The K-T Boundary

THE K-T BOUNDARY

The K-T Boundary, abbreviated for he Cretaceous period , and T is the abbreviation for the Tertiary period, which marks the end of the Mesozoic era. The K-T Boundary is normally associated with the Cretaceous-Tertiary extinction event that occurred 6.5 million years ago. It was a large mass extinction that took out animal and plant species and a geological quick time. For geologists, this event was important because it brought on the signature K-T Boundary.

The K-T Boundary is a thin layer of sedimentation found in various parts of the world. There are many different hypothesis that scientist have established to determine why there are thin layers of sedimentation found throughout the world. Some of these possible causes include the Alvarez impact hypothesis, Chicxulub Crater, Deccan Traps, Multiple Impact events, Maastrichtian marine regression, and supernova hypothesis. 

•  The Alvarez impact hypothesis suggested that since the layer of sedimentation contained concentration of iridium that an asteroid or comet, which contain high amounts of iridium, must have struck the earth at the time of the K-T boundary. 
• The Chicxulub crater suggests that a giant crater landed on the earth's coast and coast tsunamis to form the K-T boundary.
• The Deccan Traps theory suggests that Deccan Traps could have caused extinction through several mechanisms, including the release of dust and sulfuric aerosols into the air which might have blocked sunlight and thereby reduced photosynthesis in plants. In addition, Deccan Trap volcanism might have resulted in carbon dioxide emissions which would have increased the greenhouse effect when the dust and aerosols cleared from the atmosphere.
•  Multiple impact theory just suggests that there were multiple impacts to the Earth's surface to cause the K-T boundary. 
• The maastrichtian marine regression is the idea that a severe regression would have greatly reduced the continental shelf area, which is the most species-rich part of the sea, and therefore could not have been enough to cause a marine mass extinction. However, research concludes that this change would have been insufficient to cause the observed level of ammonites extinction.
• The Supernova hypothesis, which was disproved, states the the cause of the K-T boundary extinction event was cosmic radiation from a nearby supernova explosion.