Crinkle Cut Chips

Crinkle Cut Chips

On the 5th August 1966 The Beatles release their Revolver album in the United Kingdom and in the following month the Bulletin of Canadian Petroleum Geology published the Structure, Seismic Data, And Orogenic Evolution of Southern Canadian Rocky Mountains paper authored by A W Bally, P L Gordy and G A Stewart.

Both events were momentous crowning achievements.

However, many Earth Scientists in the Etch A Sketch Skool of Geology prefers to forget all about Bally et al 1966 because this paper really does illustrate the “concepts fundamental to an understanding of mountain building.”

In the Rocky Mountain Foothills, major oil and gas accumulations occur in the folded and faulted leading edges of thrust sheets involving Paleozoic carbonates .

These structures underlie a complex of imbrications involving Mesozoic clastic rocks.

In this area the integration of seismic and geologic data leads to the definition of prospects and also illustrates concepts fundamental to an understanding of mountain building.

Reflection data show that for its entire width of about 80 miles, the Rocky Mountain fold belt is underlain by the gently westward dipping extension of the crystalline Precambrian Shield .

Shortening, exceeding 100 miles in Paleozoic beds, takes place along decollement zones and curved thrust faults which flatten at depth (listric thrust faults).

Late Mesozoic and early Tertiary thrusting was followed by late Tertiary normal faulting.

Reflection data suggest that these normal faults, which are steep at the surface, also flatten at depth (listric normal faults) and may merge with older thrust faults.

Reflection sections show that at depth the structural style on both sides of the Rocky Mountain Trench is similar and they suggest a continuation of the westward dipping basement beneath, and well to the west of the Trench.

Therefore the Trench and the associated post-orogenic Tertiary basins are probably related to a system of shallow, listric, normal faults that are responsible for the location and direction of this morphologic feature.

A palinspastic reconstruction based on seismic and subsurface data is essential background for discussions concerning the relations between the Rocky Mountains and the igneous and metamorphic western half of the Cordillera.

More generally, relations between continental drift and the formation of the Western Cordillera are placed in perspective using such reconstructions.

The seismic reflection data shown provide insight into the structure of the crust down to depths of ten kilometers, and effectively bridge the gap between surface geology and deep crustal refraction data.

Bally 1966 Study Area

Bulletin of Canadian Petroleum Geology – Vol 14 No 3 – Sept 1966
Structure, Seismic Data, and Orogenic Evolution of Southern Canadian Rocky Mountains
A . W . Bally, P . L . Gordy and G . A . Stewart – Calgary and Edmonton, Alberta
http://www.searchanddiscovery.com/documents/2007/07038hatcher/pdfs/0337.pdf

The introduction of the Bally et al 1966 provides a wonderful historical perspective and underlines how seismic data [from Shell Canada], good illustrations [mainly by C. G. Devenyi] and scholarly work can transform our understanding of the Earth that we inhabit.

Some one hundred years ago the British Government issued a “Blue Book” reporting the results of Captain Palliser’s expedition to the Canadian west in which James Hector (1863) published the first geologic observations on the Canadian Rocky Mountains .

Today the Southern Canadian Rockies rank among the best known mountain ranges of the
world, both geologically and geophysically.

Pioneer work by Dawson, McConnell, Willis and Daly, to name a few, established basic stratigraphy and led to the recognition of widespread overthrust and folding phenomena.

This period was followed by mapping, done mainly by officers of the Geological Survey of Canada, a project that is still in progress.

The discovery of gas, and later of oil, at Turner Valley stimulated the search for additional hydrocarbon accumulations.

Petroleum geologists have published many valuable contribution sto the geology of the area.

Excellent summaries of the state of knowledge of the time are given in the “Western Canada Sedimentary Basin Symposium” (Clark, 1954), North and Henderson (1954a), Hume (1957), Fox (1959), and Shaw (1963).

Recently, the stratigraphy of western Canada has been compiled in the “Geological History of Western Canada” (A .S .P .G ., 1964b).

During the early Forties the first geophysical surveys (gravity and seismic) were undertaken in selected areas.

They led to discovery of the Jumping Pound, Sarcee and Pincher Creek gas fields.

A stimulating synthesis of geologic and geophysical data was published by Link (1949).

During the Fifties extensive regional seismic surveys were undertaken, culminating in discovery of the Waterton, Wildcat Hills, West Jumping Pound and other, not yet fully evaluated gas fields.

