The Cretaceous-Tertiary Impact Theory

Introduction The Cretaceous- Tertiary extinction event was one of the largest view extinctions constantly recorded on Earth. Occurring 65 million long time ago, this cataclysmal event marked the extinction of thousands of animal species including dinosaurs, mosasaurs, plesiosaurs, and pterosaurs. hammy extinctions withal occurred among microscopic floating organisms; both chalky plankton and calcareous nanoplankton were close exterminated with only a few species go (Alvarez et al. 1980). Alternatively, well-nigh groups were diminutive affected, including the terrestrial plants, crocodiles, snakes, mammals, and many kinds of invertebrates. It is estimated that a little e reallyplace half of all living species surrender at the balance of the Cretaceous did not survive the mass extinction (Russell 1979). A dark grey clay sediment grade 3-8 centimeters cryptic divides the end of the Cretaceous period and the beginning of the Tertiary, this grade is referred to a s the K-T boundary and is found nearly globally (K is the conventional 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 ray 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 present evidentiary proof that an asteroid impact caused the Cretaceous-Tertiary (K-T) mass extinction. In this motif we will discuss the Cretaceous-Tertiary Impact theory and learn 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. atomic number 77 concentrations Iridium is an eleme nt of the platinum group of metals; it is v! ery hard, very dense and is one of the rarest...If you essential to get a exuberant essay, order it on our website: BestEssayCheap.com

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