<p><a href="https://www.britannica.com/science/Jurassic-Period" rel="nofollow noreferrer">Britannica</a> says:</p>

<blockquote>
  <p>... because of the significant tectonic activity occurring around the world, it is not clear which of these local changes can be correlated
  to global sea level change. Because there is no evidence of major
  glaciations in the Jurassic, any global sea level change must have
  been due to thermal expansion of seawater or plate tectonic activity
  (such as major activity at seafloor ridges). Some geologists have
  proposed that average sea levels <strong>increased from Early to Late Jurassic time</strong>.</p>
</blockquote>

<p>Notice, that we have no information about the change of the mass of water from Jurassic till now.</p>

<p>Even the articles <a href="https://www.sciencedirect.com/science/article/pii/S2095383615000267" rel="nofollow noreferrer">https://www.sciencedirect.com/science/article/pii/S2095383615000267</a> that shows, how the sea level changed, touch only relative changes in the sea level. As we don't know the statistics for depths and heights for these times, we can <strong>guess</strong>, that the ocean/land area ratio was greater than now, but the guess is very wild. Any number of percents could be only a sheer speculation.</p>

CC BY-SA 4.0
2018-09-13T15:40:20.663Z
2018-09-13T15:40:20.663Z
Gangnus
<p>In todays world, 71% of the surface is covered in water. But was this always the case, far prehistoric times?
Id guess you can estimate pretty precisely where the prehistoric oceans were based on sediments, but i cant find a single answer to the question - even though you can see detailed maps of Laurassia, Gondwana and Pangaea.</p>

CC BY-SA 4.0
2018-09-13T15:19:58.620Z
Jurassic Period, not Era
Gangnus
<geography>
Land to ocean ratio in jurassic era
Flying Thunder
# Land to ocean ratio in jurassic era

(Asked by: username_0 on 2018-09-13)

In todays world, 71% of the surface is covered in water. But was this always the case, far prehistoric times?
Id guess you can estimate pretty precisely where the prehistoric oceans were based on sediments, but i cant find a single answer to the question - even though you can see detailed maps of Laurassia, Gondwana and Pangaea.

**Tags:** geography

> **Comments:**
> **username_1**: Jurassic Period, not Era  

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## 1 answers

### Answer by username_1 on 2018-09-13. Score: 2 | Accepted answer

[Britannica](https://www.britannica.com/science/Jurassic-Period) says:

> ... because of the significant tectonic activity occurring around the world, it is not clear which of these local changes can be correlated
> to global sea level change. Because there is no evidence of major
> glaciations in the Jurassic, any global sea level change must have
> been due to thermal expansion of seawater or plate tectonic activity
> (such as major activity at seafloor ridges). Some geologists have
> proposed that average sea levels **increased from Early to Late Jurassic time**.

Notice, that we have no information about the change of the mass of water from Jurassic till now.

Even the articles <https://www.sciencedirect.com/science/article/pii/S2095383615000267> that shows, how the sea level changed, touch only relative changes in the sea level. As we don't know the statistics for depths and heights for these times, we can **guess**, that the ocean/land area ratio was greater than now, but the guess is very wild. Any number of percents could be only a sheer speculation.


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