The upper part of the core is sandy debris flow deposits, the lower part may be a gravity flow sand body reformed by the bottom flow, and a mixed event layer is developed at the bottom of the upper sandy debris flow. Generally, there is no erosion at the bottom of the sandy debris flow. Even if there is erosion, mud and gravel usually It will be suspended to the top of the debris flow, and the mud gravel in the picture just develops at the bottom of the sandy debris flow. why is that?
Based on the description given, it appears that there is some inconsistency between the observed characteristics of the sedimentary layers and the typical behavior of sandy debris flows. Normally, sandy debris flows do not erode the bottom surface over which they flow, and any eroded mud or gravel is typically suspended within the flow itself and deposited at the top. However, in this case, a mixed event layer containing mud and gravel has been observed at the bottom of the sandy debris flow.
There could be several possible explanations for this inconsistency. One possibility is that the sedimentary layers were not formed solely by a single sandy debris flow event, but rather by a complex sequence of sediment transport events over time. For example, the mixed event layer at the bottom could have been formed by a separate mudflow event that occurred before the sandy debris flow, which was then overlain by the sandy debris flow deposits.
Another possibility is that the sandy debris flow was unusually turbulent or had a higher concentration of suspended sediment than is typical. This could have caused more erosion and entrainment of sediment from the bottom surface, leading to the observed mixed event layer at the bottom.
Without additional information or direct observation, it is difficult to say definitively what caused the observed characteristics of the sedimentary layers. However, the observed characteristics do not fit neatly into the typical behavior of sandy debris flows, suggesting that there may be some other processes at work that are not fully understood.
Murimi Mwai
Thanks for the advice and some new ideas, it was very helpful. Judging from the sedimentary characteristics of the core samples, there are indeed the several possibilities you mentioned. In addition, I am wondering if this is because the storm acts on the soft sediment at the bottom of the lake before the deposition of the sandy debris flow, making it show the sedimentary structure in the picture? I think that's also a possibility.
- Badges
- Science topic
- Similar topics
- Geoscience
- Asia
- India