What lead the Alvarez team to suspect that the asteroid impact crater they were looking for
existed under the sea?
O Analysis of the iridium layers around the globe revealed
salt content.
O They had not found an eligible crater on land, and Earth
is mostly covered by water.
O Analysis of craters on land revealed shock-fractured
quartz
O They found iridium in bedrock that was once under the
sea, and they could measure it.