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Shweshwe (/ ˈ ʃ w ɛ ʃ w ɛ /) [1] is a printed dyed cotton fabric widely used for traditional Southern African clothing. [ 2 ] [ 3 ] Originally dyed indigo , the fabric is manufactured in a variety of colours and printing designs characterised by intricate geometric patterns.
The aftermath of the asteroid collision, which occurred approximately 66 million years ago, is believed to have caused the mass extinction of non-avian dinosaurs and many other species on Earth. [13] The impact spewed hundreds of billions of tons of sulfur into the atmosphere, producing a worldwide blackout and freezing temperatures which ...
Luis Walter Alvarez, left, and his son Walter, right, at the K–T Boundary in Gubbio, Italy, 1981. The Alvarez hypothesis posits that the mass extinction of the non-avian dinosaurs and many other living things during the Cretaceous–Paleogene extinction event was caused by the impact of a large asteroid on the Earth.
As originally proposed in 1980 [9] by a team of scientists led by Luis Alvarez and his son Walter, it is now generally thought that the K–Pg extinction was caused by the impact of a massive asteroid 10 to 15 km (6 to 9 mi) wide, [10] [11] 66 million years ago causing the Chicxulub crater, which devastated the global environment, mainly ...
Analysis of the Hiawatha Glacier reveals the presence of a 31 km wide impact crater dated at 58 million years of age, less than 10 million years after the Cretaceous–Paleogene extinction event, scientists believe that the impactor was a metallic asteroid with a diameter in the order of 1.5 kilometres (0.9 mi). The impact would have had global ...
Swisher and others dated the formation of the Chicxulub Crater to 65 million years ago. [39] More precisely, they dated igneous rock from the Chicxulub crater to 64.98 million years ago. [100] Sheehan and Fastovsky found terrestrial vertebrates to be the primary victims of the end Cretaceous extinction event, with 88% of their biodiversity lost.
From between ten thousand years and one million years ago, and with a diameter of one km (0.62 mi) or more. The largest in the last one million years is the 14-kilometre (8.7 mi) Zhamanshin crater in Kazakhstan and has been described as being capable of producing a nuclear-like winter. [11]
The Orosirian Period (/ ˌ ɒr oʊ ˈ s ɪər i ən /; Ancient Greek: ὀροσειρά, romanized: oroseirá, meaning "mountain range") is the third geologic period in the Paleoproterozoic Era and lasted from 2050 Mya to 1800 Mya (million years ago). [2] Instead of being based on stratigraphy, these dates are defined chronometrically.