During this period only one field, Savanna Creek, was discovered using surface geologic methods .

It soon became apparent that seismic data were not only valuable from an economic point of view, but that they contributed greatly to a better understanding of regional structure and problems related to mountain building.

The importance of widespread decollement phenomena was clearly demonstrated.

Fox (1959), Shaw (1963) and others published regional sections which evidently were based on seismic information, but only recently has Keating (1966) published some of the supporting data.

Because of the lack of geophysical documentation relating to the geology of the Rockies and Foothills of Alberta and southeastern British Columbia, the authors consider it desirable to publish basic seismic reflection data at this time.

The seismic sections presented provide illustrations of the internal structure of a typical thrusted and folded mountain belt and permit dealing with the “shortening” aspects of mountain building in a reasonably quantitative manner.

This paper is based on the fundamental contributions of many predecessors.

It is not possible to credit all who have contributed to a better understanding of the geology of the Rockies but we must single out the work of the Geological Survey of Canada, particularly its fine surface maps and Memoirs.

Publications of the Alberta Society of Petroleum Geologists have also added much to a geological understanding of the Rockies.

We thank Shell Canada Limited for releasing the seismic information and allowing publication of this paper.

A judicious amalgamation of geophysical and geological talents and know-how is the key to an adequate understanding of most geologic problems.

We cannot name all the numerous past and present colleagues at Shell who helped us to arrive at a better understanding of the geology and geophysics of the Rockies and Foothills, but we wish to thank our closest associates: among the geophysicists, A. Junger, G. Robertson, D. W. Smith and F. Van Goor, and among the geologists, J. M. Alston, J. E. Davidson, G. I. Lewis and O. L. Slind.

We also extend our thanks to G. E. Merritt who critically reviewed the manuscript and to C. G. Devenyi who is responsible for the majority of the drawings in this report.

Bulletin of Canadian Petroleum Geology – Vol 14 No 3 – Sept 1966
Structure, Seismic Data, and Orogenic Evolution of Southern Canadian Rocky Mountains
A . W . Bally, P . L . Gordy and G . A . Stewart – Calgary and Edmonton, Alberta
http://www.searchanddiscovery.com/documents/2007/07038hatcher/pdfs/0337.pdf

Thankfully, Carlos Cramez [Universidade Fernando Pessoa – Porto] has preserved and published on the internet many of the plates provided by Prof. Dr. Albert Bally which are “are largely self-explanatory and so they required limited comments.”

These notes were prepared to show that the knowledge of the geological context of a basin strongly favor the interpretation of the seismic lines.

Such a conjecture is particularly true in basins characterized by predominant compressional tectonic regimes.

The Southern Canadian Rocky Mountains is an ideal area to test such a conjecture.

The geological setting can be easily understood just reading the publications of Shell’s geologists and a lot of seismic lines are available.

Geological Setting & Seismic Interpretation – Carlos Cramez
Universidade Fernando Pessoa – Porto, Portugal
http://homepage.ufp.pt/biblioteca/GeolSettingSeisInterpre/GeologicSetting&SeismicInterpretation/Index.htm

The majority of the plates used on these notes was provided by Prof. Dr. Albert Bally.

These plates are largely self-explanatory and so they required limited comments.

Originally, they formed a booklet entitled “The Well-Tempered Mountain Range” (as illustrated by western Cordillera and Alps) that Dr. Bally prepared when he was Chief Geologist of Shell Canada Limited.

http://homepage.ufp.pt/biblioteca/GeolSettingSeisInterpre/GeologicSetting&SeismicInterpretation/Pages/Page2.htm

Thrusting and Folding needs little explanation except to say that the heat generated by friction, deformation and exothermic degassing powers rock metamorphism [and volcanism].

Main Orogenic Phase

Geological Setting & Seismic Interpretation – Carlos Cramez
Universidade Fernando Pessoa – Porto, Portugal
http://homepage.ufp.pt/biblioteca/GeolSettingSeisInterpre/GeologicSetting&SeismicInterpretation/Pages/Page9.htm

The lateral compression force is driven by the up welling [and exothermic degassing] of molten granite and basalt.

Major Expansion

Geological Setting & Seismic Interpretation – Carlos Cramez
Universidade Fernando Pessoa – Porto, Portugal
http://homepage.ufp.pt/biblioteca/GeolSettingSeisInterpre/GeologicSetting&SeismicInterpretation/Pages/Page3.htm

This basic up welling [and degassing] process is more easily understandable when both sides of the inflation process are viewed in the context of the Pacific Ocean.

