Questions tagged [earth-history]

Questions relating to Historical Geology.

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2answers
191 views

How long ago was the first limestone formed?

It is readily apparent from the fossil record that the first limestone was laid down hundreds of millions of years ago, but how long ago was the very first limestone formed? It could be approximately ...
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1answer
704 views

How much energy released by the Theia-Gaia impact?

I read somewhere that the Chicxulub impact released the energy equivalent of anywhere from 100-300 teratons of TNT. That's an impressive amount of energy. Assuming a head on collision (according to ...
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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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1answer
79 views

Earth History Book

I'm a PhD student studying the (current) climate of the Earth. I'm also quite interested in the history of planet Earth, although I have little academic background in that area. Is there a good ...
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1answer
97 views

What were the geometric coordinates of the Chicxulub impactor 66 million years ago?

At the moment around mexico we can find the leftovers of the Chicxulub impactor which could have extincted most dinosaurs. But 66 million years ago was after the breakdown of Gondwana. So back to ...
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1answer
175 views

What was the percentage of land mass in prehistoric times when temperatures were high enough that we had no ice caps?

I grew curious after watching a presentation about the large creatures of prehistoric times. One of the theories cited about why creatures were so big was the increased oxygen in the atmosphere due to ...
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1answer
135 views

Ocean water coming from Mantle vs coming from meteorites

Posibly duplicate from Water on Mars and Earth I remember well a hydrology course where our teacher made some calculations of the total flux of water from Mantle ejections in Earth's history. He ...
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1answer
259 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 ...
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85 views

What were the Two Largest Forests of Western and Central Europe (circa 600 BC)

I am trying to find out what forests were the largest in Western and Central Europe, around 600 BC. I understand that accounts dating that far back may be difficult to find, but I hope other sciences ...
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0answers
125 views

Cratonization - how did the Archean cratons form?

Before the onset of modern style plate tectonics and the Wilson cycles in the late Archean, it is thought that smaller units of continental crust, called cratons, roamed the oceanic crust over a more ...
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53 views

Biomes that existed during the Paleocene-Eocene Thermal Max (PETM)

I understand that you could fill multiple books with descriptions of the PETM and the mechanisms that incited the event. I have always wondered what regions of the world were covered in what types of ...
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34 views

Where did the heiltsuk's find obsidian?

The discovery of hearths and other carbon dated items on an island off the north east coast of Canada puts modern humans there 2,000 years before the Alaskan land bridge existed. The glaciers of ...
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322 views

Puzzle using relative dating principles

This isn't directly looking at a real life ecological example kind of thing, but it requires knowledge of relative dating, so I thought I would come here. Here is what was told: -"Worms" (curved ...
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228 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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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. ...
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129 views

Are we entering a new Ice Age according to Milankovitch cycles?

Milankovitch cycles consist of three orbital parameters: eccentricity, obliquity, and precession of equinoxes. According to Milutin Milankovitch, the most recent glacial period ended nearly 11,000 ...
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3answers
406 views

Why Do Supercontinents Form? [duplicate]

It would seem, on the face of it, improbable that the continental land-masses would accumulate into a single composite, yet it has happened numerous times, and is expected to again in the future. ...
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2answers
590 views

Was the Earth's sea-level significantly lower in ancient times?

A lot of times, ancient artifacts or even whole ancient civilizations are found buried very deep into the ground surface of the earth. Entire civilizations that had high buildings have been found ...
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1answer
123 views

Do earthquakes produce folds on rocks?

Earth rocks are frequently folded at surface. Folds in alternating layers of limestone and chert in Crete, Greece. Source: commons.wikimedia Are earthquakes the main mechanism ...
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1answer
136 views

Which ocean is going to be swallowed by the Supercontinent Cycle, Atlantic or Pacific?

The register shows several supercontinents have been formed on Earth's History: "The most recent supercontinent, Pangaea, formed about 300 million years ago (0.3 Ga). There are two different ...
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1answer
155 views

How Good is The Evidence For Snowball Earth?

Some geologists say there were times between 770 million years BP and 630 million years BP when ice ages were so profound that the Arctic and Antarctic ice caps met at the equator. This is called the ...
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1answer
113 views

How many times in total has Earth formed a super continent?

I know there was a Pangaea at one point in history that broke into the continents of today, but I could have sworn there was another instance in Earth's history that there was a super continent, maybe ...
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1answer
150 views

Where did the carbon, neon and nitrogen go?

