1. What is the grain size of the sediment at each location, expressed as one or
ID: 108954 • Letter: 1
Question
1. What is the grain size of the sediment at each location, expressed as one or more Wentworth size classes?
2. What is the grain roundness at each of the following locations?
3. In general, would you describe the sediment in these images as detrital (siliciclastc), biochemical, or chemical? Why?
4. Name the kind of rock that the sediment in each image would form if it became lithified (Figure 6.9, Step 3).
5. Notice the yellow-orange color of the sedimentary grains at Location B. What is the yellow-orange material and where did it come from?
6. Each image is a photograph of materials that are the product of chemical and physical sedimentary processes. For each image, list the processes that must have occurred to form the sediment.
REFLECT & DISCUSS
Based on your work, write a sentence that describes what happens to detrital (siliciclastic) sediment with distance from its source. Then describe how you could use your statement to interpret detrital (siliciclastic) rocks
2 km B. Mount Rainier slope, 5600 feet above sea level. A. Mount Rainier outcrop, 6600 feet above sea level. 45 47 23.5N, 121 44 23.4W in Google Earth 2 kilometers from Location A 46 48 15.2N, 121 43 57.8W in Google Earth 9 km 30 km C. Nisqually River, near Longmire, southwest of D. Alder Lake delta, at Elbe, southwest of Mount Rainier, 2600 feet above sea level. 46 44 26.4N, 121 49 27W in Google EarthTM 9 kilometers downhill from Location B Mount Rainier, 1200 feet above sea level. 46 45 52N, 122 11 45W in Google EarthM 30 kilometers downstream from Location CExplanation / Answer
1. Grain size for the following figures are
A= gravel sized,
B=gravel size
C= pebble size
D= mud or wet clay
2. Grain roundness for the figure A, B, C are very angular, subangular to sunrounded, rounded to very well rounded. In figure D the grains are too fine to resolve it into roundness. The grain roundness changes from angular to rounded from the sediment source as the distance travelled by the sediments during transportation also increases as we move away from the sediment sources.
3. The sediment in the images are siliclastic since this contains fragmented material and quartz grains. It consists of a mixture of sand, clay and mud.
5. At location B the yellow orange colour of the sedimentary grains is due to presence of iron bearing minerals. The iron is formed by the chemical process due to leaching of irons by ground water and then precipitate in the sediments.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.