I doubt we can measure any 10-year span at any given point a billion years ago. Even a million years ago. Even 100,000 years ago, I'm not sure that there is a way to accurately measure a 10-year segment.
That said, I've watched shows about oceanic cooling recently where the scientist noted a 10 degree change that happened over a few thousand years, and he was amazed. That sort of thing is anomalous, and indicates a major climate event.
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