Wesley Chapel Gulf was designated as a U.S. National Natural Landmark in 1972 because of its impressive geologic features. The gulf provides a rare glimpse of the Lost River on its subturannean path. Other karst features in the area include sinkholes, swallowholes, and caves.
How The Gulf Was Formed
A gulf is always associated with an underground stream. Its development is dependant on the collapse of overhead rock and the solution and removal of the rock. Wesley Chapel Gulf began as 1 or more collapsed sinkholes. When a collapse feature has its steep-walled perimeter enlarged to the point that it has an alluviated floor with a stream that rises and sinks in can be referred to as a gulf. The floor is marked by a rise as well as a channel with one or more swallow holes where the water returns to its underground channel.
Approximately 720,000 cubic yards of native Indiana Limestone have been disolved and removed to create the gulf. The width of the gulf is far greater than any known section of the Lost River. The gulf is more than a section of cavern whose ceiling has collapsed and been disolved away. The gulf began with the creation of a series of round sinkholes over a broad area of the cave system. The collapse obstructed the free flow of the water, which in turn led to further weakening of the walls. Further collapse than increased the perimeter of the depression. It time 2 or 3 such areas merged creating a very large and long depression with semicircular ends.
Wesley Chapel Gulf is one of the most impressive geologic features of the Lost River basin. The gulf is located along a direct line between the main rise(2 miles west) and sink (5 miles east).
Wesley Chapel Gulf is a large steap sided depression that resembles a peanut. The gulf measures 1,075 feet in length and 350 feet in width. It varies in height from 25 feet on the northwest to 95 feet on the southwest.
The Lost River rises from a 125 foot diameter rise pool called boiling spring at the south end of the gulf. The artesian waters rise from the main underground course of the lost river. The pool overlies a 3 foot opening that slopes downward until it intersects a larger passage about 160 feet from the rise pool and about 45 feet below normal pool level. The passage is 10 feet high, 30 feet wide, and extends to the northeast for at least 200 yards. The waters of the passage are forced to rise 20 feet or more during low water periods and 50 or more during high water periods.
During low water boiling spring pool is about 25-30 feet deep. The water is azure blue and perfectly calm. It flows a short distance before disappearing through the mud covered talus rock at the base of the south wall. During periods of high water the volume of flow increases and the water may become silty and brown. The pool overflows and the water is discharged into channels. The channels are littered with swallow holes. Each hole succesively fills to capacity.
Following heavy rain the floor of the gulf may be innundated with as much as 5 feet of water. At these times water issuing from the pit is very turbulent and large boils of water violently discharge from it. As much as 5,000 cubic feet of water per second are discharged from the underground course. The flood occurs because water enters from the pit faster than it can be drained away by the numerous swallow holes.
The processes that formed the gulf are still in operation and it still continues to grow. The underground streams still continue to disolve away at the foundation of the walls. Over time 720,000 cubic yards of limestone have been undermined, collapsed, disolved, and carried away. This has created a new level. The waters surrounding the gulf are constantly working to enlarge it into a lengthing valley.
To log this as a find you will have to visit the gulf and then email me the answers to several questions.
1.)Visit the boiling spring waypoint. What was the estimated water level during your visit and what was the color of the water? Also was the pool overflowing?
2.)Visit the overlook waypoint. What is the change in elevation from the boiling spring waypoint to the overlook?
3.)What kind of rock is visible in the walls of the valley?
4.)How many cubic yards of rock have been disolved and carried away?
5.)Include a photo in your log of yourself at your favorite point along your explorations.(Appreciated but not required)