Central Washington Geology in a Nutshell

A quick overview of some Central Washington geological features to see over Labor Day weekend, on an easy day trip from Cle Elum including a stop at the big Cashmere fruit stand to stock-up on fresh peaches and apples.

Now if you're REALLY interested in doing the detailed research, Prof. Nick Zentner of Central Washington University has a comprehensive set of geology lectures and field trips posted for free on YouTube.


Otherwise, here's the weekend highlights in a nutshell…

CHUMSTICK FORMATION: Sandstones and conglomerates deposited 50-42 Mya by the prehistoric Chumstick River, that once flowed westward from Wenatchee to the Bellingham basin. Alluvial evidence supports the hypothesis that the direction of the river reversed as the modern Cascades formed in this timeframe. 

A great place to see the Chumstick Formation is at Peshastin Pinnacles State Park.

TEANAWAY BASALTS: Flood basalts predating the Columbia River flood basalts, from roughly 50 Mya, believed to be related to tectonic plate fracturing due the accretion of Siletzia. Feeder dikes can be observed at many places along along US 97, including in the parking lot of the Rock House Café at milepost 178. Red Top Lookout and surrounding peaks are blanketed with Teanaway basalt.

SWAUK FORMATION: Sedimentary formation thousands of feet thick, containing metamorphosized erosional deposits and some plant fossils, deposited over tens of millions of years, prior to about 50 Mya. The Swauk formation was folded and deformed by the same tectonic forces from the accretion of Siletzia that eventually allowed the Teanaway Basalt feeder dikes to rupture. Fossils may be found at an outcrop near the top of the Old Blewett Highway, a scenic detour off the main road.

INGALLS TECTONIC COMPLEX: 'Exotic terrane' bedrock so-called because it is believed to have formed somewhere else, subsequently transported by plate tectonics and accreted to North America more 100 Mya. Contains ancient sedimentary seafloor deposits of argellite and serpentenite, relatively uncommon in Washington State. The hike starts off as an easy gradual incline for several miles, with optional distance suitable to any fitness level. To reach the trailhead, turn on the access road west from US 97 at the Rock House Café.

Here's a Google Earth geological map of the area, courtesy Washington State DNR and modified by yours truly, showing the above formations color-coded. Pull it up full-screen to see the details, including our base camp at Wright By The River. 

Notable in the upper left is the Mount Stuart batholith, a huge, almost-continuous intrusion of granite, believed to be the magma chamber of an ancient volcano dating from about 100 Mya.

In the lower right is Grande Ronde Basalt, the largest of several vast Columbia River basalt flows, originating from feeder dikes near La Grande, Oregon, and dating from about about 16 Mya. 

Mima Mounds & Missoula Floods

Preliminary Findings Report

Table of Contents

1. A Preconceived Hypothesis
   
2. Playing with Isoclines
3. Lake Allison Erratics
4. Assumptions to Paradigms
   
5. Elevation Profiles
6. Dynamic Stratigraphy
7. The Goods Formation
8. Argillite & 99.9%
9. Occam's Razor

Summary

The purpose of this preliminary findings report is to establish that one or more exceptional Missoula Floods entered the Chehalis watershed, and may have delivered sedimentary material consistent with the constituency of Mima Mounds either directly or indirectly to the formative process.

This preliminary findings report details hypothetical predictions substantiated by field evidence and observations that Missoula Floods did in fact enter the Chehalis watershed, and delivered substantial quantities of ultra-pulverized mineral clays previously thought exclusively to be the result of in-situ basalt weathering. The complete list of materials made available to a Mima Mounds formative process by the intrusion of Missoula Flood events is as follows:

• Ultra-pulverized mineral clays
• Ultra-pulverized organic material
• A substantial quantity and variety of ice-rafted erratic rocks
• Chehalis spillway soil and in-situ weathered clays eroded from the spillway channels
• Chehalis spillway live organic material uprooted by the floodwaters

Proving to a high confidence that Missoula Floods were in fact instrumental in the formation of Mima Mounds will require considerably more effort, and while this report postulates a hypothetical framework for that work, the computational flow modeling and other tasks required are outside of the present scope.

