SALT how did it all get here? EarthCache

The coordinates take you to the road leading into the Salt Plains National Wildlife Refuge and the Crystal digging area. From this view point you can see the large area that is covered by salt. This cache is to teach you how ALL that salt got here, and how it stays here. By reading the information below and your observation of the area you can complete this earthcache.
 

GREAT SALT PLAINS.

A relatively untapped resource in Oklahoma, salt held an early importance in the region. Geologists estimate that twenty trillion tons lie within the state's borders. A number of salt plains exist in western Oklahoma due to the varying depth of a layer of Permian-age rock salt. Alfalfa, Woods, Harper, Woodward, Blaine, Beckham, and Harmon counties all contain salt plains.

The Great Salt Plains may be the most well known and is the only one without large salt springs. There is a large fresh water artesian well located on the north side of the Salt Plains along highway 11.

The small north-central Oklahoma wonder called the Great Salt Plains, known for its selenite crystals, is a flat, bare, eleven-thousand-acre slab of land in Alfalfa County. This geological phenomenon, which gained its name from the thin layer of salt that covers the entire area, has attracted geologists and sightseers for years. Scientists believe that salt was deposited during repeated water level rises of a shallow sea millions of years ago. Through years of evaporation and refilling of the sea, a large concentration of salt was left. The supply of salt is kept intact by saline groundwater that flows just a few feet below the surface. When the water evaporates, a layer of salt remains on the surface. This process also plays a role in the formation of selenite crystals, which visitors covet.
At the beginning of the twenty-first century the Salt Plains became the home to Great Salt Plains Dam and Great Salt Plains National Wildlife Refuge.

Credits: Oklahoma Historical Society and Kurtis W. Boucher and Richard A. Marston
              The Great Salt Plains National Wildlife Refuge.

To get credit for this Earthcache please send me the answers the following questions: Information can be obtained from the information board on the plains and the above article.
1. This area was once covered by a shallow sea. Through years of __________________ and ___________of the sea, a large _____________ of ___________ was left.

2. The supply of salt is kept intact by _________________ ______________________ that flows just a few feet below the surface. When the water evaporates, a layer of salt remains on the surface.

3. From your observations of the salt flats in front of you, estimate how big you believe the area to be. ( in miles or percentage of miles.)

4. Can you see any water on the surface of the salt area?

5. (OPTIONAL) If you would like to post of picture of yourself and the salt, please feel free to do so.

Be sure and do Earthcache GC2B3XY about the crystals while you are in the area.