One item, everything we know about it, and everything it is connected to.
Words we use: Mystery A question nobody has answered yet. Clue from people Something people wrote down or told long ago: a chronicle, a diary, a story, a carving. Clue from nature Something nature recorded by itself: tree rings, ice, rock layers, or the leftovers of an exploded star. Hunch Our guess that a clue from people and a clue from nature are about the same event. Book or paper Where we read it, so anyone can check our work. Step Something we did, in the order we did it.
Erlitou phase IV is about 1565-1530 BC, which takes in the 1561-1550 BC eruptions, but the rival Xia-Shang boundary near 1635-1610 BC sits near eruptions too, and eruptions came every 16 years or so. Nothing here can test the link. Parked OPEN until a dated Yellow River climate record appears.