scepter1
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Post by scepter1 on May 15, 2011 2:41:40 GMT -5
Below is an agate arrowhead found on a Puget Sound beach. You can see that it is covered with a white patina. My question is how to date arrowheads such as this: How much time does it take to develop a white patina like this example? Obviously the actual chemical composition and the minerals it has been exposed to play a big part, but what does that mean time-wise? Anyone have any information / knowledge as to the aging process in order to rough guess age? Thanks, Rich. Attachments:
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Post by texaswoodie on May 15, 2011 5:46:47 GMT -5
Points are usually identified and dated by their shape. I couldn't find this exact shape in my book but someone can probably help out. If not Google arrrowhead identification puget sound.
Curt
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Fossilman
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Post by Fossilman on May 15, 2011 9:32:20 GMT -5
Looks sharp on the rounded end,could that be a scraper?
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Sabre52
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Post by Sabre52 on May 15, 2011 23:18:42 GMT -5
My best guess would be that the piece is actually a knife. Those triangular forms were pretty common in California too. There were also triangular and diamond shaped projectile point blanks that were traded in that form to be notched later for attachment to shafts. Similar triangular point blanks are super common here in Texas too. When trading it was much easier to transport a trade blank than a heavy nodule of obsidian, agate, or flint. Knives are difficult to date as similar forms persisted for thousands of years because a knife is a purpose built tool. Basically same usage means same shape. Patina would be a tough thing to access on an ocean shore find as wave action might remove patina or cause frosting due to sand action. Often patina is caused by hydration too so I don't know how sea water would affect that characteristic. Probably much easier to guess age from patina on an inland find.....Mel
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agatemaggot
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Post by agatemaggot on May 16, 2011 5:58:36 GMT -5
That looks a bit small to be a knife, might be a dart point. Looks close to being a Woodland point, 500 years plus.
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dtcmor
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Post by dtcmor on May 16, 2011 6:04:53 GMT -5
I would agree with Mel in that it was probably a blade or knife at one time. The flake patterns are very consistant at the point end(flowing across, and blended together very smoothly), but as you move to the back half it shows that it was broken and had been much longer at one time - the back half flake patterns and the bottom edge flaking show that it has been reworked extensivly(you can see the how the flakes stop short instead of flowing across and into each other and in places are hinged, giving it a lumpy appearance) in an attempt at a smaller blade or more probable -a scraper. Many broken tools were turned into something else when possible. Very nice and interesting piece!
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marinedad
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Post by marinedad on May 16, 2011 7:31:56 GMT -5
nice find.
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Post by Woodyrock on May 17, 2011 1:45:42 GMT -5
Being a material other than basalt does make it a great find for Puget Sound. 99% of points found in this area are basalt. Woody
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scepter1
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Post by scepter1 on May 19, 2011 1:09:04 GMT -5
Thanks everyone for your comments and insights. They are very much appreciated ! Here's photo of a point flake from another Puget Sound agate with heavy white patina, with a small window into the agate. No way to guess age by it's shape or design. It's interesting that the 'newly exposed' interior portion of the agate is what typically has the most patina rather than the more exposed outer rind. Rich. Attachments:
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