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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Dynamic Stratigraphy

'Stratigraphy' is essentially the study of rock and sediment layering. 'Classic' sediment deposits form in perfectly planar, parallel layers. It is when these layers get compressed, scorched, warped, punctured, folded over, and uplifted that geologists really start to get interested. And when sedimentary layers become folded-over to the point where they form rolling dynamic aggregating nodules, its time to call the mechanical engineers!

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Field Work Summary

Spent most of the morning of October 20th, 2010 at Goods Quarry #2 near Napavine, WA. Also briefly visited Goods Quarry #3, and documented the day's findings in this geotagged photo set. After ruminating on these first-hand observations, in my mind the debate about whether or not Missoula Floods had any influence here is over but for the details in the report writing.

Strong evidence was provided by a multitude of spheroid and ovoid clay nodules with an evident 'dynamic stratigraphy' suggesting a rolling motion as they were deposited. Nodules were observed most commonly in the lowest clay strata, varying in size from a few centimeters to the more than half-meter specimen shown in this photo:

Half-meter long clay nodule, More Photos

Geologists have cautioned that what I am describing as 'dynamic stratigraphy' may in fact be 'spheroidal weathering' of the underlying basalt bedrock. At first, I was certain that what I was seeing could not be in-situ weathered clay due to the fact that erratics may be observed both within the strata containing the large nodules, and within the large nodules themselves.

But after witnessing actual in-situ basalt weathering at Goods Quarry #3, in a strata which appeared unaffected and thus containing no erratics, I've devoted both careful thought and some initial investigation into the subject of sedimentary structures. And I can now envision a scenario where we may both be right, which is the focus of the next sub-section.

Extraction site of GQ2001, an example of gray sandstone, More Photos

Formative Engineering Conjecture

Study of fluid mechanics teaches that aggregating nodules such as these must be formed dynamically, in a viscous fluid flow. Essentially the process can be described as a 'snowball effect', where a 'kernel' becomes ever-larger as it rolled by a viscous fluid through a layer of sticky material.

Two conditions help the nodule maintain its integrity as it becomes larger:

• Rolling it at an ever-slowing rate, and
• Gradually increasing the viscosity of the surrounding fluid

In the case of Missoula Flood flows applied to this location, both of these conditions are predictably expected as floodwaters receded. After observing the strata of undisturbed in-situ weathered basalt at Goods Quarry #3, my hypothesis has now come to expect a layer of native clay, predictable after the roughly 16 million years that this likely Grande Ronde Basalt has been sitting here at the foot of Mt. Rainier saturated with moisture. But depending upon location within the spillway and elevation with respect to the saddle, there is evidence to suggest that some floodwaters were powerful enough to strip the in-situ clay down to bedrock.

As floodwaters rose quickly and reached maximum elevation, the topsoil was scoured from the spillways down to the in-situ weathered basalt, and thus the in-situ clay may have provided a significant portion of the material observed in the photos above, as it was peeled-off and rolled by the current. In the process of formation, erratics would fall from ice-rafts and become trapped within structures comprised significantly of the in-situ clay.

This elevation with respect to Lake Allison was at the very maximum achieved by a Missoula Floods event, and thus the only material expected from floodwaters here are the suspended ultra-pulverized clay and organic material, and ice-rafted erratics ranging two orders of magnitude in size -- from grains of sand to bowling ball cobbles. Larger erratics are not excluded, but they have not yet been found at this location.

Then almost as quickly as it had risen, Lake Allison's altitude began falling, trapping the suspended clay material in a decelerating flow along with innumerable ice rafts. As the flow decelerated, the viscosity increased as the suspended material became ever-more concentrated.

Conclusion

Here and at the upper inundation elevations of the Willamette Valley are the only areas to date where Missoula Floods clay has been identified. But above 122m in the Willamette Valley, geologists seem to favor the explanation that clay deposits were formed from aeolian (wind-blown) clay. This explanation is difficult to rebut with a Missoula Floods conjecture, since around the ancient shoreline at the high-stand of Lake Allison, any Missoula Floods clay deposit will likely not contain erratics due to ice raft scattering.

