Geology: the environments of some sediments

  • Thread starter Thread starter Asmaa Mohammad
  • Start date Start date
  • Tags Tags
    geology
Click For Summary

Discussion Overview

The discussion revolves around the classification of different sedimentary environments based on observations from a mountainous area. Participants analyze the characteristics of three distinct parts of a mountain: the top consisting of fossiliferous limestone, the middle made up of fine-grained rocks, and the base featuring boulders, gravel, and tree trunks. The focus is on identifying which parts correspond to marine, aerobic, and river environments.

Discussion Character

  • Homework-related
  • Debate/contested

Main Points Raised

  • One participant claims that the top of the mountain (fossiliferous limestone) belongs to a marine environment, the middle (fine-grained rocks) to an aerobic environment, and the base (boulder, gravel, and tree trunks) to a river environment.
  • Another participant agrees with the marine classification but suggests that the middle and base classifications may be incorrect, proposing that fine-grained rocks are typically indicative of river erosional sediment.
  • A similar viewpoint is echoed by another participant, who emphasizes that the base's gravel and boulders suggest a high-energy river environment rather than an aerobic one.
  • One participant argues that while boulders can be found in river environments, they are not typically associated with them, suggesting that the base represents an aerobic environment near the sediment source.
  • Another participant speculates that the question may be designed to eliminate the marine and river options, leaving the remaining classification as the correct one.

Areas of Agreement / Disagreement

Participants generally agree on the marine classification of the top part of the mountain, but there is disagreement regarding the classifications of the middle and base parts, with multiple competing views presented without resolution.

Contextual Notes

Participants express uncertainty regarding the classifications and the conditions under which certain sediments are found, indicating that assumptions about energy levels and sediment types may vary.

Asmaa Mohammad
Messages
182
Reaction score
7

Homework Statement


During a visit to mountainous area, students noticed a high mountain consists of 3 different parts: The top of the mountain consists of fossiliferous limestone. The middle of the mountain consists of fine grained rocks. The foot of the mountain consists of thick layers of boulder, gravel and tree trunks.

Which of those parts belongs to a marine environment? And which belongs to an aerobic environment? And which belongs to a river environment?

The Attempt at a Solution



The top (fossiliferous limestone) -----> marine environment
The middle (fine grained rocks) -----> aerobic environment.
The base (boulder, gravel and tree trunks -----> River environment.
Am I right?
 
Physics news on Phys.org
The first answer is right. I'm not sure, but I think the other two are switched. You usually think of fine grained rocks as an indication of river erosional sediment.
 
Chestermiller said:
The first answer is right. I'm not sure, but I think the other two are switched. You usually think of fine grained rocks as an indication of river erosional sediment.
But the base contains gravel and boulders which suggest high energy as in a river not an aerobic environment, right?
 
Asmaa Mohammad said:
But the base contains gravel and boulders which suggest high energy as in a river not an aerobic environment, right?
Like I said, I'm not sure.
 
Boulders can be found in river environments, but typically are not associated with river environments. With the mix of gravels, tree trunks, boulders you're looking at an aerobic environment near the source of those sediments. Typically you'll find the boulders and cobble and gravel sized piece near where they weathered and eroded off the source rock, also in glacial moraines. Rivers have to be extremely high energy to transport that type of large sediment. Your fine grained sands are going to be more river environments. And since they mentioned fine grained sands it's more likely a meandering or an anastomosing river which are lower energy.
 
  • Like
Likes   Reactions: Asmaa Mohammad
My bet is that the question wants you to eliminate two obvious things (marine & river), and then whatever is left must be a third pair.
 

Similar threads

Replies
8
Views
3K
  • · Replies 21 ·
Replies
21
Views
6K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 2 ·
Replies
2
Views
4K
  • · Replies 1 ·
Replies
1
Views
4K
  • · Replies 6 ·
Replies
6
Views
5K
  • · Replies 48 ·
2
Replies
48
Views
11K
  • · Replies 5 ·
Replies
5
Views
5K