A blog is an interesting way to compile a report. Reading reverse-chronologically, it roughly reveals the sequence in which ideas were formulated, expanded, and linked to one another. Which is usually not the same sequence in which ideas are best presented for comprehensive understanding!

The Goods Formation

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But the clincher for me was a menagerie of glacial erratics, found embedded throughout these clay deposits, from surface to bedrock. For example: sandstones both gray and blonde, sedimentary metamorphic 'mudstones' of several types, white and pink quartzite, fine-grained 'black granite' dacite or andesite (very tough to break w/ hammer), and two 'fire opal' specimens, one orange the other red. Almost all of these specimens exhibit glacial fracturing; many appear to have once been oval and stream-worn, while exhibiting unmistakable evidence of recent stressful trauma (meaning before I got to 'em with a hammer!).

Fig. 1: Fire Agate, also known as Carnelian, More Photos

The nearest well-known for fire agates is Francois Lake, British Columbia, where the University of Nebraska's Agate Lexicon Database reports this 1966 entry: "Omineca Agate, British Columbia, red, crimson, and pink amygdaloidal agates from the vicinity of Francois Lake near Omineca and the Omineca Mountains".  Francois Lake and the Omineca Mountains are right in the feeder zone to the Rocky Mountain Trench system, so this is a significant find in building a circumstantial case for Missoula Floods deposits.

This entire area seems to be an Ice Raft Graveyard, and here's a my initial 'engineering conjecture' explaining why it may be so:

• Flood flows here at times were over 185 meters, which is more than 50 meters above the crest of the Chehalis Saddle resulting in a spillway more than 15km wide. Another geologist once asked me 'If this happened as you say, where's the spillway?" Answer: We built Interstate 5, and the towns of Chehalis and Centralia in it!

Fig. 2: Chehalis Spillway

• Lake Allison in the Willamette Valley was a 'bathtub', with no outlet and perhaps 1000km of shoreline. Ice rafts entering there had plenty of space in which to scatter. Ice rafts entering what I call the 'Cowlitz Slough' on the other hand would be funneled and drawn along by the current to the outlet spillway near this site. The processional flotilla of ice rafts were melting at this point, dropping debris (sand, gravel, cobbles and larger) into the muck on the bottom as they passed.
• Then the level of Lake Allison began to fall almost as quickly as it had risen, and the suspended clays here were dewatered and decelerated to a stop, forming nodules where conditions were favorable. And a squadron of in-transit ice rafts became stranded in the icky gooey brown slime. Where they quietly melted away, depositing their tell-tale cargo in several eventful layers throughout the recent Ice Age.
• Then about a month ago, somebody finally noticed! While it is rewarding to be the first to figure something like this out, I'll be the first to admit I stand on the shoulders of some real giants...Harlen Bretz, Ira Allison -- without their groundbreaking efforts, there simply would be no framework upon which to build an explanation for these observations.
• And also a big 'thanks' is owed by everyone with an interest in the history of the Missoula Floods and the geology of Washington State to Alan Good of Napavine WA and his industrious enterprise; without Goods Quarries opening windows into the past, this mystery likely would remain unsolved yet today.

In something like 50 years of diligent searching, Ira Allison and his OSU colleagues managed to find just over 400 glacial erratics in the Willamette Valley. Here on the Chehalis Saddle, I'm certain that an organized effort could find hundreds of glacial erratics in a single day at any one of several promising sites in these extensive Missoula Floods clay deposits I have discovered and named the 'Goods Formation'.

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Occam's Razor

Occam's Razor is a logical principle, which can be mathematically demonstrated, that the 'simplest' of two competing explanations is usually the correct one. Note that in this context, 'simplest' is defined as 'the explanation requiring the fewest new assumptions'. Natural philosophers given to waxing metaphysical may find this discussion of Occam's Razor entertaining!

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"But this could have come down the Toutle River", said the geologist, examining my prize chunk of multi-hundred-million-year-old brown mudstone, glacier-gouged and fresh from the quarry that morning.

