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| Asking braided stream & meandering http://www.epgeology.com/sedimentology-f19/asking-braided-stream-meandering-t2044.html |
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| Author: | hestu [ Wed Feb 22, 2012 2:36 am ] |
| Post subject: | Asking braided stream & meandering |
what is the characteristic of braided stream and meandering, 1. characteristic in wireline log curve 2. structure sedimen 3. mineralogy (if any) if braided mostly in river, how can it be calcareous, where from clacareous ? Thanks |
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| Author: | Darryl [ Wed May 02, 2012 11:27 pm ] |
| Post subject: | Re: Asking braided stream & meandering |
Hello, I just joined the group today and see that no one has responded to your question. I have only a few minutes and discussing the characteristics of braided and meandering rivers will take longer than I have but I promise to get back to the question in a few days as it is one of my favorite topics. In the time I have, I offer the following 3 suggestions for ways of getting calcereous cement in braided river sands. 1) As occurs locally, microscopic limestone can be picked up by the wind and scattered over distances of 10's to 100's of km. Along the way it will be deposited as dust on the ground and the dry bed or water surface of any river it encounteres. From there it can be incorperated directlyl into the sediment or dissolved and carried down into the sands. 2) The tributaries to the braided river can be eroding limestone fragments from outcrops and/ or picking it up in solution before emptying into the braided river channel. 3) Assuming you are dealing with a subsurface braided stream deposit, the calcium could be dissolved anyplace and then precipitated in the sands long after the sands were buried. This does not pertain strictly to braided or meandering streams but I have seen extreme examples where the question I had to answer was "Is this a sand that had the matrix dissolved out and then replaced with limestone or is it a limestone that received the clastic particles from the wind or (?) while being precipitated. I did not have a petrographic microscope to examine thin sections so the question remained unanswered. More later. Darryl |
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| Author: | Darryl [ Wed May 16, 2012 2:11 pm ] |
| Post subject: | Re: Asking braided stream & meandering |
| Author: | DKarlstadt [ Wed May 16, 2012 9:52 pm ] |
| Post subject: | Re: Asking braided stream & meandering |
| Author: | Darryl [ Wed May 16, 2012 10:23 pm ] |
| Post subject: | Re: Asking braided stream & meandering |
| Author: | hestu [ Wed Jun 27, 2012 2:08 am ] |
| Post subject: | Re: Asking braided stream & meandering |
thank you very much for all contributor to my topics it valuable info for me. |
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