<p>I would say it's reasonable to infer that the strata stay at roughly the same dip angle and thickness in areas not directly visible on the chart you're using.</p>

CC BY-SA 4.0
2021-01-19T00:38:09.973Z
2021-01-19T00:38:09.973Z
Karst
<p>Here is a schematic of a cross section which should represent an anticline:</p>
<p><a href="https://postimg.cc/4HcmmZ26" rel="nofollow noreferrer">https://postimg.cc/4HcmmZ26</a></p>
<p>Below sea level, I have inferred what the units might look like with the dashed lines. As I have interpreted this to be an anticline, it was quite straightforward to understand the possible shape, and by working out true thickness I would represent uniform thickness.</p>
<p>Here is another example of a cross section which should represent a thrust fault system (I may have added these faults at a strange angle, but hopefully this gets my point across):</p>
<p><a href="https://postimg.cc/CRkXJ2Xc" rel="nofollow noreferrer">https://postimg.cc/CRkXJ2Xc</a></p>
<p>Would I assume these beds are uniformly dipping? How deep should units be represented?</p>

CC BY-SA 4.0
2021-01-04T00:25:24.753Z
It's kind of preplexing why you might think sea level is the boundary between known stratigraphy and stuff you have to infer.  Boreholes frequently go below sea level (there are lots of boreholes of the sea bottom).
Spencer
CC BY-SA 4.0
2021-01-04T12:43:55.330Z
This is not based from borehole data, only boundaries from a topographic map. In any case, say that I did not infer the shape below sea level and kept a continuous line, how would I accurately know what it looked like? Like in the second case, can I assume beds are uniformly dipping?
Vilo 
<geology><mapping><education>
How do you infer what a cross section might look like below sea level?
Vilo 
# How do you infer what a cross section might look like below sea level?

(Asked by: username_0 on 2021-01-02)

Here is a schematic of a cross section which should represent an anticline:

<https://postimg.cc/4HcmmZ26>

Below sea level, I have inferred what the units might look like with the dashed lines. As I have interpreted this to be an anticline, it was quite straightforward to understand the possible shape, and by working out true thickness I would represent uniform thickness.

Here is another example of a cross section which should represent a thrust fault system (I may have added these faults at a strange angle, but hopefully this gets my point across):

<https://postimg.cc/CRkXJ2Xc>

Would I assume these beds are uniformly dipping? How deep should units be represented?

**Tags:** geology, mapping, education

> **Comments:**
> **username_1**: It's kind of preplexing why you might think sea level is the boundary between known stratigraphy and stuff you have to infer.  Boreholes frequently go below sea level (there are lots of boreholes of the sea bottom).  
> **username_0**: This is not based from borehole data, only boundaries from a topographic map. In any case, say that I did not infer the shape below sea level and kept a continuous line, how would I accurately know what it looked like? Like in the second case, can I assume beds are uniformly dipping?  

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## 1 answers

### Answer by username_2 on 2021-01-19. Score: 0 | Accepted answer

I would say it's reasonable to infer that the strata stay at roughly the same dip angle and thickness in areas not directly visible on the chart you're using.


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