I have an Earth Science Question!! Please Help!!!?

Question

For a class I am searching for the lost city of Ubetcha, which is known for its buildings made of Granite. The granite was quarried from a site adjacent to this lost city. Lore has it that the headwaters for a now dried-up river, originating in the area of Ubetcha, was a spring at the base of the granite quarry.This granite is made of a quartz that contains radioactive elements. You have located two poorly cemented sandstones that are both composed of radioactive quartz grains. This is the same radioactive quartz that was a constituent of the granite. Additionally, you have located traces of the ancient river that you believe sprang from the spring. Finally you conclude that the two sandstones must have originated from the area, and possibly the quarry itself.

Sandstone #1 well sorted quartzose sandstone

Sandstone #2 -- a somewhat coarse arkose sandstone

*Now you must find the lost city. Which way do you lead your trip. Sandstone1 SE of the river bed and 2 is NW of river

Answer 1

Can I solve this for you? You bet I can.  Will I do your homework for you, you bet I won't.  The quarry must be upstream from where the products of erosion are found - go upstream.

Answer 2

ubetcha???

Answer 3

Go upriver beyond sandstone two.

Why? The coarser sedimentary rock is, the closer it is to its source. Arkosic sandstones also indicate immature sedimentary rocks, meaning that sandstone two is closer to its point of origin than sandstone one. Since both contain this radioactive element, your best bet is to head toward the coarse outcrop and beyond it, going up this ancient riverbed.

See if you can reread about depositional environments and sedimentary rocks. If you have a question like this on a test, look at the key words in the description, and make sure you understand what words like "well sorted" and "breccia" mean. Also, understand what these indicate about point of origin.