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Geological Periods Mnemonic

Updated on May 29, 2011

Why?

Well, it can be very confusing to the beginner (or amateur rockologist like me), to see a long list of unfamiliar and complicated names of geological periods, with no obvious way to remember them or their sequence in time.

A mnemonic is a simple way of remembering the initials of the names, at least, which is a start! It is then but a small step to recall the names that go with the initials and they automatically fall into sequence for you.

Hence my proposed mnemonic. Of course, there are other mnemonics out in the public domain, purporting to help beginners to learn the periods of geological time and their sequence. However, none of these that I have seen bears any relevance to geology or makes any semblance of sense. More importantly, they don't float my boat!

folded slate Cardigan Bay - Ordovician
folded slate Cardigan Bay - Ordovician

The Geological Periods

Here we mainly concern ourselves with the Phanerozoic Eon (Aeon). This is our current aeon and is the time of abundant animal life on Earth, as evidenced by unearthed fossils. We do not debate here the nomenclature, the accuracy or the veracity of the current majority view.

The twelve geological periods comprising the Phanerozoic Eon (Aeon) each cover a time band measured in tens of millions of years. The Pre-Cambrian super-eon (super-aeon) is included simply for context, although it is clearly not a 'period'. The exact boundary of the Phanerozoic with the Pre-Cambrian is much debated.

For clarity and to avoid international variations, the timescale and nomenclature adopted in this lens is based on that proposed by the International Commission on Stratigraphy (ICS). In practical life, it shouldn't worry the beginner that there are differences of opinion around the world about exact boundaries and nomencalture, as the basis of the scale is perfectly functional and renders comprehensible those texts that use these technical terms.

Geological time is here expressed in mya (millions of years ago).

The periods are, approximately:

Quarternary 2.5 mya - present

Neogene 23 - 2.5 mya

Paleogene (Palaeogene) 65 - 23 mya

Cretaceous 144 - 65 mya

Jurassic 206 - 144 mya

Triassic 248 - 206 mya

Permian 290 - 248 mya

Carboniferous 354 - 290 mya

Devonian 417 - 354 mya

Silurian 443 - 417 mya

Ordovician 490 - 443 mya

Cambrian 543 - 490 mya

Pre-Cambrian 4,500 - 543 mya

This timescale is listed from the most recent to the oldest.

El Torcal Jurassic Limestone
El Torcal Jurassic Limestone

The proposed Mnemonic

"Professors Contend Older Strata Definitely Confirm Previous Times, Judging Current Period Non-Quiescent"

This is, in common with many such mnemonics, in any field, a little 'strange' in its language and structure but bears relevance to its mother topic and makes some sort of sense, relevant to our subject material. In my opinion, it beats reference to cows or camels having difficulty rising and needing oiling of their joints! It also incorporates the concept that the process of deposition is ongoing (non-quiescent).

Of course, it might have been simpler to rename all the periods in such a way as to make an easier mnemonic!

Silurian Limestone Wenlock
Silurian Limestone Wenlock

Summary

Well, that's my best effort to date. If it proves to be of value to children and adults who are trying to gain a grasp of the geological time scale (as it has been to me), I shall be delighted. However, while it might be a challenge to my brain to have to struggle to learn a new version of this, I would welcome comment on it and suggested imporovements.

The author is an amateur 'rockologist', is independent of commercial interest or sponsorship and cannot endorse any products or advertising material attached to this lens.

For more information, visit AVMC's information website (over 600 pages).

Chris Day - holistic vet - runs the Alternative Veterinary Medicine Centre in Oxfordshire (AVMC) in Oxfordshire, UK.

Mnemonic

"Professors Contend Older Strata Definitely Confirm Previous Times, Judging Current Period Non-Quiescent"

I'd like to hear from you

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    • ChrisDay LM profile image
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      ChrisDay LM 6 years ago

      @Blackspaniel1: Thanks so much - thanks for reading.

    • Blackspaniel1 profile image

      Blackspaniel1 6 years ago

      Beautiful lens.

    • ChrisDay LM profile image
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      ChrisDay LM 6 years ago

      @MargoPArrowsmith: Oh yes, those geodes are amazing! Thanks for contributing.

    • MargoPArrowsmith profile image

      MargoPArrowsmith 6 years ago

      I am a rock hound, I have several geodes they have so much power, its great to learn about the basics.

    • ChrisDay LM profile image
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      ChrisDay LM 6 years ago

      @ShamanicShift: I'm glad it was of use and you're very welcome, particularly as you sprinkled some of that special dust. THANKS!

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      ShamanicShift 6 years ago

      Thanks -- I needed this -- blessed by a SquidAngel!

    • ChrisDay LM profile image
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      ChrisDay LM 6 years ago

      @sousababy: Whatever pushes your buttons!

    • sousababy profile image

      sousababy 6 years ago

      Oh, mine use to be: Pretty Confusing Odd Scientific Data Can Predispose Thou Just Calmly Pondering New Qrap (Crap spelled with a "Q") to become even more confused. Ha! Rose

    • sousababy profile image

      sousababy 6 years ago

      Oh, mine use to be: Pretty Confusing Odd Scientific Data Can Predispose Thou Just Calmly Pondering New Qrap (Crap spelled with a "Q") to become even more confused. Ha! Rose

    • ChrisDay LM profile image
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      ChrisDay LM 6 years ago

      @dwnovacek: I hope it helps others. Thanks for your visit and positive comment.

    • dwnovacek profile image

      dwnovacek 6 years ago

      This would have helped me so much in my college geology courses! Thoughtful and helpful lens. Thank you!

    • ChrisDay LM profile image
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      ChrisDay LM 6 years ago

      @anonymous: You're very supportive - thanks

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      anonymous 6 years ago

      It's so interesting lense about Mnemonic. Some seems to be incredible. Nice lense as well .. Chris :)

    • ChrisDay LM profile image
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      ChrisDay LM 6 years ago

      @ElizabethJeanAl: Thanks - glad you called by.

    • ElizabethJeanAl profile image

      ElizabethJeanAl 6 years ago

      Useful! I use mnemonics in class all the time.

    • ChrisDay LM profile image
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      ChrisDay LM 6 years ago

      @LaurenIM: Thanks! Great to hear from you.

    • LaurenIM profile image

      LaurenIM 6 years ago

      What a good resource. Thanks for making it interesting too! Faved it and joined your fan club!

    • ChrisDay LM profile image
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      ChrisDay LM 6 years ago

      @Geeve: Thanks for your interest and positive comment

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      Geeve 6 years ago

      Very nice lens Chris, lensrolled to the Jurassic Coast, living proof that "Professors Contend Older Strata Definitely Confirm Previous Times, Judging Current Period Non-Quiescent"