Wherever these particles settled, they formed a pan, a layer that water couldn't penetrate.
不管这些粒子沉降在哪里，它们会形成一个平面板块，一层水无法渗透的平面。
2
The explosion lifted about 100 trillion tons of dust into the atmosphere, as can be determined by measuring the thickness of the sediment layer formed when this dust settled to the surface.
Sediment cores are essentially a record of sediments that settled at the sea floor, layer by layer, and they record the conditions of the ocean system during the time they settled.