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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