However, now that it has been demonstrated that Missoula Floods clay was in fact deposited above 122m elevation and thus representative sampling can be done with confidence, geologists may perform laboratory analysis to identify signature constituents. With this new information, there may be more Missoula Floods clay yet positively identified at some surprising locations and elevations in both Washington and Oregon.

And while the final chapter of how they were created needs more careful study and input from sedimentology experts, it is predictable that here and only here with respect to Missoula Floods will be found the highly-unique 'dynamic stratigraphy' observed in these enormous clay nodules.

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Elevation Profiles

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Pulp Nonfiction

In many ways this really is a scientific detective story. We have a crime scene, Mima Mounds, where the evidence, many hundreds of thousands of tons of gravel and sand vertically displaced in a regular pattern, suggests an extraordinarily large and powerful perpetrator.

And here's a tip just phoned in by some mechanical engineer playing with Google Earth -- we now have a suspect, a Pleistocene monster called 'Missoula Floods'. How do we either establish the potential connection, or clear this suspect from further investigation?

As a detective, the top three items on your investigative checklist are 'Means, Motive and Opportunity'. 

• Means: Was the suspect, Missoula Floods, powerful enough to create the crime scene observed at Mima Mounds?  Given the grand-scale mayhem this suspect is famous for, the modest vertical material displacements at Mima Mounds seem like a trifling distraction.  But make no mistake, this suspect had the means to do this deed.
  
  'Check' on Means, continue investigating!
  
  
• Motive: A rampaging maniac like Missoula Floods doesn't needs a motive, just the simple opportunity to commit the crime is enough provocation.
  
  'Check' on Motive, continue investigating!
  
  
• Opportunity: To determine if the suspect had the opportunity to commit this crime, we just need to answer three simple questions:
  
  

• Proximity: Was the suspect known to be perpetrating other crimes near to where this crime was committed? The answer to this question is 'yes', Mima Mounds were formed near Olympia, Washington and Missoula Floods always finished-up an interstate rampage by running amok down in the Willamette Valley of Oregon. The distance is about 170km.
  
  Check on Proximity for Opportunity, close enough to continue investigating!
  
  

• Timing: Were the crimes known to be perpetrated by the suspect committed in the same time-frame of the crime under investigation? Again, the answer to this question is 'yes', Mima Mounds were formed and Missoula Floods rampaged near the end of the last Ice Age.
  
  'Check' on Timing for Opportunity, close enough to continue investigating!
  
  

• Access: Is there an access route to this crime scene that the suspect may have used? Perhaps, but the topography is challenging...170km is the distance from Oregon to Mima Mounds, but up and over an intermediate drainage divide, or ridge. We have reports from Oregon detectives that the suspect was able to scale elevations as high as 122m, and perhaps even higher.
  
  Since we know this monster came from Montana, the 170km distance doesn't sound like a problem. What about the elevation? How high is the ridge? Is it really high enough to discourage a cold-blooded serial killer?
  
  To finish answering the 'access' question, we need to determine the approximate minimum height of the ridge, and then check it against the suspect's known capability. The highest elevation at the lowest point of the ridge is called the 'saddle', and this is where our suspect most likely would've accessed the scene of the crime, if indeed our suspect actually committed it.
  
  But finding the saddle was a bit easier said than done using Google Earth. The real problem is, you can find many saddles. Is the one you have just found the lowest, or do you keep looking? With some ridges, it is obvious by inspection where the saddle is. With this one, saddle candidates stretched for 15km across what I now believe to be the Main Spillway.
  
  After some trial-and-error, at last I found a satisfactory saddle candidate at elevation 140m. This was only 15% more than the suspect's known capability, and well within the 'reported' estimates up to 180m.
  
  So 'check' on the question of 'Access for Opportunity', and 'check' on the overall question of Opportunity!
  
  

Thus, the results of our initial investigative checklist has determined that the suspect, Missoula Floods, had the means, motive, and opportunity to commit the crime for which the roughly 40 square kilometer extents of Mima Mounds lay in mute testament when discovered, some 150 years ago.

Hydraulic Elevation Profile

But speculation about means, motive, and opportunity alone are insufficient for a conviction in any Geological Supreme Court. To obtain a conviction, we will need to find physical evidence linking the suspect to the crime scene, and the more evidence the better. To begin our search for evidence, we should consider looking at a place where we know the suspect had to be in order to access the crime scene.