It is interesting to compare estimated Earth abundances with estimated Milky way abundances. Obviously the hydrogen and helium were gaseous and too light for Earth's gravitational field (other than ...
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1answer
42 views

Sediment boundarys produced by largest meteors? Vredefort, Sudbury and Chicxulub

Chicxulub crater is the third largest crater on earth, which is said to have produced the KT boundary. What is the sediment layer produced by the 1st and 2nd largest craters? Also, there many ...
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82 views

What do scientists mean when they say the Earth formed 4.56 billion years ago? [duplicate]

Does that mean that the Earth gained the classification of a planet that long ago rather than some other celestial body? How did they determine that this happened that long ago? How discrete is the ...
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295 views

Why is a future increase in solar luminosity by 10% supposed to have disastrous consequences for life on earth when the last 30% did not?

One remarkable thing about the climate history of earth is that despite the fact that solar luminosity was fully 30% lower in the beginning, temperatures were actually quite close to today. Since then ...
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115 views

What has been the influence of the moon on Earth's temperature?

What proportion of Earth's internal heat is generated by tidal flexion as a result of the orbiting moon, and would it have been significantly greater four billion years ago when the moon was closer? ...
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2answers
331 views

Earth's orbit and historical sun-earth distance

Purpose of my question: I create program to calculate solar radiation and I need to calculate radius between sun and earth. The based on book "Guide to HTML, JavaScript and PHP" For Scientists and ...
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2answers
667 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 ...
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2answers
139 views

Is Earth inhospitable?

It's thought that, shortly after Earth was done being refurbished resurfaced during the Late Heavy Bombardment, life abio-generated almost as soon as it was able to. The short delay led to speculation ...
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1answer
114 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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1answer
78 views

How can radiometric dating of meteorites determine the age of the earth? Wouldn't this only determine the age of the decaying nuclide in each rock? [duplicate]

How can the radiometric dating of different meteorites determine the age of the earth? Wouldn't radioactive decay have already been occurring in all of those meteorites long before they hit earth? ...
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1answer
91 views

How much of the petroleum ever formed has made it into reservoire rocks?

I am aware that it's a bit general a question, and petroleum geology (or petrology ;-)) has never been a field of interest to me. A superficial search using related keywords brings up only economic ...
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1answer
49 views

Approximation of ancient landmasses using current ocean floor data

I am wondering how accurate such an approximation would be. I wish to take a current height map of the earth (including the ocean floor) and approximate the form of ancient landmasses by changing the ...
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87 views

Geo-Spherical shape of Earth

I know that the best possible approximation of the shape of earth is an oblate sphere. But people also call it as geo-spherical shape of the Earth. What is the meaning of geospherical shape? Does this ...
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83 views

Earth-like conditions on Titan: is it feasible that Titan once had seas and lakes of liquid water?

Given that: 1) Four billion years ago Saturn was hotter and radiated strongly in the infra-red. . . . . . . . . . 2) Like Earth's moon, Titan was then closer to its planet. . . . . . . . . . 3) Like ...
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20 views

Mass contribution during the LHB

How much mass (either absolute or relative to the Earth) was [estimate to have been] added to the Earth during the Late Heavy Bombardment?
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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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2answers
216 views

Original Diameter of Ancient Impact Craters [closed]

The 2.25 billion-year-old Yarrabubba crater in Western Australia has recently been identified as the world's oldest impact crater. It is said to be 43 miles (69 km) in diameter, yet the photo which ...
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2answers
138 views

How was the onset of the Cambrian period dated?

What dating method was used to determine the beginning of the Cambrian, and what was its margin of error? Was only one fossil dated, or were a number of similar fossils used?
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1answer
112 views

Can someone provide a map of Nazca lines with this image in it?

I found this image of a bird with another image below its right wing on google earth in nazca peru. Is there any maps or infomation available that can help me identify this one? Kind regards Jeff B.
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43 views

Are Iron Meteorites a Good Guide to the Composition of the Earth's Core?

Occasionally, very large nickel/iron meteorites strike the Earth, and on examination it is apparent that they were once part of a much larger body which had differentiated into a metallic core and ...
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280 views

If Earth had rings would gravity exerted by Earth decrease?

If Earth had enough mass in its own rings, more than the weight of Earth: What could it decrease the gravity to? Would the atmosphere have more depth or be thinner? What would the weather be like? ...

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