Geologists. Gotta love 'em. At any convention of skeptics, geologist make us engineers look like a wild-eyed rabble of windmill-tilters. And that's a tip of the hat to y'all, geo-guys and gals!

Attending the Seattle-area IAFI Chapter meeting last week to introduce myself and some preliminary findings, I began to understand that communicating the 'context' in which these samples were found was of equal if not greater importance to obtaining and classifying the actual samples themselves.

Fig. 1: Multi-hundred-million-year-old Brown Mudstone exhibiting exemplary planar, parallel layering. Smooth 'gouge' where number is affixed likely caused by ice pressure insufficient to break the specimen.  More Photos  | View in Google Earth

After all, should anyone be surprised to find this assortment along a river bank somewhere in the Canadian Rockies? Not at all. It was evident that I needed to better communicate the complete picture of what is truly remarkable about this collection to convincingly claim that 'glacial-ice rafting' is the most reasonable explanation.

Listed here are some noteworthy aspects of the context in which these erratic samples were found:

• Location: Not in a river wash, but near the top of a saddle between two watersheds
• Elevation: At an elevation that local rivers find difficult to access
• Proximity: In close 'hydraulic proximity' to a known Missoula Floods path
• Lithology: Erratics collected are indigenous to the Canadian Rocky Mountains, and many are relatively rare, if not unknown, locally
• Stratigraphy: Fractured erratics are dispersed throughout all layers of deposited clay
• In Absentia: Conspicuously absent from the deposited clay layers is by far the most ubiquitous local rock of all, basalt

Each of these aspects will now be discussed in more detail. No one item stands alone as 'proof positive' evidence, but taken collectively they form a strong basis for adding a singular, previously-unknown scientific assumption to explain the observed data: That 'some' exceptional Missoula Floods were able to enter the Chehalis watershed.

Location

By studying the image below, it is easy to see something that is fairly intuitive to anyone who has either worked on or recreated upon rivers for any length of time -- namely, that natural rivers are averse to running down the top of a ridge line. Man-made canals of course can be made to do so, but a fundamental law of statistical mechanics called entropy simply does not allow for this to occur in nature to any practical extent.

The ridge line in the image below runs from right to left, and the 'low point' is flagged as the 'Chehalis Saddle @132m'. East, to the right, is Mt. Rainier and the Cascade Range. West, to the left, are the scraggly weather-worn remnants of what passes for the Coast Range in these parts, called the Willipa Hills.

Fig. 2: Overview of Goods Quarry hydraulic relationships.
View in Google Earth

Both of the major rivers in this image originate from the glaciers of Mt. Rainier, and initially run more or less westward. In this field of view, the Chehalis River is beginning to break north, and the Cowlitz River beginning to break south.

The closest approach of the Cowlitz is about 14km to Chehalis Saddle, and the closest approach of the Chehalis is about 8km. There is no discernible evidence that any abandoned westerly-flowing stream-bed of either was ever any closer, within the relevant time-frame. Such streams would be called upon to deliver rocks from source formations on Mt. Rainier to provide local accounting for the suspected erratics.

Further, there is no discernible evidence of any perennial easterly-flowing stream-bed originating in the Willipa Hills approaching the Chehalis Saddle, within the relevant time-frame. Such a stream would be called upon to account for the great quantities of clay, ostensibly delivered from the "in-situ weathered basalt" clay deposits evident at higher elevations locally in the Willipa Hills. These local Willipa Hills clay deposits are explored in the Trailing a Whopper [currently in work] section of this report.

Elevation

At closest approach, the Cowlitz River is 100 meters below and 14km southeast of the Chehalis Saddle. At closest approach, the Chehalis River is 69 meters below and 8km northwest of the Chehalis Saddle.

Given their wide, capacious outwash valleys, it seems implausible that either of these rivers could have affected the others watershed in a meaningful way via the Chehalis Saddle, within the relevant time-frame.

Recognizing that both sampling sites thus far are located in the Chehalis watershed, and to verify that the Goods Formation is essentially uniform across the saddle, samples will be collected from Goods Quarry #1 and some other representative sites in the Cowlitz watershed before the final draft of this report is complete.