And that place, in this case, is the hydraulic saddle between the Cowlitz River and Chehalis River watersheds. 'Hydraulic saddle' is an arcane engineering term that may be defined essentially as the 'lowest line of passage between two watersheds'.  Of the many saddles stretching across the drainage divide, the hydraulic saddle will be the least of all in elevation.

Not satisfied with my trial-and-error estimate, I was determined to find out exactly where the hydraulic saddle occurred on the Cowlitz-Chehalis drainage divide before starting the search for actual physical evidence. 

Beginning at the Columbia River near Kalama, Washington and following railroad tracks and stream-beds, I carefully traced a close approximation of the minimum, or 'hydraulic' (because that is the path that a flowing stream would follow) elevation change path up and over the drainage divide, down to Mima Mounds, and out to the Pacific Ocean at Aberdeen, Washington. When this path is plotted on a vertical scale showing elevation change, engineers call it the 'hydraulic elevation profile'.

Fig. 1: Hydraulic Elevation Profile from Kalama to Aberdeen.
View in Google Earth

• The hydraulic elevation profile's highest point was 132m, 8m lower than my 'trial-and-error' first approximation, and only 10m higher than the suspect's documented capability.
  
• More importantly, the true hydraulic saddle was about 10km west of my initial, trial-and-error estimated location.
  
• This turned out to be crucial in locating Goods Quarries, which are shown in the frame of the satellite image above, although I didn't actually spot them for perhaps another week.
  
• But in a stroke of serendipity, I did manage to locate the two quarries noted, less than 3km from the true hydraulic saddle.
  
  

  

  Fig. 2: Goods Quarry #1
  View in Google Earth

• There I spotted 'scads' of interesting-looking material that bore a striking resemblance to sedimentary deposits throughout the Willamette Valley.
  
  

Fig. 3: Goods Quarry #2

• So I made an initial investigative field trip in early October 2010 that netted the name and phone number of the quarry operator. It was Sunday afternoon and the quarry gates were locked, but in another stroke of serendipity I found, in less than 30 seconds of searching, a chunk of coarse-grained 'granite' in a pile of pit run containing the tell-tale 'yellow clay' at a city park under construction nearby in Napavine, Washington.
  
  

  

  Fig. 4: Coarse-grained 'granite' posed on basalt for reference

  
  
• Now maybe, just maybe, this granite was from a Mt. Rainier formation. But in photographs, the granite in those formations appeared fine-grained. This coarse-grained specimen I had a suspicion could very well be my first apprehended fugitive from the Canadian Rockies.
• But far more evidence would be required than one random rock, so I vowed to return during quarry operational hours to search for more. Also in this time frame Goods Quarry #3 was identified, about 8 km northwest of the first two.
  
  

  

  Fig. 5: Goods Quarry #3

• Finally I was able to make advance arrangements with quarry owner Alan Goode, and returned on Wednesday, October 20th 2010 to begin a serious search for evidence of that Pleistocene monster called 'Missoula Floods'.
  

And what I found at Goods Quarry #2 far exceeded my wildest expectations -- the engineering insight of my 'preconceived hypothesis' led directly to the discovery of a previously-unrecognized geological formation!

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Lake Allison Erratics

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What is an Erratic?

'Erratics' are simply rocks of a type that have been transported to a location that is far from where we would expect to find them, which is usually near the formation of origin. The most common transport mechanisms for erratics are ice and water. A combination of the two, called 'ice rafting', transports a rock first by ice in a glacier, and then by water while still trapped in the ice. This can result, as in the case of Missoula Floods, in transport distances over thousands of kilometers. Erratics can be of any size, but as a general rule, 'larger is better' for increased confidence in the 'forensic evaluation'.

Technically, forensic geology attempts to answer questions raised by the legal system using principles of geological science. In this discussion I will purposefully use the term 'forensic evaluation' in a more facetious sense, meaning 'an effort to determine whether or not the rock specimen in question has been kidnapped and assaulted by a glacier'.

Specifically, the forensic evaluation will examine the composition and condition of the rock to determine if possible the formation of origin, estimate the age of the specimen, and deduce the forces that have acted over time to result in its current condition.

