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The date of the impact coincides precisely with the Cretaceous–Paleogene boundary (K–Pg boundary), slightly more than 66 million years ago. [7] The crater is estimated to be over 150 km (93 mi) in diameter [10] and 20 km (12 mi) in depth, well into the continental crust of the region of about 10–30 km (6.2–18.6 mi) depth.
In 1980, a team of researchers consisting of Nobel Prize-winning physicist Luis Alvarez, his son, geologist Walter Alvarez, and chemists Frank Asaro and Helen Michel discovered that sedimentary layers found all over the world at the Cretaceous–Paleogene boundary contain a concentration of iridium many times greater than normal (30, 160, and ...
The Hell Creek Formation in Montana overlies the Fox Hills Formation and underlies the Fort Union Formation, and the boundary with the latter occurs near the Cretaceous–Paleogene boundary (K–Pg), which defines the end of the Cretaceous period and has been dated to 66 ± 0.07 Ma old. [6]
The Paleogene Period (IPA: / ˈ p eɪ l i. ə dʒ iː n,-l i. oʊ-, ˈ p æ l i-/ PAY-lee-ə-jeen, -lee-oh-, PAL-ee-; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period 66 Ma (million years ago) to the beginning of the Neogene Period 23.04 Ma.
The Lopez de Bertodano Formation is a geological formation in the James Ross archipelago of the Antarctic Peninsula.The strata date from the end of the Late Cretaceous (upper-lower Maastrichtian stage [1]) to the Danian stage of the lower Paleocene, from about 70 to 65.5 million years ago, straddling the Cretaceous-Paleogene boundary.
The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary (K–Pg boundary), a geologic signature associated with the mass extinction that lies between the Mesozoic and Cenozoic Eras.
The crater features all characteristics of an impact crater: appropriate ratio of width to depth, the height of the rims, and the height of the central uplift. [3] It was formed at or near the Cretaceous–Paleogene boundary about 66 mya around the same time as the Chicxulub crater. [1]
The Cretaceous-Paleogene boundary occurs in the lower part of the formation, and an exposure of the boundary layer has been identified and documented on South Table Mountain near the city of Golden. [12] Plant fossils [13] and remains of vertebrates, including turtles [14] and mammals, [15] are found throughout the Denver Formation. [6]