<p>These are calcite-based rock layers and the reaction between these and H2CO3 (CO2 +H2O) causes the calcite to erode.</p>
<p>Consequently, the reaction:</p>
<p>H2O +CO2 -&gt; H2CO3</p>
<p>H2CO3 +CaCO3 &lt;-&gt; Ca + 2 HCO3</p>
<p>This reactin is mainly found in slightly acidic environments.</p>

CC BY-SA 4.0
2024-03-24T11:15:56.687Z
2024-03-24T11:15:56.687Z
Weiss
<p>I was casually browsing the google earth street view map today. And I noticed strange cavities in a rock wall on Henderson Island, a coral island in the South Pacific. What could have caused this to form?</p>
<p><a href="https://earth.app.goo.gl/?apn=com.google.earth&amp;isi=293622097&amp;ius=googleearth&amp;link=https%3A%2F%2Fearth.google.com%2Fweb%2F%40-24.34041526,-128.3284743,28.870924a,0d,90y,119.85663851h,103.66404756t,0r%2Fdata%3DIhoKFlJJMzBsVUVOSnFraUpOS2xsUmUzVmcQAjoDCgEw" rel="nofollow noreferrer">link</a>
<a href="https://i.sstatic.net/oUG3O.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/oUG3O.jpg" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2024-03-24T14:51:43.580Z
look up chemical weathering.
John
<geology><rocks><islands><pacific>
How do these holes form?
Thomas Peng
# How do these holes form?

(Asked by: username_0 on 2024-03-24)

I was casually browsing the google earth street view map today. And I noticed strange cavities in a rock wall on Henderson Island, a coral island in the South Pacific. What could have caused this to form?

[link](https://earth.app.goo.gl/?apn=com.google.earth&isi=293622097&ius=googleearth&link=https%3A%2F%2Fearth.google.com%2Fweb%2F%40-24.34041526,-128.3284743,28.870924a,0d,90y,119.85663851h,103.66404756t,0r%2Fdata%3DIhoKFlJJMzBsVUVOSnFraUpOS2xsUmUzVmcQAjoDCgEw)
[![enter image description here](https://i.sstatic.net/oUG3O.jpg)](https://i.sstatic.net/oUG3O.jpg)

**Tags:** geology, rocks, islands, pacific

> **Comments:**
> **username_1**: look up chemical weathering.  

---

## 1 answers

### Answer by username_2 on 2024-03-24. Score: 1

These are calcite-based rock layers and the reaction between these and H2CO3 (CO2 +H2O) causes the calcite to erode.

Consequently, the reaction:

H2O +CO2 -> H2CO3

H2CO3 +CaCO3 <-> Ca + 2 HCO3

This reactin is mainly found in slightly acidic environments.


---