• What is the relative bluntness of the edges?
• Do the edges exhibit uniform bluntness, or are there both smooth and sharp edges?
• Do any of the faces exhibit scratches, gouges, cracking or chipping?
• What are the dimensions (length, width, height) of a box that could contain the specimen?

Another important aspect of the forensic evaluation is the 'context' in which the specimen was found.

• Was it isolated, or in a group?
• On the surface, or buried in some material?
• If buried, what was the nature of the material in which is was found?
• If the specimen was evidently broken, were mating pieces found nearby?
• At what elevation was the specimen found?

Answers to these questions provide the investigator with varying confidence levels for making the determination as to whether or not the specimen was a victim of glacial trauma. These criteria are beyond the scope of this article, but are not terribly complex and will be addressed in a future topic with respect to the samples ultimately collected at Goods Quarries.

Lake Allison

For purposes of this discussion with respect to the Chehalis River watershed, we are most interested in the elevation at which erratics were found in the Willamette Valley of Oregon, as this provides clear indication of the elevation potential for Missoula Floods to spill over from the adjacent Cowlitz River watershed to the south. Given a Columbia River flow restriction at Longview, Washington or beyond, the Cowlitz watershed and the Willamette Valley are 'hydraulically inseparable'.

The lake which formed in the Willamette Valley as a result of Missoula Floods is now called 'Lake Allison' in honor of Prof. Emeritus Ira S. Allison of Oregon State University. The work of Prof. Allison and others to collect the Willamette Valley erratic database and many other interesting facts are elegantly summarized on a color wall chart suitable for framing, available for download from the US Geological Survey and linked to the image here:

USGS Lake Allison Erratics Chart

In studying the 'key' for interpreting the USGS chart, reprinted below, it is immediately clear how the idea of Missoula Floods never exceeding 122m (400 feet) in the Willamette Valley became established in the minds of so many geologists.

Key for Chart Above

But always remember students, to read the text and don't just look at the pictures! In the case of the text on this chart, there are some intriguing statements with respect to erratic elevation:

• The vast majority of erratics lie below 122m above sea level; however, Piper (1942) noted boulders "widely scattered in valleys and on tops of hills and knolls 800-1,500 ft. [244-457m] high" eight miles south of Portland, near Prosser mine, east of Lake Oswego. This location has not been confirmed.
• Allison (1935) described "A half dozen small [erratics], ranging in size up to 8 inches [20 cm] lying on Judkin's Point, Eugene, Oregon, at an altitude of about 650 feet [198m] above sea level, are so far above any other known occurrence that their authenticity is doubtful". Allison attributes the high elevations of these erratics to transport by Native Americans.

These statements clearly indicate that 'some' erratics were reported or found at elevations higher than 122m, but what exactly does the "vast majority" mean, quantitatively? To answer this, we need to examine the actual erratic database, which I have downloaded from USGS, sorted by elevation, and made available via the preceding link. From that data, the following summary information may be extracted:

• One documented erratic was found at 430' in 2001
• Eleven found by Allison in the 1930's were recorded at elevations from 400' to 500',
• Seven found by Allison were recorded at elevations from 500' to 600'
• One was recorded by Allison at a difficult-to-reconcile 827'
• And the Judkin's Point erratics at 650' discounted by Allison are not included

So 19 out of about 400, or roughly 5%, of the erratics were found at an elevation higher than 122m, all but one by Ira Allison himself. Quantitatively then, 95% is what the 'vast majority' means in the USGS context. Surely, even though Allison lacked the modern convenience of precise coordinate and elevation determination via GPS, he could not have over-estimated the elevations of 18 erratic locations, nor were they all likely to have been transported by Native Americans.

After studying this information, I was confident that the 122m 'maximum elevation' of Lake Allison was in fact a statistical simplification, useful for understanding the chronology of flood events and their cumulative impacts in the Willamette Valley.

And by the same token, equally confident in the fact there were 'some' exceptional Missoula Floods with the elevation potential to access the Chehalis watershed.

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Playing With Isoclines

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Note 2010-10-25: Essentially this is how my geological pursuit of Missoula Floods in southwest Washington State started off just over a month ago, reconstructed from an e-mail exchange with a respected geologist.

