The 1-cm-thick clay layer that marks the Cretaceous/Paleogene (K/Pg)boundary has a high percentage of the element ________ in the clay layer,an enrichment about 300 times greater than the normal abundance.

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The K/Pg boundary is marked by a thin layer of clay that contains a high concentration of the element iridium, which is not commonly found in the Earth's crust. This is believed to be evidence of a massive asteroid impact that occurred at the end of the Cretaceous period, which led to the extinction of the dinosaurs and many other species.

The 1-Cm-Thick Clay Layer That Marks the Cretaceous/Paleogene (K/Pg)boundary Has