Proximity

The Cowlitz River is a tributary of the Columbia, and as such the Cowlitz watershed is hydraulically inseparable from that of the Columbia's. As discussed at length elsewhere in Elevation Profiles and The Cowlitz Slough [currently in-work] sections of this report, the minimum elevation separating the Cowlitz from the Chehalis watersheds is 132m, which appears to be within easy reach of some exceptional Missoula Floods.

Lithology

Lithology is essentially the defining characteristics of a rock or mineral. The sedimentary and metamorphic lithologies found in the Goods Formation are common in the Foreland, Omineca and Intermontane Belts of the Canadian Rocky Mountains. The Foreland Belt in particular is notable for a minimum 15km thick layer of multi-hundred-million year old sedimentary rocks. In US geology references, the term 'Belt Supergroup' is often used to refer to these and several other related belts collectively. The range of sedimentary structures preserved in the Belt Supergroup is striking, as demonstrated in the preceding link provided by the Digital Geology of Idaho online reference.

In contrast, the local Cascade Range is known to have some equivalently-ancient sedimentary formations, but both the range of structures and breadth of variation within structures is predictably limited. This statement holds true to an even greater degree when we focus on known formations local to the sampling sites, at elevations which may have ostensibly contributed to alluvial deposition of the samples.

In a nutshell, elevated local formations for many of the sampled lithologies are unknown: [specific list to follow, when sample cataloging is complete and lithology identifications developed to a higher confidence level; i.e. including microscopic evaluations]

Stratigraphy

Stratigraphy is essentially the study of rock and sediment layering. At Goods Quarries, the strata from bedrock basalt to surface are few, and their composition essentially homogeneous with slight variation and two exceptions. Except for the layer of surface soil observed at both sites, and except for a layer of in-situ weathered basalt-turned-clay observed at Goods Quarry #3, erratics were observed throughout the clay strata, in some locations from surface to bedrock.

Fig. 3: A 'stratigraphy sandwich' of orange clay layers above and below a brown center layer of clay, conjectured to represent three distinct 'rhythmites' deposited by separate Missoula Floods events. More Photos | View in Google Earth

Three erratic-rich clay 'rhythmites' may be evident here, conjectured to contain variable concentrations of ultra-pulverized organic material, which accounts for the variation in color. If this initial engineering conjecture is supported by follow-up geological analysis, the layers containing higher concentrations of organic material will evidence more 'accelerated weathering', predictably resulting in the enhanced rusty-orange color observed in the upper and lower strata.

In Abstentia

Conspicuously absent from the lithology of the erratics found in the clay layers is the most common local rock type, the omnipresent Columbia Basalt observed everywhere in the vicinity. The basalt bedrock evidenced in the photo above extends for untold kilometers in every direction. For a local river to have collected the unlikely assortment of lithologies found in the clay deposits, while selectively excluding basalt, is a conjecture that by inspection seems implausible.

Conclusion

As a summary of the A Working Hypothesis [currently in-work] section of this report, the engineer's preliminary evaluation of these findings is that a significant, previously-unrecognized Missoula Floods sedimentary clay deposit has been discovered at these sampling sites that likely extends between, and for an unknown extent, beyond them.

Summary Hypothesis

This formation has been duly named the 'Goods Formation' by its discoverer, one Brandon W. Nichols, Professional Engineer, of Seattle WA. The simplified hypothetical explanation for the high concentration of glacial erratics found in these deposits is as follows:

• That the sampling sites lay within or adjacent to a northerly-discharging spillway, which
• Funneled and concentrated a procession of erratic-laden ice rafts to these locations
• The water transported over the spillway contained a high concentration of ultra-pulverized mineral clays,
• Some of which settled here as the spillway altitude fell when the floodwaters receded
• Most of the erratics here fell from the ice rafts as they melted, while the ice rafts continued onward
• The balance of erratics are accounted for by those ice rafts trapped in the sediment as the spillway altitude fell when floodwaters receded

For this hypothesis to be true, only one new scientific assumption is required:

• That 'some' exceptional Missoula Floods entered the Chehalis watershed

Rebuttal to Locally-Derived Alluvium Conjecture

In rebuttal to the conjecture that these deposits can be accounted for by the work of local rivers depositing localized alluvium, the following list of new scientific assumptions are required:

• There exists formations both known and unknown for all erratic lithologies on Mt. Rainier, since all known local Willipa Hills exposures are basalt
• A westward river once flowed from Mt. Rainier, delivering erratics to the sampling sites
  
• The westward river traversed the Chehalis Saddle, defying the law of entropy
• The westward river flowed so briefly that it did not leave a channel
  
• An eastward river flowed concurrently, delivering clay from the Willipa Hills
• The eastward river flowed so briefly that it did not leave a channel
  
• The westward river was able to selectively exclude basalt from the transport lithology

Where exactly did we pass the tipping point of ridiculousness? Thus, until a substantive alternative hypothesis is proposed for the existence of these deposits, one that stands up to the scrutiny of Occam's Razor, this project is moving forward with high confidence that the Goods Formation is the result of some exceptional Missoula Floods.

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Assumptions to Paradigms

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The diligent work of Ira Allison and his colleagues provides us today with a vivid picture of what impacts Missoula Floods had in northwest Oregon. Based on field-collected evidence and a 'catastrophic blueprint' as drafted by Harlen Bretz, these scientists and scholars determined that 'Lake Allison' filled the Willamette Valley as far south as Eugene, Oregon and reached a 'maximum' depth of 122m due to a partial obstruction of the Columbia River channel formed near Kalama, Washington by flood debris such as boulders, sand, mud and ice.

However, as shown in the 'Lake Allison Erratics' section of this report, this 'maximum' depth was in fact a statistical assumption, based on disregarding the highest 19 data points, all but one recorded by Ira Allison himself in the 1930's. And electing to model the flow restriction, or 'throttle', at Kalama as an 'ice dam' that melted away in a fixed position until failure is a premise misleading to the false conclusion that Missoula Floods were of insignificant impact in southwest Washington State.

The following graphic illustrates Lake Allison, and the blue annotations show the effect of moving what may more descriptively be termed the 'debris throttle' from Kalama to Longview, Washington in an effort to understand the actual, observed effects of some exceptional-elevation Missoula Floods in the Cowlitz River watershed.


But how can I claim, with any degree of certainty, that this 'debris throttle' was ever actually present at Longview? Before obtaining actual field evidence from Goods Quarries, my only confidence was from a prediction coming out of the 'Theoretical Fluid Dynamics Common-Sense Modeling Lab', which postulated that this outcome is actually the expected condition: If the flow restriction formed at Kalama, then it also formed at Longview because it was, in fact, the same flow restriction!

Following is the perfect mechanical engineering analogy, to help readers envision how this could be true:

• To return the Columbia to free-flowing, the flow restriction at Kalama first needs to be pushed out the mouth of the Columbia River. The river will remain 'debris throttled' until the restriction clears the 'S-bend' and enters the expanding channel beyond Longview, Washington.
  
• Analogous to shoving a hairball through a P-trap with a plumbing snake, your bathroom sink is going to remain clogged until you get that hairball to the riser in the wall.
  

Yes, mechanical engineers -- we're the profession that designed your plumbing system. Next time after visiting the restroom, why don't you give the first mechanical engineer you see a big 'Thanks, pal!' and a high-five (wash your hands, first!) for not having to resort to any of the alternatives?

So how this relates to the Cowlitz Slough is that, far from being unlikely to form, in fact the formation of the Cowlitz Slough is nearly impossible to prevent, as this predictably massive flow restriction was hydraulically shoved through a section of the Columbia Gorge, with sea levels 100m lower than they are today. The process evidently took from several days to perhaps weeks.

In summary we can conclude that sometime in the recent pedagogical past were formulated two simplifying assumptions, each of which were useful to some degree in reconstructing the chronology of Lake Allison:

• Disregard about 5% of the most extreme samples of the erratic elevation data set, and
• Always estimate the flow restriction to be at Kalama, and disregard what may or may not have happened elsewhere.

