<p>Groundwater is stored in the porosity of rocks, that is space between <a href="https://en.wikipedia.org/wiki/Clastic_rock" rel="noreferrer">clasts</a> or cracks. Larger cavities, e.g. <a href="https://en.wikipedia.org/wiki/Karst" rel="noreferrer">karsts</a>, is usually only a minor contribution to ground water reservoirs and are only common in limestone. </p>

<p>The Great Artesian Basin aquifer is made up of Mesozoic sandstone. It is covered by impermeable rocks that allow pressure to build up within the aquifer so that as rainwater enters at high elevation it will keep the hydrostatic pressure, even when the topography is lower. </p>

<p>The only way to see the rocks at great depths is by drilling and, if the budget allows, also keep <a href="https://en.wikipedia.org/wiki/Core_sample" rel="noreferrer">core sample</a> to be able to analyze it. Important information also comes from <a href="https://en.wikipedia.org/wiki/Well_logging" rel="noreferrer">borehole logging</a> when geophysical instruments are lowered into the borehole to measure e.g. porosity and density of the rocks. One can also see the continuation of the formation on the surface and study the rocks to understand how they look at great depths. </p>

<p><a href="https://www.environment.gov.au/system/files/resources/6405b0fb-1956-4790-9ca4-b138ed810717/files/great-artesian-basin-managing.pdf" rel="noreferrer">This informative document</a> explains some of the features of The Great Artesian Basin rather well, but don't be mislead to think about the aquifers as caves, it is only water soaked rocks. </p>

CC BY-SA 3.0
2017-05-08T10:38:08.903Z
Nice answer. Thanks, I learned a lot by reading it.
alan2here
CC BY-SA 4.0
2020-11-08T12:55:51.350Z
Fascinating! I had imagined it as a massive underground ocean/cave. Out of interest, how much water does 1 cubic meter of Mesozoic sandstone hold?
stevec
CC BY-SA 3.0
2017-05-08T01:45:54.257Z
2017-05-08T01:54:18.773Z
2017-05-08T01:54:18.773Z
user2821
<p>I can find information about the basin as a water-source, along with photos of the ground over its 1,700,000 square km surface. But have divers ever entered this space, or tunnels been dug for cameras, have photos ever been taken of it from under its waters?</p>

CC BY-SA 3.0
2017-05-07T21:35:08.320Z
Do you mean "square megameter"? But that's 1,000,000 sq km by definition.
Spencer
CC BY-SA 3.0
2017-05-07T21:47:11.237Z
it's 3 km deep...  are you asking if people have tunneled under it?  Or if someone has gone into it?
f.thorpe
CC BY-SA 3.0
2017-05-08T00:05:46.960Z
Gone into personally, or filmed whiten robotically, using tunnels etc... Not scans from the surface.
alan2here
CC BY-SA 3.0
2017-05-08T00:15:17.087Z
Hopefully I've fixed the unit related wording.
alan2here
CC BY-SA 3.0
2017-05-08T10:31:34.270Z
It is more than a square megameter, a unit that can rarely be used, I think a reasonable addition.
alan2here
<geology><groundwater>
Has anyone driven under, or received camera footage from, the Great Artesian Basin in Australia?
alan2here
# Has anyone driven under, or received camera footage from, the Great Artesian Basin in Australia?

(Asked by: username_0 on 2017-05-07)

I can find information about the basin as a water-source, along with photos of the ground over its 1,700,000 square km surface. But have divers ever entered this space, or tunnels been dug for cameras, have photos ever been taken of it from under its waters?

**Tags:** geology, groundwater

> **Comments:**
> **username_1**: Do you mean "square megameter"? But that's 1,000,000 sq km by definition.  
> **username_2**: it's 3 km deep...  are you asking if people have tunneled under it?  Or if someone has gone into it?  
> **username_0**: Gone into personally, or filmed whiten robotically, using tunnels etc... Not scans from the surface.  
> **username_0**: Hopefully I've fixed the unit related wording.  
> **username_0**: It is more than a square megameter, a unit that can rarely be used, I think a reasonable addition.  

---

## 1 answers

### Answer by username_3 on 2017-05-08. Score: 7 | Accepted answer

Groundwater is stored in the porosity of rocks, that is space between [clasts](https://en.wikipedia.org/wiki/Clastic_rock) or cracks. Larger cavities, e.g. [karsts](https://en.wikipedia.org/wiki/Karst), is usually only a minor contribution to ground water reservoirs and are only common in limestone.

The Great Artesian Basin aquifer is made up of Mesozoic sandstone. It is covered by impermeable rocks that allow pressure to build up within the aquifer so that as rainwater enters at high elevation it will keep the hydrostatic pressure, even when the topography is lower.

The only way to see the rocks at great depths is by drilling and, if the budget allows, also keep [core sample](https://en.wikipedia.org/wiki/Core_sample) to be able to analyze it. Important information also comes from [borehole logging](https://en.wikipedia.org/wiki/Well_logging) when geophysical instruments are lowered into the borehole to measure e.g. porosity and density of the rocks. One can also see the continuation of the formation on the surface and study the rocks to understand how they look at great depths.

[This informative document](https://www.environment.gov.au/system/files/resources/6405b0fb-1956-4790-9ca4-b138ed810717/files/great-artesian-basin-managing.pdf) explains some of the features of The Great Artesian Basin rather well, but don't be mislead to think about the aquifers as caves, it is only water soaked rocks.

> **Comments:**
> **username_0**: Nice answer. Thanks, I learned a lot by reading it.  
> **username_4**: Fascinating! I had imagined it as a massive underground ocean/cave. Out of interest, how much water does 1 cubic meter of Mesozoic sandstone hold?  

---

