Geologist Jad D’Allura will lead this hike from Greensprings Mountain to Little Hyatt Reservoir, crossing a variety of different geologic rock units, each typical to different types of ancient volcanic eruptions which produced vastly different topographies and vegetation.
We start our trip through time at the 25.5 million year old (25.5 Ma) tree-covered lavas that comprise Greensprings Mountain which belong to the primeval Western Cascade volcanic series. Pause for beautiful views of the Bear Creek valley--allow me to wax eloquently as to why the valley exists and to comment upon the older rocks that lie to our west. The Greensprings lavas differ markedly from the violent volcanic eruptions that occurred around 24-23.3 Ma. Those eruptions produced a subdued, easily-eroded terrain with sticky, grass-covered soils and ribs of welded hot incandescent ash flows. At the end of the hike we will observe the reason for the existence of Little Hyatt lake then take a short hike to observe the young (3.1 Ma) High Cascade lavas of Chinquapin Mountain.
If you want to go on the Saturday, May 14 hike:
Sign up for Hike and Learn programs on Eventbrite! Stay tuned for more detailed descriptions and directions as the event approaches. If you have already signed up via email, we have your registration and look forward to seeing you there.
See On the Day of the Hike--what to bring.