Thoughts About Laurentia

Okay, Laurentia is not a super-continent, although it has been involved in those. It is today known as the North American Craton, because it is a bit of crust that makes up about the eastern 2/3 of North America. Originally, this craton included Greenland and a piece of Scotland, but those have split off.

The base of Laurentia is composed of metamorphic and igneous rocks formed 1.5 to 1 billion years ago. Above that are younger sedimentary rocks that were deposited when most of the craton was covered by a shallow (with a depth of no more than 200 feet) tropical sea where much marine life lived and died, settled to the bottom and eventually became rock such as limestone and dolomites.

During the Cretaceous Period, this type of sea - known as the Western Interior Seaway - ran from today’s Gulf of Mexico to the Arctic Ocean, diving North American into eastern and western land masses

The southwestern area of Laurentia has been deformed by continental collisions and has been stretched up to 100% of its original width. This area has experienced numerous large volcanic eruptions.

Laurentia sat on the equator some 458-444 million years ago.

About 1.82 billion years ago, Laurentia was part of the supercontinent Columbia. But by 1.35-1.3 billion years ago, Laurentia was an independent continent.

1.3 billion years ago, Laurentia joined other bits to form the supercontinent Protorodinia, and by 1.07 billion years ago, enough bits had joined to become the supercontinent Rodinia. This article didn’t mention when Rodinia broke apart.

750 million years ago, Laurentia had again joined others to form Protolaurasia, but Laurentia very nearly drifted away from the others. Still, it stuck around at least until 600 million years ago, when they formed the supercontinent Pannotia. (I’ve already written about that.)

419.2 to 358.9 million years, Laurentia and Baltica collided, forming Euramerica.

298.9 to 252.1 million years ago, all the ‘big boys’ got together to form the supercontinent Pangaea. That lasted until 201.3 to 145 million years ago, when Pangea broke into 2 supercontinents: Laurasia and Gondwana. Laurentia was part of Laurasia.

145 to 66 million years ago, Laurentia was again an independent continent. And about 23 million years ago, North America (Laurentia) crashed against South America, forming the minor supercontinent America.

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

The Dorset culture

Starting around 500 BC and lasting 1500 to 2000 years, the Arctic area of North America was inhabited by the Dorset, a Paleo-Eskimo culture. It is named after Cape Dorset in Nunavut in Canada, where the first evidence of it was found. It is said to have 4 phases due to differences in the technology related to hunting and tool making. Dorset artifacts include triangular end-blades, soapstone lamps, and burins, a specific type of stone tool.

The Dorset were first identified as a separate culture in 1925. They appear to have been extinct by 1500 AD at the latest, and possibly as early as 1000 AD. At some time during the 1000s, the Thule people (a pre-Innuit group) began migrating east from Alaska, and eventually spread through all the land previously inhabited by the Dorset. There is no evidence that the Inuit and the Dorset ever met. In fact, genetic studies show that the Dorset were distinct from later groups and that there is virtually no evidence of genetic or cultural interaction between the Dorset and Thule peoples.

Inuit legends say that they did encounter people they called ‘First Inhabitants’. According to these stories, the first inhabitants were taller and stronger than the Inuit, but they were afraid to interact and were easily frightened off. There is also a controversial theory of contact and trade between the Dorset and the Norse.

Some of the artifacts that indicated a culture different from the Inuit included sophisticated pieces of art. Carvings featured uniquely large hairstyles for women, and both sexes are depicted wearing hoodless parkas with large, tall collars.

Not only do scientists not know for certain what happened to the Dorset people, they aren’t sure where they came from, either. Some have suggested that they may have developed from a previous culture, perhaps the Pre-Dorset, the Saqqaq or - even less likely - from the Independence I. However, these earlier cultures all had bow and arrow technology, while the Dorsets did not. Possibly they set aside the bow and arrow as they switched from land to aquatic hunting.

Another piece of technology that the Dorset lacked was drills. There are no drill holes in Dorset artifacts. Whatever holes they created, they painstakingly carved or gouged into the artifact where it was needed. This was even true of the bone needles that are so common in Dorset sites. It is confusing, since the Pre-Dorset and the Thule had and used drills to great effect.

However little has been discovered about the Dorset people, their history is divided into 4 periods: The Early (500-1 BC), Middle (1-500 AD), and Late phases (500-1000 AD), as well as the Terminal phase from 1000 AD onward. The Terminal phase would have been closely related to the Medieval Warm Period, which began to warm the Arctic around 950 AD. Under those conditions, the sea ice became far less predictable.

The Dorset were adapted to a very cold climate, and it is thought that much of their food consisted of sea mammals that breathe through holes in the ice. A massive decline in sea ice would have forced the Dorset further north. Most agree they disappeared at some point between 1000 and 1500 AD, possibly because they could not adapt to the climate change or perhaps because they were introduced to diseases they had not known before.

I wish the article had included some type of rendition of the triangular end-blades. I have a series of stories in the works about a culture that is based on the number 3, and I keep imagining them developing 3-sided blades of all sizes, even arrow-heads. But I don’t know enough about bladed weapons to know if such a shape would be feasible. Anybody have any ideas about that?

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