What kinds of sediments accumulate in river and delta systems? How can they be distinguished from glacial sediments? (E)

In river and delta systems, the sediments that accumulate are primarily made up of clastic sediments, which are derived from the mechanical weathering of rocks. These sediments can be classified according to their size, such as gravel, sand, silt, and clay. River and delta sediments can be distinguished by their sorting, layering, and the presence of trace fossils like plant and animal remains.

River and delta sediments have a few main characteristics that can help us identify them: 1. Well-sorted sediments: In river systems, sediments are well-sorted with a gradual decrease in grain size downstream. 2. Stratification: River sediments usually have well-developed layering (stratification) and are often cross-bedded. 3. Fossils and organic material: River and delta systems often contain well-preserved fossils and organic material, including plant and animal remains. 4. Rounded sediments: The sediments in river systems are usually well-rounded and have smooth edges due to the constant transport and abrasion by moving water.

To distinguish river and delta sediments from glacial sediments, it's essential to learn about the characteristics of glacial sediments: 1. Poorly-sorted sediments: Glacial sediments are usually poorly sorted, which means they have various grain sizes mixed together, ranging from larger boulders to fine silt and clay. 2. Angular sediments: The rock fragments in glacial sediments often have angular and irregular shapes, as they are not transported far from their source and have not been extensively weathered or rounded. 3. Sediment structures: Glacial sediments have unique structures like glacial striations, chatter marks, and roches moutonnées. 4. Lack of fossils/organic material: Glacial sediments usually contain a minimal amount of organic material and fossils because the cold and ice make it challenging for organisms to survive.

In conclusion, river and delta sediments can be distinguished from glacial sediments based on the following characteristics: 1. Sorting of sediments: River and delta sediments are well-sorted, while glacial sediments are poorly sorted. 2. Sediment shapes: River sediments are typically rounded and smooth, while glacial sediments are angular and irregular. 3. Stratification and sediment structures: River sediments have well-developed stratification and cross-bedding, while glacial sediments have unique structures like glacial striations, chatter marks, and roches moutonnées. 4. Fossils and organic material: River and delta systems include abundant fossils and organic material, while glacial sediments contain minimal organic material and fossils.