Where did the Change Islands biface cache come from, chemically speaking?

In the fall of 2010, Neil White and Marion Adams were at the ferry terminal at Change Islands waiting for the ferry. They took a stroll around the parking lot and in the area just off the pavement they noticed something unusual sticking out of the ground. They recognized the stone they were looking at as having been knapped into the shape of a biface tip. They eventually recovered 30 bifaces made of a steel-blue coloured stone called rhyolite.

Location of Change Islands
Location of Change Islands

Neil and Marion are to be commended for what they did next. Rather than hide the collection away for themselves they shared their discovery with the province. This cache is just one of two biface caches known on the Island; the other one was found at Port au Choix. There are a few more biface caches known in Labrador and in Quebec. Neil and Marion’s discovery was very significant. They were pretty sure they understood what they had found but they wanted to bring the collection to the proper authorities. Within a few days they made contact with the Beothuk Interpretation Centre at Boyd’s Cove. Upon seeing the artifacts the staff at the Centre contacted the Provincial Archaeology Office (PAO) who later investigated the site and found two more artifacts bringing the total collection to 32 bifaces.

Change Islands biface cache (Rast).
Change Islands biface cache (Rast).

According to Neil and Marion the bifaces were stacked next to one another like a deck of cards. This suggests the cache was buried in a rather small area, perhaps in a bark or leather pouch of some sort. Unfortunately there was no physical evidence of such an organic container or any other organic remains associated with the bifaces. Without organic material there is nothing to radiocarbon date the site and we are left with less exact methods to speculate how old the objects are and who made them.

Given the size of the bifaces and their overall shape it is unlikely they were made by any of the Palaeoeskimo groups who lived on the Island in the past. It’s more likely they were made by either someone within the Maritime Archaic or Recent Indian cultural groups. The cache was found at an elevation of 1 to 2 metres above sea level. Since this area of Newfoundland has been submerging since the last glacial period, the site would likely have been underwater during the Maritime Archaic period. So, we are left with the cache having likely been created by someone in the Recent Indian population.

There are two known quarries for rhyolite that are relatively close. One is at Brimstone Head on Fogo Island, just ~10 km in a straight line north east of the discovery. The other quarry is at Bloody Bay Cove in Bonavista Bay, ~100 km in a straight line south east of the discovery. In an effort to try and find the source for the rhyolite used to make the bifaces the PAO had five samples taken from each of the quarries. Those samples and five biface fragments from the cache were loaned to the Dr. Derek Wilton of the Department of Earth Sciences at Memorial University of Newfoundland. The samples and bifaces were subjected to Laser Ablation Microprobe (LAM) – Inductively Coupled Plasma (ICP) – Mass Spectrometry (LAM-ICP-MS) tests. I am not going to pretend that I know exactly how this works, but my understanding is the samples and bifaces are shot with a laser. The material that comes off the sample from the laser is a gas. The chemicals, and their relative quantities, that make up the gas can be identified. Each biface and each sample will have unique chemical signatures but, for example, all the samples from Brimstone Head will be similar enough to each other that we can tell they all came from the same source at Brimstone Head. By conducting this test we can figure out the chemical elements and their quantities that make up each sample. Then we can compare the quarry numbers to the biface numbers and hopefully the biface numbers will be similar enough to either one of the quarry numbers that we can say the biface material likely came from this quarry.

Brimstone Head is in the background of the community of Fogo
Brimstone Head is in the background of the community of Fogo
Bloody Bay Cove quarry. The entire hill behind archaeologist Laurie McLean are pieces of rhyolite flaked from the quarry
Bloody Bay Cove quarry. The entire hill behind archaeologist Laurie McLean are pieces of rhyolite flaked from the quarry

Before anyone complains that we destroyed or damaged the bifaces by letting them be blasted by a laser, the blasted pits are just 30 – 50 microns deep. They would just barely be visible to the human eye.

How big is a micron?
How big is a micron?

Based on the LAM-ICP-MS tests the bifaces were determined to be geochemically identical to the Bloody Bay Cove samples. The LAM-ICP-MS tests also showed that the Brimstone Head samples were highly variable amongst themselves and none of them were chemically close to the bifaces.

Location of the Bloody Bay quarry (bottom left) in relation to Change Islands
Location of the Bloody Bay quarry (bottom right) in relation to Change Islands

In the end, we are left with a good guess as to who made the bifaces, most likely it was a person from the Newfoundland portion of the Recent Indian culture. This gives us an approximate time period, ~2000 years ago up to prolonged European contact. We may be able to narrow this period down a little more. The cache was made up of bifaces that would be interpreted as knives and throwing or thrusting spears, certainly not arrowheads.

In the first half of the Recent Indian period, ~2000-~1000 years ago, Newfoundland was home to two contemporaneous but unrelated groups of people that archaeologists refer to as the Cow Head complex and the Beaches complex. Both of these groups made larger stone tools usually thought of as throwing or thrusting spears. The last group of people in the Recent Indian culture, (~1000 to prolonged European contact) the people of the Little Passage complex, made and used stone tools usually seen as much smaller and more likely arrowheads.

It appears as though someone from the Recent Indian period, perhaps from either the Cow Head or Beaches complex, ~2000-~1000 years ago, used stone sourced from the Bloody Bay Cove quarry to make the bifaces that were left on Change Island. But we are still left wondering why were the bifaces made and why were they left on the shore of Change Islands? We can speculate, but we will likely never know the exact answer to these questions.

WELLS, Karen 2011 Change Islands Couple Makes Rare FindThe Pilot

WILTON, Derek 2012 Report on the LAM-ICP-MS analysis of Arrowheads from Change islands and rhyolitic flakes from the Brimstone Head and Bloody Bay Cove regions, Newfoundland and Labrador.




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