6.5 Sediment Analysis, Classification, and Interpretation ACTIVITY Name Course/S
ID: 115156 • Letter: 6
Question
6.5 Sediment Analysis, Classification, and Interpretation ACTIVITY Name Course/Section: Date: Complete parts 1 through 6 for cach sample below. Refer to FIGURES 6.2 and 6.3 as meedesd. SAMPLE A 1. Grain sine range in mnm 2. Percene of each Wentworth size class day -silt sand 3. Grain sorting (circle): 4. Grain roundness (circle): 5. Sediment composition (cirde): Moderate Well SubroandWell-rounded Biochemical Chemical Poor Angular Detrical (Siliciclastic) (Bioclastic) 6. Describe how and in what enviroement (FIGURE 6.10) this sediment may have formed SAMPLE B 2mm1. Grain size range in mm: 2. Percent of each Wentworth size class 3. Grain sorting (circle): 4. Grain coundness (circle): 5. Sediment composition (circle) 6. Describe how and in what environment (FIGURE 6.10) this sediment may have formed caysile sand gravel Poor Moderate Well Angular Detrital (Siliciclastic)Biochemical (Bioclastic) SAMPLEC o mm 1. Grain size range inmm: 2. Percent of each Wentworth size class: 3. Grain sorting (circle): 4. Grain roundness (circde): silt and gravel . Moderateel Subround Well-rounded Biochemical Chemical Poor Angular 5. Sediment compasition (cirde): Detrital (Siliciclastid) (Biocdassic) 6. Describe how and in what eavironment (FIGURE 6.10) this sediment may have formed. D REFLECT & DISCUSS Imagine that these sediments are rocks. Which of the samples do you think would be the least diagnostic of a specific ancient environment? Why 178Explanation / Answer
Sample A:
1. Grain size range is 0.5mm to 1mm.
2. Clay=0 %, SIlt= 20%, Sand= 80% and Gravel = 0%
3. Grain sorthing is well.
4. Grain roundness is well rounded.
5. Chemical composition: Chemical sedimentary rock
6. These type of sediments are usually formed in warm, supersaturated, shallow, highly agitated marine water intertidal environments, though some are formed in inland lakes. Their mechanism of formation begins with a small fragment of sediment acting as a 'seed', e.g. a piece of a shell. Strong intertidal currents washes the 'seeds' on seabed, where they accumulate layers of chemically precipitated calcite from the supersaturated water. The oolites are commonly found in large current bedding structures that resemble sand dunes. Their size reflects the time they have exposed to the water before they were covered with later sediment.
Sample B:
1. Grain size range is 0.25mm to 2mm.
2. Clay=0 %, SIlt= 40%, Sand= 60% and Gravel = 0%
3. Grain sorthing is moderate.
4. Grain roundness is subrounded.
5. Chemical composition: Detrital(siliciclastic).
6. These sediments looks like to be quartz crystals, which in majority crystallizes from molten magma, they are also chemically precipitates from hot hydrothermal veins as gangue, sometimes with ore minerals like gold, silver and copper. Their Large crystals can be found in magmatic pegmatites.
Sample C:
1. Grain size range is 0.00006mm to 10mm.
2. Clay=25 %, SIlt= 25%, Sand= 30% and Gravel = 20%
3. Grain sorthing is poor.
4. Grain roundness is angular.
5. Chemical composition: Biochemical(bioclastic).
6. These type of sediments are usually reffered to as bioclasts, these are skeletal fossil fragments of once living marine or land organisms and are found in sedimentary rocks laid down in a marine environment. They are usually found in various varieties of limestone.
D.
Sample "C" is least diagnostic of a specific ancient environment because its angularity is very high compared to other samples hence it has not been moved for a very long time apart from this the organic shells are very intact to be called from an ancient time.
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