FTP, name this dark clay layer which represents the results of the dinosauricidal asteroid impact and is named for the two geologic periods whose fossils it separates.
It was created at the same time as the Manson structure, which was likely caused by a renegade fragment of the same object that caused this. The Brazos Sandstone is partially traced to events that created it. Grains of stishovite, or "shocked quartz," are found here, and it is the major non-volcanic source of sphaerules or microtektites. It divides plant populations between 10 to 30 percent fern representation on one side and 70 to 100 percent fern representation on the other, and it displays high levels of platinum-family metals, especially iridium. Formed as a result of the event at Chicxulub in the Yucatan, its nature was identified by Luis Alvarez. FTP, name this dark clay layer which represents the results of the dinosauricidal asteroid impact and is named for the two geologic periods whose fossils it separates.
It was created at the same time as the Manson structure, which was likely caused by a renegade fragment of the same object that caused this.
K-T boundary (or Cretaceous-Tertiary boundary)