This dropstone is one of my prized possessions that originated from the ~700Ma Kingston Peak Formation in the Eastern Death Valley region. It was collected by a now deceased relative in the 1950’s and given to me about ten years ago. The cobble was plucked off a river bed by glaciers which calved and floated out to sea. The resulting iceberg then melted and dropped its sediments into the fine grained sediment. The only problem is that this area was near the equator (and attached to Antarctica & Australia) 700Ma when these glacial dropstones were sinking through the sea. That means the rest of the Earth had to be very cold at the time. Like almost completely frozen. Current estimates put the unfrozen part of the Earth in a band within 10 degrees north or south of the equator.
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