Raton Basin, Colorado Observations of the continental K-T boundary sequence in the Raton Basin, when integrated with observations of the marine K-T boundary sequence in Haiti and elsewhere, are summarized here. Cretaceous-Tertiary Boundary Photo by David A. Kring Raton Basin, Colorado Tertiary flora and fauna Cretaceous flora and fauna Cretaceous-Tertiary Boundary Photo by David A. Kring Tertiary flora and fauna Thickness of basal impact Cretaceous flora and fauna ejecta layer decreases radially from the Chicxulub impact crater (and at the precise rate expected for a crater of that size) Cretaceous-Tertiary Boundary Photo by David A. Kring Tertiary flora and fauna Impact melt spherules w/ chemical composition similar to Chicxulub impact melt sheet Thickness of basal impact Cretaceous flora and fauna ejecta layer decreases radially from the Chicxulub impact crater (and at the precise rate expected for a crater of that size) Cretaceous-Tertiary Boundary Photo by David A. Kring Tertiary flora and fauna Impact melt spherules w/ the same radiometric Ar-Ar age as Chicxulub impact melt sheet Impact melt spherules w/ chemical composition similar to Chicxulub impact melt sheet Thickness of basal impact Cretaceous flora and fauna ejecta layer decreases radially from the Chicxulub impact crater (and at the precise rate expected for a crater of that size) Cretaceous-Tertiary Boundary Photo by David A. Kring Iridium anomaly along with PGE ratios similar to those in chondritic asteroids Tertiary flora and fauna Impact melt spherules w/ the same radiometric Ar-Ar age as Chicxulub impact melt sheet Impact melt spherules w/ chemical composition similar to Chicxulub impact melt sheet Thickness of basal impact Cretaceous flora and fauna ejecta layer decreases radially from the Chicxulub impact crater (and at the precise rate expected for a crater of that size) Cretaceous-Tertiary Boundary Photo by David A. Kring Shocked quartz, feldspar, and lithics similar to Chicxulub basement Iridium anomaly along with PGE ratios similar to those in chondritic asteroids Tertiary flora and fauna Impact melt spherules w/ the same radiometric Ar-Ar age as Chicxulub impact melt sheet Impact melt spherules w/ chemical composition similar to Chicxulub impact melt sheet Thickness of basal impact Cretaceous flora and fauna ejecta layer decreases radially from the Chicxulub impact crater (and at the precise rate expected for a crater of that size) Cretaceous-Tertiary Boundary Photo by David A. Kring Shocked quartz, feldspar, and lithics similar to Chicxulub basement Iridium anomaly along with PGE ratios similar to those in chondritic asteroids Tertiary flora and fauna Impact melt spherules w/ the same radiometric Ar-Ar age as Chicxulub impact melt sheet Impact melt spherules w/ chemical composition similar to Chicxulub impact melt sheet Thickness of basal impact Cretaceous flora and fauna ejecta layer decreases radially from the Chicxulub impact crater (and at the precise rate expected for a crater of that Zircon with same terrain ages size) as Chicxulub basement Cretaceous-Tertiary Boundary Photo by David A. Kring Shocked quartz, feldspar, and lithics similar to Chicxulub basement Iridium anomaly along with PGE ratios similar to those in chondritic asteroids Tertiary flora and fauna Impact melt spherules w/ the same radiometric Ar-Ar age as Chicxulub impact melt sheet Impact melt spherules w/ chemical composition similar to Chicxulub impact melt sheet Thickness of basal impact Cretaceous flora and fauna Shocked zircon with same ejecta layer decreases radially radiometric U-Pb age as from the Chicxulub impact Chicxulub melt sheet crater (and at the precise rate expected for a crater of that Zircon with same terrain ages size) as Chicxulub basement Cretaceous-Tertiary Boundary Photo by David A. Kring Shocked quartz, feldspar, and lithics similar to Chicxulub basement Iridium anomaly along with PGE ratios similar to those in chondritic asteroids Tertiary flora and fauna Impact melt spherules w/ the same radiometric Ar-Ar age as Chicxulub impact melt sheet Impact melt spherules w/ chemical composition similar to Chromite with the isotopic Chicxulub impact melt sheet composition of a carbonaceous chondritic asteroid Thickness of basal impact Cretaceous flora and fauna Shocked zircon with same ejecta layer decreases radially radiometric U-Pb age as from the Chicxulub impact Chicxulub melt sheet crater (and at the precise rate expected for a crater of that Zircon with same terrain ages size) as Chicxulub basement Cretaceous-Tertiary Boundary Photo by David A. Kring Shocked quartz, feldspar, and lithics similar to Chicxulub basement Iridium anomaly along with PGE ratios similar to those in chondritic asteroids Tertiary flora and fauna Impact melt spherules w/ the In an equivalent marine same radiometric Ar-Ar age as sequence, a fragment of a Chicxulub impact melt sheet carbonaceous chondritic asteroid has been found Impact melt spherules w/ chemical composition similar to Chromite with the isotopic Chicxulub impact melt sheet composition of a carbonaceous chondritic asteroid Thickness of basal impact Cretaceous flora and fauna Shocked zircon with same ejecta layer decreases radially radiometric U-Pb age as from the Chicxulub impact Chicxulub melt sheet crater (and at the precise rate expected for a crater of that Zircon with same terrain ages size) as Chicxulub basement Cretaceous-Tertiary Boundary Photo by David A. Kring Shocked quartz, feldspar, and lithics similar to Chicxulub basement Iridium anomaly along with Soot, charcoal, and PAH PGE ratios similar to those in spectrum consistent with chondritic asteroids impact-generated wildfires Tertiary flora and fauna Impact melt spherules w/ the In an equivalent marine same radiometric Ar-Ar age as sequence, a fragment of a Chicxulub impact melt sheet carbonaceous chondritic asteroid has been found Impact melt spherules w/ chemical composition similar to Chromite with the isotopic Chicxulub impact melt sheet composition of a carbonaceous chondritic asteroid Thickness of basal impact Cretaceous flora and fauna Shocked zircon with same ejecta layer decreases radially radiometric U-Pb age as from the Chicxulub impact Chicxulub melt sheet crater (and at the precise rate expected for a crater of that Zircon with same terrain ages size) as Chicxulub basement Cretaceous-Tertiary Boundary Photo by David A. Kring Shocked quartz, feldspar, and Palynoflora signature (e.g., fern lithics similar to Chicxulub spore spike) consistent with basement impact-generated wildfires Iridium anomaly along with Soot, charcoal, and PAH PGE ratios similar to those in spectrum consistent with chondritic asteroids impact-generated wildfires Tertiary flora and fauna Impact melt spherules w/ the In an equivalent marine same radiometric Ar-Ar age as sequence, a fragment of a Chicxulub impact melt sheet carbonaceous chondritic asteroid has been found Impact melt spherules w/ chemical composition similar to Chromite with the isotopic Chicxulub impact melt sheet composition of a carbonaceous chondritic asteroid Thickness of basal impact Cretaceous flora and fauna Shocked zircon with same ejecta layer decreases radially radiometric U-Pb age as from the Chicxulub impact Chicxulub melt sheet crater (and at the precise rate expected for a crater of that Zircon with same terrain ages size) as Chicxulub basement Cretaceous-Tertiary Boundary Photo by David A. Kring A compelling case for the impact-mass extinction hypothesis exists in the K-T boundary stratigraphic sequence Tertiary flora and fauna Cretaceous flora and fauna Cretaceous-Tertiary Boundary Photo by David A. Kring .