Project supported by the National Natural Science Foundation of China, and Lab of Loess and Quaternary Geology at Xi'an, Academia Sinica.
It is first in continental sediment-loess that 16 microtektites and 3 ablated glassy Si-Mg microspherules were found. They occur only in the upper layer of L8, a 40—70-cm horizon above the B/M boundary. The age of de...