1. What is this karst landform (N 47.21181 W 121.94142), how did it form, and what do the hatchered contours mean (that you can see in Acme Mapper topo tap)?

  

a.

This blind lake formed when the hole to the   underground cavern system plugged up with silt. The hatchered contours   indicate that the area collects water.

 

b.

This depression formed when the limestone   roof fell into an underground cavern, and this is what the hatchered contours   mean.

 

c.

This doline formed by the dissolution of granite rock, and the   hatchered contours tell you that the location is a depression. 

 

d.

This doline formed through limestone dissolution, and the   hatchered contours tell you that the location is a depression. 

1 points    

QUESTION 2

1. What is this karst landform (N 37.94188 W 80.45261) and how did it form?

Hint: this is the end of Culverson Creek. It is the lowest elevation along Culverson Creek! Really. You can check the elevations on Acme Mapper topo tab or Google Earth. Where does it go from this point?

  

a.

This blind valley formed because the water goes down into an   underground cave system.

 

b.

This offset stream formed when a fault separated the upstream   portion of the stream from its downstream segment.

 

c.

This dead-end stream was built during the civil war as a trap   for the union army. 

 

d.

This interrupted stream formed because the water goes down a   sinkhole into an underground water storage system built by the surrounding   farms.

1 points    

QUESTION 3

1. Karst involves landscapes created from rocks that dissolve. While limestone is the most typical rock that dissolves, halite (sodium chloride) salt can also create karst landforms.  Please look immediately to the east of the Tuomu Erfeng Shenqi Grand Canyon in Xinjiang, China (N 41.557846, W 80.772667). There is also a larger feature to the northwest (N 41.618222, E 80.627570). If you look at these forms in Google Earth, you will see a bizzare landscape. This is what the landscape looks like on the ground:

http://eoimages.gsfc.nasa.gov/images/imagerecords/86000/86861/awate_pho.jpg

This features would completely dissolve away in a humid climate. However, in this hyperarid area, the salt absorbs enough moisture to ooze and flow with gravity creating this form. If you want to read more about this form, just click here:

http://earthobservatory.nasa.gov/IOTD/view.php?id=86861

  

salt glacier

 

cave system

 

salt river

 

halite dome

1 points    

QUESTION 4

1. What is this (N 34.64914 W 111.75221) karst landform,  how did it form, and what is the elevation difference between the water in this landform and the stream immediately to the east? 

  

a.

This landform is a collapse doline formed by the dissolution of   rock (limestone) in a cavern. Then, when the cavern ceiling collapsed this   sinkhole formed. The elevation of the river to the east is a few meters lower   than the lake. 

 

b.

This landform is a sinkhole formed by faulting dropping down the   basin. The river to the east is a few meters lower than the lake in the   sinkhole.

 

c.

This landform is a blind valley formed by fluvial processes   eroding the depressions, and the river to the east is about 10 meters higher   than the lake surface.

 

d.

This landform is a caldera formed by the collapse of the   volcanic basalt lava upon evaluation of the lava. The current lake surface is   the same elevation as the river to the east. 

1 points    

QUESTION 5

1. What is this karst landform (N 37.81090 W 80.49637) and how did it form? Hint: this is the end of Milligan Creek. Where does it go from this point?

  

a.

This blind valley formed because the water   goes down into an underground cave system.

 

b.

This offset stream formed when a fault separated the upstream   portion of the stream from its downstream segment.

 

c.

This interrupted stream formed because the water goes down a   sinkhole into an underground water storage system built by the surrounding   farms.

 

d.

This dead-end stream was built during the civil war as a trap   for the union army.