survived. In deep water, under the ice, which ...
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1answer
131 views

What does geochemical data tell us about Earth's earliest palaeoclimatic conditions?

Given that the age of the oldest zircon samples are about 4.4 billion years old, and meteorites and other extraterrestrial samples can also give us some indication about the Earth's composition into ...
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511 views

How was the Earth formed?

What events took place in our Solar System which led to formation of the Earth? I have heard from sources that a big giant star exploded and the Earth was formed. Is this true ?
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Is there conclusive evidence for the Antarctic Circumpolar Current developing after the glaciation of Antarctica?

The Antarctic Circumpolar Current (ACC) is the continuous oceanic current that encircles the Antarctic continent, as is often explained in the literature as being the cause of the onset of glaciation ...
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Where did the energy released due to gravitational binding energy of the Earth go? [closed]

The gravitational binding energy of the Earth is $2×10^{32} J $, so the same amount of energy must have been released during the Earth's history. According to this and this, the current internal ...
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1answer
357 views

How did helium deposits form?

I always wondered, because helium gas is so lightweight, how did it get into the deposits like the ones that people tap? Is it formed underground, or was it trapped?
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Historical atmospheric partial pressure & Henry's law constant

The explanation given for the fact that temperature has historically led CO₂ levels is Henry's law. Figure 1: Vostok ice core records for carbon dioxide concentration (Petit 2000) and temperature ...
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1answer
118 views

Who originated Taylor's axiom of lunar formation, and where?

I've been doing a bit of reading about the formation of the moon, and I've found multiple references (1, 2, 3) to something called Taylor's axiom, stated in link (3) above as: The best models for ...
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1answer
247 views

'Late Veneer' on other planets

Is there any evidence of external material source events, like the 'Late Veneer' on other planets? Or is this theory specific just for Earth? Note, that this question may be related to How and why ...
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1answer
289 views

Regarding the theory of the origin of water on Earth through meteorites, why wouldn't the water evaporate on impact?

Water on earth has been theorized to have come through comets trapped inside crystals. But why wouldn't that water evaporate on impact, and wouldn't the atmosphere at that time allow the vapours to ...
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Why is earth's axis tilted?

Why is the axis of earth tilted? It can't possibly be that the Northern hemisphere is larger causing it to be pulled toward the sun, because then it would always be summer in the N hemisphere and ...
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1answer
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How old is Casiquiare canal?

Casiquiare canal is the world's largest bifurcation. Since such a large bifurcation seems unlikely to be produced and even less likely to stay for centuries, I wonder how old it is and why all the ...
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809 views

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" of ...
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3answers
398 views

How do archaeologists address time dilation when analyzing carbon dating results?

It is a proven fact that the gravitational force exerted upon an object directly affects that objects experience of time; the greater the gravity, the slower time passes, and visa versa. While the ...
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1answer
414 views

How long did it take for Earth's magnetic field to first appear?

Merely what the title states. My knowledge of geography/geology/*logy is limited to high-school, and some snippets, and snatches of conversation. As I understand Earth's magnetic field is attributed ...
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2answers
1k views

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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1answer
123 views

In what sense did the Oklo reactor “trap” its own nuclear waste?

A number of popular writings on the natural fission reactor at Oklo, Gabon (e.g. here) state that some of the energetic byproducts (krypton and xenon, presumably 85Kr and 133Xe) of the reactor were "...
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1answer
167 views

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 the ...
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2answers
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Are there more earthquakes near the equator or poles?

When comparing the average distance of the all known earthquake epicenters to the nearest pole, is the longitudinal distance to the equator or the poles the smallest of the two? Please note that any ...
7
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1answer
835 views

Is a billion years of Earth's history missing?

Appears that a 4.4 billion-year-old crystal is oldest piece of Earth, and the crystal's chemistry -- specifically, the ratio of oxygen isotopes within it -- suggests that the temperatures on Earth 4.4 ...
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3answers
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Is Earth an organism?

According to Wikipedia, "all known types of organism are capable of some degree of response to stimuli, reproduction, growth and development and self-regulation via homeostasis." Further, watching a ...

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