For the Cis-Sunda folk amongst us: the third-millennium BC drought. This spur of Asia is fed by the Indian Ocean monsoon system... in other millennia. Southeast Asia actually has TWO missing millennia here, 6000-4000 BC; looking like a population crash in the hunter-gatherer economy. There followed a shift to the Neolithic village; but in between, most assume, people starved.
Michael Griffiths and Kathleen Johnson (and ever-present Et Al.) went looking at speleothems, because wood isn't preserved well down there. From it, Johnson's part of the team collaborated with Francesco Pausata from Montreal to find a correlation with the Sahara 6000-4000 BC, a pleasant savanna before that.
They used also Carbon-14. They were still calibrating the carbon with IntCal13, not owning IntCal20; but usually '20 just gets you a more-informed lack of confidence.
The correlation - they say - is because, with more dust blowing off the Sahara, the Indian ocean to the east was cooler. It was a vast El Niño. I'd thought Sahara mostly blows over the Sahara's other ocean, witness Hurricane Laura; and that Africa (and Central America) got mountains to trap the rest. I take it Quantity Has Quality Of Her Own.
No comments:
Post a Comment