TOP 10 ICE AGES

 

Ice, ice, baby – and a shallow dip top ten on the spot for my Top 10 Ice Ages!

As I said in my entry for Ice Age in my Top 10 Ages, there have been a number of ice ages in the history of the planet such that I could compile a top ten of them, albeit I’ve gone with the periods of glaciation within the longer five or six major ice ages. For example, we are presently in an ice age which commenced about 33.9 million years ago but we just happen to be in one of the interglacial periods that alternate with the glacial ones.

So here they are (with all of them ranking as B-tier or high tier, with the exception of the top entry as A-tier or top tier, such that I’ve ranked them in reverse chronological order)

 

 

A-TIER (TOP TIER)

 

(1) LATE CENOZOIC – QUATERNARY: PLEISTOCENE

 

No surprise here – the Ice Age, or the ice age everyone thinks of when they think of an ice age.

The most recent one – indeed, the one we’re stil in, albeit an intergalacial period of it. Hence in popular culture and usage the term Ice Age usually refers to the most recent glacial period within the longer ice age – the Pleistocene Epoch (which is part of and largely coincides with the Quaternary Period, except the latter extends to include our own interglacial Holocene Epoch commencing 11,700 years ago) .

That is, the Pleistocene Epoch that began about 2.58 million years ago, although as I said in my introduction, the Late Cenozoic Era Ice Age or Antarctic Glaciation (of which the Quaternary Period and hence Pleistocene Epoch are part) goes all the way back to about 33.9 million years ago (when the Antarctic Ice Sheet began to form).

You know, the one with mammalian megafauna such as mammoths (Ice Age megafauna deserving their own top ten). And us, as the Ice Age largely coincides with the Stone Age, all the way back to our earliest hominin ancestors. We hunted the mammoth and all that.

 

B-TIER (HIGH TIER)

 

(2) LATE PALEOZOIC: KAROO

 

The next most recent ice age glacial period before our own – 360 to 255 million years ago, preceding the dinosaurs (which first appeared about 243 million years ago). Also the most silly sounding name for an ice age with Karoo, hence why it tends to go by Late Paleozoic these days.

 

(3) EARLY PALEOZOIC: HIRNANTIAN / ANDEAN-SAHARAN

 

460 to 420 million years ago – life on land was just getting started, albeit not once the glacial period got started as it is widely considered to be the leading cause of the Late Ordovician mass extinction, the only ice age glacial period to have coincided with a mass extinction event.

 

(4) NEOPROTEROZOIC: BAYKONURIAN

 

547 – 541.5 million years ago (or possibly 549-530 million years ago) – not much around to see it as it was just multicellular life in the seas.

 

(5) NEOPROTEROZOIC: GASKIERS

 

Shortest of the glacial periods in this era – under 340,000 years about 579 million years ago or so.

 

(6) NEOPROTEROZOIC: CYROGENIAN – MARINOAN

 

650 – 635 million years ago in the aptly named Cryogenian Period. Arguably this ice age glacial period should outrank all but one of the others for a reason you’ll see in one of my special mentions.

 

(7) NEOPROTEROZOIC: CYROGENIAN – STURTIAN

 

717 to 660 million years ago – “most severe known glacial event preserved in the geological record” which arguably should outrank all other entries in this top ten (also for the reason you’ll see in one of my special mentions).

 

(8) PALEOPROTEROZOIC – HURONIAN

 

Ice age – or at least three ice age glacial periods – approximately 2.5 to 2.2 billion years ago. Nothing around to see it though with just cellular life

 

(9) MESOARCHEAN – PONGOLA

 

Oldest known ice age 2.9 to 2.78 billion years or so, chilling the microbes.

 

(10) NEXT GLACIAL PERIOD

 

We’re still in the Ice Age (the Quarternary Ice Age), just an intergalacial period – and some estimates are that we’re overdue for another glacial period, with human impact “now seen as possibly extending what would already be an unusually long warm period.”