Part I of this Chuckanut Formation story was mostly about the development of the formation and some of the interesting seaside sandstone features such as the tafoni. Part II will go into other features that the formation provides us including eocene fossils, building materials, coal, and recreation.
Sandstone Formation in Chuckanut Bay at the foot of Chuckanut Mountain
In stark contrast to the mountainous Pacific Northwest of today, during the Eocene epoch (~ 55 ~ 34 Million Years Ago (MYA) it was quite flat. However just as today, the region then was lush with vegetation and interlaced with braided streams meandering from what is now Eastern Washington on to the Pacific Ocean. This was a tropical swamp with exotic plants and animals (although some would be familiar yet today). As the streams approached the ocean, they slowed and their sediments of sand, clay, and silt carried from huge rock formations to the east, settled out. Over millions of years these sediments accumulated, were compressed by gravity and tectonic forces, and solidified into immense geologic rock formations. This bucket is about one of these structures – the Chuckanut Formation made up primarily of sandstone, siltstone, conglomerate, and shale, with pockets of coal from the ancient compressed vegetation.
I have referred to this formation in three previous diaries that were focused on various aspects of it including its Eocene fauna and flora, and more recently, graffiti sprayed on the rock formations along its beaches. Here I want to focus on the formation itself and all it has afforded our region.
This formation is not only in my backyard, it is under it as well. These sedimentary deposits extend to depths of nearly 20,000 feet in places. My focus here is on the Chuckanut Mountains which comprise 10 separate but related mountains (and hills) in and around Whatcom and Skagit Counties in northwest WA. In particular, I will focus mainly on Chuckanut Mountain itself (for which the formation was named) and a bit on Sehome Hill which is most directly in my back yard. In addition segments of this and related sedimentary formations are spread across the northwest, including the San Juan Islands and up into British Columbia.
This diary threatened to get too long so I decided to do it in two parts. This is Part I.
I have been monitoring the local sea star (Pisaster ochraceus) population following the devastating die-off from Wasting Syndrome over that past three years. As previously discussed, some pathogen and/or processes that are as yet not fully understood, have quite literally melted into goo upwards of 90% of west coast sea stars ranging from Baja California to Alaska.
Having traversed the North Cascades Highway (previous diary), I continued east, through the Methow Valley to Pateros on the Columbia River. From there I headed South on U.S. 97 to Chelan. This area, nestled in the foothills of the Cascades is arguably the center of the largest and best apple growing region in the country and maybe the world. They grow about one billion pounds of apples each year and export them to 60 countries. Although the region’s apples are impressive, I believe that Chelan’s major attraction is their 50.5 mile long, fjord-like lake. Lake Chelan is the third deepest lake in the U.S. at 1,486 feet, behind Lake Tahoe, and Crater Lake. More remarkable is its setting within the Cascade Mountains. At the southwestern edge of the lake, Pyramid Peak rises to 8,245 feet above sea level and below, just off shore the lake bottom falls to 386 feet below sea level. This peak to bottom differential of 8,631 feet renders it the deepest gorge in the U.S., surpassing Hell’s Canyon which is the deepest river gorge. Further, the bedrock floor, covered with silt and sediment is several hundred feet deeper yet. The lake’s surface at “full pool” lays 1,100 feet above sea Level and the deepest point, as noted above is the 386 feet below sea level. Five percent of the lake’s water is below sea level which lays 76 miles, due west through the mountains to Puget Sound/Salish Sea. The lake’s clear blue water is fed by 27 glaciers and 59 creeks.
Late October, 2015
North Cascades Mountains
A trip in late October took me over the North Cascades Highway, through the North Cascades National Park and to Chelan where I met my two brothers for our annual three day exploration of the region’s natural wonders. We traveled to the Grand Coulee and its Dam along with other remarkable remnants of the giant Ice sheets that carved out large segments of Washington State. At Chelan, we boarded a foot ferry for a 100 mile round trip up Lake Chelan to the isolated village of Stehekin. Finally I returned home to Bellingham via Stevens Pass to complete the North Cascades Highway Loop. I took too many photos for a single diary so I’ll break the trip into segments: the North Cascades National Park, Lake Chelan, and the Grand Coulee. All along the way the residue of the summer’s massive forest fires was prominent.
Massive old growth Douglas Fir stump with springboard cut, now a forest nurse
This stump, probably logged a 100 years ago, dates back untold 100s of years. This area was once selectively logged which left a number of old growth trees and stumps to shelter and nourish the ancient forest floor of the Stimpson Family Nature Preserve.
This diary may seem a bit disjointed but each part is in fact related and I hope of interest to this group. Each of the components emanates from a beautiful beach and pertains to various environmental and geologic issues currently and historically in play in Whatcom County and Washington State.
Point Whitehorn Marine Reserve Beach
Some items can be seen as hopeful, positive, and far sighted like the State’s aquatic reserve program. Others are worrisome and seen by many as looming disasters waiting to happen such as the potential coal export terminal slated to be situated in this area. And finally, I describe some geology of how our beautiful region, including this beach became what it is today.
The Columbia River flowing through carved out basalt cliffs at Vantage Washington
This diary describes an Ice Age Floods Institute field trip that I took in September last year that explored some of the remnants of the ice age floods in the pacific Northwest that periodically burst from Glacial Lake Missoula and later from Lake Columbia over the last approximately one million years. This particular field trip covered the Central Columbia region, the Hanford Reach National Monument, White Bluffs, including the larger Pasco Basin. This diary covers just one segment of this huge flood area that is too large to describe in a single diary. I described the part that flooded the Walla Walla Valley previously and plan to cover other areas in the future.
Some of the largest cataclysmic geologic events on earth occurred in what is now the Pacific North West. About 11 million years of volcanic flow activity, ending about 6 million years ago, created the Columbia Plateau with basaltic lava formations up to two miles deep. This huge basaltic plateau covering much of Eastern Washington and Oregon and adjacent parts of Idaho was later inundated by massive Ice Age floods ending about 15,000 calendar years ago. The scale of these events has been seldom seen elsewhere as it carved a landscape that appears other worldly. (In fact, the resulting terrain so closely matches that seen on Mars that NASA tested the Sojourner robotic rover here before its 1997 mission to Mars. (Bjornstad, 2006).
Scablands from basalt and flooding
The Columbia River continues to cut into basalt
As many as 100 floods deposited layers of sediment atop the basalt that today provide the soil for growing some of the best wine grapes and hence wines in the country and in some cases, the world. These are the wines of Oregon and Washington State.