Know Your Artifacts
Throughout this web site you may see words and terms thrown around that you may not understand. So I have put together a brief explanation of era & time periods as well as a glossary of terms. If you are still confused and need help, or if you have any questions at all just contact me
Cultural Time Periods for Western USA and Canada:
All artifacts can be traced back to a specific “time era” or what is known as a “period” in history, each having it’s own “period” name… the pre-historic and historic time periods for the Western USA and Canada are listed below with their respective names and date ranges. Also of note, these time eras occurred at a different time between the Eastern and Western North America.
|Time Era||Date Range|
|Paleo||12,000 to 11,000 BC|
|Late Paleo||10,000 to 8,000 BC|
|Transitional Paleo||9,000 to 7,000 BC|
|Early Archaic||8,000 to 5,000 BC|
|Middle Archaic||5,000 to 2,000 BC|
|Late Archaic||2,000 to 1,000 BC|
|Woodland||1,000 BC to 700 AD|
|Mississippian||700 AD to 1600 AD|
|Historic||1600 AD to 1830 AD|
|Time Era||Date Range|
|Paleo||12,000 to 6,000 BC|
|Early Archaic||6,000 to 3,500 BC|
|Middle Archaic||3,550 to 1,300 BC|
|Late Archaic||1,500 to 300 BC|
|Time Era||Date Range|
|Transitional||300 BC to 400 AD|
|Developmental||400 to 1300 AD|
|Classic||1300 to 1600 AD|
|Historic||1600 to 1830 AD|
Agate Basin Complex
(a) A fluted, lanceolate stone spear point made by early hunter-gatherers who lived in central and southern North America about 11,500 years BP. Clovis points are usually fairly large, about 7–12 cm long and up to 3-4 cm wide. They have a concave base and a longitudinal groove, or flute, running about halfway up the point from the base.
(b) The archaeological culture that made and used the Clovis point. Other stone tools associated with Clovis sites are scrapers, blades, chopping tools and some bone tools.
The Clovis culture is accepted by most archaeologists as the earliest widespread human occupation of North America.
A recurring collection of artifacts and elements that are found at archaeological sites within a particular geographic location and time span, and which may represent a common culture.
Cordilleran Ice Sheet
Foothills Erratics Train
A train of boulders (erratics) more than 600 kilometres long, that runs along the eastern side of the Rocky Mountains in southern Alberta. These rocks were deposited by slow-moving glacial ice and contain clues that have helped scientists to understand the movements of the ice sheets that covered Canada during the ice age.
The source of the rock is an area near Mount Edith Cavell in Jasper Park. Thousands of years ago, these large stones fell onto the surface of the Cordilleran ice sheet during a landslide, and then were slowly carried by the ice sheet outward onto the Plains. When the ice melted, a long train of boulders was left behind.
Last Glacial Maximum
Late Wisconsinan Glaciation
Laurentide Ice Sheet
Pebble Tool Tradition
Queen Charlotte Islands
Radiocarbon Dating – The Method
The radiocarbon dating method was developed in the late 1940’s by Dr. Willard F. Libby, who later won a Nobel Prize in chemistry for this work. After its introduction to the scientific community in 1950, it quickly became the method most frequently used to determine the age of organic materials.
Radiocarbon dating is based on the fact that a radioactive isotope of carbon (14carbon) that is present in the earth’s atmosphere is absorbed into the tissues of all organisms while they are alive. After death, the 14carbon starts to slowly decay at a known rate. The length of time that has passed since death can be calculated by measuring the amount of 14carbon that remains in the organism.
Radiocarbon dating can only be used on organic materials such as bone, wood, charcoal, and shell, and has a limit of about 60,000 – 70,000 years. Radiocarbon dates are expressed as “Years BP” or just “BP”. “BP” stands for “Before Present”, but actually means “Before 1950” (the year radiocarbon dating was introduced).
Radiocarbon Years and Calendar Years
When radiocarbon dating was introduced, it was assumed that a radiocarbon year was equal to a calendar year. This was based on the premise that the level of 14carbon in the atmosphere has remained constant over time.
However, when radiocarbon dates were compared with calendar year dates derived from ancient tree-rings, it became clear that radiocarbon years and calendar years are not equivalent. This is because atmospheric concentrations of 14carbon have, in fact, fluctuated over time.
The correction, or calibration, of radiocarbon dates younger than approximately 15,000 years can be accomplished by means of a calculation based on tree ring dates. This calculation results in a “calibrated radiocarbon age” that is usually expressed as “cal BP”.