Questions tagged [earth-history]

Questions relating to Historical Geology.

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Is there likely to be coal under the Sahara?

In Pangaea, northern Africa would have had humid onshore winds from the Tethys Ocean, making dense vegetation/rainforest biome likely. Consequently, would we be likely to find coal underneath the ...
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7 votes
4 answers
4k views

Does the Plate tectonics contradict the theory of continental drift?

According to the theory of continental drift, South America and Africa was so closed to each other that the convex triangle of South America meets the concave hollow of Africa. Source: usgs.gov; ...
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When did mosquitoes reach Australia?

When and how did mosquitoes reach Australia? It's east of the Wallace line, so 'they got there from Asia' is not an obviously unproblematic conclusion. In general, when and how mosquitoes reached ...
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1 vote
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Variability in 4.5 billion year age of earth based on radioactive dating of meteorites?

Which meteorites in particular give an age of 4.5 billion years and which isotopes are used for radioactive analysis? Is there much variability if different meteorites or isotopes are used?
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2 votes
3 answers
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What methods/apparatus are used to model the early Earth? What do we know of their accuracy?

A friend of mine asked our teacher but the class was over and in online mode, I can't ask my teacher until the next lecture. It sparked my curiosity, I know we use carbon dating for finding the age of ...
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-1 votes
1 answer
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Where to find graphite rocks? [closed]

Where to find graphite rocks? I made researches in my city beach but I don't know where to find them.
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6 votes
0 answers
92 views

Why did the Tigris and Euphrates but not the Nile river basins experience desertification?

The sites of ancient Mesopotamian civilizations tend to be very dry, unlike those of ancient Egypt. Looking at the areas via online maps also shows, that while the Nile river basin remains very green, ...
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9 votes
4 answers
2k views

What significant factors influencing geological change are still occurring?

I am teaching a secondary school course on my state's local history. The textbook begins with the history of the first humans, yet I think it is unfair not to start back much earlier, introducing the ...
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57 views

Is there any source that shows all of Earth's terrain changes from Pangea to present?

I teach a class on my state's history to middle school students. Our textbooks do not cover much historical geology, but its a subject students are fascinated in, and feel needs to be added. I want to ...
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  • 251
1 vote
1 answer
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Why are the south, the west and the north of the Caspian sea lush but its east completely dry?

About the Caspian sea area today: The south is very lush with the subtropical forests of the Iranian provinces of Gilan, Mazandaran and Golestan (although less "tropical" in Golestan) The ...
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0 votes
0 answers
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puzzling statement on earth history!

A Geology proffessor recently told me that around 200,000 years ago, when homo sapiens emerged, that "...all of civilisation can now fit on the width of a single strand of human hair." I am ...
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2 votes
1 answer
106 views

What was the oxygen concentration in the air during the late miocene period?

As the title says, I'd like to know what the O2 concentration was during the late Miocene period. I've tried to look this up but I'm having a hard time finding any conclusive data on it, or even any ...
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1 answer
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Would it be possible, from the earth’s creation or during its various geomorphological changes, for all the following hypotheses to be probable?

I’m designing a fictional world setting for a game, and I would like to know whether it has a relative coherence based on science. (Don’t mind if it is an almost improbable scenario). Would it be ...
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2 answers
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Solution for the coexistence of overpopulated human species with nature [closed]

Is there any solution to deal with the overpopulation of our species at the same time protect the natural environment of ours? (other than finding a inhabitable planet?)
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4 votes
1 answer
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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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5 votes
1 answer
111 views

Book on the history of Earth and life on Earth

I am interested in getting a better overview of the full history of the Earth and the evolution of life. Therefore I am looking for a book that goes through the different geological time scales of the ...
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4 votes
1 answer
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How far would average sea level rise from a 25% increase in total ocean volume?

