Middle Fork Rocks
While floating the Middle Fork, guests are often awed by the variety of rock formations they see on their journey. The steep descent of the river allows us to experience a range of geologic phenomenon that spark wonder at the events that shape the landscape. Whether it’s the avalanche paths that scar the high alpine forests, or the sheer cliff walls of the Impassable Canyon that impress us, the Middle Fork affords ample opportunity to contemplate the impressive forces of nature.
The scope of geologic history makes comprehension in relation to human history a challenge. One of my favorite representations of geologic history comes from Middle Fork of the Salmon Guidebook writer Matt Leidecker:
“ If you squeezed the 4 billion years of the Earth’s geologic history into a 365- day calendar, Jan. 1st would represent the formation of the planet and midnight on Dec 31st would represent modern day. In this hypothetical geologic year, the
the formation of the bedrock along the Middle Fork began around Nov. 15th while humans do not enter the picture until the last second of the New Year.”
So much of the change occurs over thousands or millions of years; we rarely get to experience definite geologic events while rafting.
This past week we got to see several blowouts along the river, where mud and debris had poured into the river. The events were mostly minor, doing little more than adding additional sediment load to the river and mucking up the clarity of the water. However, it reminded me of days when I have been on the river and experienced the creation of new rapids, or experienced changes in the flow that have affected our route finding shallow sections of the river. Our experience of geologic time is confined by our insignificance in the bigger picture. However, there are days when we have the opportunity to understand that the magnitude of geologic change is incrementally occurring before our eyes. For an incomparable write up on the geology of the Middle Fork, I highly recommend checking out Matt Leidecker’s guidebook.