Cretaceous

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    The Cretaceous Period The Cretaceous period was the last and longest part of the Mesozoic Era. This period of time lasted around 79 million years! It lasted from the end of the Jurassic Period’s extinction (145 million years ago) to the beginning of the Paleogene Period (65.5 million years ago.) In this time, the earth’s continents were not in the same shape as they are today. Pangea, the supercontinent, was still drifting apart from itself. The ocean was still separating Northern Laurasia and Southern

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    The Cretaceous-Tertiary extinction or K-T extinction, which marks the Late Cretaceous, is a massive and large-scale extinction of animal and plant species that occurred over a short period of time 66 million years ago. The fossils of non-avian dinosaurs (the Group of birds) found almost only below the K-T boundary, paleontologists mostly estimate that the dinosaurs were extinguished just before, or during the event. Scientific theories explain the extinctions of K-T by one or more catastrophic events

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    "The Cretaceous Period was the last and longest segment of the Mesozoic Era. It lasted approximately 79 million years, from the minor extinction event that closed the Jurassic Period about 145.5 million years ago to the Cretaceous-Paleogene extinction event dated at 65.5 million years ago"(Mary Bagley, LS). In the cretaceous period, the continent of Pangea was still breaking away from itself, forming what we now know as the seven world continents. In the many eras of dinosaurs, the cretaceous era

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    Cretaceous Period Everyone knows about the dinosaurs and how they went extinct. This was one of the major events that took place in the Cretaceous Time Period. The Cretaceous Period was the longest and last of three time periods in the Mesozoic Era. This time period lasted from about 144 million years ago until about million years ago (about 79 million years), and over that 79 million years the earth changed dramatically. Way back in the Cretaceous all of earth’s land was together in

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    crisis) is a widespread and rapid decrease in the amount of life on Earth. It occurs when the rate of extinction increases with respect to the rate of speciation. Extinction occurs at an uneven rate. The most recent and debatably best-known, the Cretaceous–Paleogene extinction event, which occurred approximately 66 million years ago (Ma), was a large-scale mass extinction of animal and plant species in a geologically short period of time. It is now generally believed that the K–Pg extinction was

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    comprehensive biostratigraphic evolution of the Late Jurassic – Early Cretaceous sequence at Messak escarpment based on the stratigraphic distribution of the charophytes species as this type of microfossils have not been studied before in Libya as well as the study area has never been studied for charophytes beforehand. On the basis of the stratigraphic distribution of charophytes it is possible to subdivide the Late Jurassic – Early Cretaceous sequence into four assemblage zones. These are described in ascending

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    The Cretaceous mass extinction had two theories on how and why it happened through the impact hypothesis. The first one was suggested that an asteroid collided with Earth 65 million years ago. Luis Alvarez and his son, Walter Alvarez found “high levels of the rare metal iridium” in the layers of the Earth during the periods of the Cretaceous and Tertiary located in Italy. Their proof is that it was the cause of extinction by an asteroid the size of 10 kilometers. The second impact hypothesis was

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    The Cretaceous period is a period of time within the Mesozoic Era lasting from 146 million years ago to 65.5 million years ago. It is one of three periods in the Mesozoic Era along with the Triassic and Jurassic periods. The Cretaceous period is well known for the amount of dinosaurs it had, and the event that put an end to the dinosaurs reign, the K-T mass extinction. During the K-T mass extinction, a huge asteroid hit earth and caused tons of dust to infiltrate the air. Only a small portion

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    The Cretaceous-Paleogene Mass Extinction Wil Creasy Student Number: 20921355 The Cretaceous-Paleogene boundary (K-Pg boundary) was host to one of the three largest mass extinctions in the past 500 million years. Evidence suggests it was the result of a large asteroid impact approximately 65.5 million years ago in Chicxulub, Mexico; hence why the crater it formed was named the Chicxulub crater. The crater was approximately 180 kilometres in diameter and was believed to have led to the extinction

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    The cretaceous-tertiary (KT) boundary extinction happened approximately sixty five million years ago. Sixty to eighty percent of all living species became extinct at this boundary (Raup 1988). The KT extinction was indeed a mass extinction event. Mass extinctions are periods in Earth's history when extremely large numbers of species die out simultaneously or within a limited time frame. The most severe mass extinction ever occurred at the end of the Permian period when 96% of all species died out

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