VASHON GLACIATION
Below is a video showing an animation of the Vashon Glaciation process that happened thousand of years ago. As a result of this process, we saw a change in land formations, rivers/brooks, and lakes. The Vashon Ice Glaciation is most likely were this large erratic came from.
Half way along the trail there is a stream that runs though Ravenna park. Along the stream there is a bridge that leads you to the other side of the trail. Next to the bridge, there is a huge boulder which is covered in moss. This is a main attraction for people that are interesting in Geology/Geomorphology of Washington. This type of erratic can be found not only in Ravenna park but also in places
Process:
This Granodiorite erratic most likely came from the Cordilleran that descended from the Frasier River and made its way here from the coast of Vancouver BC. All of these erratics seen in Washington, most likely came from the Vashon Ice sheet that covered Seattle between 16,000 and 18,000 years ago. The layer of ice covered the area for roughly a few thousand years before melting and creating the water channels that are present here today. For any boulder to make it this far, it would have had to make its way here on an ice deposit, flowing down one of the major rivers we have here in Washington.
End Result:
The Vashon Glacial Ice Sheet was responsible for many lakes, rivers, ravines and land formations we see here in Seattle today. Some of them include; Greenlake, Cowen Park, Ravenna Park, and several others. This places would have never formed if it was not for the ice sheet melting and ultimately the disappearance of Lake Russel. Over the years, Ravenna has proven to be non-comparable geomorphology wise to what is was in the past. It is now significantly smaller than it once was although it does still bear resemblance.
No comments:
Post a Comment