Fig. 1: Rectangular Isocline Covering Missoula Floods Extents

In early September 2010, I was 'doing some experimental work' (i.e. essentially goofing off) in Google Earth, mapping the various levels of a Missoula Floods lake that formed around the Tri-Cities area of Washington State, called 'Lake Lewis'. To start off, I simply made a very large rectangle of constant elevation called an 'isocline', large enough to completely cover both Lake Lewis and the source of the floodwaters, Lake Missoula in Montana. When I learned that a lake also formed in the Willamette Valley as a result of these events, I made the isocline even bigger. So I now had a rectangle that extended from Newport Oregon and Vancouver Island on the west, to Yellowstone Park in Wyoming on the east (see image above), and was playing around with the elevation to get a feel for the extents of these ancient lakes. This is when I happened to notice something curious going on in southwest Washington State.

Excerpted from e-mail to respected geologist, 2010-09-23...

But there's something interesting I noticed in working with Google Earth, about what happens downstream of Lake Lewis, call it 'Lake Willamette' perhaps [I didn't know at the time it is actually called 'Lake Allison']. So north of the Columbia, in the 'Chehalis Arm' of Lake Willamette [actually the Cowlitz River watershed], presuming Puget Sound is blocked with ice, then floodwaters would want to drain down what looks to me like an ancient path of the Columbia, now occupied by the Chehalis River. And that path happens to pass by a 'mysterious' geologic feature called....Mima Mounds!

As a mechanical engineer, what gave me some inkling of curiosity into the possible influence of Missoula Floods on the formation of Mima Mounds was realizing the magnitude of the kinetic energy required; something that none of the hypotheses put forward thus far had addressed.

Yessir, I think we could have us a Missoula Flood feature right here in Puget Sound [no leap of faith required here, right?]. The mounds I think may have been formed by 'standing ripples' -- under the right conditions, standing ripples in a wide, relatively shallow fast-flowing stream can form 'bumps' instead of the more common 'wave' shape [this I knew simply from experience; further education on my part determined that the proper term is 'interference ripples', and the 'right conditions' are perpendicularly intersecting wave fronts of equal amplitude]. The 'smoking gun' would be some granite Rocky Mountain erratics down there, and I've already started spotting candidates for a field trip with...you guessed it, Google Earth.

It was a lucky break that I later found Goods Quarries, because the most promising 'wild erratic' spotted from satellite imagery turned out to be a dead tree!

Fig. 2: 175m Isocline in SW Washington State

The flint and steel were struck together, and the spark of a 'preconceived hypothesis' began to smolder when I noticed that this potential Missoula Floods path passed right by Mima Mounds. Attempting to brainstorm this notion with my correspondent soon revealed however, that geologists might just be more skeptical in general than my typical engineering colleagues.

Excerpted from e-mail to respected geologist, 2010-09-27...

So if there's a significant population of Rocky Mountain erratics buried in the Mima Mounds material, wouldn't that seem like convincing evidence for linkage with a Missoula flood event? Perhaps my 'interference ripple' mechanism needs some tweaking, but wouldn't the presence of Purcell Trench argillite start to make 'suncups' sound as far-fetched as 'giant Pleistocene gophers'?

Despite this series of nutty e-mails received from a total stranger, as a credit to his profession and personal character, instead of just hitting the 'delete' key, my correspondent took pity on the enthusiastic profundity of my ignorance, and was kind enough to provide this informative graphic, illustrating the US Geological Survey's published maximum height for Lake Allison of 122 meters (400 feet):

Fig. 3: Digital Elevation Model (DEM) of
Cowlitz-Chehalis Watersheds

Well that should pretty much settle it, right? No connection between watersheds, therefore Missoula Floods not a suspect, case closed, time to move on. Except for two nagging little items that I just couldn't reconcile, and my preconceived hunch that Mima Mounds needed a big dose of kinetic energy to formulate a really plausible explanation.

• If you look very closely, the two watersheds almost connect at this elevation...in three places!
• And that '400 feet' number sounded just a little too conveniently rounded-off to be a hard-limit for any event that happened over 13,000 years ago.

So I decided to do a bit more digging to figure out exactly where that number came from, before allowing this batch of wet tinder to extinguish the tiny flame of my preconceived hypothesis.

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