Over the years, I have dug up a dozen or so pieces of shiny black glass in Columbia County, Georgia, now known as my “Chicken Coop Site”. Pre-membership, routine was limited to rock identification, so tried to determine if slag or obsidian. Pieces were not found together and not found on surface or in flowing water; none had often tell-tale slag sign of imbedded dirt or debris (which may look kinda like partial cortex, and occurs when factory dumps molten by-product onto ground); none had visible bubbles (teeny tiny or otherwise); all had degree of translucency (brown). ... So, ok, pieces checked out as obsidian according to my little test Qs, and I moved on to other rocks.
Last week or so, I casually examined a coupla these pieces laying around my room with post-membership eyes. Thot “is this a ‘spall’ (my word of the week)”? Took pic, sent to TomF
who confirmed obsidian was indeed modified by Man, and maybe was debitage or even a preform for scraper. This info thrilled me of course (I’m happy with anything artifactual!), but it wasn’t until Tom reviewed obsidian-source considerations that I started 💃🏽, and then felt like 🏇🪂🤸🏽♂️!!
First, the basics: obsidian is an igneous rock, extrusively formed from flowing lava that has cooled too quickly for its silica content to crystallize. Thus, it becomes “glass”, fragile by rock standards; it shatters easily, and its sharp, sharp slivers weather and breakdown relatively quickly, geologically. In geological-time terms, it is a short-lived lithic. These are factual dots of which I was aware, but failed to connect at the time I found my backyard “Georgia” obsidian.
Around 300 million years ago, the landmass that is now North America collided with Gondwana, a supercontinent now Africa and South America. That clash lifted tons of rock high above the surrounding terrain to form the southern end of the Appalachian Mountains of Alabama, Tennessee and Georgia. This means that the obsidian produced by volcanos in what’s now the Southeastern USA has long, long, long, long, long since disintegrated. In fact, no volcanic activity east of the Mississippi is recent enough to have remaining obsidian repositories, even in the most ancient of the People’s times. However, we know that the People discovered the beauty and value of the ultimate “ergonomic” lithic, sought out and found every obsidian repository in our North America, and then traded it extensively. How extensively? Well, the Rockies were formed 85-55 million years ago, when plates began sliding underneath other plates (the “Laramide Orogeny”), and the “new” obsidian produced is lithic of many artifacts. And, the site TomF references, “Glass Mountain”, in California, only about a million years old, a lil’ infant in our geological nursery!
Connecting these dots means that “my” obsidians are more than just spalls. They are “portafacts”, as Tom says. ( I love syllables, so I’m calling them transportafacts). I always knew Chicken-Coop-site folks made tools, but, Gahw-ley Moses, they made (or were gonna make) tools from MoonRocks (.......or might as well have been!). Think gonna make display just for them....
Here are the some of the other transportafacts:
Last week or so, I casually examined a coupla these pieces laying around my room with post-membership eyes. Thot “is this a ‘spall’ (my word of the week)”? Took pic, sent to TomF
who confirmed obsidian was indeed modified by Man, and maybe was debitage or even a preform for scraper. This info thrilled me of course (I’m happy with anything artifactual!), but it wasn’t until Tom reviewed obsidian-source considerations that I started 💃🏽, and then felt like 🏇🪂🤸🏽♂️!!
First, the basics: obsidian is an igneous rock, extrusively formed from flowing lava that has cooled too quickly for its silica content to crystallize. Thus, it becomes “glass”, fragile by rock standards; it shatters easily, and its sharp, sharp slivers weather and breakdown relatively quickly, geologically. In geological-time terms, it is a short-lived lithic. These are factual dots of which I was aware, but failed to connect at the time I found my backyard “Georgia” obsidian.
Around 300 million years ago, the landmass that is now North America collided with Gondwana, a supercontinent now Africa and South America. That clash lifted tons of rock high above the surrounding terrain to form the southern end of the Appalachian Mountains of Alabama, Tennessee and Georgia. This means that the obsidian produced by volcanos in what’s now the Southeastern USA has long, long, long, long, long since disintegrated. In fact, no volcanic activity east of the Mississippi is recent enough to have remaining obsidian repositories, even in the most ancient of the People’s times. However, we know that the People discovered the beauty and value of the ultimate “ergonomic” lithic, sought out and found every obsidian repository in our North America, and then traded it extensively. How extensively? Well, the Rockies were formed 85-55 million years ago, when plates began sliding underneath other plates (the “Laramide Orogeny”), and the “new” obsidian produced is lithic of many artifacts. And, the site TomF references, “Glass Mountain”, in California, only about a million years old, a lil’ infant in our geological nursery!
Connecting these dots means that “my” obsidians are more than just spalls. They are “portafacts”, as Tom says. ( I love syllables, so I’m calling them transportafacts). I always knew Chicken-Coop-site folks made tools, but, Gahw-ley Moses, they made (or were gonna make) tools from MoonRocks (.......or might as well have been!). Think gonna make display just for them....
Here are the some of the other transportafacts:
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