Soon one scholarly report begets another and another, by reference upon reference, prolific as hamsters and gerbils. And before many generations of knowledge-building were complete, these two modest assumptions evolved into 'guidepost paradigms' that steered many inquisitive minds away from investigating the impact of Missoula Floods in southwest Washington.

Thus the moral of this story is to never let a reasonable hypothesis be dissuaded by guidepost paradigms. Be sure to investigate the origin of these paradigms, because if they can be cut-down with verifiable evidence and common sense, you can split them into kindling wood for your hypothetical fire!

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A Preconceived Hypothesis

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A scientist friend once tried to bait me with the accusation of "desperately trying to prove a preconceived hypothesis". To which I responded with a grin that I was "way beyond needing to 'desperately' prove anything", and then diplomatically changed the subject. Not that there ever was any scandal in "trying to prove a preconceived hypothesis" -- because in fact all hypotheses are 'preconceived'.

'Preconception' occurs in a mind with the ability to postulate and hold-open a question for which there seems to be no immediate answer, pending future data inputs that may provide resolution. Simply stated, no set of facts, observations or data ever arranges itself as a coherent explanation for anything. Someone with a 'preconception' for what it is they want to explain must first perceive the facts, observations and data in a way that seems to sensibly answer the held-open question. And this is the very essence of any hypothesis.

Before conceptual unification, the 'preconceived hypothesis' to which my scientist friend was referring did admittedly preexist in my mind as a 'fact' and a 'question':

• Fact: If ever there were a set of events that could provide excessive kinetic energy to shape landforms unexpectedly, it was the Missoula Floods.
• Question: No explanation for the process that created Mima Mounds had adequately accounted for the enormous kinetic energy required. Where did it come from?
  

But each were stored separately, at different addresses in the cerebral database. Like flint and steel to make a spark, they first needed to be somehow struck together to light the tiny flame of a 'preconceived hypothesis'.

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Argillite & 99.9%

'Lithology' is essentially the defining characteristics of rocks and minerals, and 'Stratigraphy' is essentially the study of rock and sediment layering. As engineers seek to answer questions with the Laws of Thermodynamics, geologists seek answers in the fundamental truths of Lithology and Stratigraphy.

While this may seem like just two professional examples of Maslow's Law of the Instrument, in practical application the study of Root Cause Analysis shows that independent lines of reasoning with alternate bases of assumptions, both arriving at the same conclusion, provides a much higher level of statistical confidence in the results than either line of reasoning alone.

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Geologists are a skeptical lot. And I can certainly appreciate why: When your profession is the gatekeeper for the Earth's natural history, one needs to be consistently vigilant in response to those who seek colorful revisions in accordance to their own personal agenda. And when your professional expertise includes superbly-honed rock and mineral identification skills, it is only natural to look for fundamental truths framed by question of lithology.

So while I may be 95% certain of my conclusions with respect to the origin of the Goods Formation, based on an engineering prediction of the required hydraulics subsequently supported by field data, and 95% certainty is a 'green light' criteria for many engineering and business decisions, for a respected geologist to support a revision to the Earth's natural history proposed by another profession, 95% just isn't good enough. And here again I can appreciate why: Because the last thing you might do in your professional geology career is defend some engineer's tilted windmill in front of a roomful of skeptical colleagues.

Thus one of the geologist for this research effort has set the following criteria for 99.9% certainty with respect to the Goods Formation, framed in terms of lithology: Locate several glacial erratics constituted primarily of the sedimentary metamorphic mineral known as 'argillite', similar in composition to this 30-ton specimen found at Erratic State Park in Oregon.

Now that I know what we're looking for, given these excellent detailed photos courtesy of the Geological Survey of Canada and the extensive glacial erratic content of the Goods Formation, I am 95% certain that it is simply a matter of time and effort, ranging from a few days to a few months, before we find them.

If by chance we don't find argillite after a reasonable effort, then we'll need to deduce another other way to elevate the geological confidence level to 99.9% for some exceptional Missoula Floods entering the Chehalis watershed. Because from an engineering confidence level of 95%, it is pretty clear where the kinetic energy and unaccountable materials came from that helped create Mima Mounds!

Chehalis Spillway from Mima Mounds

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