Questions tagged [earth-history]

Questions relating to Historical Geology.

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4
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1answer
280 views

Surface temperature in early hadean period

I am considering earth's internal heat budget for a project in university. For this I need an estimate on the temperature of the earth shortly after it had formed. In Kelvin's On the Secular cooling ...
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2answers
992 views

How are the banded-iron-formation iron-ores formed?

Many of the richest and purest iron ores are found in so called banded iron formations, cm thick magnetite or hematite layers intermixed with iron poor rock layers. Since these are usually of pre-...
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0answers
230 views

Pangaea, supercontinent formation and fragmentation [duplicate]

Is there a widely accepted model for the supercontinent cycles ? From the novice point of view, it is not obvious why the continents would be fragmented all over the earth as now, but 300 millions ...
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2answers
701 views

Speed of tectonic plate movement

I'm doing some research about tectonic plates and at which speeds they move and in which directions, because I'm writing a program to simulate the movement of the tectonic plates and also calculate ...
4
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1answer
136 views

Difference between the oxygen/$CO_2$ ratio during the period of the dinosaurs and the present

Here's the base of my question: Was volcanic activity more prevalent when the dinosaurs roamed? Is it true that during the time of the dinosaurs, both the oxygen requirements (by all living creatures ...
9
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1answer
293 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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5answers
3k views

How do we know the asteroids formed at the same time as earth?

In continuation of the question Why is Earth's age given by dating meteorites rather than its own rocks?, what evidence do we have that the asteroids indeed formed at the same time as earth? Is there ...
3
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1answer
275 views

Why do we see the limestone on top of Cambrian layer?

The official story says like Cambrian Ordovician transition was caused/accompanied by animals learned how to build the Ca-based skeletons. These skeletons and shells started to fall upon the sea bed ...
6
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1answer
639 views

The age of tectonic plates

There is information which says that East European Platform sticks out at the Baltic Sea and, therefore, we can see the ordovican layer in Estonia whereas ...
4
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1answer
244 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 ...
5
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2answers
659 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 ...
3
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1answer
261 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 ...
5
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1answer
224 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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3answers
359 views

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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0answers
52 views

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
3k views

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
205 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'...
9
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1answer
234 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, ...
14
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3answers
275 views

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

Do we have a graph of how sedimentation rates changed over time?
3
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1answer
124 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.
6
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1answer
191 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
704 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
154 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 ...
3
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2answers
370 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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2answers
655 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?
12
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1answer
382 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 ...
11
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1answer
278 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 (...
5
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1answer
557 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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1answer
2k views

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 (...
9
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1answer
132 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 ...
10
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1answer
132 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 ...
6
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1answer
521 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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1answer
268 views

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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0answers
107 views

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
386 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?
7
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1answer
367 views

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 ...
7
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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 ...
10
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1answer
257 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 ...
11
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1answer
307 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 ...
8
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2answers
1k views

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 ...
12
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1answer
1k views

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 ...
18
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2answers
982 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 ...
8
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3answers
424 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 ...
11
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1answer
419 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 ...
7
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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-...
14
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1answer
126 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 "...
10
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1answer
175 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
6k views

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
902 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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