3. Examine the sand from Colorado in the photo below Sand from a dry stream bed
ID: 296518 • Letter: 3
Question
3. Examine the sand from Colorado in the photo below Sand from a dry stream bed at the foot of the Rocky Mountains near Pikes Peak, Colorado a (Scale in millimeters.) a. The angular pink grains in this sand are what mineral? b. The white or light gray grains in this sand are what mineral? c. There is a dark gray grain on the left side of this image that is not an individual mineral grain. What type of grain is it? d. What type of sandstone would you predict that the sand from Colorado would form e. What would you interpret about the source area lithology from this sand? (Give the rock type, not the minerals.) f. What would you interpret about the climate from examining this sand? g. What would you interpret about the time in the depositional basin from this h. Using the guide in this lab, describe the sorting of this sand specimen. Is this sand very well-sorted, well-sorted, moderately well-sorted, poorly sorted, or very poorly sorted? i. Using the guide in this lab, describe the roundness of the grains in this sand specimen. Are they well-rounded, rounded, subrounded, subangular, or angular? j. What would you interpret about the tectonic setting of these sands or their source area? k. What would you interpret about the energy levels of the depositional environment of these sands?Explanation / Answer
a) The angular pink grains are orthoclase feldspar.
b) The white and grey coloured grains are mostly quartz and some are plagioclase feldspar.
c) It may be some erotional grain.
d) Arkosic arenite may be formed from the sand of the colorado.
e) As the sand is found from the foot of the Rocky mountain and considering the composition of the sand the source lithotype may be granitic rocks,gneiss or schist ect basically some rocks that contais quartz, feldspar in a large proportion.
f) The climate must be cold arid.
g) The deposition occured over short span of time.
h) This sand is moderately sorted.
i) They are mostly sub-angular and some are angular.
j) There is low tectonic acitivity.
k) The energy level was not so high.It was medium to low thats what led to poor shorting and least abrasion of the grains.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.