By Steven Wade Veatch
Leelanau’s Ice Age history is on full display in the Lighthouse West Natural Area. This 42-acre conservation area, with 640 feet of cobble strewn shoreline along Lake Michigan, is on the tip of the Leelanau Peninsula. It is near Leelanau State Park, which has a lighthouse. This preserve, although it has “lighthouse” in its name, does not have one. The Leelanau Conservancy established the preserve in 2004, and it is known for attracting birds that stop for food and rest during their migration to nesting grounds farther north (DuFresne, 2021; Lighthouse West website). A 1.2-mile trail, built in 2009, crosses various habitats and geological features.
Much of the Lighthouse West Natural Area’s trail goes through dense woodlands. Photo date August 2023 by Shelly Veatch. |
First, the trail enters an old orchard with pear and apple trees. Patches of wild raspberries and blackberries are profuse there.
Next, the trail enters the woods and then goes along the edge of a steep bluff with views of the hardwood forest below. You can hear the wind stir the tree leaves. The waves of nearby Lake Michigan crash on the shore and echo through the forest. The air is alive with birdsong and filled with the scent of flowers, forest, and earth.
The trail descends the bluff via a steep stairway and levels off on a boulder terrace shaded by maple and beech trees. Lake Michigan, when it was about 20 feet higher than it is today, created the terrace. This area displays these ancient lake levels and wave-cut bluffs. As glaciers receded, they deposited the boulders. The ice was gone by 10,000 years ago (Fagan, 2009).
Boulders of various sizes, deposited by receding glaciers, are along the stairs and trail. Photo date 2023 by Shelly Veatch. |
Soon the trail goes around a large glacial erratic, the size of a compact car. This boulder is a felsic granite with small phenocrysts of garnet (almandine-spessartine series). Glacial erratics of all sizes are strewn along the trail.
A large boulder or glacial erratic, carried by Ice Age glaciers, was dropped here when the ice melted. The boulder is made of granite. Photo date 2023 by Shelly Veatch. |
Closeup of a freshly broken surface of the large granite erratic. Note garnet phenocryst (approximately 1 cm) circled in red. Photo date 2023 by Shelly Veatch. |
The Lake Michigan shoreline is a cobble beach. The boulders and cobbles were released here by melting glaciers. Photo date 2023 by S. W. Veatch. |
A large Paleozoic limestone erratic has impressions of coiled ammonoid fossils. Photo date 2023 by S. W. Veatch. |
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