Earth Expansion

It is now very easy to visualise how the up welling [and degassing] of granite and basalt formed the Pacific Ocean basin surrounded by a Ring of Fire and Island Chains.

The smooth, curved arcs associated with many of these Pacific Ocean Island Chains suggests that the initial [catastrophic] surge of up welling granite and basalt transferred momentum to the fractured Island Chains that resulted in these chains forming their characteristic [whiplash] arcs.

Pacific Ocean

It is important to note that granite and basalt are closely related.

Mineralogy_igneous_rocks

But it’s probably the chemical composition of granite that provides the best clue to understanding the internal composition of the Earth, the source of atmospheric oxygen and the oxygen that is required to form water on Earth.

chemical composition of granite

https://en.wikipedia.org/wiki/Granite

Unsurprisingly, the Etch A Sketch Skool of Geology don’t endorse this analysis.

FOOTNOTE
Regrettably, English Wikipedia doesn’t appear to have an entry for Albert Bally.

However, thanks to the Google translation service it’s possible to learn more about Albert Bally from German Wikipedia.

Albert W. Bally (* April 21, 1925 in The Hague) is a Dutch-American geophysicist and geologist.

Bally was in Switzerland to school and studied at the University of Zurich, where he was in 1952 a doctorate in geology.

As a post-doctoral researcher, he was at the Lamont-Doherty Observatory geophysical Columbia University.

From 1954 he worked as a petroleum geologist with Shell, where he remained until his retirement 1981.

Initially, he worked for Shell Canada in Alberta in the Canadian Rockies (where he worked out in a classic work in 1966 that the folding dynamics only a relatively thin sedimentary surface layer concerned), and since 1966 as head of the geological research for the Shell Bellaire Research and Development Laboratory in Houston, where he especially turned to the Gulf of Mexico (where he particularly recognized the role of salt tectonics for oil deposits).

He was chief geologist of the US division of Shell Oil and exploration there in 1976 and 1980.

Consultant Senior Exploration Consultant 1968 after he left Shell in retirement, he became a professor of geology at Rice University.

He played as a petroleum geologist a pioneering role in the integration of methods of reflection seismology with stratigraphic and structural geological research.

He arranged for the publication of research results (partially sensitive proprietary information of Shell were) in a row geological publications and atlases publicly available.

Bally was one of the initiators of the national US Edge project for seismic exploration of the continental margins.

In 1987 he received the Gustav-Steinmann Medal.

He also received the 1998 Career Contribution Award of Structural Geology and Tectonics Division of the Geological Society of America, the Sidney Powers Medal of Petroleum Geologists and the American Association of the William Smith Medal of the Geological Society of London.

In 1988, he was President of the Centennial Geological Society of America.

https://de.wikipedia.org/wiki/Albert_W._Bally

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4 Responses to Crinkle Cut Chips

  1. gymnosperm says:

    Hmmm. Basalt is not closely related to granite except by virtue of both being rocks. Granite is Aluminum silicate and Basalt is Iron and Manganese silicate as a first order approximation. Granite, mostly as a result of its hydrated chemistry has a less dense structure than basalt and is far more buoyant. Iron and Manganese have nearly twice the atomic mass of Aluminum as well.

    There is no question that a hell of a lot of basalt has emerged from the Pacific Ocean beginning in the general vicinity of Indonesia even as the decidedly second rate opening of the Atlantic and breakup of “pangeo” (misspelling intended) got all the credit.

    In the laboratory granite can be created from any rock. In this sense it is “metamorphic”. That is the plate tectonic meme and it pretty much works. Seismic tomography shows that subduction is the only real aspect of plate tectonics. Subduction zones are the perfect factories for granite. A hydrated fractionation of basalt.

    Yet weird blurbs of granite emerge all over western North America in places that cannot be seriously attributed to subduction.

    Always a work in progress…

  2. malagabay says:

    Hmmm. Basalt is not closely related to granite except by virtue of both being rocks.
    and both being closely related by their SiO2 content [see diagram above] which appears to provide a continuum that relates all volcanic and plutonic rocks.

  3. Pingback: A Scandinavian Saga | MalagaBay

  4. Pingback: The Fold Up Beds of Glen Roy | MalagaBay

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