What amount of average sea level rise (in meters above 2020 levels) would be associated with a 25% increase in total ocean volume? The reason I ask is because of this study that indicates Earth has ...
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4 votes
2 answers
335 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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4 votes
1 answer
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How much of the petroleum ever formed has made it into reservoir 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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2 votes
0 answers
86 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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4 votes
1 answer
587 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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3 votes
0 answers
91 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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6 votes
1 answer
146 views

Has a scientific consensus been reached concerning the formation of the Grand Canyon?

new student of Oceanography here! I'm studying Earth Science right now, and I found conflicting reporting re: the formation of the Grand Canyon; whether it was formed singularly by the Colorado ...
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2 answers
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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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0 votes
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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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3 votes
3 answers
265 views

How many days has it been since the Cambrian explosion?

I want to know how to calculate the number of days since an event in Earth's past, and am using the Cambrian explosion as an example. I define a day to be one rotation of Earth with respect to the ...
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1 vote
2 answers
155 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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10 votes
1 answer
245 views

How quickly is the Earth shrinking?

Except for ice, acetic acid, bismuth and gallium and a few other things materials generally shrink when they cool and solidify, so I'm pretty sure Earth has as well. It probably wouldn't be ...
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4 votes
2 answers
432 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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1 vote
2 answers
173 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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7 votes
1 answer
247 views

Where did the continents come from?

In animations that show the location / drift of the continents over the aeons, it seems that the continents (or cratons?) are just floating / drifting around, sometimes fusing or splitting, but having ...
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5 votes
2 answers
95 views

Why are $\small\sf{CH_4}$ and $\small\sf{CO_2}$ levels coupled during the Pleistocene?

CH4 and CO2 levels show correlation throughout the Pleistocene: Source: trustyetverify.wordpress.com What are the reasons of this coupling?
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6 votes
1 answer
392 views

What Caused The Sea Levels to Drop During the Maastrichtian Epoch?

Anyone who has studied ice ages would know that during the last two-and-a-half million years of Earth's history, there have been periods where there was enough ice to suck up a lot of water. As a ...
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3 votes
1 answer
108 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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5 votes
1 answer
150 views

Has Earth's atmosphere lost mass throughout the geological ages due to biological $\small\sf{CO_2}$ fixation?

Stromatolites and other organisms have been storing $\small\sf{CO_2}$ in the form of $\small\sf{CaCO_3}$ throughout the geological ages, forming extensive limestone deposits scattered across Earth's ...
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8 votes
1 answer
1k views

Where did the atmosphere's nitrogen come from? [duplicate]

According to Wikipedia's article Atmosphere of Earth: Outgassing from volcanism, supplemented by gases produced during the late heavy bombardment of Earth by huge asteroids, produced [Earth's ...
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2 answers
222 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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4 votes
0 answers
241 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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3 votes
1 answer
97 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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10 votes
2 answers
261 views

With so many positive feedbacks accelerating global warming, how did the earth ever re-enter ice ages after it came out of one?

We hear a lot about positive feedbacks when it comes to global warming. For example: ice reflects solar radiation, so as the ice melts more solar radiation is absorbed which accelerates warming; ...
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1 vote
1 answer
488 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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2 votes
1 answer
325 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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3 votes
1 answer
206 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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5 votes
2 answers
127 views

Molten salt seas on the future Earth

As the sun gets brighter, the oceans are expected to evaporate by the next billion years or so (the vapor slowly gets stripped off into space). The salt, which is less dense than most rocks, will be ...
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2 votes
1 answer
207 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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4 votes
2 answers
149 views

Why is the bedrock buried so deeply in much of northern Minnesota?

Although parts of northern Minnesota have bedrock exposed at the surface (especially in the Boundary Waters area and along the short of Lake Superior), the more usual situation here is for the bedrock ...
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  • 317
5 votes
0 answers
47 views

Age of the Earth without radiometric dating?

It is common knowledge that age of the Earth is roughly 4.5 billion years. Radiometric dating of meteorites (which were formed during the formation of Earth) and earliest rocks on Earth have both ...
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5 votes
0 answers
112 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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4 votes
0 answers
37 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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5 votes
2 answers
287 views

How much climate history can be reconstructed using marine sediment cores?

Today I learnt in college that marine sediments can be used to reconstruct the climate up to 500 million years back. I find that number very strange because in another class we learnt that the ocean ...
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