The Cretaceous-Tertiary Impact Theory

Introduction The Cretaceous- Tertiary experimental extinction event was one of the largest throne extinctions constantly recorded on Earth. Occurring 65 million geezerhood ago, this cataclysmal event marked the extinction of thousands of animal species including dinosaurs, mosasaurs, plesiosaurs, and pterosaurs. melodramatic extinctions withal occurred among microscopic floating organisms; both calcareous plankton and calcareous nanoplankton were close exterminated with only a few species hold up (Alvarez et al. 1980). Alternatively, well-nigh groups were precise affected, including the terrestrial plants, crocodiles, snakes, mammals, and many kinds of invertebrates. It is estimated that a little e very(prenominal)place half of all living species award at the balance of the Cretaceous did not survive the mass extinction (Russell 1979). A dark grey clay sediment stage 3-8 centimeters cryptic divides the end of the Cretaceous period and the beginning of the T ertiary, this horizontal surface is referred to as the K-T boundary and is found nearly globally (K is the traditional abridgment for the Cretaceous Period, and T is the abbreviation for the Tertiary Period). For years the scientific community debated the cause the extinction; many hypotheses, such(prenominal) as massive volcanic eruptions, excessive solar beam of light and others, were presented however they lacked the proper supporting evidence.

Finally, beginning in the 1980s through until the early 1990s several prominent researchers including Luis Alvarez, Bruce Bohor, and Alan Hildebrand began to prese nt evidentiary proof that an asteroid impac! t caused the Cretaceous-Tertiary (K-T) mass extinction. In this motif we will discuss the Cretaceous-Tertiary Impact theory and opinion at the important pieces of evidence supporting it, including the high levels of iridium and blow out of the water quartz in the K-T layers, as well as the Chicxulub crater in southern Mexico. iridium concentrations Iridium is an element of the platinum group of metals; it is very hard, very dense and is one of the rarest...If you essential to get a luxuriant essay, order it on our website: BestEssayCheap.com

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