Grant Park

The Trip to the beach at Grant Park starts at the Seven Bridges parking area. The walk to the beach takes you through some old forests, and along a deep stream valley.

This valley is similar to what you see at Drs' Park, only here it is more extensive and more accessible. This stream always enters the lake forming a small estuary that changes shape rapidly with waves from the lake and high water flow after storms. Why would storm cause the shape of the estuary to change shape?

The shoreline bluffs are very similar to those north of Milwaukee, although the top of the bluff here has more sand.

The cliff swallows have made good use of it for their homes as seen at Grant Park near picnic area 6.

If one is interested in figuring out the history of this site, you need to ask, how is it possible to have a beach that is now over 100 feet above the present lake level?

	Most of the exposed material is called diamictite.
	This is fine grained sediments formed in a glacial lake. There are some very large boulders that were deposited in this glacial sediment. They have been washed out to the shoreline.

This glacial till is the called the Oak Creek Till, it is older than what is found at Drs Park, and it is gray rather than the red color of the Ozaukee Till north of Milwaukee. For the truly curious student look up the paper by Rovey and Boruki, 1995, Re-Examination of Quaterary Bluff Stratigraphy, Southeastern Wisconsin, Geosciences Wisconsin Vol.15, pp 1-13, which provides more detail on the geologic history of this site.

However, because this is unconsolidated glacial material, these bluffs fall into the lake as easily as anywhere else.

What you don't see here is a great effort to preserve the slopes because there are no homes on top to worry about losing. This location does not have the old beach terrace that is found at Drs Park either. Therefore the water is much closer to the steep bluff.

	This provides all the ingredients for spectacular bluff failure.
	Rain water and snow melt along with freezing surfaces provide a very unstable surface that easily slides down slope.
	When this is combined with waves that cut at the base of the slope, the only way is down! This mass wasted material frequently brings trees.

	and soil layers with plants still growing on the slump blocks.
	However, where the bluff is protected from the ravages of the waves, trees do a great job at holding the bluff in place. How would removing trees affect the rate of erosion in an area such as this?
	One can also see small stream flow characteristics as water flows off the bluff and produce alluvial fan deposits, meanders, and braided stream patterns, as the water flows onto the beach.
	This shoreline has many similarities with Drs Park. The beach is composed of sand and cobbles that have washed out from the till.
	One can collect all types of rocks at this beach, just as at Drs Park, because most of these rocks have been transported from Canada and Northern Wisconsin, which has very rich tectonic history, including volcanoes. This beach also has several groins, which trap the sediment as the longshore transport carries the beach material along the shore in the direction of the wind.

	Sometimes the sand moves northward, other times it moves southward, as seen here.
	If you look into the water on a fairly calm day, you can observe ripples that forming in the shallow water.
	Ripples in the sand can also be seen on shore where the wind moves over the dry sand.
	Wind on the dry sand will also move the fine grained sand on shore closer to the bluff, and leave behind the courser or larger sized cobbles.

Sorting of sediments by wind and water is a very common process on beaches and in streams. All along the Lake Michigan shoreline, one can sometimes see layers of dark sand which is mostly made of the magnetic mineral magnetite. Because it is heavier, or more appropriately, more dense, it becomes separated by the waves.